diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/mailbox/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/mailbox/Makefile | 2 | ||||
| -rw-r--r-- | drivers/mailbox/sun6i-msgbox.c | 326 |
3 files changed, 337 insertions, 0 deletions
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index ab4eb750bbdd..5a577a6734cf 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -227,4 +227,13 @@ config ZYNQMP_IPI_MBOX message to the IPI buffer and will access the IPI control registers to kick the other processor or enquire status. +config SUN6I_MSGBOX + tristate "Allwinner sun6i/sun8i/sun9i/sun50i Message Box" + depends on ARCH_SUNXI || COMPILE_TEST + default ARCH_SUNXI + help + Mailbox implementation for the hardware message box present in + various Allwinner SoCs. This mailbox is used for communication + between the application CPUs and the power management coprocessor. + endif diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index c22fad6f696b..2e4364ef5c47 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -48,3 +48,5 @@ obj-$(CONFIG_STM32_IPCC) += stm32-ipcc.o obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o + +obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o diff --git a/drivers/mailbox/sun6i-msgbox.c b/drivers/mailbox/sun6i-msgbox.c new file mode 100644 index 000000000000..ccecf2e5941d --- /dev/null +++ b/drivers/mailbox/sun6i-msgbox.c @@ -0,0 +1,326 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (c) 2017-2019 Samuel Holland <samuel@sholland.org> + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mailbox_controller.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/reset.h> +#include <linux/spinlock.h> + +#define NUM_CHANS 8 + +#define CTRL_REG(n) (0x0000 + 0x4 * ((n) / 4)) +#define CTRL_RX(n) BIT(0 + 8 * ((n) % 4)) +#define CTRL_TX(n) BIT(4 + 8 * ((n) % 4)) + +#define REMOTE_IRQ_EN_REG 0x0040 +#define REMOTE_IRQ_STAT_REG 0x0050 +#define LOCAL_IRQ_EN_REG 0x0060 +#define LOCAL_IRQ_STAT_REG 0x0070 + +#define RX_IRQ(n) BIT(0 + 2 * (n)) +#define RX_IRQ_MASK 0x5555 +#define TX_IRQ(n) BIT(1 + 2 * (n)) +#define TX_IRQ_MASK 0xaaaa + +#define FIFO_STAT_REG(n) (0x0100 + 0x4 * (n)) +#define FIFO_STAT_MASK GENMASK(0, 0) + +#define MSG_STAT_REG(n) (0x0140 + 0x4 * (n)) +#define MSG_STAT_MASK GENMASK(2, 0) + +#define MSG_DATA_REG(n) (0x0180 + 0x4 * (n)) + +#define mbox_dbg(mbox, ...) dev_dbg((mbox)->controller.dev, __VA_ARGS__) + +struct sun6i_msgbox { + struct mbox_controller controller; + struct clk *clk; + spinlock_t lock; + void __iomem *regs; +}; + +static bool sun6i_msgbox_last_tx_done(struct mbox_chan *chan); +static bool sun6i_msgbox_peek_data(struct mbox_chan *chan); + +static inline int channel_number(struct mbox_chan *chan) +{ + return chan - chan->mbox->chans; +} + +static inline struct sun6i_msgbox *to_sun6i_msgbox(struct mbox_chan *chan) +{ + return chan->con_priv; +} + +static irqreturn_t sun6i_msgbox_irq(int irq, void *dev_id) +{ + struct sun6i_msgbox *mbox = dev_id; + uint32_t status; + int n; + + /* Only examine channels that are currently enabled. */ + status = readl(mbox->regs + LOCAL_IRQ_EN_REG) & + readl(mbox->regs + LOCAL_IRQ_STAT_REG); + + if (!(status & RX_IRQ_MASK)) + return IRQ_NONE; + + for (n = 0; n < NUM_CHANS; ++n) { + struct mbox_chan *chan = &mbox->controller.chans[n]; + + if (!