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Date: Tue, 05 Aug 2014 17:18:40 +0530
From: Varka Bhadram <varkabhadram@...il.com>
To: Yuan Yao <yao.yuan@...escale.com>, wsa@...-dreams.de, marex@...x.de
CC: LW@...O-electronics.de, mark.rutland@....com, shawn.guo@...aro.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-i2c@...r.kernel.org
Subject: Re: [PATCH v6 1/2] i2c: imx: add DMA support for freescale i2c driver
On 08/05/2014 03:26 PM, Yuan Yao wrote:
(...)
> +/* Functions for DMA support */
> +static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
> + dma_addr_t phy_addr)
should match open parenthesis...
static int 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(struct imx_i2c_dma), GFP_KERNEL);
sizeof(*dma) ....?
> + if (!dma)
> + return -ENOMEM;
> +
> + 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 0;
> +
> +fail_rx:
> + dma_release_channel(dma->chan_rx);
> +fail_tx:
> + dma_release_channel(dma->chan_tx);
> +fail_al:
> + devm_kfree(dev, dma);
no need to use devm_kfree() if we use devm_kzalloc()...
> + dev_info(dev, "can't use DMA\n");
> +
> + 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)
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);
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");
> + 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);
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(chan_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 ***************************************
> *******************************************************************************/
>
> @@ -379,6 +530,7 @@ 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;
> }
> @@ -432,6 +584,160 @@ 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)
static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
struct i2c_msg *msgs)
run checkpatch.pl on this patch...
--
Regards,
Varka Bhadram.
--
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