From e08e19c331fb249e6dc86365ee80d16045c4aeb1 Mon Sep 17 00:00:00 2001 From: "H. Nikolaus Schaller" Date: Fri, 16 Oct 2015 14:53:38 +0200 Subject: iio:adc: add iio driver for Palmas (twl6035/7) gpadc This driver code was found as: https://android.googlesource.com/kernel/tegra/+/aaabb2e045f31e5a970109ffdaae900dd403d17e/drivers/staging/iio/adc Fixed various compilation issues and test this driver on omap5 evm. Signed-off-by: Pradeep Goudagunta Signed-off-by: H. Nikolaus Schaller Signed-off-by: Marek Belisko Acked-by: Laxman Dewangan Reviewed-by: Jonathan Cameron Acked-by: Lee Jones Signed-off-by: Jonathan Cameron --- include/linux/mfd/palmas.h | 75 +++++++++++++++++++++++++++++++--------------- 1 file changed, 51 insertions(+), 24 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mfd/palmas.h b/include/linux/mfd/palmas.h index 13e1d96935ed..c800dbc42079 100644 --- a/include/linux/mfd/palmas.h +++ b/include/linux/mfd/palmas.h @@ -134,21 +134,32 @@ struct palmas_pmic_driver_data { struct regulator_config config); }; +struct palmas_adc_wakeup_property { + int adc_channel_number; + int adc_high_threshold; + int adc_low_threshold; +}; + struct palmas_gpadc_platform_data { /* Channel 3 current source is only enabled during conversion */ - int ch3_current; + int ch3_current; /* 0: off; 1: 10uA; 2: 400uA; 3: 800 uA */ /* Channel 0 current source can be used for battery detection. * If used for battery detection this will cause a permanent current * consumption depending on current level set here. */ - int ch0_current; + int ch0_current; /* 0: off; 1: 5uA; 2: 15uA; 3: 20 uA */ + bool extended_delay; /* use extended delay for conversion */ /* default BAT_REMOVAL_DAT setting on device probe */ int bat_removal; /* Sets the START_POLARITY bit in the RT_CTRL register */ int start_polarity; + + int auto_conversion_period_ms; + struct palmas_adc_wakeup_property *adc_wakeup1_data; + struct palmas_adc_wakeup_property *adc_wakeup2_data; }; struct palmas_reg_init { @@ -405,28 +416,7 @@ struct palmas_gpadc_calibration { s32 offset_error; }; -struct palmas_gpadc { - struct device *dev; - struct palmas *palmas; - - int ch3_current; - int ch0_current; - - int gpadc_force; - - int bat_removal; - - struct mutex reading_lock; - struct completion irq_complete; - - int eoc_sw_irq; - - struct palmas_gpadc_calibration *palmas_cal_tbl; - - int conv0_channel; - int conv1_channel; - int rt_channel; -}; +#define PALMAS_DATASHEET_NAME(_name) "palmas-gpadc-chan-"#_name struct palmas_gpadc_result { s32 raw_code; @@ -520,6 +510,43 @@ enum palmas_irqs { PALMAS_NUM_IRQ, }; +/* Palmas GPADC Channels */ +enum { + PALMAS_ADC_CH_IN0, + PALMAS_ADC_CH_IN1, + PALMAS_ADC_CH_IN2, + PALMAS_ADC_CH_IN3, + PALMAS_ADC_CH_IN4, + PALMAS_ADC_CH_IN5, + PALMAS_ADC_CH_IN6, + PALMAS_ADC_CH_IN7, + PALMAS_ADC_CH_IN8, + PALMAS_ADC_CH_IN9, + PALMAS_ADC_CH_IN10, + PALMAS_ADC_CH_IN11, + PALMAS_ADC_CH_IN12, + PALMAS_ADC_CH_IN13, + PALMAS_ADC_CH_IN14, + PALMAS_ADC_CH_IN15, + PALMAS_ADC_CH_MAX, +}; + +/* Palmas GPADC Channel0 Current Source */ +enum { + PALMAS_ADC_CH0_CURRENT_SRC_0, + PALMAS_ADC_CH0_CURRENT_SRC_5, + PALMAS_ADC_CH0_CURRENT_SRC_15, + PALMAS_ADC_CH0_CURRENT_SRC_20, +}; + +/* Palmas GPADC Channel3 Current Source */ +enum { + PALMAS_ADC_CH3_CURRENT_SRC_0, + PALMAS_ADC_CH3_CURRENT_SRC_10, + PALMAS_ADC_CH3_CURRENT_SRC_400, + PALMAS_ADC_CH3_CURRENT_SRC_800, +}; + struct palmas_pmic { struct palmas *palmas; struct device *dev; -- cgit v1.2.3 From b440655b896b2d5a2fb5f918801fb0e281a537cd Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 13 Oct 2015 18:10:26 +0200 Subject: iio: Add support for indicating fixed watermarks For buffers which have a fixed wake-up watermark the watermark attribute should be read-only. Add a new FIXED_WATERMARK flag to the struct iio_buffer_access_funcs, which can be set by a buffer implementation. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/industrialio-buffer.c | 5 +++++ include/linux/iio/buffer.h | 8 ++++++++ 2 files changed, 13 insertions(+) (limited to 'include/linux') diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 5f2c8c8c436e..98a6447a61d3 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -998,6 +998,8 @@ static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, iio_buffer_show_enable, iio_buffer_store_enable); static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR, iio_buffer_show_watermark, iio_buffer_store_watermark); +static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark, + S_IRUGO, iio_buffer_show_watermark, NULL); static struct attribute *iio_buffer_attrs[] = { &dev_attr_length.attr, @@ -1040,6 +1042,9 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) if (!buffer->access->set_length) attr[0] = &dev_attr_length_ro.attr; + if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK) + attr[2] = &dev_attr_watermark_ro.attr; + if (buffer->attrs) memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs, sizeof(struct attribute *) * attrcount); diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h index 1600c55828e0..4d99a53d1fe7 100644 --- a/include/linux/iio/buffer.h +++ b/include/linux/iio/buffer.h @@ -17,6 +17,12 @@ struct iio_buffer; +/** + * INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be + * configured. It has a fixed value which will be buffer specific. + */ +#define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0) + /** * struct iio_buffer_access_funcs - access functions for buffers. * @store_to: actually store stuff to the buffer @@ -30,6 +36,7 @@ struct iio_buffer; * @release: called when the last reference to the buffer is dropped, * should free all resources allocated by the buffer. * @modes: Supported operating modes by this buffer type + * @flags: A bitmask combination of INDIO_BUFFER_FLAG_* * * The purpose of this structure is to make the buffer element * modular as event for a given driver, different usecases may require @@ -54,6 +61,7 @@ struct iio_buffer_access_funcs { void (*release)(struct iio_buffer *buffer); unsigned int modes; + unsigned int flags; }; /** -- cgit v1.2.3 From e18a2ad45caeb11226e49c25068d0f2efe2adf6c Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 13 Oct 2015 18:10:27 +0200 Subject: iio: Add buffer enable/disable callbacks This patch adds a enable and disable callback that is called when the buffer is enabled/disabled. This can be used by buffer implementations that need to do some setup or teardown work. E.g. a DMA based buffer can use this to start/stop the DMA transfer. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/industrialio-buffer.c | 36 +++++++++++++++++++++++++++++++++++- include/linux/iio/buffer.h | 8 ++++++++ 2 files changed, 43 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 98a6447a61d3..a4b164a478c4 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -568,6 +568,22 @@ static void iio_buffer_deactivate_all(struct iio_dev *indio_dev) iio_buffer_deactivate(buffer); } +static int iio_buffer_enable(struct iio_buffer *buffer, + struct iio_dev *indio_dev) +{ + if (!buffer->access->enable) + return 0; + return buffer->access->enable(buffer, indio_dev); +} + +static int iio_buffer_disable(struct iio_buffer *buffer, + struct iio_dev *indio_dev) +{ + if (!buffer->access->disable) + return 0; + return buffer->access->disable(buffer, indio_dev); +} + static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev, struct iio_buffer *buffer) { @@ -719,6 +735,7 @@ static int iio_verify_update(struct iio_dev *indio_dev, static int iio_enable_buffers(struct iio_dev *indio_dev, struct iio_device_config *config) { + struct iio_buffer *buffer; int ret; indio_dev->active_scan_mask = config->scan_mask; @@ -753,6 +770,12 @@ static int iio_enable_buffers(struct iio_dev *indio_dev, indio_dev->info->hwfifo_set_watermark(indio_dev, config->watermark); + list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) { + ret = iio_buffer_enable(buffer, indio_dev); + if (ret) + goto err_disable_buffers; + } + indio_dev->currentmode = config->mode; if (indio_dev->setup_ops->postenable) { @@ -760,12 +783,16 @@ static int iio_enable_buffers(struct iio_dev *indio_dev, if (ret) { dev_dbg(&indio_dev->dev, "Buffer not started: postenable failed (%d)\n", ret); - goto err_run_postdisable; + goto err_disable_buffers; } } return 0; +err_disable_buffers: + list_for_each_entry_continue_reverse(buffer, &indio_dev->buffer_list, + buffer_list) + iio_buffer_disable(buffer, indio_dev); err_run_postdisable: indio_dev->currentmode = INDIO_DIRECT_MODE; if (indio_dev->setup_ops->postdisable) @@ -778,6 +805,7 @@ err_undo_config: static int iio_disable_buffers(struct iio_dev *indio_dev) { + struct iio_buffer *buffer; int ret = 0; int ret2; @@ -798,6 +826,12 @@ static int iio_disable_buffers(struct iio_dev *indio_dev) ret = ret2; } + list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) { + ret2 = iio_buffer_disable(buffer, indio_dev); + if (ret2 && !ret) + ret = ret2; + } + indio_dev->currentmode = INDIO_DIRECT_MODE; if (indio_dev->setup_ops->postdisable) { diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h index 4d99a53d1fe7..2ec3ad58e8a0 100644 --- a/include/linux/iio/buffer.h +++ b/include/linux/iio/buffer.h @@ -33,6 +33,11 @@ struct iio_buffer; * storage. * @set_bytes_per_datum:set number of bytes per datum * @set_length: set number of datums in buffer + * @enable: called if the buffer is attached to a device and the + * device starts sampling. Calls are balanced with + * @disable. + * @disable: called if the buffer is attached to a device and the + * device stops sampling. Calles are balanced with @enable. * @release: called when the last reference to the buffer is dropped, * should free all resources allocated by the buffer. * @modes: Supported operating modes by this buffer type @@ -58,6 +63,9 @@ struct iio_buffer_access_funcs { int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); int (*set_length)(struct iio_buffer *buffer, int length); + int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); + int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); + void (*release)(struct iio_buffer *buffer); unsigned int modes; -- cgit v1.2.3 From 670b19ae9bfdbcb4ce2c2ffb2ec1659a7f4a2074 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 13 Oct 2015 18:10:28 +0200 Subject: iio: Add generic DMA buffer infrastructure The traditional approach used in IIO to implement buffered capture requires the generation of at least one interrupt per sample. In the interrupt handler the driver reads the sample from the device and copies it to a software buffer. This approach has a rather large per sample overhead associated with it. And while it works fine for samplerates in the range of up to 1000 samples per second it starts to consume a rather large share of the available CPU processing time once we go beyond that, this is especially true on an embedded system with limited processing power. The regular interrupt also causes increased power consumption by not allowing the hardware into deeper sleep states, which is something that becomes more and more important on mobile battery powered devices. And while the recently added watermark support mitigates some of the issues by allowing the device to generate interrupts at a rate lower than the data output rate, this still requires a storage buffer inside the device and even if it exists it is only a few 100 samples deep at most. DMA support on the other hand allows to capture multiple millions or even more samples without any CPU interaction. This allows the CPU to either go to sleep for longer periods or focus on other tasks which increases overall system performance and power consumption. In addition to that some devices might not even offer a way to read the data other than using DMA, which makes DMA mandatory to use for them. The tasks involved in implementing a DMA buffer can be divided into two categories. The first category is memory buffer management (allocation, mapping, etc.) and hooking this up the IIO buffer callbacks like read(), enable(), disable(), etc. The second category of tasks is to setup the DMA hardware and manage the DMA transfers. Tasks from the first category will be very similar for all IIO drivers supporting DMA buffers, while the tasks from the second category will be hardware specific. This patch implements a generic infrastructure that take care of the former tasks. It provides a set of functions that implement the standard IIO buffer iio_buffer_access_funcs callbacks. These can either be used as is or be overloaded and augmented with driver specific code where necessary. For the DMA buffer support infrastructure that is introduced in this series sample data is grouped by so called blocks. A block is the basic unit at which data is exchanged between the application and the hardware. The application is responsible for allocating the memory associated with the block and then passes the block to the hardware. When the hardware has captured the amount of samples equal to size of a block it will notify the application, which can then read the data from the block and process it. The block size can freely chosen (within the constraints of the hardware). This allows to make a trade-off between latency and management overhead. The larger the block size the lower the per sample overhead but the latency between when the data was captured and when the application will be able to access it increases, in a similar way smaller block sizes have a larger per sample management overhead but a lower latency. The ideal block size thus depends on system and application requirements. For the time being the infrastructure only implements a simple double buffered scheme which allocates two blocks each with half the size of the configured buffer size. This provides basic support for capturing continuous uninterrupted data over the existing file-IO ABI. Future extensions to the DMA buffer infrastructure will give applications a more fine grained control over how many blocks are allocated and the size of each block. But this requires userspace ABI additions which are intentionally not part of this patch and will be added separately. Tasks of the second category need to be implemented by a device specific driver. They can be hooked up into the generic infrastructure using two simple callbacks, submit() and abort(). The submit() callback is used to schedule DMA transfers for blocks. Once a DMA transfer has been completed it is expected that the buffer driver calls iio_dma_buffer_block_done() to notify. The abort() callback is used for stopping all pending and active DMA transfers when the buffer is disabled. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/buffer/Kconfig | 9 + drivers/iio/buffer/Makefile | 1 + drivers/iio/buffer/industrialio-buffer-dma.c | 683 +++++++++++++++++++++++++++ include/linux/iio/buffer-dma.h | 152 ++++++ 4 files changed, 845 insertions(+) create mode 100644 drivers/iio/buffer/industrialio-buffer-dma.c create mode 100644 include/linux/iio/buffer-dma.h (limited to 'include/linux') diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig index 0a7b2fd3699b..b2fda1afc03e 100644 --- a/drivers/iio/buffer/Kconfig +++ b/drivers/iio/buffer/Kconfig @@ -9,6 +9,15 @@ config IIO_BUFFER_CB Should be selected by any drivers that do in-kernel push usage. That is, those where the data is pushed to the consumer. +config IIO_BUFFER_DMA + tristate + help + Provides the generic IIO DMA buffer infrastructure that can be used by + drivers for devices with DMA support to implement the IIO buffer. + + Should be selected by drivers that want to use the generic DMA buffer + infrastructure. + config IIO_KFIFO_BUF tristate "Industrial I/O buffering based on kfifo" help diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile index 4d193b9a9123..bda3f1143e72 100644 --- a/drivers/iio/buffer/Makefile +++ b/drivers/iio/buffer/Makefile @@ -4,5 +4,6 @@ # When adding new entries keep the list in alphabetical order obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o +obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c new file mode 100644 index 000000000000..212cbedc7abb --- /dev/null +++ b/drivers/iio/buffer/industrialio-buffer-dma.c @@ -0,0 +1,683 @@ +/* + * Copyright 2013-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen + * + * Licensed under the GPL-2. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * For DMA buffers the storage is sub-divided into so called blocks. Each block + * has its own memory buffer. The size of the block is the granularity at which + * memory is exchanged between the hardware and the application. Increasing the + * basic unit of data exchange from one sample to one block decreases the + * management overhead that is associated with each sample. E.g. if we say the + * management overhead for one exchange is x and the unit of exchange is one + * sample the overhead will be x for each sample. Whereas when using a block + * which contains n samples the overhead per sample is reduced to x/n. This + * allows to achieve much higher samplerates than what can be sustained with + * the one sample approach. + * + * Blocks are exchanged between the DMA controller and the application via the + * means of two queues. The incoming queue and the outgoing queue. Blocks on the + * incoming queue are waiting for the DMA controller to pick them up and fill + * them with data. Block on the outgoing queue have been filled with data and + * are waiting for the application to dequeue them and read the data. + * + * A block can be in one of the following states: + * * Owned by the application. In this state the application can read data from + * the block. + * * On the incoming list: Blocks on the incoming list are queued up to be + * processed by the DMA controller. + * * Owned by the DMA controller: The DMA controller is processing the block + * and filling it with data. + * * On the outgoing list: Blocks on the outgoing list have been successfully + * processed by the DMA controller and contain data. They can be dequeued by + * the application. + * * Dead: A block that is dead has been marked as to be freed. It might still + * be owned by either the application or the DMA controller at the moment. + * But once they are done processing it instead of going to either the + * incoming or outgoing queue the block will be freed. + * + * In addition to this blocks are reference counted and the memory associated + * with both the block structure as well as the storage memory for the block + * will be freed when the last reference to the block is dropped. This means a + * block must not be accessed without holding a reference. + * + * The iio_dma_buffer implementation provides a generic infrastructure for + * managing the blocks. + * + * A driver for a specific piece of hardware that has DMA capabilities need to + * implement the submit() callback from the iio_dma_buffer_ops structure. This + * callback is supposed to initiate the DMA transfer copying data from the + * converter to the memory region of the block. Once the DMA transfer has been + * completed the driver must call iio_dma_buffer_block_done() for the completed + * block. + * + * Prior to this it must set the bytes_used field of the block contains + * the actual number of bytes in the buffer. Typically this will be equal to the + * size of the block, but if the DMA hardware has certain alignment requirements + * for the transfer length it might choose to use less than the full size. In + * either case it is expected that bytes_used is a multiple of the bytes per + * datum, i.e. the block must not contain partial samples. + * + * The driver must call iio_dma_buffer_block_done() for each block it has + * received through its submit_block() callback, even if it does not actually + * perform a DMA transfer for the block, e.g. because the buffer was disabled + * before the block transfer was started. In this case it should set bytes_used + * to 0. + * + * In addition it is recommended that a driver implements the abort() callback. + * It will be called when the buffer is disabled and can be used to cancel + * pending and stop active transfers. + * + * The specific driver implementation should use the default callback + * implementations provided by this module for the iio_buffer_access_funcs + * struct. It may overload some callbacks with custom variants if the hardware + * has special requirements that are not handled by the generic functions. If a + * driver chooses to overload a callback it has to ensure that the generic + * callback is called from within the custom callback. + */ + +static void iio_buffer_block_release(struct kref *kref) +{ + struct iio_dma_buffer_block *block = container_of(kref, + struct iio_dma_buffer_block, kref); + + WARN_ON(block->state != IIO_BLOCK_STATE_DEAD); + + dma_free_coherent(block->queue->dev, PAGE_ALIGN(block->size), + block->vaddr, block->phys_addr); + + iio_buffer_put(&block->queue->buffer); + kfree(block); +} + +static void iio_buffer_block_get(struct iio_dma_buffer_block *block) +{ + kref_get(&block->kref); +} + +static void iio_buffer_block_put(struct iio_dma_buffer_block *block) +{ + kref_put(&block->kref, iio_buffer_block_release); +} + +/* + * dma_free_coherent can sleep, hence we need to take some special care to be + * able to drop a reference from an atomic context. + */ +static LIST_HEAD(iio_dma_buffer_dead_blocks); +static DEFINE_SPINLOCK(iio_dma_buffer_dead_blocks_lock); + +static void iio_dma_buffer_cleanup_worker(struct work_struct *work) +{ + struct iio_dma_buffer_block *block, *_block; + LIST_HEAD(block_list); + + spin_lock_irq(&iio_dma_buffer_dead_blocks_lock); + list_splice_tail_init(&iio_dma_buffer_dead_blocks, &block_list); + spin_unlock_irq(&iio_dma_buffer_dead_blocks_lock); + + list_for_each_entry_safe(block, _block, &block_list, head) + iio_buffer_block_release(&block->kref); +} +static DECLARE_WORK(iio_dma_buffer_cleanup_work, iio_dma_buffer_cleanup_worker); + +static void iio_buffer_block_release_atomic(struct kref *kref) +{ + struct iio_dma_buffer_block *block; + unsigned long flags; + + block = container_of(kref, struct iio_dma_buffer_block, kref); + + spin_lock_irqsave(&iio_dma_buffer_dead_blocks_lock, flags); + list_add_tail(&block->head, &iio_dma_buffer_dead_blocks); + spin_unlock_irqrestore(&iio_dma_buffer_dead_blocks_lock, flags); + + schedule_work(&iio_dma_buffer_cleanup_work); +} + +/* + * Version of iio_buffer_block_put() that can be called from atomic context + */ +static void iio_buffer_block_put_atomic(struct iio_dma_buffer_block *block) +{ + kref_put(&block->kref, iio_buffer_block_release_atomic); +} + +static struct iio_dma_buffer_queue *iio_buffer_to_queue(struct iio_buffer *buf) +{ + return container_of(buf, struct iio_dma_buffer_queue, buffer); +} + +static struct iio_dma_buffer_block *iio_dma_buffer_alloc_block( + struct iio_dma_buffer_queue *queue, size_t size) +{ + struct iio_dma_buffer_block *block; + + block = kzalloc(sizeof(*block), GFP_KERNEL); + if (!block) + return NULL; + + block->vaddr = dma_alloc_coherent(queue->dev, PAGE_ALIGN(size), + &block->phys_addr, GFP_KERNEL); + if (!block->vaddr) { + kfree(block); + return NULL; + } + + block->size = size; + block->state = IIO_BLOCK_STATE_DEQUEUED; + block->queue = queue; + INIT_LIST_HEAD(&block->head); + kref_init(&block->kref); + + iio_buffer_get(&queue->buffer); + + return block; +} + +static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) +{ + struct iio_dma_buffer_queue *queue = block->queue; + + /* + * The buffer has already been freed by the application, just drop the + * reference. + */ + if (block->state != IIO_BLOCK_STATE_DEAD) { + block->state = IIO_BLOCK_STATE_DONE; + list_add_tail(&block->head, &queue->outgoing); + } +} + +/** + * iio_dma_buffer_block_done() - Indicate that a block has been completed + * @block: The completed block + * + * Should be called when the DMA controller has finished handling the block to + * pass back ownership of the block to the queue. + */ +void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) +{ + struct iio_dma_buffer_queue *queue = block->queue; + unsigned long flags; + + spin_lock_irqsave(&queue->list_lock, flags); + _iio_dma_buffer_block_done(block); + spin_unlock_irqrestore(&queue->list_lock, flags); + + iio_buffer_block_put_atomic(block); + wake_up_interruptible_poll(&queue->buffer.pollq, POLLIN | POLLRDNORM); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_block_done); + +/** + * iio_dma_buffer_block_list_abort() - Indicate that a list block has been + * aborted + * @queue: Queue for which to complete blocks. + * @list: List of aborted blocks. All blocks in this list must be from @queue. + * + * Typically called from the abort() callback after the DMA controller has been + * stopped. This will set bytes_used to 0 for each block in the list and then + * hand the blocks back to the queue. + */ +void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, + struct list_head *list) +{ + struct iio_dma_buffer_block *block, *_block; + unsigned long flags; + + spin_lock_irqsave(&queue->list_lock, flags); + list_for_each_entry_safe(block, _block, list, head) { + list_del(&block->head); + block->bytes_used = 0; + _iio_dma_buffer_block_done(block); + iio_buffer_block_put_atomic(block); + } + spin_unlock_irqrestore(&queue->list_lock, flags); + + wake_up_interruptible_poll(&queue->buffer.pollq, POLLIN | POLLRDNORM); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_block_list_abort); + +static bool iio_dma_block_reusable(struct iio_dma_buffer_block *block) +{ + /* + * If the core owns the block it can be re-used. This should be the + * default case when enabling the buffer, unless the DMA controller does + * not support abort and has not given back the block yet. + */ + switch (block->state) { + case IIO_BLOCK_STATE_DEQUEUED: + case IIO_BLOCK_STATE_QUEUED: + case IIO_BLOCK_STATE_DONE: + return true; + default: + return false; + } +} + +/** + * iio_dma_buffer_request_update() - DMA buffer request_update callback + * @buffer: The buffer which to request an update + * + * Should be used as the iio_dma_buffer_request_update() callback for + * iio_buffer_access_ops struct for DMA buffers. + */ +int iio_dma_buffer_request_update(struct iio_buffer *buffer) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block; + bool try_reuse = false; + size_t size; + int ret = 0; + int i; + + /* + * Split the buffer into two even parts. This is used as a double + * buffering scheme with usually one block at a time being used by the + * DMA and the other one by the application. + */ + size = DIV_ROUND_UP(queue->buffer.bytes_per_datum * + queue->buffer.length, 2); + + mutex_lock(&queue->lock); + + /* Allocations are page aligned */ + if (PAGE_ALIGN(queue->fileio.block_size) == PAGE_ALIGN(size)) + try_reuse = true; + + queue->fileio.block_size = size; + queue->fileio.active_block = NULL; + + spin_lock_irq(&queue->list_lock); + for (i = 0; i < 2; i++) { + block = queue->fileio.blocks[i]; + + /* If we can't re-use it free it */ + if (block && (!iio_dma_block_reusable(block) || !try_reuse)) + block->state = IIO_BLOCK_STATE_DEAD; + } + + /* + * At this point all blocks are either owned by the core or marked as + * dead. This means we can reset the lists without having to fear + * corrution. + */ + INIT_LIST_HEAD(&queue->outgoing); + spin_unlock_irq(&queue->list_lock); + + INIT_LIST_HEAD(&queue->incoming); + + for (i = 0; i < 2; i++) { + if (queue->fileio.blocks[i]) { + block = queue->fileio.blocks[i]; + if (block->state == IIO_BLOCK_STATE_DEAD) { + /* Could not reuse it */ + iio_buffer_block_put(block); + block = NULL; + } else { + block->size = size; + } + } else { + block = NULL; + } + + if (!block) { + block = iio_dma_buffer_alloc_block(queue, size); + if (!block) { + ret = -ENOMEM; + goto out_unlock; + } + queue->fileio.blocks[i] = block; + } + + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } + +out_unlock: + mutex_unlock(&queue->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_request_update); + +static void iio_dma_buffer_submit_block(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + int ret; + + /* + * If the hardware has already been removed we put the block into + * limbo. It will neither be on the incoming nor outgoing list, nor will + * it ever complete. It will just wait to be freed eventually. + */ + if (!queue->ops) + return; + + block->state = IIO_BLOCK_STATE_ACTIVE; + iio_buffer_block_get(block); + ret = queue->ops->submit(queue, block); + if (ret) { + /* + * This is a bit of a problem and there is not much we can do + * other then wait for the buffer to be disabled and re-enabled + * and try again. But it should not really happen unless we run + * out of memory or something similar. + * + * TODO: Implement support in the IIO core to allow buffers to + * notify consumers that something went wrong and the buffer + * should be disabled. + */ + iio_buffer_block_put(block); + } +} + +/** + * iio_dma_buffer_enable() - Enable DMA buffer + * @buffer: IIO buffer to enable + * @indio_dev: IIO device the buffer is attached to + * + * Needs to be called when the device that the buffer is attached to starts + * sampling. Typically should be the iio_buffer_access_ops enable callback. + * + * This will allocate the DMA buffers and start the DMA transfers. + */ +int iio_dma_buffer_enable(struct iio_buffer *buffer, + struct iio_dev *indio_dev) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block, *_block; + + mutex_lock(&queue->lock); + queue->active = true; + list_for_each_entry_safe(block, _block, &queue->incoming, head) { + list_del(&block->head); + iio_dma_buffer_submit_block(queue, block); + } + mutex_unlock(&queue->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_enable); + +/** + * iio_dma_buffer_disable() - Disable DMA buffer + * @buffer: IIO DMA buffer to disable + * @indio_dev: IIO device the buffer is attached to + * + * Needs to be called when the device that the buffer is attached to stops + * sampling. Typically should be the iio_buffer_access_ops disable callback. + */ +int iio_dma_buffer_disable(struct iio_buffer *buffer, + struct iio_dev *indio_dev) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + + mutex_lock(&queue->lock); + queue->active = false; + + if (queue->ops && queue->ops->abort) + queue->ops->abort(queue); + mutex_unlock(&queue->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); + +static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + if (block->state == IIO_BLOCK_STATE_DEAD) { + iio_buffer_block_put(block); + } else if (queue->active) { + iio_dma_buffer_submit_block(queue, block); + } else { + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } +} + +static struct iio_dma_buffer_block *iio_dma_buffer_dequeue( + struct iio_dma_buffer_queue *queue) +{ + struct iio_dma_buffer_block *block; + + spin_lock_irq(&queue->list_lock); + block = list_first_entry_or_null(&queue->outgoing, struct + iio_dma_buffer_block, head); + if (block != NULL) { + list_del(&block->head); + block->state = IIO_BLOCK_STATE_DEQUEUED; + } + spin_unlock_irq(&queue->list_lock); + + return block; +} + +/** + * iio_dma_buffer_read() - DMA buffer read callback + * @buffer: Buffer to read form + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data to + * + * Should be used as the read_first_n callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, + char __user *user_buffer) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block; + int