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SubjectRe: [PATCH v4 1/2] i2c: add DMA support for freescale i2c driver

>> +
>> + dma->chan_tx = dma_request_slave_channel(dev, "tx");
>> + return 0;

To be more clear,
return here looks to be some leftover.

> ?? Looks to be some leftover?
>> + if (!dma->chan_tx) {
>> + dev_info(dev, "DMA tx channel request failed\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_info(dev, "DMA slave config failed, err = %d\n", ret);
>> + goto fail_tx;
>> + }
>> +
>> + dma->chan_rx = dma_request_slave_channel(dev, "rx");
>> + if (!dma->chan_rx) {
>> + dev_info(dev, "DMA rx channel request failed\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_info(dev, "DMA slave config failed, err = %d\n", ret);
>> + goto fail_rx;
>> + }
>> +
>> + i2c_imx->dma = dma;
>> +
>> + init_completion(&dma->cmd_complete);
>> +
>> + return 0;
>> +
>> +fail_rx:
>> + dma_release_channel(dma->chan_rx);
>> +fail_tx:
>> + dma_release_channel(dma->chan_tx);
>> +fail_al:
>> + devm_kfree(dev, dma);
>> +
>> + return ret;
>> +}
>> +
>> +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;
>> +
>> + dma->dma_buf = dma_map_single(dma->chan_using->device->dev,
>> msgs->buf,
>> + dma->dma_len, dma->dma_data_dir);
>> + if (dma_mapping_error(dma->chan_using->device->dev,
>> dma->dma_buf)) {
>> + dev_err(dev, "DMA mapping failed\n");
>> + return -EINVAL;
>> + }
>> +
>> + 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");
>> + dma_unmap_single(dma->chan_using->device->dev, dma->dma_buf,
>> + dma->dma_len, dma->dma_data_dir);
>> + return -EINVAL;
>> + }
>> +
>> + txdesc->callback = i2c_imx_dma_callback;
>> + txdesc->callback_param = i2c_imx;
>> + dmaengine_submit(txdesc);
>> + dma_async_issue_pending(dma->chan_using);
>> +
>> + return 0;
>> +}
>> +
>> +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
>> ***************************************
>>
>> *******************************************************************************/
>>
>> @@ -334,6 +483,11 @@ static int i2c_imx_start(struct imx_i2c_struct
>> *i2c_imx)
>>
>> temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
>> imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> +
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> + temp&= ~I2CR_DMAEN;
>> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> +
>> return result;
>> }
>>
>> @@ -427,44 +581,101 @@ static irqreturn_t i2c_imx_isr(int irq, void
>> *dev_id)
>>
>> static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct
>> i2c_msg *msgs)
>> {
>> - int i, result;
>> + int i, result, timeout = IMX_I2C_DMA_TIMEOUT;
>> + unsigned int temp = 0;
>> + struct imx_i2c_dma *dma = i2c_imx->dma;
>> + struct device *dev =&i2c_imx->adapter.dev;
>>
>> - dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address:
>> addr=0x%x\n",
>> + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n",
>> __func__, msgs->addr<< 1);
>> + if (dma&& msgs->len>= IMX_I2C_DMA_THRESHOLD) {
>> + reinit_completion(&i2c_imx->dma->cmd_complete);
>> + 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;
>>
>> - /* write slave address */
>> - imx_i2c_write_reg(msgs->addr<< 1, i2c_imx, IMX_I2C_I2DR);
>> - result = i2c_imx_trx_complete(i2c_imx);
>> - if (result)
>> - return result;
>> - result = i2c_imx_acked(i2c_imx);
>> - if (result)
>> - return result;
>> - dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> + temp |= I2CR_DMAEN;
>> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>>
>> - /* write data */
>> - for (i = 0; i< msgs->len; i++) {
>> - dev_dbg(&i2c_imx->adapter.dev,
>> - "<%s> write byte: B%d=0x%X\n",
>> - __func__, i, msgs->buf[i]);
>> - imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR);
>> + /* write slave address */
>> + imx_i2c_write_reg(msgs->addr<< 1, i2c_imx, IMX_I2C_I2DR);
>> + result = wait_for_completion_interruptible_timeout(
>> + &i2c_imx->dma->cmd_complete,
>> + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT));
>> + if (result<= 0) {
>> + dmaengine_terminate_all(dma->chan_using);
>> + if (result)
>> + return result;
>> + else
>> + return -ETIMEDOUT;
>> + }
>> +
>> + /* waiting for Transfer complete. */
>> + while (timeout--) {
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
>> + if (temp& I2SR_ICF)
>> + break;
>> + udelay(10);
>> + }
>> +
>> + if (!timeout)
>> + return -ETIMEDOUT;
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> + temp&= ~I2CR_DMAEN;
>> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> +
>> + /* write the last byte */
>> + 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;
>> +
>> + result = i2c_imx_acked(i2c_imx);
>> + if (result)
>> + return result;
>> + } else {
>> + /* write slave address */
>> + imx_i2c_write_reg(msgs->addr<< 1, i2c_imx, IMX_I2C_I2DR);
>> + result = i2c_imx_trx_complete(i2c_imx);
>> + if (result)
>> + return result;
>> +
>> result = i2c_imx_acked(i2c_imx);
>> if (result)
>> return result;
>> +
>> + dev_dbg(dev, "<%s> write data\n", __func__);
