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SubjectRe: [PATCH V3 2/6] i2c: qup: Add V2 tags support
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Hi Sricharan,

On Sat, 2015-04-11 at 12:39 +0530, Sricharan R wrote:
> From: Andy Gross <agross@codeaurora.org>
>
> QUP from version 2.1.1 onwards, supports a new format of
> i2c command tags. Tag codes instructs the controller to
> perform a operation like read/write. This new tagging version
> supports bam dma and transfers of more than 256 bytes without 'stop'
> in between. Adding the support for the same.
>

But the read and write messages size QUP_READ_LIMIT?

> For each block a data_write/read tag and data_len tag is added to
> the output fifo. For the final block of data write_stop/read_stop
> tag is used.
>
> Signed-off-by: Andy Gross <agross@codeaurora.org>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> ---
> [V3] Addressed comments from Andy Gross <agross@codeaurora.org>
> to coalesce each i2c_msg in i2c_msgs as a single transfer.
> Added macros to i2c_wait_ready function.
>
> drivers/i2c/busses/i2c-qup.c | 393 +++++++++++++++++++++++++++++++++++++------
> 1 file changed, 337 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> index 9ccf3e8..16a8f69 100644
> --- a/drivers/i2c/busses/i2c-qup.c
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -24,6 +24,7 @@
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/slab.h>
>
> /* QUP Registers */
> #define QUP_CONFIG 0x000
> @@ -42,6 +43,7 @@
> #define QUP_IN_FIFO_BASE 0x218
> #define QUP_I2C_CLK_CTL 0x400
> #define QUP_I2C_STATUS 0x404
> +#define QUP_I2C_MASTER_GEN 0x408
>
> /* QUP States and reset values */
> #define QUP_RESET_STATE 0
> @@ -69,6 +71,8 @@
> #define QUP_CLOCK_AUTO_GATE BIT(13)
> #define I2C_MINI_CORE (2 << 8)
> #define I2C_N_VAL 15
> +#define I2C_N_VAL_V2 7
> +
> /* Most significant word offset in FIFO port */
> #define QUP_MSW_SHIFT (I2C_N_VAL + 1)
>
> @@ -80,17 +84,30 @@
>
> #define QUP_REPACK_EN (QUP_UNPACK_EN | QUP_PACK_EN)
>
> +#define QUP_V2_TAGS_EN 1
> +
> #define QUP_OUTPUT_BLOCK_SIZE(x)(((x) >> 0) & 0x03)
> #define QUP_OUTPUT_FIFO_SIZE(x) (((x) >> 2) & 0x07)
> #define QUP_INPUT_BLOCK_SIZE(x) (((x) >> 5) & 0x03)
> #define QUP_INPUT_FIFO_SIZE(x) (((x) >> 7) & 0x07)
>
> -/* QUP tags */
> +/* QUP V1 tags */
> #define QUP_TAG_START (1 << 8)
> #define QUP_TAG_DATA (2 << 8)
> #define QUP_TAG_STOP (3 << 8)
> #define QUP_TAG_REC (4 << 8)
>
> +/* QUP v2 tags */
> +#define QUP_TAG_V2_HS 0xff
> +#define QUP_TAG_V2_START 0x81
> +#define QUP_TAG_V2_DATAWR 0x82
> +#define QUP_TAG_V2_DATAWR_STOP 0x83
> +#define QUP_TAG_V2_DATARD 0x85
> +#define QUP_TAG_V2_DATARD_STOP 0x87
> +
> +/* frequency definitions for high speed and max speed */
> +#define I2C_QUP_CLK_FAST_FREQ 1000000

This is fast mode, if I am not mistaken.

> +
> /* Status, Error flags */
> #define I2C_STATUS_WR_BUFFER_FULL BIT(0)
> #define I2C_STATUS_BUS_ACTIVE BIT(8)
> @@ -102,6 +119,15 @@
> #define RESET_BIT 0x0
> #define ONE_BYTE 0x1
>
> +#define QUP_I2C_MX_CONFIG_DURING_RUN BIT(31)

Could you explain what is this for?

