[PATCH V2 2/6] i2c: qup: Add V2 tags support

From: Sricharan R
Date: Mon Apr 06 2015 - 14:32:26 EST

From: Andy Gross <agross@xxxxxxxxxxxxxx>

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.

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@xxxxxxxxxxxxxx>
Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
---
[v2] Addressed comments from Ivan T. Ivanov <iivanov@xxxxxxxxxx>

drivers/i2c/busses/i2c-qup.c | 336 ++++++++++++++++++++++++++++++++++++++-----
1 file changed, 299 insertions(+), 37 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 49c6cba..8605557 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
+
/* Status, Error flags */
#define I2C_STATUS_WR_BUFFER_FULL BIT(0)
#define I2C_STATUS_BUS_ACTIVE BIT(8)
@@ -99,6 +116,13 @@

#define QUP_READ_LIMIT 256

+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;
@@ -112,9 +136,17 @@ struct qup_i2c_dev {
int in_fifo_sz;
int out_blk_sz;
int in_blk_sz;
-
+ struct qup_i2c_block blk;
unsigned long one_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;
@@ -262,8 +294,13 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,

static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
- /* 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;
+ else
+ total = msg->len + 1; /* plus start tag */

if (total < qup->out_fifo_sz) {
/* FIFO mode */
@@ -277,7 +314,7 @@ 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;
@@ -318,6 +355,134 @@ static void qup_i2c_issue_write(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)
+{
+ 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);
+
+ 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;
+ }
+
+ /* Send _STOP commands for the last block */
+ if (blocks == (qup->blk.blocks - 1)) {
+ 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;
+ blocks++;
+ }
+
+ 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;
+ }
+
+ 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);
+}
+
+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)
{
unsigned long left;
@@ -326,6 +491,11 @@ 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);
+ else
+ qup->blk.blocks = 0;
+
enable_irq(qup->irq);

qup_i2c_set_write_mode(qup, msg);
@@ -360,7 +530,8 @@ 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, 0, 1);
@@ -374,6 +545,11 @@ err:

static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup, int len)
{
+ if (qup->use_v2_tags) {
+ len += qup->rx_tag_len;
+ 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);
@@ -386,7 +562,8 @@ 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;

@@ -399,20 +576,28 @@ 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;

- 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)) {
+ dev_err(qup->dev, "timeout for fifo not empty");
break;
-
+ }
/* Reading 2 words at time */
val = readl(qup->base + QUP_IN_FIFO_BASE);

@@ -423,11 +608,49 @@ static void qup_i2c_read_fifo(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;
+ }
+ 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)
{
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
@@ -441,6 +664,10 @@ 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);
+ else
+ qup->blk.blocks = 0;

enable_irq(qup->irq);

@@ -452,17 +679,17 @@ static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)

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);
@@ -478,7 +705,8 @@ 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++;
+ } while (qup->blk.block_pos < qup->blk.blocks);

err:
disable_irq(qup->irq);
@@ -504,7 +732,12 @@ 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) {
@@ -517,6 +750,8 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
goto out;
}

+ reinit_completion(&qup->xfer);
+
if (msgs[idx].flags & I2C_M_RD)
ret = qup_i2c_read_one(qup, &msgs[idx]);
else
@@ -534,6 +769,12 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
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);

@@ -556,6 +797,14 @@ 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"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);
+
static void qup_i2c_disable_clocks(struct qup_i2c_dev *qup)
{
u32 config;
@@ -577,8 +826,9 @@ static int qup_i2c_probe(struct platform_device *pdev)
struct resource *res;
u32 io_mode, hw_ver, size;
int ret, fs_div, hs_div;
- int src_clk_freq;
+ int src_clk_freq, clk_freq_max;
u32 clk_freq = 100000;
+ const struct of_device_id *of_id;

qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
if (!qup)
@@ -590,8 +840,19 @@ static int qup_i2c_probe(struct platform_device *pdev)

of_property_read_u32(node, "clock-frequency", &clk_freq);

- /* We support frequencies up to FAST Mode (400KHz) */
- if (!clk_freq || clk_freq > 400000) {
+ of_id = of_match_node(qup_i2c_dt_match, node);
+
+ if (of_device_is_compatible(pdev->dev.of_node,
+ "qcom,i2c-qup-v1.1.1")) {
+ qup->use_v2_tags = 0;
+ clk_freq_max = 400000;
+ } else {
+ qup->use_v2_tags = 1;
+ clk_freq_max = 3400000;
+ }
+
+ /* We support frequencies up to HIGH SPEED Mode (3400KHz) */
+ if (!clk_freq || clk_freq > clk_freq_max) {
dev_err(qup->dev, "clock frequency not supported %d\n",
clk_freq);
return -EINVAL;
@@ -669,8 +930,17 @@ static int qup_i2c_probe(struct platform_device *pdev)
qup->in_fifo_sz = qup->in_blk_sz * (2 << size);

src_clk_freq = clk_get_rate(qup->clk);
- fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
- hs_div = 3;
+ if (clk_freq > I2C_QUP_CLK_FAST_FREQ) {
+ fs_div = I2C_QUP_CLK_FAST_FREQ;
+ hs_div = (src_clk_freq / clk_freq) / 3;
+
+ qup->is_hs = 1;
+ } else {
+ fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
+ hs_div = 3;
+ }
+
+ hs_div = min_t(int, hs_div, 0x7);
qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff);

/*
@@ -767,14 +1037,6 @@ static const struct dev_pm_ops qup_i2c_qup_pm_ops = {
NULL)
};

-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" },
- {}
-};
-MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);
-
static struct platform_driver qup_i2c_driver = {
.probe = qup_i2c_probe,
.remove = qup_i2c_remove,
--
1.8.2.1

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