For i2c read operation in GSI mode, we are getting timeout
due to malformed TRE basically incorrect TRE sequence
in gpi(drivers/dma/qcom/gpi.c) driver.
I2C driver has geni_i2c_gpi(I2C_WRITE) function which generates GO TRE and
geni_i2c_gpi(I2C_READ)generates DMA TRE. Hence to generate GO TRE before
DMA TRE, we should move geni_i2c_gpi(I2C_WRITE) before
geni_i2c_gpi(I2C_READ) inside the I2C GSI mode transfer function
i.e. geni_i2c_gpi_xfer().
TRE stands for Transfer Ring Element - which is basically an element with
size of 4 words. It contains all information like slave address,
clk divider, dma address value data size etc).
Mainly we have 3 TREs(Config, GO and DMA tre).
- CONFIG TRE : consists of internal register configuration which is
required before start of the transfer.
- DMA TRE : contains DDR/Memory address, called as DMA descriptor.
- GO TRE : contains Transfer directions, slave ID, Delay flags, Length
of the transfer.
I2c driver calls GPI driver API to config each TRE depending on the
protocol.
For read operation tre sequence will be as below which is not aligned
to hardware programming guide.
- CONFIG tre
- DMA tre
- GO tre
As per Qualcomm's internal Hardware Programming Guide, we should configure
TREs in below sequence for any RX only transfer.
- CONFIG tre
- GO tre
- DMA tre
Fixes: d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")
Reviewed-by: Andi Shyti <[email protected]>
Reviewed-by: Bryan O'Donoghue <[email protected]>
Tested-by: Bryan O'Donoghue <[email protected]> # qrb5165-rb5
Co-developed-by: Mukesh Kumar Savaliya <[email protected]>
Signed-off-by: Mukesh Kumar Savaliya <[email protected]>
Signed-off-by: Viken Dadhaniya <[email protected]>
---
v3 -> v4:
- Update commit log.
- Add review/tested/co-develop tag.
- Fix patch title by adding "PATCH" string.
v2 -> v3:
- Update commit log to explain change in simple way.
- Correct fix tag format.
v1 -> v2:
- Remove redundant check.
- update commit log.
- add fix tag.
---
---
drivers/i2c/busses/i2c-qcom-geni.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 0d2e7171e3a6..da94df466e83 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -613,20 +613,20 @@ static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], i
peripheral.addr = msgs[i].addr;
+ ret = geni_i2c_gpi(gi2c, &msgs[i], &config,
+ &tx_addr, &tx_buf, I2C_WRITE, gi2c->tx_c);
+ if (ret)
+ goto err;
+
if (msgs[i].flags & I2C_M_RD) {
ret = geni_i2c_gpi(gi2c, &msgs[i], &config,
&rx_addr, &rx_buf, I2C_READ, gi2c->rx_c);
if (ret)
goto err;
- }
-
- ret = geni_i2c_gpi(gi2c, &msgs[i], &config,
- &tx_addr, &tx_buf, I2C_WRITE, gi2c->tx_c);
- if (ret)
- goto err;
- if (msgs[i].flags & I2C_M_RD)
dma_async_issue_pending(gi2c->rx_c);
+ }
+
dma_async_issue_pending(gi2c->tx_c);
timeout = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
On Mon, 12 Feb 2024 at 14:52, Viken Dadhaniya <[email protected]> wrote:
>
> For i2c read operation in GSI mode, we are getting timeout
> due to malformed TRE basically incorrect TRE sequence
> in gpi(drivers/dma/qcom/gpi.c) driver.
>
> I2C driver has geni_i2c_gpi(I2C_WRITE) function which generates GO TRE and
> geni_i2c_gpi(I2C_READ)generates DMA TRE. Hence to generate GO TRE before
> DMA TRE, we should move geni_i2c_gpi(I2C_WRITE) before
> geni_i2c_gpi(I2C_READ) inside the I2C GSI mode transfer function
> i.e. geni_i2c_gpi_xfer().
>
> TRE stands for Transfer Ring Element - which is basically an element with
> size of 4 words. It contains all information like slave address,
> clk divider, dma address value data size etc).
>
> Mainly we have 3 TREs(Config, GO and DMA tre).
> - CONFIG TRE : consists of internal register configuration which is
> required before start of the transfer.
> - DMA TRE : contains DDR/Memory address, called as DMA descriptor.
> - GO TRE : contains Transfer directions, slave ID, Delay flags, Length
> of the transfer.
>
> I2c driver calls GPI driver API to config each TRE depending on the
> protocol.
>
> For read operation tre sequence will be as below which is not aligned
> to hardware programming guide.
>
> - CONFIG tre
> - DMA tre
> - GO tre
>
> As per Qualcomm's internal Hardware Programming Guide, we should configure
> TREs in below sequence for any RX only transfer.
>
> - CONFIG tre
> - GO tre
> - DMA tre
>
> Fixes: d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")
> Reviewed-by: Andi Shyti <[email protected]>
> Reviewed-by: Bryan O'Donoghue <[email protected]>
> Tested-by: Bryan O'Donoghue <[email protected]> # qrb5165-rb5
> Co-developed-by: Mukesh Kumar Savaliya <[email protected]>
> Signed-off-by: Mukesh Kumar Savaliya <[email protected]>
> Signed-off-by: Viken Dadhaniya <[email protected]>
Thank you,
Reviewed-by: Dmitry Baryshkov <[email protected]>
--
With best wishes
Dmitry
Hi
On Mon, 12 Feb 2024 18:22:39 +0530, Viken Dadhaniya wrote:
> For i2c read operation in GSI mode, we are getting timeout
> due to malformed TRE basically incorrect TRE sequence
> in gpi(drivers/dma/qcom/gpi.c) driver.
>
> I2C driver has geni_i2c_gpi(I2C_WRITE) function which generates GO TRE and
> geni_i2c_gpi(I2C_READ)generates DMA TRE. Hence to generate GO TRE before
> DMA TRE, we should move geni_i2c_gpi(I2C_WRITE) before
> geni_i2c_gpi(I2C_READ) inside the I2C GSI mode transfer function
> i.e. geni_i2c_gpi_xfer().
>
> [...]
Applied to i2c/i2c-host-fixes on
git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git
Thank you,
Andi
Patches applied
===============
[1/1] i2c: i2c-qcom-geni: Correct I2C TRE sequence
commit: 32e9b680de4b46cfe835cbc7ee3dc721f7cc65fb