> +
> +struct qup_i2c_block {
> + int blocks;
> + u8 *block_tag_len;
> + int *block_data_len;
> + int block_pos;
> +};
> +
> struct qup_i2c_dev {
> struct device*dev;
> void __iomem*base;
> @@ -115,9 +141,17 @@ struct qup_i2c_dev {
> int in_fifo_sz;
> int out_blk_sz;
> int in_blk_sz;
> -
> + struct qup_i2c_blockblk;
> unsigned longone_byte_t;
>
> + int is_hs;
> + bool use_v2_tags;
> +
> + int tx_tag_len;
> + int rx_tag_len;
> + u8 *tags;
> + int tags_pos;
> +
> struct i2c_msg*msg;
> /* Current posion in user message buffer */
> int pos;
> @@ -263,10 +297,19 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
> }
> }

Is this better tag related fields grouping?

struct qup_i2c_tag_block {

u8 tag[2];
// int tag_len; this is alway 2, or?
int data_len; // this could be zero, right?
};

>
> -static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg,
> + int run)

And 'run' stands for?

> {
> - /* Number of entries to shift out, including the start */
> - int total = msg->len + 1;
> + /* Total Number of entries to shift out, including the tags */
> + int total;
> +
> + if (qup->use_v2_tags) {
> + total = msg->len + qup->tx_tag_len;
> + if (run)
> + total |= QUP_I2C_MX_CONFIG_DURING_RUN;

What?

> + } else {
> + total = msg->len + 1; /* plus start tag */
> + }
>
> if (total < qup->out_fifo_sz) {
> /* FIFO mode */
> @@ -280,7 +323,7 @@ static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg
> *msg)
> }
> }
>
> -static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_issue_write_v1(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> {
> u32 addr = msg->addr << 1;
> u32 qup_tag;
> @@ -321,7 +364,136 @@ static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg
> *msg)
> }
> }
>
> -static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_create_tag_v2(struct qup_i2c_dev *qup,
> + struct i2c_msg *msg, int last)
> +{
> + u16 addr = (msg->addr << 1) | ((msg->flags & I2C_M_RD) == I2C_M_RD);
> + int len = 0, prev_len = 0;
> + int blocks = 0;
> + int rem;
> + int block_len = 0;
> + int data_len;
> +
> + qup->blk.block_pos = 0;
> + qup->pos = 0;
> + qup->blk.blocks = (msg->len + QUP_READ_LIMIT - 1) / QUP_READ_LIMIT;
> + rem = msg->len % QUP_READ_LIMIT;
> +
> + /* 2 tag bytes for each block + 2 extra bytes for first block */
> + qup->tags = kzalloc((qup->blk.blocks * 2) + 2, GFP_KERNEL);
> + qup->blk.block_tag_len = kzalloc(qup->blk.blocks, GFP_KERNEL);
> + qup->blk.block_data_len = kzalloc(sizeof(*qup->blk.block_data_len) *
> + qup->blk.blocks, GFP_KERNEL);

Whouldn't be easy to kcalloc struct qup_i2c_tag_block?


Allocations could fail and memory is leaking here.

> +
> + while (blocks < qup->blk.blocks) {
> + /* 0 is used to specify a READ_LIMIT of 256 bytes */
> + data_len = (blocks < (qup->blk.blocks - 1)) ? 0 : rem;
> +
> + /* Send START and ADDR bytes only for the first block */
> + if (!blocks) {
> + qup->tags[len++] = QUP_TAG_V2_START;
> +
> + if (qup->is_hs) {
> + qup->tags[len++] = QUP_TAG_V2_HS;
> + qup->tags[len++] = QUP_TAG_V2_START;
> + }
> +
> + qup->tags[len++] = addr & 0xff;
> + if (msg->flags & I2C_M_TEN)
> + qup->tags[len++] = addr >> 8;

I have counted 5 bytes for first block?

