Re: [PATCH v2] i2c: i2c-qcom-geni: Parse Error correctly in i2c GSI mode

[Dmitry Baryshkov]

On Thu, 7 Mar 2024 at 11:36, Mukesh Kumar Savaliya
<quic_msavaliy@xxxxxxxxxxx> wrote:
>
> We are seeing transfer failure instead of NACK error for simple
> device scan test.Ideally it should report exact error like NACK
> if device is not present.
>
> We may also expect errors like BUS_PROTO or ARB_LOST, hence we are
> adding such error support in GSI mode and reporting it accordingly
> by adding respective error logs.

Please take a look at the
Documentation/process/submitting-patches.rst. This is not the expected
style of commit messages.

>
> During geni_i2c_gpi_xfer(), we should expect callback param as a
> transfer result. For that we have added a new structure named
> gpi_i2c_result, which will store xfer result.
>
> Upon receiving an interrupt, gpi_process_xfer_compl_event() will
> store transfer result into status variable and then call the
> dmaengine_desc_callback_invoke(). Hence i2c_gpi_cb_result() can
> parse the respective errors.
>
> while parsing error from the status param, use FIELD_GET with the

Sentences start with the uppercase letter.

> mask instead of multiple shifting operations for each error.


>
> Fixes: d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")
> Co-developed-by: Viken Dadhaniya <quic_vdadhani@xxxxxxxxxxx>
> Signed-off-by: Viken Dadhaniya <quic_vdadhani@xxxxxxxxxxx>
> Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@xxxxxxxxxxx>
> ---
> ---
> - Commit log changed we->We.
> - Explained the problem that we are not detecing NACK error.
> - Removed Heap based memory allocation and hence memory leakage issue.
> - Used FIELD_GET and removed shiting and masking every time as suggested by Bjorn.
> - Changed commit log to reflect the code changes done.
> - Removed adding anything into struct gpi_i2c_config and created new structure
>   for error status as suggested by Bjorn.
> ---
>  drivers/dma/qcom/gpi.c             | 12 +++++++++++-
>  drivers/i2c/busses/i2c-qcom-geni.c | 19 +++++++++++++++----
>  include/linux/dma/qcom-gpi-dma.h   | 10 ++++++++++
>  3 files changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c
> index 1c93864e0e4d..e3508d51fdc9 100644
> --- a/drivers/dma/qcom/gpi.c
> +++ b/drivers/dma/qcom/gpi.c
> @@ -1076,7 +1076,17 @@ static void gpi_process_xfer_compl_event(struct gchan *gchan,
>         dev_dbg(gpii->gpi_dev->dev, "Residue %d\n", result.residue);
>
>         dma_cookie_complete(&vd->tx);
> -       dmaengine_desc_get_callback_invoke(&vd->tx, &result);
> +       if (gchan->protocol == QCOM_GPI_I2C) {
> +               struct dmaengine_desc_callback cb;
> +               struct gpi_i2c_result *i2c;
> +
> +               dmaengine_desc_get_callback(&vd->tx, &cb);
> +               i2c = cb.callback_param;
> +               i2c->status = compl_event->status;
> +               dmaengine_desc_callback_invoke(&cb, &result);
> +       } else {
> +               dmaengine_desc_get_callback_invoke(&vd->tx, &result);

Is there such error reporting for SPI or UART protocols?

> +       }
>
>  gpi_free_desc:
>         spin_lock_irqsave(&gchan->vc.lock, flags);
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index da94df466e83..36a7c0c0ff54 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -66,6 +66,7 @@ enum geni_i2c_err_code {
>         GENI_TIMEOUT,
>  };
>
> +#define I2C_DMA_TX_IRQ_MASK    GENMASK(12, 5)
>  #define DM_I2C_CB_ERR          ((BIT(NACK) | BIT(BUS_PROTO) | BIT(ARB_LOST)) \
>                                                                         << 5)
>
> @@ -99,6 +100,7 @@ struct geni_i2c_dev {
>         struct dma_chan *rx_c;
>         bool gpi_mode;
>         bool abort_done;
> +       struct gpi_i2c_result i2c_result;
>  };
>
>  struct geni_i2c_desc {
> @@ -484,9 +486,18 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>
>  static void i2c_gpi_cb_result(void *cb, const struct dmaengine_result *result)
>  {
> -       struct geni_i2c_dev *gi2c = cb;
> -
> -       if (result->result != DMA_TRANS_NOERROR) {
> +       struct gpi_i2c_result *i2c_res = cb;
> +       struct geni_i2c_dev *gi2c = container_of(i2c_res, struct geni_i2c_dev, i2c_result);
> +       u32 status;
> +
> +       status = FIELD_GET(I2C_DMA_TX_IRQ_MASK, i2c_res->status);
> +       if (status == BIT(NACK)) {
> +               geni_i2c_err(gi2c, NACK);
> +       } else if (status == BIT(BUS_PROTO)) {
> +               geni_i2c_err(gi2c, BUS_PROTO);
> +       } else if (status == BIT(ARB_LOST)) {
> +               geni_i2c_err(gi2c, ARB_LOST);
> +       } else if (result->result != DMA_TRANS_NOERROR) {
>                 dev_err(gi2c->se.dev, "DMA txn failed:%d\n", result->result);
>                 gi2c->err = -EIO;
>         } else if (result->residue) {
> @@ -568,7 +579,7 @@ static int geni_i2c_gpi(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>         }
>
>         desc->callback_result = i2c_gpi_cb_result;
> -       desc->callback_param = gi2c;
> +       desc->callback_param = &gi2c->i2c_result;
>
>         dmaengine_submit(desc);
>         *buf = dma_buf;
> diff --git a/include/linux/dma/qcom-gpi-dma.h b/include/linux/dma/qcom-gpi-dma.h
> index 6680dd1a43c6..f585c6a35e51 100644
> --- a/include/linux/dma/qcom-gpi-dma.h
> +++ b/include/linux/dma/qcom-gpi-dma.h
> @@ -80,4 +80,14 @@ struct gpi_i2c_config {
>         bool multi_msg;
>  };
>
> +/**
> + * struct gpi_i2c_result - i2c transfer status result in GSI mode
> + *
> + * @status: store txfer status value as part of callback
> + *
> + */
> +struct gpi_i2c_result {
> +       u32 status;
> +};
> +
>  #endif /* QCOM_GPI_DMA_H */
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
>


-- 
With best wishes
Dmitry