Re: [PATCH] wifi: wilc1000: add SPI commands retry mechanism

[Simon Horman <simon.horman@corigine.com>]

On Thu, May 25, 2023 at 06:17:48PM +0000, Amisha.Patel@microchip.com wrote:
> From: Amisha Patel <amisha.patel@microchip.com>
> 
> In some situations like, chip wake-up with powersave enabled, SPI
> commands are failing temporarily. Reissuing commands after reset helps
> to overcome the failure. So, add the retry limit and reset command
> sequence API for read/write SPI commands.
> 
> Signed-off-by: Amisha Patel <amisha.patel@microchip.com>

Hi Amisha,

thanks for your patch.
Some minor nits from my side.

...

>  static int wilc_spi_read_reg(struct wilc *wilc, u32 addr, u32 *data)
>  {
>  	struct spi_device *spi = to_spi_device(wilc->dev);
>  	int result;
>  	u8 cmd = CMD_SINGLE_READ;
>  	u8 clockless = 0;
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
>  
> -	if (addr < WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
> +	if (addr <= WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
>  		/* Clockless register */
>  		cmd = CMD_INTERNAL_READ;
>  		clockless = 1;
>  	}
> -
> +	

nit: trailing tabs on the line above

> +retry:
>  	result = wilc_spi_single_read(wilc, cmd, addr, data, clockless);
>  	if (result) {
>  		dev_err(&spi->dev, "Failed cmd, read reg (%08x)...\n", addr);
> -		return result;
> +		

Ditto

> +		/* retry is not applicable for clockless registers */
> +		if (clockless || !retry_limit)
> +			return result;
> +
> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, addr);
> +		retry_limit--;
> +		goto retry;
>  	}
>  
>  	le32_to_cpus(data);
> @@ -858,14 +881,22 @@ static int wilc_spi_read(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
>  {
>  	struct spi_device *spi = to_spi_device(wilc->dev);
>  	int result;
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
>  
>  	if (size <= 4)
>  		return -EINVAL;
>  
> +retry:
>  	result = wilc_spi_dma_rw(wilc, CMD_DMA_EXT_READ, addr, buf, size);
>  	if (result) {
>  		dev_err(&spi->dev, "Failed cmd, read block (%08x)...\n", addr);
> -		return result;
> +		

Ditto

> +		if (!retry_limit)
> +			return result;
> +
> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, addr);
> +		retry_limit--;
> +		goto retry;
>  	}
>  
>  	return 0;
> @@ -875,11 +906,19 @@ static int spi_internal_write(struct wilc *wilc, u32 adr, u32 dat)
>  {
>  	struct spi_device *spi = to_spi_device(wilc->dev);
>  	int result;
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
>  
> +retry:
>  	result = wilc_spi_write_cmd(wilc, CMD_INTERNAL_WRITE, adr, dat, 0);
>  	if (result) {
>  		dev_err(&spi->dev, "Failed internal write cmd...\n");
> -		return result;
> +		

Ditto

> +		if (!retry_limit)
> +			return result;
> +
> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, adr);
> +		retry_limit--;
> +		goto retry;
>  	}
>  
>  	return 0;
> @@ -890,12 +929,20 @@ static int spi_internal_read(struct wilc *wilc, u32 adr, u32 *data)
>  	struct spi_device *spi = to_spi_device(wilc->dev);
>  	struct wilc_spi *spi_priv = wilc->bus_data;
>  	int result;
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
>  
> +retry:
>  	result = wilc_spi_single_read(wilc, CMD_INTERNAL_READ, adr, data, 0);
>  	if (result) {
>  		if (!spi_priv->probing_crc)
>  			dev_err(&spi->dev, "Failed internal read cmd...\n");
> -		return result;
> +			

Ditto

> +		if (!retry_limit)
> +			return result;
> +
> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, adr);
> +		retry_limit--;
> +		goto retry;
>  	}
>  
>  	le32_to_cpus(data);
> @@ -915,19 +962,26 @@ static int wilc_spi_write_reg(struct wilc *wilc, u32 addr, u32 data)
>  	int result;
>  	u8 cmd = CMD_SINGLE_WRITE;
>  	u8 clockless = 0;
> -
> -	if (addr < WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
> +	

Ditto

> +	if (addr <= WILC_SPI_CLOCKLESS_ADDR_LIMIT) {
>  		/* Clockless register */
>  		cmd = CMD_INTERNAL_WRITE;
>  		clockless = 1;
>  	}
>  
> +retry:
>  	result = wilc_spi_write_cmd(wilc, cmd, addr, data, clockless);
>  	if (result) {
>  		dev_err(&spi->dev, "Failed cmd, write reg (%08x)...\n", addr);
> -		return result;
> -	}
> +		

Ditto

> +		if (clockless || !retry_limit)
> +			return result;
>  
> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, addr);
> +		retry_limit--;
> +		goto retry;
> +	}
>  	return 0;
>  }
>  
> @@ -981,6 +1035,7 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
>  {
>  	struct spi_device *spi = to_spi_device(wilc->dev);
>  	int result;
> +	u8 retry_limit = SPI_RETRY_MAX_LIMIT;
>  
>  	/*
>  	 * has to be greated than 4
> @@ -988,11 +1043,12 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
>  	if (size <= 4)
>  		return -EINVAL;
>  
> +retry:
>  	result = wilc_spi_dma_rw(wilc, CMD_DMA_EXT_WRITE, addr, NULL, size);
>  	if (result) {
>  		dev_err(&spi->dev,
>  			"Failed cmd, write block (%08x)...\n", addr);
> -		return result;
> +		goto fail;
>  	}
>  
>  	/*
> @@ -1001,13 +1057,27 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
>  	result = spi_data_write(wilc, buf, size);
>  	if (result) {
>  		dev_err(&spi->dev, "Failed block data write...\n");
> -		return result;
> +		goto fail;
>  	}
>  
>  	/*
>  	 * Data response
>  	 */
> -	return spi_data_rsp(wilc, CMD_DMA_EXT_WRITE);
> +	result = spi_data_rsp(wilc, CMD_DMA_EXT_WRITE);
> +	if (result) {
> +		dev_err(&spi->dev, "Failed block data rsp...\n");
> +		goto fail;
> +	}
> +
> +	return 0;
> +
> +fail:
> +	if (result && retry_limit) {

nit: is result always non-zero here?

> +		wilc_spi_reset_cmd_sequence(wilc, retry_limit, addr);
> +		retry_limit--;
> +		goto retry;
> +	}
> +	return result;
>  }
>  
>  /********************************************