> + }
> +
> + /* Send _STOP commands for the last block */
> + if ((blocks == (qup->blk.blocks - 1)) && last) {
> + if (msg->flags & I2C_M_RD)
> + qup->tags[len++] = QUP_TAG_V2_DATARD_STOP;
> + else
> + qup->tags[len++] = QUP_TAG_V2_DATAWR_STOP;
> + } else {
> + if (msg->flags & I2C_M_RD)
> + qup->tags[len++] = QUP_TAG_V2_DATARD;
> + else
> + qup->tags[len++] = QUP_TAG_V2_DATAWR;
> + }
> +
> + qup->tags[len++] = data_len;
> + block_len = len - prev_len;
> + prev_len = len;
> + qup->blk.block_tag_len[blocks] = block_len;
> +
> + if (!data_len)
> + qup->blk.block_data_len[blocks] = QUP_READ_LIMIT;
> + else
> + qup->blk.block_data_len[blocks] = data_len;
> +
> + qup->tags_pos = 0;

Every time?
> + blocks++;

Looks like 'for' cycle to me.

> + }
> +
> + qup->tx_tag_len = len;
> +
> + if (msg->flags & I2C_M_RD)
> + qup->rx_tag_len = (qup->blk.blocks * 2);
> + else
> + qup->rx_tag_len = 0;
> +}
> +
> +static u32 qup_i2c_send_data(struct qup_i2c_dev *qup, int tlen, u8 *tbuf,
> + int dlen, u8 *dbuf)
> +{
> + u32 val = 0, idx = 0, pos = 0, i = 0, t;
> + int len = tlen + dlen;
> + u8 *buf = tbuf;
> +
> + while (len > 0) {
> + if (qup_i2c_wait_ready(qup, QUP_OUT_FULL, 0, 4)) {
> + dev_err(qup->dev, "timeout for fifo out full");
> + break;

Error not propagated?

> + }
> +
> + t = (len >= 4) ? 4 : len;
> +
> + while (idx < t) {
> + if (!i && (pos >= tlen)) {
> + buf = dbuf;
> + pos = 0;
> + i = 1;
> + }
> + val |= buf[pos++] << (idx++ * 8);
> + }
> +
> + writel(val, qup->base + QUP_OUT_FIFO_BASE);
> + idx = 0;
> + val = 0;
> + len -= 4;
> + }
> +
> + return 0;
> +}
> +
> +static void qup_i2c_issue_xfer_v2(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +{
> + u32 data_len = 0, tag_len;
> +
> + tag_len = qup->blk.block_tag_len[qup->blk.block_pos];
> +
> + if (!(msg->flags & I2C_M_RD))
> + data_len = qup->blk.block_data_len[qup->blk.block_pos];
> +
> + qup_i2c_send_data(qup, tag_len, qup->tags, data_len, msg->buf);

This assumes that writes are up to 256 bytes, and tags and data blocks
are completely written to FIFO buffer, right?

> +}
> +
> +static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg
> + *msg)
> +{
> + if (qup->use_v2_tags)
> + qup_i2c_issue_xfer_v2(qup, msg);
> + else
> + qup_i2c_issue_write_v1(qup, msg);
> +}
> +
> +static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg,
> + int run, int last)
> {
> unsigned long left;
> int ret;
> @@ -329,13 +501,20 @@ static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> qup->msg = msg;
> qup->pos = 0;
>
> + if (qup->use_v2_tags)
> + qup_i2c_create_tag_v2(qup, msg, last);
> + else
> + qup->blk.blocks = 0;
> +
> enable_irq(qup->irq);
>
> - qup_i2c_set_write_mode(qup, msg);
> + qup_i2c_set_write_mode(qup, msg, run);
>
> - ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> - if (ret)
> - goto err;
> + if (!run) {
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);

To run away, or not?

