diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-imx-lpi2c.c | 524 |
1 files changed, 517 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c index 8adf2963d764..9778dc8f6d36 100644 --- a/drivers/i2c/busses/i2c-imx-lpi2c.c +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -8,6 +8,8 @@ #include <linux/clk.h> #include <linux/completion.h> #include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> #include <linux/err.h> #include <linux/errno.h> #include <linux/i2c.h> @@ -29,6 +31,7 @@ #define LPI2C_MCR 0x10 /* i2c contrl register */ #define LPI2C_MSR 0x14 /* i2c status register */ #define LPI2C_MIER 0x18 /* i2c interrupt enable */ +#define LPI2C_MDER 0x1C /* i2c DMA enable */ #define LPI2C_MCFGR0 0x20 /* i2c master configuration */ #define LPI2C_MCFGR1 0x24 /* i2c master configuration */ #define LPI2C_MCFGR2 0x28 /* i2c master configuration */ @@ -70,11 +73,14 @@ #define MCFGR1_AUTOSTOP BIT(8) #define MCFGR1_IGNACK BIT(9) #define MRDR_RXEMPTY BIT(14) +#define MDER_TDDE BIT(0) +#define MDER_RDDE BIT(1) #define I2C_CLK_RATIO 2 #define CHUNK_DATA 256 #define I2C_PM_TIMEOUT 10 /* ms */ +#define I2C_DMA_THRESHOLD 8 /* bytes */ enum lpi2c_imx_mode { STANDARD, /* 100+Kbps */ @@ -91,6 +97,24 @@ enum lpi2c_imx_pincfg { FOUR_PIN_PP, }; +struct lpi2c_imx_dma { + bool using_pio_mode; + u8 rx_cmd_buf_len; + u8 *dma_buf; + u16 *rx_cmd_buf; + unsigned int dma_len; + unsigned int tx_burst_num; + unsigned int rx_burst_num; + unsigned long dma_msg_flag; + resource_size_t phy_addr; + dma_addr_t dma_tx_addr; + dma_addr_t dma_addr; + enum dma_data_direction dma_data_dir; + enum dma_transfer_direction dma_transfer_dir; + struct dma_chan *chan_tx; + struct dma_chan *chan_rx; +}; + struct lpi2c_imx_struct { struct i2c_adapter adapter; int num_clks; @@ -108,6 +132,8 @@ struct lpi2c_imx_struct { unsigned int rxfifosize; enum lpi2c_imx_mode mode; struct i2c_bus_recovery_info rinfo; + bool can_use_dma; + struct lpi2c_imx_dma *dma; }; static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, @@ -305,7 +331,7 @@ static int lpi2c_imx_master_disable(struct lpi2c_imx_struct *lpi2c_imx) return 0; } -static int lpi2c_imx_msg_complete(struct lpi2c_imx_struct *lpi2c_imx) +static int lpi2c_imx_pio_msg_complete(struct lpi2c_imx_struct *lpi2c_imx) { unsigned long time_left; @@ -451,6 +477,425 @@ static void lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx, lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE); } +static bool is_use_dma(struct lpi2c_imx_struct *lpi2c_imx, struct i2c_msg *msg) +{ + if (!lpi2c_imx->can_use_dma) + return false; + + /* + * When the length of data is less than I2C_DMA_THRESHOLD, + * cpu mode is used directly to avoid low performance. + */ + return !(msg->len < I2C_DMA_THRESHOLD); +} + +static int lpi2c_imx_pio_xfer(struct lpi2c_imx_struct *lpi2c_imx, + struct i2c_msg *msg) +{ + reinit_completion(&lpi2c_imx->complete); + + if (msg->flags & I2C_M_RD) + lpi2c_imx_read(lpi2c_imx, msg); + else + lpi2c_imx_write(lpi2c_imx, msg); + + return lpi2c_imx_pio_msg_complete(lpi2c_imx); +} + +static int lpi2c_imx_dma_timeout_calculate(struct lpi2c_imx_struct *lpi2c_imx) +{ + unsigned long time = 0; + + time = 8 * lpi2c_imx->dma->dma_len * 1000 / lpi2c_imx->bitrate; + + /* Add extra second for scheduler related activities */ + time += 1; + + /* Double calculated time */ + return msecs_to_jiffies(time * MSEC_PER_SEC); +} + +static int lpi2c_imx_alloc_rx_cmd_buf(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + u16 rx_remain = dma->dma_len; + int