Re: [PATCH v4] i2c: i2c-qcom-geni: Parse Error correctly in i2c GSI mode

[Vinod Koul <vkoul@kernel.org>]

On 13-03-24, 10:56, Mukesh Kumar Savaliya wrote:
> I2C driver currently reports "DMA txn failed" error even though it's
> NACK OR BUS_PROTO OR ARB_LOST. Detect NACK error when no device ACKs
> on the bus instead of generic transfer failure which doesn't give any
> specific clue.
> 
> Make Changes inside i2c driver callback handler function
> i2c_gpi_cb_result() to parse these errors and make sure GSI driver
> stores the error status during error interrupt.
> 
> Co-developed-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
> Signed-off-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
> Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
> v3 -> v4:
> - Included bitfield.h to fix compilation issue for x86 arch.
> - Removed Fixes tag as this is not fixing any crash.
> - Added Reviewed-by tag.
> 
> v2 -> v3:
> - Modifed commit log reflecting an imperative mood.
> 
> v1 -> v2:
> - 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 | 20 ++++++++++++++++----
>  include/linux/dma/qcom-gpi-dma.h   | 10 ++++++++++
>  3 files changed, 37 insertions(+), 5 deletions(-)

Urgh, why do we have i2c and dma changes in single patch? I dont think
they would be dependent

> 
> 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);

This is generic, why should this be i2c specific... we should set
generic status value


> +	} else {
> +		dmaengine_desc_get_callback_invoke(&vd->tx, &result);
> +	}
>  
>  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..11dcfcf13d8b 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -2,6 +2,7 @@
>  // Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>  
>  #include <linux/acpi.h>
> +#include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/dmaengine.h>
>  #include <linux/dma-mapping.h>
> @@ -66,6 +67,7 @@ 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 +101,7 @@ 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 +487,18 @@ 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 +580,7 @@ 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

-- 
~Vinod