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Date: Wed, 25 Mar 2015 15:10:56 +0200
From: "Ivan T. Ivanov" <iivanov@...sol.com>
To: Sricharan R <sricharan@...eaurora.org>
Cc: devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, dmaengine@...r.kernel.org,
galak@...eaurora.org, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org, agross@...eaurora.org
Subject: Re: [PATCH 3/6] i2c: qup: Add bam dma capabilities
Hi Sricharan,
On Fri, 2015-03-13 at 23:19 +0530, Sricharan R wrote:
> #define QUP_I2C_MASTER_GEN 0x408
> +#define QUP_I2C_MASTER_CONFIG 0x408
>
Unused.
> #define QUP_READ_LIMIT 256
> +#define MX_TX_RX_LEN SZ_64K
> +#define MX_BLOCKS (MX_TX_RX_LEN / QUP_READ_LIMIT)
> +
> +#define TOUT_MAX 300 /* Max timeout for 32k tx/tx */
>
seconds, muliseconds?
> struct qup_i2c_config {
> int tag_ver;
> int max_freq;
> };
>
> +struct tag {
Please use consistent naming convention.
> + u8 *start;
> + dma_addr_t addr;
> +};
> +
> struct qup_i2c_dev {
> struct device*dev;
> void __iomem*base;
> @@ -157,9 +181,35 @@ struct qup_i2c_dev {
> /* QUP core errors */
> u32 qup_err;
>
> + /* dma parameters */
> + bool is_dma;
> + struct dma_pool *dpool;
> + struct tag start_tag;
> + struct tag scratch_tag;
> + struct tag footer_tag;
> + struct dma_chan *dma_tx;
> + struct dma_chan *dma_rx;
> + struct scatterlist *sg_tx;
> + struct scatterlist *sg_rx;
> + dma_addr_tsg_tx_phys;
> + dma_addr_tsg_rx_phys;
Maybe these could be organized in structure per direction.
> +
> struct completionxfer;
> };
>
> +struct i2c_bam_xfer {
Unused.
> + struct qup_i2c_dev *qup;
> + u32 start_len;
> +
> + u32 rx_nents;
> + u32 tx_nents;
> +
> + struct dma_async_tx_descriptor *tx_desc;
> + dma_cookie_t tx_cookie;
> + struct dma_async_tx_descriptor *rx_desc;
> + dma_cookie_t rx_cookie;
structure per direction.
> +};
> +
>
> +static void bam_i2c_callback(void *data)
> +{
Please use consistent naming, here and bellow.
> + struct qup_i2c_dev *qup = data;
> +
> + complete(&qup->xfer);
> +}
> +
> +static int get_start_tag(u8 *tag, struct i2c_msg *msg, int first, int last,
> + int blen)
> +{
> + u8 addr = (msg->addr << 1) | ((msg->flags & I2C_M_RD) == I2C_M_RD);
> + u8 op;
> + int len = 0;
> +
> + /* always issue stop for each read block */
> + if (last) {
> + if (msg->flags & I2C_M_RD)
> + op = QUP_TAG_V2_DATARD_STOP;
> + else
> + op = QUP_TAG_V2_DATAWR_STOP;
> + } else {
> + if (msg->flags & I2C_M_RD)
> + op = QUP_TAG_V2_DATARD;
> + else
> + op = QUP_TAG_V2_DATAWR;
> + }
> +
> + if (msg->flags & I2C_M_TEN) {
> + len += 5;
> + tag[0] = QUP_TAG_V2_START;
> + tag[1] = addr;
> + tag[2] = op;
> + tag[3] = blen;
> +
> + if (msg->flags & I2C_M_RD && last) {
> + len += 2;
> + tag[4] = QUP_BAM_INPUT_EOT;
> + tag[5] = QUP_BAM_FLUSH_STOP;
> + }
> + } else {
> + if (first) {
> + tag[len++] = QUP_TAG_V2_START;
> + tag[len++] = addr;
> + }
> +
> + tag[len++] = op;
> + tag[len++] = blen;
> +
> + if (msg->flags & I2C_M_RD & last) {
> + tag[len++] = QUP_BAM_INPUT_EOT;
> + tag[len++] = QUP_BAM_FLUSH_STOP;
> + }
> + }
> +
> + return len;
> +}
Maybe could be split to 2 functions?
> -static const struct i2c_algorithm qup_i2c_algo = {
> +static struct i2c_algorithm qup_i2c_algo = {
Why?
> .master_xfer= qup_i2c_xfer,
> .functionality= qup_i2c_func,
> };
> @@ -839,6 +1136,7 @@ static int qup_i2c_probe(struct platform_device *pdev)
> u32 clk_freq = 100000;
> const struct qup_i2c_config *config;
> const struct of_device_id *of_id;
> + int blocks;
>
> qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
> if (!qup)
> @@ -875,6 +1173,53 @@ static int qup_i2c_probe(struct platform_device *pdev)
> return qup->irq;
> }
>
> + if (of_device_is_compatible(pdev->dev.of_node, "qcom,i2c-qup-v2.1.1") ||
> + of_device_is_compatible(pdev->dev.of_node,
> + "qcom,i2c-qup-v2.2.1")) {
Logic will be simpler if you check just for version 1 of the controller.
> + qup->dma_rx = dma_request_slave_channel(&pdev->dev, "bam-rx");
> +
Please use dma_request_slave_channel_reason.
As Andy noted, please use just "rx", "tx"
> + if (!qup->dma_rx)
> + return -EPROBE_DEFER;
Don't mask other errors, here and bellow. DMA support should be optional.
> dev_err(qup->dev, "Could not get core clock\n");
> @@ -989,6 +1334,14 @@ static int qup_i2c_remove(struct platform_device *pdev)
> {
> struct qup_i2c_dev *qup = platform_get_drvdata(pdev);
>
> + dma_pool_free(qup->dpool, qup->start_tag.start,
> + qup->start_tag.addr);
> + dma_pool_free(qup->dpool, qup->scratch_tag.start,
> + qup->scratch_tag.addr);
> + dma_pool_free(qup->dpool, qup->footer_tag.start,
> + qup->footer_tag.addr);
> + dma_pool_destroy(qup->dpool);
Only if is_dma, right?
DMA mapping code omitted from review. I don't understand it well enough, sorry.
Regards,
Ivan
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