(status & RX_IRQ(n))) + continue; + + while (sun6i_msgbox_peek_data(chan)) { + uint32_t msg = readl(mbox->regs + MSG_DATA_REG(n)); + + mbox_dbg(mbox, "Channel %d received 0x%08x\n", n, msg); + mbox_chan_received_data(chan, &msg); + } + + /* The IRQ can be cleared only once the FIFO is empty. */ + writel(RX_IRQ(n), mbox->regs + LOCAL_IRQ_STAT_REG); + } + + return IRQ_HANDLED; +} + +static int sun6i_msgbox_send_data(struct mbox_chan *chan, void *data) +{ + struct sun6i_msgbox *mbox = to_sun6i_msgbox(chan); + int n = channel_number(chan); + uint32_t msg = *(uint32_t *)data; + + /* Using a channel backwards gets the hardware into a bad state. */ + if (WARN_ON_ONCE(!(readl(mbox->regs + CTRL_REG(n)) & CTRL_TX(n)))) + return 0; + + writel(msg, mbox->regs + MSG_DATA_REG(n)); + mbox_dbg(mbox, "Channel %d sent 0x%08x\n", n, msg); + + return 0; +} + +static int sun6i_msgbox_startup(struct mbox_chan *chan) +{ + struct sun6i_msgbox *mbox = to_sun6i_msgbox(chan); + int n = channel_number(chan); + + /* The coprocessor is responsible for setting channel directions. */ + if (readl(mbox->regs + CTRL_REG(n)) & CTRL_RX(n)) { + /* Flush the receive FIFO. */ + while (sun6i_msgbox_peek_data(chan)) + readl(mbox->regs + MSG_DATA_REG(n)); + writel(RX_IRQ(n), mbox->regs + LOCAL_IRQ_STAT_REG); + + /* Enable the receive IRQ. */ + spin_lock(&mbox->lock); + writel(readl(mbox->regs + LOCAL_IRQ_EN_REG) | RX_IRQ(n), + mbox->regs + LOCAL_IRQ_EN_REG); + spin_unlock(&mbox->lock); + } + + mbox_dbg(mbox, "Channel %d startup complete\n", n); + + return 0; +} + +static void sun6i_msgbox_shutdown(struct mbox_chan *chan) +{ + struct sun6i_msgbox *mbox = to_sun6i_msgbox(chan); + int n = channel_number(chan); + + if (readl(mbox->regs + CTRL_REG(n)) & CTRL_RX(n)) { + /* Disable the receive IRQ. */ + spin_lock(&mbox->lock); + writel(readl(mbox->regs + LOCAL_IRQ_EN_REG) & ~RX_IRQ(n), + mbox->regs + LOCAL_IRQ_EN_REG); + spin_unlock(&mbox->lock); + + /* Attempt to flush the FIFO until the IRQ is cleared. */ + do { + while (sun6i_msgbox_peek_data(chan)) + readl(mbox->regs + MSG_DATA_REG(n)); + writel(RX_IRQ(n), mbox->regs + LOCAL_IRQ_STAT_REG); + } while (readl(mbox->regs + LOCAL_IRQ_STAT_REG) & RX_IRQ(n)); + } + + mbox_dbg(mbox, "Channel %d shutdown complete\n", n); +} + +static bool sun6i_msgbox_last_tx_done(struct mbox_chan *chan) +{ + struct sun6i_msgbox *mbox = to_sun6i_msgbox(chan); + int n = channel_number(chan); + + /* + * The hardware allows snooping on the remote user's IRQ statuses. + * We consider a message to be acknowledged only once the receive IRQ + * for that channel is cleared. Since the receive IRQ for a channel + * cannot be cleared until the FIFO for that channel is empty, this + * ensures that the message has actually been read. It also gives the + * recipient an opportunity to perform minimal processing before + * acknowledging the message. + */ + return !(readl(mbox->regs + REMOTE_IRQ_STAT_REG) & RX_IRQ(n)); +} + +static bool sun6i_msgbox_peek_data(struct mbox_chan *chan) +{ + struct sun6i_msgbox *mbox = to_sun6i_msgbox(chan); + int n = channel_number(chan); + + return readl(mbox->regs + MSG_STAT_REG(n)) & MSG_STAT_MASK; +} + +static const struct mbox_chan_ops sun6i_msgbox_chan_ops = { + .send_data = sun6i_msgbox_send_data, + .startup = sun6i_msgbox_startup, + .shutdown = sun6i_msgbox_shutdown, + .last_tx_done = sun6i_msgbox_last_tx_done, + .peek_data = sun6i_msgbox_peek_data, +}; + +static int sun6i_msgbox_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct mbox_chan *chans; + struct reset_control *reset; + struct resource *res; + struct sun6i_msgbox *mbox; + int i, ret; + + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); + if (!mbox) + return -ENOMEM; + + chans = devm_kcalloc(dev, NUM_CHANS, sizeof(*chans), GFP_KERNEL); + if (!chans) + return -ENOMEM; + + for (i = 0; i < NUM_CHANS; ++i) + chans[i].con_priv = mbox; + + mbox->clk = devm_clk_get(dev, NULL); + if (IS_ERR(mbox->clk)) { + ret = PTR_ERR(mbox->clk); + dev_err(dev, "Failed to get clock: %d\n", ret); + return ret; + } + + ret = clk_prepare_enable(mbox->clk); + if (ret) { + dev_err(dev, "Failed to enable clock: %d\n", ret); + return ret; + } + + reset = devm_reset_control_get_exclusive(dev, NULL); + if (IS_ERR(reset)) { + ret = PTR_ERR(reset); + dev_err(dev, "Failed to get reset control: %d\n", ret); + goto err_disable_unprepare; + } + + /* + * NOTE: We rely on platform firmware to preconfigure the channel + * directions, and we share this hardware block with other firmware + * that runs concurrently with Linux (e.g. a trusted monitor). + * + * Therefore, we do *not* assert the reset line if probing fails or + * when removing the device. + */ + ret = reset_control_deassert(reset); + if (ret) { + dev_err(dev, "Failed to deassert reset: %d\n", ret); + goto err_disable_unprepare; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + ret = -ENODEV; + goto err_disable_unprepare; + } + + mbox->regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(mbox->regs)) { + ret = PTR_ERR(mbox->regs); + dev_err(dev, "Failed to map MMIO resource: %d\n", ret); + goto err_disable_unprepare; + } + + /* Disable all IRQs for this end of the msgbox. */ + writel(0, mbox->regs + LOCAL_IRQ_EN_REG); + + ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0), + sun6i_msgbox_irq, 0, dev_name(dev), mbox); + if (ret) { + dev_err(dev, "Failed to register IRQ handler: %d\n", ret); + goto err_disable_unprepare; + } + + mbox->controller.dev = dev; + mbox->controller.ops = &sun6i_msgbox_chan_ops; + mbox->controller.chans = chans; + mbox->controller.num_chans = NUM_CHANS; + mbox->controller.txdone_irq = false; + mbox->controller.txdone_poll = true; + mbox->controller.txpoll_period = 5; + + spin_lock_init(&mbox->lock); + platform_set_drvdata(pdev, mbox); + + ret = mbox_controller_register(&mbox->controller); + if (ret) { + dev_err(dev, "Failed to register controller: %d\n", ret); + goto err_disable_unprepare; + } + + return 0; + +err_disable_unprepare: + clk_disable_unprepare(mbox->clk); + + return ret; +} + +static int sun6i_msgbox_remove(struct platform_device *pdev) +{ + struct sun6i_msgbox *mbox = platform_get_drvdata(pdev); + + mbox_controller_unregister(&mbox->controller); + /* See the comment in sun6i_msgbox_probe about the reset line. */ + clk_disable_unprepare(mbox->clk); + + return 0; +} + +static const struct of_device_id sun6i_msgbox_of_match[] = { + { .compatible = "allwinner,sun6i-a31-msgbox", }, + {}, +}; +MODULE_DEVICE_TABLE(of, sun6i_msgbox_of_match); + +static struct platform_driver sun6i_msgbox_driver = { + .driver = { + .name = "sun6i-msgbox", + .of_match_table = sun6i_msgbox_of_match, + }, + .probe = sun6i_msgbox_probe, + .remove = sun6i_msgbox_remove, +}; +module_platform_driver(sun6i_msgbox_driver); + +MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>"); +MODULE_DESCRIPTION("Allwinner sun6i/sun8i/sun9i/sun50i Message Box"); +MODULE_LICENSE("GPL v2"); |