diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-imx.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 355 |
1 files changed, 340 insertions, 15 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index e9fb7cf..7f3a9fe 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -32,22 +32,27 @@ /** Includes ******************************************************************* *******************************************************************************/ -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/errno.h> -#include <linux/err.h> -#include <linux/interrupt.h> +#include <linux/clk.h> +#include <linux/completion.h> #include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/dmapool.h> +#include <linux/err.h> +#include <linux/errno.h> #include <linux/i2c.h> +#include <linux/init.h> +#include <linux/interrupt.h> #include <linux/io.h> -#include <linux/sched.h> -#include <linux/platform_device.h> -#include <linux/clk.h> -#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/of_dma.h> #include <linux/platform_data/i2c-imx.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/slab.h> /** Defines ******************************************************************** *******************************************************************************/ @@ -58,6 +63,15 @@ /* Default value */ #define IMX_I2C_BIT_RATE 100000 /* 100kHz */ +/* + * Enable DMA if transfer byte size is bigger than this threshold. + * As the hardware request, it must bigger than 4 bytes.\ + * I have set '16' here, maybe it's not the best but I think it's + * the appropriate. + */ +#define DMA_THRESHOLD 16 +#define DMA_TIMEOUT 1000 + /* IMX I2C registers: * the I2C register offset is different between SoCs, * to provid support for all these chips, split the @@ -83,6 +97,7 @@ #define I2SR_IBB 0x20 #define I2SR_IAAS 0x40 #define I2SR_ICF 0x80 +#define I2CR_DMAEN 0x02 #define I2CR_RSTA 0x04 #define I2CR_TXAK 0x08 #define I2CR_MTX 0x10 @@ -169,6 +184,17 @@ struct imx_i2c_hwdata { unsigned i2cr_ien_opcode; }; +struct imx_i2c_dma { + struct dma_chan *chan_tx; + struct dma_chan *chan_rx; + struct dma_chan *chan_using; + struct completion cmd_complete; + dma_addr_t dma_buf; + unsigned int dma_len; + enum dma_transfer_direction dma_transfer_dir; + enum dma_data_direction dma_data_dir; +}; + struct imx_i2c_struct { struct i2c_adapter adapter; struct clk *clk; @@ -181,6 +207,8 @@ struct imx_i2c_struct { unsigned int cur_clk; unsigned int bitrate; const struct imx_i2c_hwdata *hwdata; + + struct imx_i2c_dma *dma; }; static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -251,6 +279,138 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); } +/* Functions for DMA support */ +static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, + dma_addr_t phy_addr) +{ + struct imx_i2c_dma *dma; + struct dma_slave_config dma_sconfig; + struct device *dev = &i2c_imx->adapter.dev; + int ret; + + dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); + if (!dma) + return; + + dma->chan_tx = dma_request_slave_channel(dev, "tx"); + if (!dma->chan_tx) { + dev_dbg(dev, "can't request DMA tx channel\n"); + ret = -ENODEV; + goto fail_al; + } + + dma_sconfig.dst_addr = phy_addr + + (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); + dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + dma_sconfig.dst_maxburst = 1; + dma_sconfig.direction = DMA_MEM_TO_DEV; + ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig); + if (ret < 0) { + dev_dbg(dev, "can't configure tx channel\n"); + goto fail_tx; + } + + dma->chan_rx = dma_request_slave_channel(dev, "rx"); + if (!dma->chan_rx) { + dev_dbg(dev, "can't request DMA rx channel\n"); + ret = -ENODEV; + goto fail_tx; + } + + dma_sconfig.src_addr = phy_addr + + (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); + dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + dma_sconfig.src_maxburst = 1; + dma_sconfig.direction = DMA_DEV_TO_MEM; + ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig); + if (ret < 0) { + dev_dbg(dev, "can't configure rx channel\n"); + goto fail_rx; + } + + i2c_imx->dma = dma; + init_completion(&dma->cmd_complete); + dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", + dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); + + return; + +fail_rx: + dma_release_channel(dma->chan_rx); +fail_tx: + dma_release_channel(dma->chan_tx); +fail_al: + devm_kfree(dev, dma); + dev_info(dev, "can't use DMA\n"); +} + +static