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Subject[PATCH AUTOSEL 4.19 095/205] i2c: mediatek: Use DMA safe buffers for i2c transactions
Date
From: Jun Gao <jun.gao@mediatek.com>

[ Upstream commit fc66b39fe36acfd06f716e338de7cd8f9550fad2 ]

DMA mode will always be used in i2c transactions, try to allocate
a DMA safe buffer if the buf of struct i2c_msg used is not DMA safe.

Signed-off-by: Jun Gao <jun.gao@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/i2c/busses/i2c-mt65xx.c | 62 +++++++++++++++++++++++++++++----
1 file changed, 55 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 1e57f58fcb001..a74ef76705e0c 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -441,6 +441,8 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
u16 control_reg;
u16 restart_flag = 0;
u32 reg_4g_mode;
+ u8 *dma_rd_buf = NULL;
+ u8 *dma_wr_buf = NULL;
dma_addr_t rpaddr = 0;
dma_addr_t wpaddr = 0;
int ret;
@@ -500,10 +502,18 @@ 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,
+
+ dma_rd_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ if (!dma_rd_buf)
+ return -ENOMEM;
+
+ rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
msgs->len, DMA_FROM_DEVICE);
- if (dma_mapping_error(i2c->dev, rpaddr))
+ if (dma_mapping_error(i2c->dev, rpaddr)) {
+ i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, false);
+
return -ENOMEM;
+ }

if (i2c->dev_comp->support_33bits) {
reg_4g_mode = mtk_i2c_set_4g_mode(rpaddr);
@@ -515,10 +525,18 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
} 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,
+
+ dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ if (!dma_wr_buf)
+ return -ENOMEM;
+
+ wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
msgs->len, DMA_TO_DEVICE);
- if (dma_mapping_error(i2c->dev, wpaddr))
+ if (dma_mapping_error(i2c->dev, wpaddr)) {
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
return -ENOMEM;
+ }

if (i2c->dev_comp->support_33bits) {
reg_4g_mode = mtk_i2c_set_4g_mode(wpaddr);
@@ -530,16 +548,39 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
} 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,
+
+ dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ if (!dma_wr_buf)
+ return -ENOMEM;
+
+ wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
msgs->len, DMA_TO_DEVICE);
- if (dma_mapping_error(i2c->dev, wpaddr))
+ if (dma_mapping_error(i2c->dev, wpaddr)) {
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
return -ENOMEM;
- rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf,
+ }
+
+ dma_rd_buf = i2c_get_dma_safe_msg_buf((msgs + 1), 0);
+ if (!dma_rd_buf) {
+ dma_unmap_single(i2c->dev, wpaddr,
+ msgs->len, DMA_TO_DEVICE);
+
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
+ return -ENOMEM;
+ }
+
+ rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
(msgs + 1)->len,
DMA_FROM_DEVICE);
if (dma_mapping_error(i2c->dev, rpaddr)) {
dma_unmap_single(i2c->dev, wpaddr,
msgs->len, DMA_TO_DEVICE);
+
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+ i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), false);
+
return -ENOMEM;
}

@@ -578,14 +619,21 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
if (i2c->op == I2C_MASTER_WR) {
dma_unmap_single(i2c->dev, wpaddr,
msgs->len, DMA_TO_DEVICE);
+
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
} else if (i2c->op == I2C_MASTER_RD) {
dma_unmap_single(i2c->dev, rpaddr,
msgs->len, DMA_FROM_DEVICE);
+
+ i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, true);
} else {
dma_unmap_single(i2c->dev, wpaddr, msgs->len,
DMA_TO_DEVICE);
dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len,
DMA_FROM_DEVICE);
+
+ i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
+ i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), true);
}

if (ret == 0) {
--
2.20.1
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