> + if (ret)
> + goto err;
> + }
>
> writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);
>
> @@ -363,10 +542,13 @@ static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> ret = -EIO;
> goto err;
> }
> - } while (qup->pos < msg->len);
> + qup->blk.block_pos++;
> + } while (qup->blk.block_pos < qup->blk.blocks);
>
> /* Wait for the outstanding data in the fifo to drain */
> - ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY, RESET_BIT, ONE_BYTE);
> + if (last)
> + ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY, RESET_BIT,
> + ONE_BYTE);
>
> err:
> disable_irq(qup->irq);
> @@ -375,8 +557,17 @@ err:
> return ret;
> }
>
> -static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup, int len)
> +static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup, int len, int run)
> {
> + if (qup->use_v2_tags) {
> + len += qup->rx_tag_len;
> + if (run) {
> + len |= QUP_I2C_MX_CONFIG_DURING_RUN;

Again? It looks like some kind of magic, to trick the controller
that there are more bytes to transfer, or?

> + qup->tx_tag_len |= QUP_I2C_MX_CONFIG_DURING_RUN;
> + }
> + writel(qup->tx_tag_len, qup->base + QUP_MX_WRITE_CNT);
> + }
> +
> if (len < qup->in_fifo_sz) {
> /* FIFO mode */
> writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
> @@ -389,7 +580,8 @@ static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup, int len)
> }
> }
>
> -static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_issue_read_v1(struct qup_i2c_dev *qup,
> + struct i2c_msg *msg)
> {
> u32 addr, len, val;
>
> @@ -402,20 +594,28 @@ static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> writel(val, qup->base + QUP_OUT_FIFO_BASE);
> }
>
> +static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg
> + *msg)
> +{
> + if (qup->use_v2_tags)
> + qup_i2c_issue_xfer_v2(qup, msg);
> + else
> + qup_i2c_issue_read_v1(qup, msg);
> +}
>
> -static void qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_read_fifo_v1(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> {
> - u32 opflags;
> u32 val = 0;
> int idx;
> + int len = msg->len + qup->rx_tag_len;

Is this intentional?

>
> - for (idx = 0; qup->pos < msg->len; idx++) {
> + for (idx = 0; qup->pos < len; idx++) {
> if ((idx & 1) == 0) {
> /* Check that FIFO have data */
> - opflags = readl(qup->base + QUP_OPERATIONAL);
> - if (!(opflags & QUP_IN_NOT_EMPTY))
> + if (qup_i2c_wait_ready(qup, QUP_IN_NOT_EMPTY, 1, 4)) {

This should be part of the first patch.

> + dev_err(qup->dev, "timeout for fifo not empty");
> break;
> -
> + }
> /* Reading 2 words at time */
> val = readl(qup->base + QUP_IN_FIFO_BASE);
>
> @@ -426,11 +626,50 @@ static void qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> }
> }
>
> -static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +static void qup_i2c_read_fifo_v2(struct qup_i2c_dev *qup,
> + struct i2c_msg *msg)
> +{
> + u32 val;
> + int idx;
> + int pos = 0;
> + /* 2 extra bytes for read tags */
> + int total = qup->blk.block_data_len[qup->blk.block_pos] + 2;
> +
> + while (pos < total) {
> + /* Check that FIFO have data */
> + if (qup_i2c_wait_ready(qup, QUP_IN_NOT_EMPTY, 1, 4)) {
> + dev_err(qup->dev, "timeout for fifo not empty");
> + break;

Error not propagated.

> + }
> + val = readl(qup->base + QUP_IN_FIFO_BASE);
> +
> + for (idx = 0; idx < 4; idx++, val >>= 8, pos++) {
> + /* first 2 bytes are tag bytes */
> + if (pos < 2)
> + continue;
> +
> + if (pos >= total)
> + return;
> +
> + msg->buf[qup->pos++] = val & 0xff;
> + }
> + }
> +}
> +
> +static void qup_i2c_read_fifo(struct qup_i2c_dev *qup,
> + struct i2c_msg *msg)
> +{
> + if (qup->use_v2_tags)
> + qup_i2c_read_fifo_v2(qup, msg);
> + else
> + qup_i2c_read_fifo_v1(qup, msg);
> +}
> +
> +static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg,
> + int run, int last)
> {
> unsigned long left;
> int ret;
> -
> /*
> * The QUP block will issue a NACK and STOP on the bus when reaching
> * the end of the read, the length of the read is specified as one byte
> @@ -444,28 +683,34 @@ static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
>
> qup->msg = msg;
> qup->pos = 0;
> + if (qup->use_v2_tags)
> + qup_i2c_create_tag_v2(qup, msg, last);
> + else
> + qup->blk.blocks = 0;
>
> enable_irq(qup->irq);
>
> - qup_i2c_set_read_mode(qup, msg->len);
> + qup_i2c_set_read_mode(qup, msg->len, run);
>
> - ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> - if (ret)
> - goto err;
> + if (!run) {
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);

If !run, place controller in RUN state?