cmd_num; + u16 temp; + + /* + * Calculate the number of rx command words via the DMA TX channel + * writing into command register based on the i2c msg len, and build + * the rx command words buffer. + */ + cmd_num = DIV_ROUND_UP(rx_remain, CHUNK_DATA); + dma->rx_cmd_buf = kcalloc(cmd_num, sizeof(u16), GFP_KERNEL); + dma->rx_cmd_buf_len = cmd_num * sizeof(u16); + + if (!dma->rx_cmd_buf) { + dev_err(&lpi2c_imx->adapter.dev, "Alloc RX cmd buffer failed\n"); + return -ENOMEM; + } + + for (int i = 0; i < cmd_num ; i++) { + temp = rx_remain > CHUNK_DATA ? CHUNK_DATA - 1 : rx_remain - 1; + temp |= (RECV_DATA << 8); + rx_remain -= CHUNK_DATA; + dma->rx_cmd_buf[i] = temp; + } + + return 0; +} + +static int lpi2c_imx_dma_msg_complete(struct lpi2c_imx_struct *lpi2c_imx) +{ + unsigned long time_left, time; + + time = lpi2c_imx_dma_timeout_calculate(lpi2c_imx); + time_left = wait_for_completion_timeout(&lpi2c_imx->complete, time); + if (time_left == 0) { + dev_err(&lpi2c_imx->adapter.dev, "I/O Error in DMA Data Transfer\n"); + return -ETIMEDOUT; + } + + return 0; +} + +static void lpi2c_dma_unmap(struct lpi2c_imx_dma *dma) +{ + struct dma_chan *chan = dma->dma_data_dir == DMA_FROM_DEVICE + ? dma->chan_rx : dma->chan_tx; + + dma_unmap_single(chan->device->dev, dma->dma_addr, + dma->dma_len, dma->dma_data_dir); + + dma->dma_data_dir = DMA_NONE; +} + +static void lpi2c_cleanup_rx_cmd_dma(struct lpi2c_imx_dma *dma) +{ + dmaengine_terminate_sync(dma->chan_tx); + dma_unmap_single(dma->chan_tx->device->dev, dma->dma_tx_addr, + dma->rx_cmd_buf_len, DMA_TO_DEVICE); +} + +static void lpi2c_cleanup_dma(struct lpi2c_imx_dma *dma) +{ + if (dma->dma_data_dir == DMA_FROM_DEVICE) + dmaengine_terminate_sync(dma->chan_rx); + else if (dma->dma_data_dir == DMA_TO_DEVICE) + dmaengine_terminate_sync(dma->chan_tx); + + lpi2c_dma_unmap(dma); +} + +static void lpi2c_dma_callback(void *data) +{ + struct lpi2c_imx_struct *lpi2c_imx = (struct lpi2c_imx_struct *)data; + + complete(&lpi2c_imx->complete); +} + +static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct dma_async_tx_descriptor *rx_cmd_desc; + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + struct dma_chan *txchan = dma->chan_tx; + dma_cookie_t cookie; + + dma->dma_tx_addr = dma_map_single(txchan->device->dev, + dma->rx_cmd_buf, dma->rx_cmd_buf_len, + DMA_TO_DEVICE); + if (dma_mapping_error(txchan->device->dev, dma->dma_tx_addr)) { + dev_err(&lpi2c_imx->adapter.dev, "DMA map failed, use pio\n"); + return -EINVAL; + } + + rx_cmd_desc = dmaengine_prep_slave_single(txchan, dma->dma_tx_addr, + dma->rx_cmd_buf_len, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!rx_cmd_desc) { + dev_err(&lpi2c_imx->adapter.dev, "DMA prep slave sg failed, use pio\n"); + goto desc_prepare_err_exit; + } + + cookie = dmaengine_submit(rx_cmd_desc); + if (dma_submit_error(cookie)) { + dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n"); + goto submit_err_exit; + } + + dma_async_issue_pending(txchan); + + return 0; + +desc_prepare_err_exit: + dma_unmap_single(txchan->device->dev, dma->dma_tx_addr, + dma->rx_cmd_buf_len, DMA_TO_DEVICE); + return -EINVAL; + +submit_err_exit: + dma_unmap_single(txchan->device->dev, dma->dma_tx_addr, + dma->rx_cmd_buf_len, DMA_TO_DEVICE); + dmaengine_desc_free(rx_cmd_desc); + return -EINVAL; +} + +static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + struct dma_async_tx_descriptor *desc; + struct dma_chan *chan; + dma_cookie_t cookie; + + if (dma->dma_msg_flag & I2C_M_RD) { + chan = dma->chan_rx; + dma->dma_data_dir = DMA_FROM_DEVICE; + dma->dma_transfer_dir = DMA_DEV_TO_MEM; + } else { + chan = dma->chan_tx; + dma->dma_data_dir = DMA_TO_DEVICE; + dma->dma_transfer_dir = DMA_MEM_TO_DEV; + } + + dma->dma_addr = dma_map_single(chan->device->dev, + dma->dma_buf, dma->dma_len, dma->dma_data_dir); + if (dma_mapping_error(chan->device->dev, dma->dma_addr)) { + dev_err(&lpi2c_imx->adapter.dev, "DMA map failed, use pio\n"); + return -EINVAL; + } + + desc = dmaengine_prep_slave_single(chan, dma->dma_addr, + dma->dma_len, dma->dma_transfer_dir, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + dev_err(&lpi2c_imx->adapter.dev, "DMA prep slave sg failed, use pio\n"); + goto desc_prepare_err_exit; + } + + reinit_completion(&lpi2c_imx->complete); + desc->callback = lpi2c_dma_callback; + desc->callback_param = lpi2c_imx; + + cookie = dmaengine_submit(desc); + if (dma_submit_error(cookie)) { + dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n"); + goto submit_err_exit; + } + + /* Can't switch to PIO mode when DMA have started transfer */ + dma->using_pio_mode = false; + + dma_async_issue_pending(chan); + + return 0; + +desc_prepare_err_exit: + lpi2c_dma_unmap(dma); + return -EINVAL; + +submit_err_exit: + lpi2c_dma_unmap(dma); + dmaengine_desc_free(desc); + return -EINVAL; +} + +static int lpi2c_imx_find_max_burst_num(unsigned int fifosize, unsigned int len) +{ + unsigned int i; + + for (i = fifosize / 2; i > 0; i--) + if (!(len % i)) + break; + + return i; +} + +/* + * For a highest DMA efficiency, tx/rx burst number should be calculated according + * to the FIFO depth. + */ +static void lpi2c_imx_dma_burst_num_calculate(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + unsigned int cmd_num; + + if (dma->dma_msg_flag & I2C_M_RD) { + /* + * One RX cmd word can trigger DMA receive no more than 256 bytes. + * The number of RX cmd words should be calculated based on the data + * length. + */ + cmd_num = DIV_ROUND_UP(dma->dma_len, CHUNK_DATA); + dma->tx_burst_num = lpi2c_imx_find_max_burst_num(lpi2c_imx->txfifosize, + cmd_num); + dma->rx_burst_num = lpi2c_imx_find_max_burst_num(lpi2c_imx->rxfifosize, + dma->dma_len); + } else { + dma->tx_burst_num = lpi2c_imx_find_max_burst_num(lpi2c_imx->txfifosize, + dma->dma_len); + } +} + +static int lpi2c_dma_config(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + struct dma_slave_config rx = {}, tx = {}; + int ret; + + lpi2c_imx_dma_burst_num_calculate(lpi2c_imx); + + if (dma->dma_msg_flag & I2C_M_RD) { + tx.dst_addr = dma->phy_addr + LPI2C_MTDR; + tx.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; + tx.dst_maxburst = dma->tx_burst_num; + tx.direction = DMA_MEM_TO_DEV; + ret = dmaengine_slave_config(dma->chan_tx, &tx); + if (ret < 0) + return ret; + + rx.src_addr = dma->phy_addr + LPI2C_MRDR; + rx.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + rx.src_maxburst = dma->rx_burst_num; + rx.direction = DMA_DEV_TO_MEM; + ret = dmaengine_slave_config(dma->chan_rx, &rx); + if (ret < 0) + return ret; + } else { + tx.dst_addr = dma->phy_addr + LPI2C_MTDR; + tx.