6.7-stable review patch. If anyone has any objections, please let me know.
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From: Viken Dadhaniya quic_vdadhani@quicinc.com
[ Upstream commit 83ef106fa732aea8558253641cd98e8a895604d7 ]
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 andi.shyti@kernel.org Reviewed-by: Bryan O'Donoghue bryan.odonoghue@linaro.org Tested-by: Bryan O'Donoghue bryan.odonoghue@linaro.org # qrb5165-rb5 Co-developed-by: Mukesh Kumar Savaliya quic_msavaliy@quicinc.com Signed-off-by: Mukesh Kumar Savaliya quic_msavaliy@quicinc.com Signed-off-by: Viken Dadhaniya quic_vdadhani@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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);