> + if (ret)
> + goto err;
> + }
>
> writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);
>
> - ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
> - if (ret)
> - goto err;
> + do {
> + ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
> + if (ret)
> + goto err;
>
> - qup_i2c_issue_read(qup, msg);
> + qup_i2c_issue_read(qup, msg);
>
> - ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> - if (ret)
> - goto err;
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> + if (ret)
> + goto err;
>
> - do {
> left = wait_for_completion_timeout(&qup->xfer, HZ);
> if (!left) {
> writel(1, qup->base + QUP_SW_RESET);
> @@ -481,7 +726,8 @@ static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> }
>
> qup_i2c_read_fifo(qup, msg);
> - } while (qup->pos < msg->len);
> + qup->blk.block_pos++;

This should not be incremented, unless we really have read this block.

> + } while (qup->blk.block_pos < qup->blk.blocks);
>
> err:
> disable_irq(qup->irq);
> @@ -495,7 +741,7 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
> int num)
> {
> struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
> - int ret, idx;
> + int ret, idx, last;
>
> ret = pm_runtime_get_sync(qup->dev);
> if (ret < 0)
> @@ -507,7 +753,12 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
> goto out;
>
> /* Configure QUP as I2C mini core */
> - writel(I2C_MINI_CORE | I2C_N_VAL, qup->base + QUP_CONFIG);
> + if (qup->use_v2_tags) {
> + writel(I2C_MINI_CORE | I2C_N_VAL_V2, qup->base + QUP_CONFIG);
> + writel(QUP_V2_TAGS_EN, qup->base + QUP_I2C_MASTER_GEN);
> + } else {
> + writel(I2C_MINI_CORE | I2C_N_VAL, qup->base + QUP_CONFIG);
> + }
>
> for (idx = 0; idx < num; idx++) {
> if (msgs[idx].len == 0) {
> @@ -520,23 +771,32 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
> goto out;
> }
>
> + reinit_completion(&qup->xfer);
> +
> + last = (idx == (num - 1));
> +
> if (msgs[idx].flags & I2C_M_RD)
> - ret = qup_i2c_read_one(qup, &msgs[idx]);
> + ret = qup_i2c_read_one(qup, &msgs[idx], idx, last);
> else
> - ret = qup_i2c_write_one(qup, &msgs[idx]);
> + ret = qup_i2c_write_one(qup, &msgs[idx], idx, last);
>
> if (ret)
> break;
> + }
>
> + if (!ret)
> ret = qup_i2c_change_state(qup, QUP_RESET_STATE);
> - if (ret)
> - break;
> - }
>
> if (ret == 0)
> ret = num;
> out:
>
> + if (qup->use_v2_tags) {
> + kfree(qup->tags);
> + kfree(qup->blk.block_tag_len);
> + kfree(qup->blk.block_data_len);
> + }
> +
> pm_runtime_mark_last_busy(qup->dev);
> pm_runtime_put_autosuspend(qup->dev);
>
> @@ -559,6 +819,14 @@ static void qup_i2c_enable_clocks(struct qup_i2c_dev *qup)
> clk_prepare_enable(qup->pclk);
> }
>
> +static const struct of_device_id qup_i2c_dt_match[] = {
> + { .compatible = "qcom,i2c-qup-v1.1.1"},
> + { .compatible = "qcom,i2c-qup-v2.1.1"},
> + { .compatible = "qcom,i2c-qup-v2.2.1"},

Space before closing brace, please.

I am starting to think that it will be more readable
if we just define qup_i2c_algo_v2 and use it, if
controller is v2 and upwards?

Ivan



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