Re: [PATCH] i2c: qcom-geni: Fix GPI DMA buffer sync-back

[Robin Reckmann]

On Mon, 8 Aug 2022, Wolfram Sang wrote:


On Sun, Aug 07, 2022 at 11:04:54PM +0900, Robin Reckmann wrote:

Fix i2c transfers using GPI DMA mode for all message types that do not set
the I2C_M_DMA_SAFE flag (e.g. SMBus "read byte").

In this case a bounce buffer is returned by i2c_get_dma_safe_msg_buf(),
and it has to synced back to the message after the transfer is done.

Add missing assignment of dma buffer in geni_i2c_gpi().

Set xferred in i2c_put_dma_safe_msg_buf() to true in case of no error to
ensure the sync-back of this dma buffer to the message.

Signed-off-by: Robin Reckmann 


Thank you! What would be a Fixes tag for this?



Thanks for having a look!

Fixes: d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")

[PATCH] i2c: qcom-geni: Fix GPI DMA buffer sync-back

[Robin Reckmann]

Fix i2c transfers using GPI DMA mode for all message types that do not set
the I2C_M_DMA_SAFE flag (e.g. SMBus "read byte").

In this case a bounce buffer is returned by i2c_get_dma_safe_msg_buf(),
and it has to synced back to the message after the transfer is done.

Add missing assignment of dma buffer in geni_i2c_gpi().

Set xferred in i2c_put_dma_safe_msg_buf() to true in case of no error to
ensure the sync-back of this dma buffer to the message.

Signed-off-by: Robin Reckmann 
---
 drivers/i2c/busses/i2c-qcom-geni.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
b/drivers/i2c/busses/i2c-qcom-geni.c
index 6ac402ea58fb..d3541e94794e 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -484,12 +484,12 @@ static void geni_i2c_gpi_unmap(struct geni_i2c_dev *gi2c, 
struct i2c_msg *msg,
 {
if (tx_buf) {
dma_unmap_single(gi2c->se.dev->parent, tx_addr, msg->len, 
DMA_TO_DEVICE);
-   i2c_put_dma_safe_msg_buf(tx_buf, msg, false);
+   i2c_put_dma_safe_msg_buf(tx_buf, msg, !gi2c->err);
}
 
if (rx_buf) {
dma_unmap_single(gi2c->se.dev->parent, rx_addr, msg->len, 
DMA_FROM_DEVICE);
-   i2c_put_dma_safe_msg_buf(rx_buf, msg, false);
+   i2c_put_dma_safe_msg_buf(rx_buf, msg, !gi2c->err);
}
 }
 
@@ -553,6 +553,7 @@ static int geni_i2c_gpi(struct geni_i2c_dev *gi2c, struct 
i2c_msg *msg,
desc->callback_param = gi2c;
 
dmaengine_submit(desc);
+   *buf = dma_buf;
*dma_addr_p = addr;
 
return 0;
-- 
2.25.1