[PATCH v3] i2c: mediatek: i2c multi transfer optimization

From: Liguo Zhang
Date: Mon Mar 07 2016 - 21:25:19 EST

Next message: Mimi Zohar: "Re: [RFC PATCH 12/12] IMA: Use the the system trusted keyrings instead of .ima_mok [ver #2]"
Previous message: Dan Williams: "Re: [PATCH v2-UPDATE 3/4] resource: Add device-managed insert/remove_resource()"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Signal complete() in the i2c irq handler after one transfer done,
and then wait_for_completion_timeout() will return, this procedure
may cost much time, so only signal complete() when the entire
transaction has been completed, it will reduce the entire transaction
time.

Signed-off-by: Liguo Zhang <liguo.zhang@xxxxxxxxxxxx>
---
change in v3:
Update the commit message of this patch.
change in v2:
Remove the unused variable left_num in mtk_i2c_transfer().
---
drivers/i2c/busses/i2c-mt65xx.c | 221 ++++++++++++++++++++++------------------
1 file changed, 123 insertions(+), 98 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 453358b..3a498e1 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -139,6 +139,15 @@ struct mtk_i2c_compatible {
unsigned char support_33bits: 1;
};

+struct mtk_i2c_transaction {
+ u32 num;
+ u32 index;
+ dma_addr_t wpaddr;
+ dma_addr_t rpaddr;
+ struct i2c_msg *msgs;
+ int result;
+};
+
struct mtk_i2c {
struct i2c_adapter adap; /* i2c host adapter */
struct device *dev;
@@ -161,6 +170,7 @@ struct mtk_i2c {
unsigned char auto_restart;
bool ignore_restart_irq;
const struct mtk_i2c_compatible *dev_comp;
+ struct mtk_i2c_transaction transac;
};

static const struct i2c_adapter_quirks mt6577_i2c_quirks = {
@@ -378,8 +388,7 @@ static inline u32 mtk_i2c_set_4g_mode(dma_addr_t addr)
return (addr & BIT_ULL(32)) ? I2C_DMA_4G_MODE : I2C_DMA_CLR_FLAG;
}

-static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
- int num, int left_num)
+static int mtk_i2c_start_transfer(struct mtk_i2c *i2c)
{
u16 addr_reg;
u16 start_reg;
@@ -388,15 +397,31 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
u32 reg_4g_mode;
dma_addr_t rpaddr = 0;
dma_addr_t wpaddr = 0;
- int ret;
+ struct i2c_msg *msg;
+ struct mtk_i2c_transaction *i2c_transac;
+ int num;
+ int left_num;

i2c->irq_stat = 0;

+ i2c_transac = &i2c->transac;
+ num = i2c_transac->num;
+ left_num = i2c_transac->num - i2c_transac->index - 1;
+ msg = &i2c_transac->msgs[i2c_transac->index];
+
+ if (!msg->buf)
+ return -EINVAL;
+
+ if (i2c->op == I2C_MASTER_WRRD)
+ left_num--;
+ else if (msg->flags & I2C_M_RD)
+ i2c->op = I2C_MASTER_RD;
+ else
+ i2c->op = I2C_MASTER_WR;
+
if (i2c->auto_restart)
restart_flag = I2C_RS_TRANSFER;

- reinit_completion(&i2c->msg_complete);
-
control_reg = readw(i2c->base + OFFSET_CONTROL) &
~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS);
if ((i2c->speed_hz > 400000) || (left_num >= 1))
@@ -413,7 +438,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
else
writew(I2C_FS_START_CON, i2c->base + OFFSET_EXT_CONF);

- addr_reg = msgs->addr << 1;
+ addr_reg = msg->addr << 1;
if (i2c->op == I2C_MASTER_RD)
addr_reg |= 0x1;

@@ -431,16 +456,16 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
/* Set transfer and transaction len */
if (i2c->op == I2C_MASTER_WRRD) {
if (i2c->dev_comp->aux_len_reg) {
- writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
- writew((msgs + 1)->len, i2c->base +
+ writew(msg->len, i2c->base + OFFSET_TRANSFER_LEN);
+ writew((msg + 1)->len, i2c->base +
OFFSET_TRANSFER_LEN_AUX);
} else {
- writew(msgs->len | ((msgs + 1)->len) << 8,
+ writew(msg->len | ((msg + 1)->len) << 8,
i2c->base + OFFSET_TRANSFER_LEN);
}
writew(I2C_WRRD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
} else {
- writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
+ writew(msg->len, i2c->base + OFFSET_TRANSFER_LEN);
writew(num, i2c->base + OFFSET_TRANSAC_LEN);
}