ret; + + if (n < buffer->bytes_per_datum) + return -EINVAL; + + mutex_lock(&queue->lock); + + if (!queue->fileio.active_block) { + block = iio_dma_buffer_dequeue(queue); + if (block == NULL) { + ret = 0; + goto out_unlock; + } + queue->fileio.pos = 0; + queue->fileio.active_block = block; + } else { + block = queue->fileio.active_block; + } + + n = rounddown(n, buffer->bytes_per_datum); + if (n > block->bytes_used - queue->fileio.pos) + n = block->bytes_used - queue->fileio.pos; + + if (copy_to_user(user_buffer, block->vaddr + queue->fileio.pos, n)) { + ret = -EFAULT; + goto out_unlock; + } + + queue->fileio.pos += n; + + if (queue->fileio.pos == block->bytes_used) { + queue->fileio.active_block = NULL; + iio_dma_buffer_enqueue(queue, block); + } + + ret = n; + +out_unlock: + mutex_unlock(&queue->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_read); + +/** + * iio_dma_buffer_data_available() - DMA buffer data_available callback + * @buf: Buffer to check for data availability + * + * Should be used as the data_available callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +size_t iio_dma_buffer_data_available(struct iio_buffer *buf) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buf); + struct iio_dma_buffer_block *block; + size_t data_available = 0; + + /* + * For counting the available bytes we'll use the size of the block not + * the number of actual bytes available in the block. Otherwise it is + * possible that we end up with a value that is lower than the watermark + * but won't increase since all blocks are in use. + */ + + mutex_lock(&queue->lock); + if (queue->fileio.active_block) + data_available += queue->fileio.active_block->size; + + spin_lock_irq(&queue->list_lock); + list_for_each_entry(block, &queue->outgoing, head) + data_available += block->size; + spin_unlock_irq(&queue->list_lock); + mutex_unlock(&queue->lock); + + return data_available; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_data_available); + +/** + * iio_dma_buffer_set_bytes_per_datum() - DMA buffer set_bytes_per_datum callback + * @buffer: Buffer to set the bytes-per-datum for + * @bpd: The new bytes-per-datum value + * + * Should be used as the set_bytes_per_datum callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd) +{ + buffer->bytes_per_datum = bpd; + + return 0; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_set_bytes_per_datum); + +/** + * iio_dma_buffer_set_length - DMA buffer set_length callback + * @buffer: Buffer to set the length for + * @length: The new buffer length + * + * Should be used as the set_length callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_set_length(struct iio_buffer *buffer, int length) +{ + /* Avoid an invalid state */ + if (length < 2) + length = 2; + buffer->length = length; + buffer->watermark = length / 2; + + return 0; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_set_length); + +/** + * iio_dma_buffer_init() - Initialize DMA buffer queue + * @queue: Buffer to initialize + * @dev: DMA device + * @ops: DMA buffer queue callback operations + * + * The DMA device will be used by the queue to do DMA memory allocations. So it + * should refer to the device that will perform the DMA to ensure that + * allocations are done from a memory region that can be accessed by the device. + */ +int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, + struct device *dev, const struct iio_dma_buffer_ops *ops) +{ + iio_buffer_init(&queue->buffer); + queue->buffer.length = PAGE_SIZE; + queue->buffer.watermark = queue->buffer.length / 2; + queue->dev = dev; + queue->ops = ops; + + INIT_LIST_HEAD(&queue->incoming); + INIT_LIST_HEAD(&queue->outgoing); + + mutex_init(&queue->lock); + spin_lock_init(&queue->list_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_init); + +/** + * iio_dma_buffer_exit() - Cleanup DMA buffer queue + * @queue: Buffer to cleanup + * + * After this function has completed it is safe to free any resources that are + * associated with the buffer and are accessed inside the callback operations. + */ +void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue) +{ + unsigned int i; + + mutex_lock(&queue->lock); + + spin_lock_irq(&queue->list_lock); + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + if (!queue->fileio.blocks[i]) + continue; + queue->fileio.blocks[i]->state = IIO_BLOCK_STATE_DEAD; + } + INIT_LIST_HEAD(&queue->outgoing); + spin_unlock_irq(&queue->list_lock); + + INIT_LIST_HEAD(&queue->incoming); + + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + if (!queue->fileio.blocks[i]) + continue; + iio_buffer_block_put(queue->fileio.blocks[i]); + queue->fileio.blocks[i] = NULL; + } + queue->fileio.active_block = NULL; + queue->ops = NULL; + + mutex_unlock(&queue->lock); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_exit); + +/** + * iio_dma_buffer_release() - Release final buffer resources + * @queue: Buffer to release + * + * Frees resources that can't yet be freed in iio_dma_buffer_exit(). Should be + * called in the buffers release callback implementation right before freeing + * the memory associated with the buffer. + */ +void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue) +{ + mutex_destroy(&queue->lock); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_release); + +MODULE_AUTHOR("Lars-Peter Clausen "); +MODULE_DESCRIPTION("DMA buffer for the IIO framework"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h new file mode 100644 index 000000000000..767467d886de --- /dev/null +++ b/include/linux/iio/buffer-dma.h @@ -0,0 +1,152 @@ +/* + * Copyright 2013-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen + * + * Licensed under the GPL-2. + */ + +#ifndef __INDUSTRIALIO_DMA_BUFFER_H__ +#define __INDUSTRIALIO_DMA_BUFFER_H__ + +#include +#include +#include +#include +#include + +struct iio_dma_buffer_queue; +struct iio_dma_buffer_ops; +struct device; + +struct iio_buffer_block { + u32 size; + u32 bytes_used; +}; + +/** + * enum iio_block_state - State of a struct iio_dma_buffer_block + * @IIO_BLOCK_STATE_DEQUEUED: Block is not queued + * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue + * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA + * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue + * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed + */ +enum iio_block_state { + IIO_BLOCK_STATE_DEQUEUED, + IIO_BLOCK_STATE_QUEUED, + IIO_BLOCK_STATE_ACTIVE, + IIO_BLOCK_STATE_DONE, + IIO_BLOCK_STATE_DEAD, +}; + +/** + * struct iio_dma_buffer_block - IIO buffer block + * @head: List head + * @size: Total size of the block in bytes + * @bytes_used: Number of bytes that contain valid data + * @vaddr: Virutal address of the blocks memory + * @phys_addr: Physical address of the blocks memory + * @queue: Parent DMA buffer queue + * @kref: kref used to manage the lifetime of block + * @state: Current state of the block + */ +struct iio_dma_buffer_block { + /* May only be accessed by the owner of the block */ + struct list_head head; + size_t bytes_used; + + /* + * Set during allocation, constant thereafter. May be accessed read-only + * by anybody holding a reference to the block. + */ + void *vaddr; + dma_addr_t phys_addr; + size_t size; + struct iio_dma_buffer_queue *queue; + + /* Must not be accessed outside the core. */ + struct kref kref; + /* + * Must not be accessed outside the core. Access needs to hold + * queue->list_lock if the block is not owned by the core. + */ + enum iio_block_state state; +}; + +/** + * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer + * @blocks: Buffer blocks used for fileio + * @active_block: Block being used in read() + * @pos: Read offset in the active block + * @block_size: Size of each block + */ +struct iio_dma_buffer_queue_fileio { + struct iio_dma_buffer_block *blocks[2]; + struct iio_dma_buffer_block *active_block; + size_t