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i2c: stm32f7: support i2c_*_dma_safe_msg_buf APIs

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`i2c_*_dma_safe_msg_buf` APIs operate on a `struct i2c_msg`.
The get operation make sure the I2C buffer is DMA'able according to its
buffer length, or if the memory use is DMA coherent for example and
return a valid pointer for safe DMA access to be used.
The put operation release the pointer.
Prefer using generic API's than relying on private tests.

Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Clément Le Goffic <clement.legoffic@foss.st.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250704-i2c-upstream-v4-3-84a095a2c728@foss.st.com
This commit is contained in:
Clément Le Goffic
2025-07-04 10:39:16 +02:00
committed by Andi Shyti
parent 0ae982df67
commit ffdd20555c
1 changed files with 21 additions and 11 deletions
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32
drivers/i2c/busses/i2c-stm32f7.c
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@@ -742,11 +742,14 @@ static void stm32f7_i2c_dma_callback(void *arg)
{
struct stm32f7_i2c_dev *i2c_dev = arg;
struct stm32_i2c_dma *dma = i2c_dev->dma;
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
stm32f7_i2c_disable_dma_req(i2c_dev);
dmaengine_terminate_async(dma->chan_using);
dma_unmap_single(i2c_dev->dev, dma->dma_buf, dma->dma_len,
dma->dma_data_dir);
if (!f7_msg->smbus)
i2c_put_dma_safe_msg_buf(f7_msg->buf, i2c_dev->msg, true);
complete(&dma->dma_complete);
}
@@ -882,6 +885,7 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
{
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
u8 *dma_buf;
u32 cr1, cr2;
int ret;
@@ -931,17 +935,23 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
/* Configure DMA or enable RX/TX interrupt */
i2c_dev->use_dma = false;
if (i2c_dev->dma && f7_msg->count >= STM32F7_I2C_DMA_LEN_MIN
&& !i2c_dev->atomic) {
ret = stm32_i2c_prep_dma_xfer(i2c_dev->dev, i2c_dev->dma,
msg->flags & I2C_M_RD,
f7_msg->count, f7_msg->buf,
stm32f7_i2c_dma_callback,
i2c_dev);
if (!ret)
i2c_dev->use_dma = true;
else
dev_warn(i2c_dev->dev, "can't use DMA\n");
if (i2c_dev->dma && !i2c_dev->atomic) {
dma_buf = i2c_get_dma_safe_msg_buf(msg, STM32F7_I2C_DMA_LEN_MIN);
if (dma_buf) {
f7_msg->buf = dma_buf;
ret = stm32_i2c_prep_dma_xfer(i2c_dev->dev, i2c_dev->dma,
msg->flags & I2C_M_RD,
f7_msg->count, f7_msg->buf,
stm32f7_i2c_dma_callback,
i2c_dev);
if (ret) {
dev_warn(i2c_dev->dev, "can't use DMA\n");
i2c_put_dma_safe_msg_buf(f7_msg->buf, msg, false);
f7_msg->buf = msg->buf;
} else {
i2c_dev->use_dma = true;
}
}
}
if (!i2c_dev->use_dma) {