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + tx.dst_maxburst = dma->tx_burst_num; + tx.direction = DMA_MEM_TO_DEV; + ret = dmaengine_slave_config(dma->chan_tx, &tx); + if (ret < 0) + return ret; + } + + return 0; +} + +static void lpi2c_dma_enable(struct lpi2c_imx_struct *lpi2c_imx) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + /* + * TX interrupt will be triggered when the number of words in + * the transmit FIFO is equal or less than TX watermark. + * RX interrupt will be triggered when the number of words in + * the receive FIFO is greater than RX watermark. + * In order to trigger the DMA interrupt, TX watermark should be + * set equal to the DMA TX burst number but RX watermark should + * be set less than the DMA RX burst number. + */ + if (dma->dma_msg_flag & I2C_M_RD) { + /* Set I2C TX/RX watermark */ + writel(dma->tx_burst_num | (dma->rx_burst_num - 1) << 16, + lpi2c_imx->base + LPI2C_MFCR); + /* Enable I2C DMA TX/RX function */ + writel(MDER_TDDE | MDER_RDDE, lpi2c_imx->base + LPI2C_MDER); + } else { + /* Set I2C TX watermark */ + writel(dma->tx_burst_num, lpi2c_imx->base + LPI2C_MFCR); + /* Enable I2C DMA TX function */ + writel(MDER_TDDE, lpi2c_imx->base + LPI2C_MDER); + } + + /* Enable NACK detected */ + lpi2c_imx_intctrl(lpi2c_imx, MIER_NDIE); +}; + +/* + * When lpi2c is in TX DMA mode we can use one DMA TX channel to write + * data word into TXFIFO, but in RX DMA mode it is different. + * + * The LPI2C MTDR register is a command data and transmit data register. + * Bits 8-10 are the command data field and Bits 0-7 are the transmit + * data field. When the LPI2C master needs to read data, the number of + * bytes to read should be set in the command field and RECV_DATA should + * be set into the command data field to receive (DATA[7:0] + 1) bytes. + * The recv data command word is made of RECV_DATA in the command data + * field and the number of bytes to read in transmit data field. When the + * length of data to be read exceeds 256 bytes, recv data command word + * needs to be written to TXFIFO multiple times. + * + * So when in RX DMA mode, the TX channel also must to be configured to + * send RX command words and the RX command word must be set in advance + * before transmitting. + */ +static int lpi2c_imx_dma_xfer(struct lpi2c_imx_struct *lpi2c_imx, + struct i2c_msg *msg) +{ + struct lpi2c_imx_dma *dma = lpi2c_imx->dma; + int ret; + + /* When DMA mode fails before transferring, CPU mode can be used. */ + dma->using_pio_mode = true; + + dma->dma_len = msg->len; + dma->dma_msg_flag = msg->flags; + dma->dma_buf = i2c_get_dma_safe_msg_buf(msg, I2C_DMA_THRESHOLD); + if (!dma->dma_buf) + return -ENOMEM; + + ret = lpi2c_dma_config(lpi2c_imx); + if (ret) { + dev_err(&lpi2c_imx->adapter.dev, "Failed to configure DMA (%d)\n", ret); + goto disable_dma; + } + + lpi2c_dma_enable(lpi2c_imx); + + ret = lpi2c_dma_submit(lpi2c_imx); + if (ret) { + dev_err(&lpi2c_imx->adapter.dev, "DMA submission failed (%d)\n", ret); + goto disable_dma; + } + + if (dma->dma_msg_flag & I2C_M_RD) { + ret = lpi2c_imx_alloc_rx_cmd_buf(lpi2c_imx); + if (ret) + goto disable_cleanup_data_dma; + + ret = lpi2c_dma_rx_cmd_submit(lpi2c_imx); + if (ret) + goto disable_cleanup_data_dma; + } + + ret = lpi2c_imx_dma_msg_complete(lpi2c_imx); + if (ret) + goto disable_cleanup_all_dma; + + /* When encountering NACK in transfer, clean up all DMA transfers */ + if ((readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) && !ret) { + ret = -EIO; + goto disable_cleanup_all_dma; + } + + if (dma->dma_msg_flag & I2C_M_RD) + dma_unmap_single(dma->chan_tx->device->dev, dma->dma_tx_addr, + dma->rx_cmd_buf_len, DMA_TO_DEVICE); + lpi2c_dma_unmap(dma); + + goto disable_dma; + +disable_cleanup_all_dma: + if (dma->dma_msg_flag & I2C_M_RD) + lpi2c_cleanup_rx_cmd_dma(dma); +disable_cleanup_data_dma: + lpi2c_cleanup_dma(dma); +disable_dma: + /* Disable I2C DMA function */ + writel(0, lpi2c_imx->base + LPI2C_MDER); + + if (dma->dma_msg_flag & I2C_M_RD) + kfree(dma->rx_cmd_buf); + + if (ret) + i2c_put_dma_safe_msg_buf(dma->dma_buf, msg, false); + else + i2c_put_dma_safe_msg_buf(dma->dma_buf, msg, true); + + return ret; +} + static int lpi2c_imx_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { @@ -477,12 +922,14 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter, lpi2c_imx->msglen = msgs[i].len; init_completion(&lpi2c_imx->complete); - if (msgs[i].flags & I2C_M_RD) - lpi2c_imx_read(lpi2c_imx, &msgs[i]); - else - lpi2c_imx_write(lpi2c_imx, &msgs[i]); + if (is_use_dma(lpi2c_imx, &msgs[i])) { + result = lpi2c_imx_dma_xfer(lpi2c_imx, &msgs[i]); + if (result && lpi2c_imx->dma->using_pio_mode) + result = lpi2c_imx_pio_xfer(lpi2c_imx, &msgs[i]); + } else { + result = lpi2c_imx_pio_xfer(lpi2c_imx, &msgs[i]); + } - result = lpi2c_imx_msg_complete(lpi2c_imx); if (result) goto stop; @@ -546,6 +993,58 @@ static int lpi2c_imx_init_recovery_info(struct lpi2c_imx_struct *lpi2c_imx, return 0; } +static void dma_exit(struct device *dev, struct lpi2c_imx_dma *dma) +{ + if (dma->chan_rx) + dma_release_channel(dma->chan_rx); + + if (dma->chan_tx) + dma_release_channel(dma->chan_tx); + + devm_kfree(dev, dma); +} + +static int lpi2c_dma_init(struct device *dev, dma_addr_t phy_addr) +{ + struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev); + struct lpi2c_imx_dma *dma; + int ret; + + dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); + if (!dma) + return -ENOMEM; + + dma->phy_addr = phy_addr; + + /* Prepare for TX DMA: */ + dma->chan_tx = dma_request_chan(dev, "tx"); + if (IS_ERR(dma->chan_tx)) { + ret = PTR_ERR(dma->chan_tx); + if (ret != -ENODEV && ret != -EPROBE_DEFER) + dev_err(dev, "can't request DMA tx channel (%d)\n", ret); + dma->chan_tx = NULL; + goto dma_exit; + } + + /* Prepare for RX DMA: */ + dma->chan_rx = dma_request_chan(dev, "rx"); + if (IS_ERR(dma->chan_rx)) { + ret = PTR_ERR(dma->chan_rx); + if (ret != -ENODEV && ret != -EPROBE_DEFER) + dev_err(dev, "can't request DMA rx channel (%d)\n", ret); + dma->chan_rx = NULL; + goto dma_exit; + } + + lpi2c_imx->can_use_dma = true; + lpi2c_imx->dma = dma; + return 0; + +dma_exit: + dma_exit(dev, dma); + return ret; +} + static u32 lpi2c_imx_func(struct i2c_adapter *adapter) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | @@ -566,6 +1065,8 @@ MODULE_DEVICE_TABLE(of, lpi2c_imx_of_match); static int lpi2c_imx_probe(struct platform_device *pdev) { struct lpi2c_imx_struct *lpi2c_imx; + struct resource *res; + dma_addr_t phy_addr; unsigned int temp; int irq, ret; @@ -573,7 +1074,7 @@ static int lpi2c_imx_probe(struct platform_device *pdev) if (!lpi2c_imx) return -ENOMEM; - lpi2c_imx->base = devm_platform_ioremap_resource(pdev, 0); + lpi2c_imx->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); if (IS_ERR(lpi2c_imx->base)) return PTR_ERR(lpi2c_imx->base); @@ -587,6 +1088,7 @@ static int lpi2c_imx_probe(struct platform_device *pdev) lpi2c_imx->adapter.dev.of_node = pdev->dev.of_node; strscpy(lpi2c_imx->adapter.name, pdev->name, sizeof(lpi2c_imx->adapter.name)); + phy_addr = (dma_addr_t)res->start; ret = devm_clk_bulk_get_all(&pdev->dev, &lpi2c_imx->clks); if (ret < 0) @@ -640,6 +1142,14 @@ static int lpi2c_imx_probe(struct platform_device *pdev) if (ret == -EPROBE_DEFER) goto rpm_disable; + /* Init DMA */ + ret = lpi2c_dma_init(&pdev->dev, phy_addr); + if (ret) { + if (ret == -EPROBE_DEFER) + goto rpm_disable; + dev_info(&pdev->dev, "use pio mode\n"); + } + ret = i2c_add_adapter(&lpi2c_imx->adapter); if (ret) goto rpm_disable; |