@@ -448,8 +473,8 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
if (i2c->op == I2C_MASTER_RD) {
writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON);
- rpaddr = dma_map_single(i2c->dev, msgs->buf,
- msgs->len, DMA_FROM_DEVICE);
+ rpaddr = dma_map_single(i2c->dev, msg->buf, msg->len,
+ DMA_FROM_DEVICE);
if (dma_mapping_error(i2c->dev, rpaddr))
return -ENOMEM;

@@ -459,12 +484,13 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
}

writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR);
- writel(msgs->len, i2c->pdmabase + OFFSET_RX_LEN);
+ writel(msg->len, i2c->pdmabase + OFFSET_RX_LEN);
+ i2c_transac->rpaddr = rpaddr;
} else if (i2c->op == I2C_MASTER_WR) {
writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON);
- wpaddr = dma_map_single(i2c->dev, msgs->buf,
- msgs->len, DMA_TO_DEVICE);
+ wpaddr = dma_map_single(i2c->dev, msg->buf, msg->len,
+ DMA_TO_DEVICE);
if (dma_mapping_error(i2c->dev, wpaddr))
return -ENOMEM;

@@ -474,20 +500,21 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
}

writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR);
- writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN);
+ writel(msg->len, i2c->pdmabase + OFFSET_TX_LEN);
+
+ i2c_transac->wpaddr = wpaddr;
} else {
writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON);
- wpaddr = dma_map_single(i2c->dev, msgs->buf,
- msgs->len, DMA_TO_DEVICE);
+ wpaddr = dma_map_single(i2c->dev, msg->buf, msg->len,
+ DMA_TO_DEVICE);
if (dma_mapping_error(i2c->dev, wpaddr))
return -ENOMEM;
- rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf,
- (msgs + 1)->len,
- DMA_FROM_DEVICE);
+ rpaddr = dma_map_single(i2c->dev, (msg + 1)->buf,
+ (msg + 1)->len, DMA_FROM_DEVICE);
if (dma_mapping_error(i2c->dev, rpaddr)) {
- dma_unmap_single(i2c->dev, wpaddr,
- msgs->len, DMA_TO_DEVICE);
+ dma_unmap_single(i2c->dev, wpaddr, msg->len,
+ DMA_TO_DEVICE);
return -ENOMEM;
}

@@ -501,8 +528,11 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,

writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR);
writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR);
- writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN);
- writel((msgs + 1)->len, i2c->pdmabase + OFFSET_RX_LEN);
+ writel(msg->len, i2c->pdmabase + OFFSET_TX_LEN);
+ writel((msg + 1)->len, i2c->pdmabase + OFFSET_RX_LEN);
+
+ i2c_transac->wpaddr = wpaddr;
+ i2c_transac->rpaddr = rpaddr;
}

writel(I2C_DMA_START_EN, i2c->pdmabase + OFFSET_EN);
@@ -516,40 +546,6 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
}
writew(start_reg, i2c->base + OFFSET_START);

- ret = wait_for_completion_timeout(&i2c->msg_complete,
- i2c->adap.timeout);
-
- /* Clear interrupt mask */
- writew(~(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
- I2C_TRANSAC_COMP), i2c->base + OFFSET_INTR_MASK);
-
- if (i2c->op == I2C_MASTER_WR) {
- dma_unmap_single(i2c->dev, wpaddr,
- msgs->len, DMA_TO_DEVICE);
- } else if (i2c->op == I2C_MASTER_RD) {
- dma_unmap_single(i2c->dev, rpaddr,
- msgs->len, DMA_FROM_DEVICE);
- } else {
- dma_unmap_single(i2c->dev, wpaddr, msgs->len,
- DMA_TO_DEVICE);
- dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len,
- DMA_FROM_DEVICE);
- }
-
- if (ret == 0) {
- dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
- mtk_i2c_init_hw(i2c);
- return -ETIMEDOUT;
- }
-
- completion_done(&i2c->msg_complete);
-
- if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) {
- dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", msgs->addr);
- mtk_i2c_init_hw(i2c);
- return -ENXIO;
- }
-
return 0;
}

@@ -557,21 +553,28 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
struct i2c_msg msgs[], int num)
{
int ret;
- int left_num = num;
struct mtk_i2c *i2c = i2c_get_adapdata(adap);
+ struct mtk_i2c_transaction *i2c_transac = &i2c->transac;
+
+ i2c_transac->num = num;
+ i2c_transac->index = 0;
+ i2c_transac->msgs = msgs;
+ i2c_transac->result = 0;
+
+ reinit_completion(&i2c->msg_complete);

ret = mtk_i2c_clock_enable(i2c);
if (ret)
return ret;

+ i2c->op = 0;
i2c->auto_restart = i2c->dev_comp->auto_restart;

