Commit ffdd2055 authored by Clément Le Goffic's avatar Clément Le Goffic Committed by Andi Shyti
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i2c: stm32f7: support i2c_*_dma_safe_msg_buf APIs 



`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: default avatarAlain Volmat <alain.volmat@foss.st.com>
Signed-off-by: default avatarClément Le Goffic <clement.legoffic@foss.st.com>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250704-i2c-upstream-v4-3-84a095a2c728@foss.st.com
parent 0ae982df

drivers/i2c/busses/i2c-stm32f7.c

+21 −11
Original line number Diff line number Diff line
@@ -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) {

	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)

			i2c_dev->use_dma = true;

		else

			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) {