pos; + size_t block_size; +}; + +/** + * struct iio_dma_buffer_queue - DMA buffer base structure + * @buffer: IIO buffer base structure + * @dev: Parent device + * @ops: DMA buffer callbacks + * @lock: Protects the incoming list, active and the fields in the fileio + * substruct + * @list_lock: Protects lists that contain blocks which can be modified in + * atomic context as well as blocks on those lists. This is the outgoing queue + * list and typically also a list of active blocks in the part that handles + * the DMA controller + * @incoming: List of buffers on the incoming queue + * @outgoing: List of buffers on the outgoing queue + * @active: Whether the buffer is currently active + * @fileio: FileIO state + */ +struct iio_dma_buffer_queue { + struct iio_buffer buffer; + struct device *dev; + const struct iio_dma_buffer_ops *ops; + + struct mutex lock; + spinlock_t list_lock; + struct list_head incoming; + struct list_head outgoing; + + bool active; + + struct iio_dma_buffer_queue_fileio fileio; +}; + +/** + * struct iio_dma_buffer_ops - DMA buffer callback operations + * @submit: Called when a block is submitted to the DMA controller + * @abort: Should abort all pending transfers + */ +struct iio_dma_buffer_ops { + int (*submit)(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block); + void (*abort)(struct iio_dma_buffer_queue *queue); +}; + +void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block); +void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, + struct list_head *list); + +int iio_dma_buffer_enable(struct iio_buffer *buffer, + struct iio_dev *indio_dev); +int iio_dma_buffer_disable(struct iio_buffer *buffer, + struct iio_dev *indio_dev); +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, + char __user *user_buffer); +size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); +int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); +int iio_dma_buffer_set_length(struct iio_buffer *buffer, int length); +int iio_dma_buffer_request_update(struct iio_buffer *buffer); + +int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, + struct device *dma_dev, const struct iio_dma_buffer_ops *ops); +void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); +void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); + +#endif -- cgit v1.2.3 From 2d6ca60f328450ff5c7802d0857d12e3711348ce Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 13 Oct 2015 18:10:29 +0200 Subject: iio: Add a DMAengine framework based buffer Add a generic fully device independent DMA buffer implementation that uses the DMAegnine framework to perform the DMA transfers. This can be used by converter drivers that whish to provide a DMA buffer for converters that are connected to a DMA core that implements the DMAengine API. Apart from allocating the buffer using iio_dmaengine_buffer_alloc() and freeing it using iio_dmaengine_buffer_free() no additional converter driver specific code is required when using this DMA buffer implementation. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/buffer/Kconfig | 11 ++ drivers/iio/buffer/Makefile | 1 + drivers/iio/buffer/industrialio-buffer-dmaengine.c | 213 +++++++++++++++++++++ include/linux/iio/buffer-dmaengine.h | 18 ++ 4 files changed, 243 insertions(+) create mode 100644 drivers/iio/buffer/industrialio-buffer-dmaengine.c create mode 100644 include/linux/iio/buffer-dmaengine.h (limited to 'include/linux') diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig index b2fda1afc03e..4ffd3db7817f 100644 --- a/drivers/iio/buffer/Kconfig +++ b/drivers/iio/buffer/Kconfig @@ -18,6 +18,17 @@ config IIO_BUFFER_DMA Should be selected by drivers that want to use the generic DMA buffer infrastructure. +config IIO_BUFFER_DMAENGINE + tristate + select IIO_BUFFER_DMA + help + Provides a bonding of the generic IIO DMA buffer infrastructure with the + DMAengine framework. This can be used by converter drivers with a DMA port + connected to an external DMA controller which is supported by the + DMAengine framework. + + Should be selected by drivers that want to use this functionality. + config IIO_KFIFO_BUF tristate "Industrial I/O buffering based on kfifo" help diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile index bda3f1143e72..85beaae831ae 100644 --- a/drivers/iio/buffer/Makefile +++ b/drivers/iio/buffer/Makefile @@ -5,5 +5,6 @@ # When adding new entries keep the list in alphabetical order obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o +obj-$(CONFIG_IIO_BUFFER_DMAENGINE) += industrialio-buffer-dmaengine.o obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c new file mode 100644 index 000000000000..ebdb838d3a1c --- /dev/null +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -0,0 +1,213 @@ +/* + * Copyright 2014-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen + * + * Licensed under the GPL-2 or later. + */ + +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +/* + * The IIO DMAengine buffer combines the generic IIO DMA buffer infrastructure + * with the DMAengine framework. The generic IIO DMA buffer infrastructure is + * used to manage the buffer memory and implement the IIO buffer operations + * while the DMAengine framework is used to perform the DMA transfers. Combined + * this results in a device independent fully functional DMA buffer + * implementation that can be used by device drivers for peripherals which are + * connected to a DMA controller which has a DMAengine driver implementation. + */ + +struct dmaengine_buffer { + struct iio_dma_buffer_queue queue; + + struct dma_chan *chan; + struct list_head active; + + size_t align; + size_t max_size; +}; + +static struct dmaengine_buffer *iio_buffer_to_dmaengine_buffer( + struct iio_buffer *buffer) +{ + return container_of(buffer, struct dmaengine_buffer, queue.buffer); +} + +static void iio_dmaengine_buffer_block_done(void *data) +{ + struct iio_dma_buffer_block *block = data; + unsigned long flags; + + spin_lock_irqsave(&block->queue->list_lock, flags); + list_del(&block->head); + spin_unlock_irqrestore(&block->queue->list_lock, flags); + iio_dma_buffer_block_done(block); +} + +static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(&queue->buffer); + struct dma_async_tx_descriptor *desc; + dma_cookie_t cookie; + + block->bytes_used = min(block->size, dmaengine_buffer->max_size); + block->bytes_used = rounddown(block->bytes_used, + dmaengine_buffer->align); + + desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, + block->phys_addr, block->bytes_used, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + if (!desc) + return -ENOMEM; + + desc->callback = iio_dmaengine_buffer_block_done; + desc->callback_param = block; + + cookie = dmaengine_submit(desc); + if (dma_submit_error(cookie)) + return dma_submit_error(cookie); + + spin_lock_irq(&dmaengine_buffer->queue.list_lock); + list_add_tail(&block->head, &dmaengine_buffer->active); + spin_unlock_irq(&dmaengine_buffer->queue.list_lock); + + dma_async_issue_pending(dmaengine_buffer->chan); + + return 0; +} + +static void iio_dmaengine_buffer_abort(struct iio_dma_buffer_queue *queue) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(&queue->buffer); + + dmaengine_terminate_all(dmaengine_buffer->chan); + /* FIXME: There is a slight chance of a race condition here. + * dmaengine_terminate_all() does not guarantee that all transfer + * callbacks have finished running. Need to introduce a + * dmaengine_terminate_all_sync(). + */ + iio_dma_buffer_block_list_abort(queue, &dmaengine_buffer->active); +} + +static void iio_dmaengine_buffer_release(struct iio_buffer *buf) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buf); + + iio_dma_buffer_release(&dmaengine_buffer->queue); + kfree(dmaengine_buffer); +} + +static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = { + .read_first_n = iio_dma_buffer_read, + .set_bytes_per_datum = iio_dma_buffer_set_bytes_per_datum, + .set_length = iio_dma_buffer_set_length, + .request_update = iio_dma_buffer_request_update, + .enable = iio_dma_buffer_enable, + .disable = iio_dma_buffer_disable, + .data_available = iio_dma_buffer_data_available, + .release = iio_dmaengine_buffer_release, + + .modes = INDIO_BUFFER_HARDWARE, + .flags = INDIO_BUFFER_FLAG_FIXED_WATERMARK, +}; + +static const struct iio_dma_buffer_ops iio_dmaengine_default_ops = { + .submit = iio_dmaengine_buffer_submit_block, + .abort = iio_dmaengine_buffer_abort, +}; + +/** + * iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine + * @dev: Parent device for the buffer + * @channel: DMA channel name, typically "rx". + * + * This allocates a new IIO buffer which internally uses the DMAengine framework + * to perform its transfers. The parent device will be used to request the DMA + * channel. + * + * Once done using the buffer iio_dmaengine_buffer_free() should be used to + * release it. + */ +struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev, + const char *channel) +{ + struct dmaengine_buffer *dmaengine_buffer; + unsigned int width, src_width, dest_width; + struct dma_slave_caps caps; + struct dma_chan *chan; + int ret; + + dmaengine_buffer = kzalloc(sizeof(*dmaengine_buffer), GFP_KERNEL); + if (!dmaengine_buffer) + return ERR_PTR(-ENOMEM); + + chan = dma_request_slave_channel_reason(dev, channel); + if (IS_ERR(chan)) { + ret = PTR_ERR(chan); + goto err_free; + } + + ret = dma_get_slave_caps(chan, &caps); + if (ret < 0) + goto err_free; + + /* Needs to be aligned to the maximum of the minimums */ + if (caps.src_addr_widths) + src_width = __ffs(caps.src_addr_widths); + else + src_width = 1; + if (caps.dst_addr_widths) + dest_width = __ffs(caps.dst_addr_widths); + else + dest_width = 1; + width = max(src_width, dest_width); + + INIT_LIST_HEAD(&dmaengine_buffer->active); + dmaengine_buffer->chan = chan; + dmaengine_buffer->align = width; + dmaengine_buffer->max_size = dma_get_max_seg_size(chan->device->dev); + + iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev, + &iio_dmaengine_default_ops); + + dmaengine_buffer->queue.buffer.access = &iio_dmaengine_buffer_ops; + + return &dmaengine_buffer->queue.buffer; + +err_free: + kfree(dmaengine_buffer); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(iio_dmaengine_buffer_alloc); + +/** + * iio_dmaengine_buffer_free() - Free dmaengine buffer + * @buffer: Buffer to free + * + * Frees a buffer previously allocated with iio_dmaengine_buffer_alloc(). + */ +void iio_dmaengine_buffer_free(struct iio_buffer *buffer) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buffer); + + iio_dma_buffer_exit(&dmaengine_buffer->queue); + dma_release_channel(dmaengine_buffer->chan); + + iio_buffer_put(buffer); +} +EXPORT_SYMBOL_GPL(iio_dmaengine_buffer_free); diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h new file mode 100644 index 000000000000..5dcddf427bb0 --- /dev/null +++ b/include/linux/iio/buffer-dmaengine.h @@ -0,0 +1,18 @@ +/* + * Copyright 2014-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen + * + * Licensed under the GPL-2 or later. + */ + +#ifndef __IIO_DMAENGINE_H__ +#define __IIO_DMAENGINE_H__ + +struct iio_buffer; +struct device; + +struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev, + const char *channel); +void iio_dmaengine_buffer_free(struct iio_buffer *buffer); + +#endif -- cgit v1.2.3 From b662f809d41009749a9ee6f9a4db3d9af579e171 Mon Sep 17 00:00:00 2001 From: Daniel Baluta Date: Mon, 9 Nov 2015 09:14:00 +0200 Subject: iio: core: Introduce IIO software triggers A software trigger associates an IIO device trigger with a software interrupt source (e.g: timer, sysfs). This patch adds the generic infrastructure for handling software triggers. Software interrupts sources are kept in a iio_trigger_types_list and registered separately when the associated kernel module is loaded. Software triggers can be created directly from drivers or from user space via configfs interface. To sum up, this dynamically creates "triggers" group to be found under /config/iio/triggers and offers the possibility of dynamically creating trigger types groups. The first supported trigger type is "hrtimer" found under /config/iio/triggers/hrtimer. Signed-off-by: Daniel Baluta Signed-off-by: Jonathan Cameron --- drivers/iio/Kconfig | 8 ++ drivers/iio/Makefile | 1 + drivers/iio/industrialio-sw-trigger.c | 183 ++++++++++++++++++++++++++++++++++ include/linux/iio/sw_trigger.h | 71 +++++++++++++ 4 files changed, 263 insertions(+) create mode 100644 drivers/iio/industrialio-sw-trigger.c create mode 100644 include/linux/iio/sw_trigger.h (limited to 'include/linux') diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig index 9509b8a4c551..ac8715e56ba1 100644 --- a/drivers/iio/Kconfig +++ b/drivers/iio/Kconfig @@ -46,6 +46,14 @@ config IIO_CONSUMERS_PER_TRIGGER This value controls the maximum number of consumers that a given trigger may handle. Default is 2. +config IIO_SW_TRIGGER + tristate "Enable software triggers support" + select IIO_CONFIGFS + help + Provides IIO core support for software triggers. A software + trigger can be created via configfs or directly by a driver + using the API provided. + config IIO_TRIGGERED_EVENT tristate select IIO_TRIGGER diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile index 39d119f18f2e..f670b82298aa 100644 --- a/drivers/iio/Makefile +++ b/drivers/iio/Makefile @@ -8,6 +8,7 @@ industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o obj-$(CONFIG_IIO_CONFIGFS) += industrialio-configfs.o +obj-$(CONFIG_IIO_SW_TRIGGER) += industrialio-sw-trigger.o obj-$(CONFIG_IIO_TRIGGERED_EVENT) += industrialio-triggered-event.o obj-y += accel/ diff --git a/drivers/iio/industrialio-sw-trigger.c b/drivers/iio/industrialio-sw-trigger.c new file mode 100644 index 000000000000..4825cfd9c4ea --- /dev/null +++ b/drivers/iio/industrialio-sw-trigger.c @@ -0,0 +1,183 @@ +/* + * The Industrial I/O core, software trigger functions + * + * Copyright (c) 2015 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ + +#include +#include +#include +#include +#include + +#include +#include + +static struct config_group *iio_triggers_group; +static struct config_item_type iio_trigger_type_group_type; + +static struct config_item_type iio_triggers_group_type = { + .ct_owner = THIS_MODULE, +}; + +static LIST_HEAD(iio_trigger_types_list); +static DEFINE_MUTEX(iio_trigger_types_lock); + +static +struct iio_sw_trigger_type *__iio_find_sw_trigger_type(const char *name, + unsigned len) +{ + struct iio_sw_trigger_type *t = NULL, *iter; + + list_for_each_entry(iter, &iio_trigger_types_list, list) + if (!strcmp(iter->name, name)) { + t = iter; + break; + } + + return t; +} + +int iio_register_sw_trigger_type(struct iio_sw_trigger_type *t) +{ + struct iio_sw_trigger_type *iter; + int ret = 0; + + mutex_lock(&iio_trigger_types_lock); + iter = __iio_find_sw_trigger_type(t->name, strlen(t->name)); + if (iter) + ret = -EBUSY; + else + list_add_tail(&t->list, &iio_trigger_types_list); + mutex_unlock(&iio_trigger_types_lock); + + if (ret) + return ret; + + t->group = configfs_register_default_group(iio_triggers_group, t->name, + &iio_trigger_type_group_type); + if (IS_ERR(t->group)) + ret = PTR_ERR(t->group); + + return ret; +} +EXPORT_SYMBOL(iio_register_sw_trigger_type); + +void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t) +{ + struct iio_sw_trigger_type *iter; + + mutex_lock(&iio_trigger_types_lock); + iter = __iio_find_sw_trigger_type(t->name, strlen(t->name)); + if (iter) + list_del(&t->list); + mutex_unlock(&iio_trigger_types_lock); + + configfs_unregister_default_group(t->group); +} +EXPORT_SYMBOL(iio_unregister_sw_trigger_type); + +static +struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name) +{ + struct iio_sw_trigger_type *t; + + mutex_lock(&iio_trigger_types_lock); + t = __iio_find_sw_trigger_type(name, strlen(name)); + if (t && !try_module_get(t->owner)) + t = NULL; + mutex_unlock(&iio_trigger_types_lock); + + return t; +} + +struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name) +{ + struct iio_sw_trigger *t; + struct iio_sw_trigger_type *tt; + + tt = iio_get_sw_trigger_type(type); + if (!tt) { + pr_err("Invalid trigger type: %s\n", type); + return ERR_PTR(-EINVAL); + } + t = tt->ops->probe(name); + if (IS_ERR(t)) + goto out_module_put; + + t->trigger_type = tt; + + return t; +out_module_put: + module_put(tt->owner); + return t; +} +EXPORT_SYMBOL(iio_sw_trigger_create); + +void iio_sw_trigger_destroy(struct iio_sw_trigger *t) +{ + struct iio_sw_trigger_type *tt = t->trigger_type; + + tt->ops->remove(t); + module_put(tt->owner); +} +EXPORT_SYMBOL(iio_sw_trigger_destroy); + +static struct config_group *trigger_make_group(struct config_group *group, + const char *name) +{ + struct iio_sw_trigger *t; + + t = iio_sw_trigger_create(group->cg_item.ci_name, name); + if (IS_ERR(t)) + return ERR_CAST(t); + + config_item_set_name(&t->group.cg_item, "%s", name); + + return &t->group; +} + +static void trigger_drop_group(struct config_group *group, + struct config_item *item) +{ + struct iio_sw_trigger *t = to_iio_sw_trigger(item); + + iio_sw_trigger_destroy(t); + config_item_put(item); +} + +static struct configfs_group_operations trigger_ops = { + .make_group = &trigger_make_group, + .drop_item = &trigger_drop_group, +}; + +static struct config_item_type iio_trigger_type_group_type = { + .ct_group_ops = &trigger_ops, + .ct_owner = THIS_MODULE, +}; + +static int __init iio_sw_trigger_init(void) +{ + iio_triggers_group = + configfs_register_default_group(&iio_configfs_subsys.su_group, + "triggers", + &iio_triggers_group_type); + if (IS_ERR(iio_triggers_group)) + return PTR_ERR(iio_triggers_group); + return 0; +} +module_init(iio_sw_trigger_init); + +static void __exit iio_sw_trigger_exit(void) +{ + configfs_unregister_default_group(iio_triggers_group); +} +module_exit(iio_sw_trigger_exit); + +MODULE_AUTHOR("Daniel Baluta "); +MODULE_DESCRIPTION("Industrial I/O software triggers support"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/iio/sw_trigger.h b/include/linux/iio/sw_trigger.h new file mode 100644 index 000000000000..c2f33b2b35a5 --- /dev/null +++ b/include/linux/iio/sw_trigger.h @@ -0,0 +1,71 @@ +/* + * Industrial I/O software trigger interface + * + * Copyright (c) 2015 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ + +#ifndef __IIO_SW_TRIGGER +#define __IIO_SW_TRIGGER + +#include +#include +#include +#include + +#define module_iio_sw_trigger_driver(__iio_sw_trigger_type) \ + module_driver(__iio_sw_trigger_type, iio_register_sw_trigger_type, \ + iio_unregister_sw_trigger_type) + +extern struct configfs_subsystem iio_configfs_subsys; +struct iio_sw_trigger_ops; + +struct iio_sw_trigger_type { + const char *name; + struct module *owner; + const struct iio_sw_trigger_ops *ops; + struct list_head list; + struct config_group *group; +}; + +struct iio_sw_trigger { + struct iio_trigger *trigger; + struct iio_sw_trigger_type *trigger_type; + struct config_group group; +}; + +struct iio_sw_trigger_ops { + struct iio_sw_trigger* (*probe)(const char *); + int (*remove)(struct iio_sw_trigger *); +}; + +static inline +struct iio_sw_trigger *to_iio_sw_trigger(struct config_item *item) +{ + return container_of(to_config_group(item), struct iio_sw_trigger, + group); +} + +int iio_register_sw_trigger_type(struct iio_sw_trigger_type *tt); +void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *tt); + +struct iio_sw_trigger *iio_sw_trigger_create(const char *, const char *); +void iio_sw_trigger_destroy(struct iio_sw_trigger *); + +int iio_sw_trigger_type_configfs_register(struct iio_sw_trigger_type *tt); +void iio_sw_trigger_type_configfs_unregister(struct iio_sw_trigger_type *tt); + +static inline +void iio_swt_group_init_type_name(struct iio_sw_trigger *t, + const char *name, + struct config_item_type *type) +{ +#ifdef CONFIG_CONFIGFS_FS + config_group_init_type_name(&t->group, name, type); +#endif +} + +#endif /* __IIO_SW_TRIGGER */ -- cgit v1.2.3 From 8d6c16dd7213fa43702416e3dd1059e9e36bc758 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Sat, 5 Dec 2015 16:23:26 +0000 Subject: iio:configfs: Introduce iio/configfs.h to provide a location for the configfs_subsystem This exported element needs to be accesible to all drivers using configfs within IIO. Previously it was in the sw_trig.h file which only convered one such usecase. This also fixes a sparse warning as it is now in a header that makes sense to include from industrialio-configfs.c Signed-off-by: Jonathan Cameron < jic23@kernel.org> --- drivers/iio/industrialio-configfs.c | 1 + drivers/iio/industrialio-sw-trigger.c | 1 + include/linux/iio/configfs.h | 15 +++++++++++++++ include/linux/iio/sw_trigger.h | 1 - 4 files changed, 17 insertions(+), 1 deletion(-) create mode 100644 include/linux/iio/configfs.h (limited to 'include/linux') diff --git a/drivers/iio/industrialio-configfs.c b/drivers/iio/industrialio-configfs.c index 83563dd7fcf4..45ce2bc47180 100644 --- a/drivers/iio/industrialio-configfs.c +++ b/drivers/iio/industrialio-configfs.c @@ -15,6 +15,7 @@ #include #include +#include static struct config_item_type iio_root_group_type = { .ct_owner = THIS_MODULE, diff --git a/drivers/iio/industrialio-sw-trigger.c b/drivers/iio/industrialio-sw-trigger.c index 4825cfd9c4ea..311f9fe5aa34 100644 --- a/drivers/iio/industrialio-sw-trigger.c +++ b/drivers/iio/industrialio-sw-trigger.c @@ -15,6 +15,7 @@ #include #include +#include #include static struct config_group *iio_triggers_group; diff --git a/include/linux/iio/configfs.h b/include/linux/iio/configfs.h new file mode 100644 index 000000000000..93befd67c15c --- /dev/null +++ b/include/linux/iio/configfs.h @@ -0,0 +1,15 @@ +/* + * Industrial I/O configfs support + * + * Copyright (c) 2015 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ +#ifndef __IIO_CONFIGFS +#define __IIO_CONFIGFS + +extern struct configfs_subsystem iio_configfs_subsys; + +#endif /* __IIO_CONFIGFS */ diff --git a/include/linux/iio/sw_trigger.h b/include/linux/iio/sw_trigger.h index c2f33b2b35a5..5198f8ed08a4 100644 --- a/include/linux/iio/sw_trigger.h +++ b/include/linux/iio/sw_trigger.h @@ -20,7 +20,6 @@ module_driver(__iio_sw_trigger_type, iio_register_sw_trigger_type, \ iio_unregister_sw_trigger_type) -extern struct configfs_subsystem iio_configfs_subsys; struct iio_sw_trigger_ops; struct iio_sw_trigger_type { -- cgit v1.2.3 From 7d2c2acac577959dbbddefefa91d1ba1b80460b3 Mon Sep 17 00:00:00 2001 From: "Andrew F. Davis" Date: Mon, 14 Dec 2015 16:35:57 -0600 Subject: iio: Make IIO value formating function globally available. Make IIO value formating function globally available to allow IIO drivers to output values as the core does. Signed-off-by: Andrew F. Davis Signed-off-by: Jonathan Cameron --- drivers/iio/industrialio-core.c | 1 + include/linux/iio/iio.h | 2 ++ 2 files changed, 3 insertions(+) (limited to 'include/linux') diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index d0a84febd435..a45eb2c53d0f 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -470,6 +470,7 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals) return 0; } } +EXPORT_SYMBOL_GPL(iio_format_value); static ssize_t iio_read_channel_info(struct device *dev, struct device_attribute *attr, diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index 19c94c9acc81..b5894118755f 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -636,6 +636,8 @@ static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev) } #endif +ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals); + int iio_str_to_fixpoint(const char *str, int fract_mult, int *integer, int *fract); -- cgit v1.2.3