>> +
>> + /* write data */
>> + for (i = 0; i< msgs->len; i++) {
>> + dev_dbg(dev, "<%s> write byte: B%d=0x%X\n",
>> + __func__, i, msgs->buf[i]);
>> + imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR);
>> + result = i2c_imx_trx_complete(i2c_imx);
>> + if (result)
>> + return result;
>> + result = i2c_imx_acked(i2c_imx);
>> + if (result)
>> + return result;
>> + }
>> }
>> return 0;
>> }
>>
>> static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct
>> i2c_msg *msgs)
>> {
>> - int i, result;
>> + int i, result, timeout = IMX_I2C_DMA_TIMEOUT;
>> unsigned int temp;
>> + struct imx_i2c_dma *dma = i2c_imx->dma;
>> + struct device *dev =&i2c_imx->adapter.dev;
>>
>> - dev_dbg(&i2c_imx->adapter.dev,
>> - "<%s> write slave address: addr=0x%x\n",
>> + dev_dbg(dev, "<%s> write slave address: addr=0x%x\n",
>> __func__, (msgs->addr<< 1) | 0x01);
>>
>> /* write slave address */
>> @@ -476,7 +687,7 @@ static int i2c_imx_read(struct imx_i2c_struct
>> *i2c_imx, struct i2c_msg *msgs)
>> if (result)
>> return result;
>>
>> - dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
>> + dev_dbg(dev, "<%s> setup bus\n", __func__);
>>
>> /* setup bus to read data */
>> temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> @@ -486,35 +697,81 @@ static int i2c_imx_read(struct imx_i2c_struct
>> *i2c_imx, struct i2c_msg *msgs)
>> imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */
>>
>> - dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
>> + dev_dbg(dev, "<%s> read data\n", __func__);
>>
>> - /* read data */
>> - for (i = 0; i< msgs->len; i++) {
>> - result = i2c_imx_trx_complete(i2c_imx);
>> + if (dma&& msgs->len>= IMX_I2C_DMA_THRESHOLD) {
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> + temp |= I2CR_DMAEN;
>> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> +
>> + reinit_completion(&i2c_imx->dma->cmd_complete);
>> + dma->chan_using = dma->chan_rx;
>> + dma->dma_transfer_dir = DMA_DEV_TO_MEM;
>> + dma->dma_data_dir = DMA_FROM_DEVICE;
>> + dma->dma_len = msgs->len - 2;
>> + result = i2c_imx_dma_xfer(i2c_imx, msgs);
>> if (result)
>> return result;
>> - if (i == (msgs->len - 1)) {
>> - /* It must generate STOP before read I2DR to prevent
>> - controller from generating another clock cycle */
>> - dev_dbg(&i2c_imx->adapter.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 if (i == (msgs->len - 2)) {
>> - dev_dbg(&i2c_imx->adapter.dev,
>> - "<%s> set TXAK\n", __func__);
>> - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> - temp |= I2CR_TXAK;
>> - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> +
>> + result = wait_for_completion_interruptible_timeout(
>> + &i2c_imx->dma->cmd_complete,
>> + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT));
>> + if (result<= 0) {
>> + dmaengine_terminate_all(dma->chan_using);
>> + if (result)
>> + return result;
>> + else
>> + return -ETIMEDOUT;
>> }
>> - msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
>> - dev_dbg(&i2c_imx->adapter.dev,
>> - "<%s> read byte: B%d=0x%X\n",
>> - __func__, i, msgs->buf[i]);
>> +
>> + /* waiting for Transfer complete. */
>> + while (timeout--) {
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
>> + if (temp& I2SR_ICF)
>> + break;
>> + udelay(10);
>> + }
>> +
>> + if(!timeout)
>> + return -ETIMEDOUT;
>> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>> + temp&= ~I2CR_DMAEN;
>> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>> + } else {
>> + /* read data */
>> + for (i = 0; i< msgs->len - 2; i++) {
>> + result = i2c_imx_trx_complete(i2c_imx);
>> + if (result)
>> + return result;
>> + msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
>> + dev_dbg(dev, "<%s> read byte: B%d=0x%X\n",
>> + __func__, i, msgs->buf[i]);
>> + }
>> + result = i2c_imx_trx_complete(i2c_imx);
>> }
>> +
>> + /* 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;
>> +
>> + /*
>> + * It must generate STOP before read I2DR to prevent
>> + * controller from generating another clock cycle
>> + */
>> + 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;
>> + msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
>> +
>> return 0;
>> }
>>
>> @@ -601,6 +858,7 @@ static int i2c_imx_probe(struct platform_device
>> *pdev)
>> void __iomem *base;
>> int irq, ret;
>> u32 bitrate;
>> + u32 phy_addr;
>>
>> dev_dbg(&pdev->dev, "<%s>\n", __func__);
>>
>> @@ -611,6 +869,7 @@ static int i2c_imx_probe(struct platform_device
>> *pdev)
>> }
>>
>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + phy_addr = res->start;
>> base = devm_ioremap_resource(&pdev->dev, res);
>> if (IS_ERR(base))
>> return PTR_ERR(base);
>> @@ -696,6 +955,10 @@ 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*/
>> + if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr))
>> + dev_warn(&pdev->dev, "can't request DMA\n");
>> +
>> return 0; /* Return OK */
>> }
>>
>> @@ -707,6 +970,9 @@ 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);
>
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