/* checking if we can skip restart and optimize using WRRD mode */
- if (i2c->auto_restart && num == 2) {
- if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) &&
- msgs[0].addr == msgs[1].addr) {
- i2c->auto_restart = 0;
- }
+ if (num == 2 && !(msgs[0].flags & I2C_M_RD) &&
+ (msgs[1].flags & I2C_M_RD) && msgs[0].addr == msgs[1].addr) {
+ i2c->op = I2C_MASTER_WRRD;
+ i2c->auto_restart = 0;
}

if (i2c->auto_restart && num >= 2 && i2c->speed_hz > MAX_FS_MODE_SPEED)
@@ -582,33 +585,33 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
else
i2c->ignore_restart_irq = false;

- while (left_num--) {
- if (!msgs->buf) {
- dev_dbg(i2c->dev, "data buffer is NULL.\n");
- ret = -EINVAL;
- goto err_exit;
- }
+ /* always use DMA mode. */
+ ret = mtk_i2c_start_transfer(i2c);
+ if (ret < 0)
+ goto err_exit;

- if (msgs->flags & I2C_M_RD)
- i2c->op = I2C_MASTER_RD;
- else
- i2c->op = I2C_MASTER_WR;
-
- if (!i2c->auto_restart) {
- if (num > 1) {
- /* combined two messages into one transaction */
- i2c->op = I2C_MASTER_WRRD;
- left_num--;
- }
- }
+ ret = wait_for_completion_timeout(&i2c->msg_complete,
+ i2c->adap.timeout);

- /* always use DMA mode. */
- ret = mtk_i2c_do_transfer(i2c, msgs, num, left_num);
- if (ret < 0)
- goto err_exit;
+ if (ret == 0) {
+ dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
+ mtk_i2c_init_hw(i2c);
+ ret = -ETIMEDOUT;
+ goto err_exit;
+ }

- msgs++;
+ if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) {
+ dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", msgs->addr);
+ mtk_i2c_init_hw(i2c);
+ ret = -ENXIO;
+ goto err_exit;
+ }
+
+ if (i2c_transac->result) {
+ ret = i2c_transac->result;
+ goto err_exit;
}
+
/* the return value is number of executed messages */
ret = num;

@@ -621,29 +624,51 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
{
struct mtk_i2c *i2c = dev_id;
u16 restart_flag = 0;
- u16 intr_stat;
+ struct i2c_msg *msg;
+ struct mtk_i2c_transaction *i2c_transac = &i2c->transac;

if (i2c->auto_restart)
restart_flag = I2C_RS_TRANSFER;

- intr_stat = readw(i2c->base + OFFSET_INTR_STAT);
- writew(intr_stat, i2c->base + OFFSET_INTR_STAT);
+ /* Clear interrupt mask */
+ writew(~(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
+ I2C_TRANSAC_COMP), i2c->base + OFFSET_INTR_MASK);

- /*
- * when occurs ack error, i2c controller generate two interrupts
- * first is the ack error interrupt, then the complete interrupt
- * i2c->irq_stat need keep the two interrupt value.
- */
- i2c->irq_stat |= intr_stat;
+ i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
+ writew(i2c->irq_stat, i2c->base + OFFSET_INTR_STAT);

if (i2c->ignore_restart_irq && (i2c->irq_stat & restart_flag)) {
i2c->ignore_restart_irq = false;
i2c->irq_stat = 0;
+ /* Enable interrupt */
+ writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
+ I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_MASK);
writew(I2C_RS_MUL_CNFG | I2C_RS_MUL_TRIG | I2C_TRANSAC_START,
i2c->base + OFFSET_START);
} else {
- if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
+ msg = &i2c_transac->msgs[i2c_transac->index];
+
+ if (i2c->op == I2C_MASTER_WR || i2c->op == I2C_MASTER_WRRD) {
+ dma_unmap_single(i2c->dev, i2c_transac->wpaddr,
+ msg->len, DMA_TO_DEVICE);
+ }
+
+ if (i2c->op == I2C_MASTER_WRRD)
+ dma_unmap_single(i2c->dev, i2c_transac->rpaddr,
+ (msg + 1)->len, DMA_FROM_DEVICE);
+
+ if (i2c->op == I2C_MASTER_RD)
+ dma_unmap_single(i2c->dev, i2c_transac->rpaddr,
+ msg->len, DMA_FROM_DEVICE);
+
+ if (i2c->irq_stat & ~restart_flag) {
complete(&i2c->msg_complete);
+ } else {
+ i2c_transac->index++;
+ i2c_transac->result = mtk_i2c_start_transfer(i2c);
+ if (i2c_transac->result)
+ complete(&i2c->msg_complete);
+ }
}

return IRQ_HANDLED;
--
1.8.1.1.dirty

Next message: Mimi Zohar: "Re: [RFC PATCH 12/12] IMA: Use the the system trusted keyrings instead of .ima_mok [ver #2]"
Previous message: Dan Williams: "Re: [PATCH v2-UPDATE 3/4] resource: Add device-managed insert/remove_resource()"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]