void i2c_imx_dma_callback(void *arg) +{ + struct imx_i2c_struct *i2c_imx = (struct imx_i2c_struct *)arg; + struct imx_i2c_dma *dma = i2c_imx->dma; + + dma_unmap_single(dma->chan_using->device->dev, dma->dma_buf, + dma->dma_len, dma->dma_data_dir); + complete(&dma->cmd_complete); +} + +static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx, + struct i2c_msg *msgs) +{ + struct imx_i2c_dma *dma = i2c_imx->dma; + struct dma_async_tx_descriptor *txdesc; + struct device *dev = &i2c_imx->adapter.dev; + struct device *chan_dev = dma->chan_using->device->dev; + + dma->dma_buf = dma_map_single(chan_dev, msgs->buf, + dma->dma_len, dma->dma_data_dir); + if (dma_mapping_error(chan_dev, dma->dma_buf)) { + dev_err(dev, "DMA mapping failed\n"); + goto err_map; + } + + txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf, + dma->dma_len, dma->dma_transfer_dir, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!txdesc) { + dev_err(dev, "Not able to get desc for DMA xfer\n"); + goto err_desc; + } + + txdesc->callback = i2c_imx_dma_callback; + txdesc->callback_param = i2c_imx; + if (dma_submit_error(dmaengine_submit(txdesc))) { + dev_err(dev, "DMA submit failed\n"); + goto err_submit; + } + + dma_async_issue_pending(dma->chan_using); + return 0; + +err_submit: +err_desc: + dma_unmap_single(chan_dev, dma->dma_buf, + dma->dma_len, dma->dma_data_dir); +err_map: + return -EINVAL; +} + +static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx) +{ + struct imx_i2c_dma *dma = i2c_imx->dma; + + dma->dma_buf = 0; + dma->dma_len = 0; + + dma_release_channel(dma->chan_tx); + dma->chan_tx = NULL; + + dma_release_channel(dma->chan_rx); + dma->chan_rx = NULL; + + dma->chan_using = NULL; +} + /** Functions for IMX I2C adapter driver *************************************** *******************************************************************************/ @@ -382,6 +542,7 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) i2c_imx->stopped = 0; temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; + temp &= ~I2CR_DMAEN; imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); return result; } @@ -395,6 +556,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); temp &= ~(I2CR_MSTA | I2CR_MTX); + if (i2c_imx->dma) + temp &= ~I2CR_DMAEN; imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); } if (is_imx1_i2c(i2c_imx)) { @@ -435,6 +598,155 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id) return IRQ_NONE; } +static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, + struct i2c_msg *msgs) +{ + int result; + unsigned int temp = 0; + unsigned long orig_jiffies = jiffies; + struct imx_i2c_dma *dma = i2c_imx->dma; + struct device *dev = &i2c_imx->adapter.dev; + + dma->chan_using = dma->chan_tx; + dma->dma_transfer_dir = DMA_MEM_TO_DEV; + dma->dma_data_dir = DMA_TO_DEVICE; + dma->dma_len = msgs->len - 1; + result = i2c_imx_dma_xfer(i2c_imx, msgs); + if (result) + return result; + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp |= I2CR_DMAEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* + * Write slave address. + * The first byte must be transmitted by the CPU. + */ + imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); + reinit_completion(&i2c_imx->dma->cmd_complete); + result = wait_for_completion_timeout( + &i2c_imx->dma->cmd_complete, + msecs_to_jiffies(DMA_TIMEOUT)); + if (result <= 0) { + dmaengine_terminate_all(dma->chan_using); + return result ?: -ETIMEDOUT; + } + + /* Waiting for transfer complete. */ + while (1) { + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); + if (temp & I2SR_ICF) + break; + if (time_after(jiffies, orig_jiffies + + msecs_to_jiffies(DMA_TIMEOUT))) { + dev_dbg(dev, "<%s> Timeout\n", __func__); + return -ETIMEDOUT; + } + schedule(); + } + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~I2CR_DMAEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* The last data byte must be transferred by the CPU. */ + imx_i2c_write_reg(msgs->buf[msgs->len-1], + i2c_imx, IMX_I2C_I2DR); + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + + return i2c_imx_acked(i2c_imx); +} + +static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, + struct i2c_msg *msgs, bool is_lastmsg) +{ + int result; + unsigned int temp; + unsigned long orig_jiffies = jiffies; + struct imx_i2c_dma *dma = i2c_imx->dma; + struct device *dev = &i2c_imx->adapter.dev; + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp |= I2CR_DMAEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + dma->chan_using = dma->chan_rx; + dma->dma_transfer_dir = DMA_DEV_TO_MEM; + dma->dma_data_dir = DMA_FROM_DEVICE; + /* The last two data bytes must be transferred by the CPU. */ + dma->dma_len = msgs->len - 2; + result = i2c_imx_dma_xfer(i2c_imx, msgs); + if (result) + return result; + + reinit_completion(&i2c_imx->dma->cmd_complete); + result = wait_for_completion_timeout( + &i2c_imx->dma->cmd_complete, + msecs_to_jiffies(DMA_TIMEOUT)); + if (result <= 0) { + dmaengine_terminate_all(dma->chan_using); + return result ?: -ETIMEDOUT; + } + + /* waiting for transfer complete. */ + while (1) { + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); + if (temp & I2SR_ICF) + break; + if (time_after(jiffies, orig_jiffies + + msecs_to_jiffies(DMA_TIMEOUT))) { + dev_dbg(dev, "<%s> Timeout\n", __func__); + return -ETIMEDOUT; + } + schedule(); + } + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~I2CR_DMAEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* read n-1 byte data */ + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp |= I2CR_TXAK; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + msgs->buf[msgs->len-2] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + /* read n byte data */ + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + + if (is_lastmsg) { + /* + * It must generate STOP before read I2DR to prevent + * controller from generating another clock cycle + */ + dev_dbg(dev, "<%s> clear MSTA\n", __func__); + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~(I2CR_MSTA | I2CR_MTX); + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + i2c_imx_bus_busy(i2c_imx, 0); + i2c_imx->stopped = 1; + } else { + /* + * For i2c master receiver repeat restart operation like: + * read -> repeat MSTA -> read/write + * The controller must set MTX before read the last byte in + * the first read operation, otherwise the first read cost + * one extra clock cycle. + */ + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_MTX; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + } + msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + + return 0; +} + static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) { int i, result; @@ -504,6 +816,9 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bo dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); + if (i2c_imx->dma && msgs->len >= DMA_THRESHOLD && !block_data) + return i2c_imx_dma_read(i2c_imx, msgs, is_lastmsg); + /* read data */ for (i = 0; i < msgs->len; i++) { u8 len = 0; @@ -618,8 +933,12 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, #endif if (msgs[i].flags & I2C_M_RD) result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg); - else - result = i2c_imx_write(i2c_imx, &msgs[i]); + else { + if (i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD) + result = i2c_imx_dma_write(i2c_imx, &msgs[i]); + else + result = i2c_imx_write(i2c_imx, &msgs[i]); + } if (result) goto fail0; } @@ -654,6 +973,7 @@ static int i2c_imx_probe(struct platform_device *pdev) struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev); void __iomem *base; int irq, ret; + dma_addr_t phy_addr; dev_dbg(&pdev->dev, "<%s>\n", __func__); @@ -668,8 +988,8 @@ static int i2c_imx_probe(struct platform_device *pdev) if (IS_ERR(base)) return PTR_ERR(base); - i2c_imx = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_struct), - GFP_KERNEL); + phy_addr = (dma_addr_t)res->start; + i2c_imx = devm_kzalloc(&pdev->dev, sizeof(*i2c_imx), GFP_KERNEL); if (!i2c_imx) return -ENOMEM; @@ -743,6 +1063,9 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_imx->adapter.name); dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); + /* Init DMA config if support*/ + i2c_imx_dma_request(i2c_imx, phy_addr); + return 0; /* Return OK */ clk_disable: @@ -758,6 +1081,9 @@ static int i2c_imx_remove(struct platform_device *pdev) dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); i2c_del_adapter(&i2c_imx->adapter); + if (i2c_imx->dma) + i2c_imx_dma_free(i2c_imx); + /* setup chip registers to defaults */ imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR); imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR); @@ -772,7 +1098,6 @@ static struct platform_driver i2c_imx_driver = { .remove = i2c_imx_remove, .driver = { .name = DRIVER_NAME, - .owner = THIS_MODULE, .of_match_table = i2c_imx_dt_ids, }, .id_table = imx_i2c_devtype, |