Re: [PATCH v4 17/20] mtd: spi-nor: Merge spansion Quad Enable methods

[Vignesh Raghavendra <vigneshr@ti.com>]

On 02/11/19 4:53 PM, Tudor.Ambarus@microchip.com wrote:
> From: Tudor Ambarus <tudor.ambarus@microchip.com>
> 
> Merge
>     spansion_no_read_cr_quad_enable()
>     spansion_read_cr_quad_enable()
> into
>     spi_nor_sr2_bit1_quad_enable().
> 
> Reduce code duplication by introducing spi_nor_write_16bit_cr_and_check().
> The Configuration Register contains bits that can be updated in future:
> FREEZE, CMP. Provide a generic method that allows updating all bits
> of the Configuration Register.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>

Regards
Vignesh

> ---
>  drivers/mtd/spi-nor/spi-nor.c | 165 +++++++++++++++++-------------------------
>  1 file changed, 68 insertions(+), 97 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index e367a4862ec1..8bc29cc073a0 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1055,6 +1055,59 @@ static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 sr1)
>  }
>  
>  /**
> + * spi_nor_write_16bit_cr_and_check() - Write the Status Register 1 and the
> + * Configuration Register in one shot. Ensure that the byte written in the
> + * Configuration Register match the received value, and that the 16-bit Write
> + * did not affect what was already in the Status Register 1.
> + * @nor:	pointer to a 'struct spi_nor'.
> + * @cr:		byte value to be written to the Configuration Register.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_write_16bit_cr_and_check(struct spi_nor *nor, u8 cr)
> +{
> +	int ret;
> +	u8 *sr_cr = nor->bouncebuf;
> +	u8 sr_written;
> +
> +	/* Keep the current value of the Status Register 1. */
> +	ret = spi_nor_read_sr(nor, sr_cr);
> +	if (ret)
> +		return ret;
> +
> +	sr_cr[1] = cr;
> +
> +	ret = spi_nor_write_sr(nor, sr_cr, 2);
> +	if (ret)
> +		return ret;
> +
> +	sr_written = sr_cr[0];
> +
> +	ret = spi_nor_read_sr(nor, sr_cr);
> +	if (ret)
> +		return ret;
> +
> +	if (sr_written != sr_cr[0]) {
> +		dev_dbg(nor->dev, "SR: Read back test failed\n");
> +		return -EIO;
> +	}
> +
> +	if (nor->flags & SNOR_F_NO_READ_CR)
> +		return 0;
> +
> +	ret = spi_nor_read_cr(nor, &sr_cr[1]);
> +	if (ret)
> +		return ret;
> +
> +	if (cr != sr_cr[1]) {
> +		dev_dbg(nor->dev, "CR: read back test failed\n");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
>   * spi_nor_write_sr_and_check() - Write the Status Register 1 and ensure that
>   * the byte written match the received value without affecting other bits in the
>   * Status Register 1 and 2.
> @@ -2051,111 +2104,29 @@ static int macronix_quad_enable(struct spi_nor *nor)
>  }
>  
>  /**
> - * spansion_no_read_cr_quad_enable() - set QE bit in Configuration Register.
> - * @nor:	pointer to a 'struct spi_nor'
> + * spi_nor_sr2_bit1_quad_enable() - set the Quad Enable BIT(1) in the Status
> + * Register 2.
> + * @nor:       pointer to a 'struct spi_nor'.
>   *
> - * Set the Quad Enable (QE) bit in the Configuration Register.
> - * This function should be used with QSPI memories not supporting the Read
> - * Configuration Register (35h) instruction.
> - *
> - * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
> - * memories.
> + * Bit 1 of the Status Register 2 is the QE bit for Spansion like QSPI memories.
>   *
>   * Return: 0 on success, -errno otherwise.
>   */
> -static int spansion_no_read_cr_quad_enable(struct spi_nor *nor)
> +static int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor)
>  {
> -	u8 *sr_cr = nor->bouncebuf;
>  	int ret;
> -	u8 sr_written;
> -
> -	/* Keep the current value of the Status Register. */
> -	ret = spi_nor_read_sr(nor, sr_cr);
> -	if (ret)
> -		return ret;
> -
> -	sr_cr[1] = SR2_QUAD_EN_BIT1;
> -
> -	ret = spi_nor_write_sr(nor, sr_cr, 2);
> -	if (ret)
> -		return ret;
>  
> -	sr_written = sr_cr[0];
> -
> -	ret = spi_nor_read_sr(nor, sr_cr);
> -	if (ret)
> -		return ret;
> -
> -	if (sr_cr[0] != sr_written) {
> -		dev_err(nor->dev, "SR: Read back test failed\n");
> -		return -EIO;
> -	}
> -
> -	return 0;
> -}
> -
> -/**
> - * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
> - * @nor:	pointer to a 'struct spi_nor'
> - *
> - * Set the Quad Enable (QE) bit in the Configuration Register.
> - * This function should be used with QSPI memories supporting the Read
> - * Configuration Register (35h) instruction.
> - *
> - * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
> - * memories.
> - *
> - * Return: 0 on success, -errno otherwise.
> - */
> -static int spansion_read_cr_quad_enable(struct spi_nor *nor)
> -{
> -	u8 *sr_cr = nor->bouncebuf;
> -	int ret;
> -	u8 sr_written;
> +	if (nor->flags & SNOR_F_NO_READ_CR)
> +		return spi_nor_write_16bit_cr_and_check(nor, SR2_QUAD_EN_BIT1);
>  
> -	/* Check current Quad Enable bit value. */
> -	ret = spi_nor_read_cr(nor, &sr_cr[1]);
> +	ret = spi_nor_read_cr(nor, nor->bouncebuf);
>  	if (ret)
>  		return ret;
>  
> -	if (sr_cr[1] & SR2_QUAD_EN_BIT1)
> +	if (nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)
>  		return 0;
>  
> -	sr_cr[1] |= SR2_QUAD_EN_BIT1;
> -
> -	/* Keep the current value of the Status Register. */
> -	ret = spi_nor_read_sr(nor, sr_cr);
> -	if (ret)
> -		return ret;
> -
> -	ret = spi_nor_write_sr(nor, sr_cr, 2);
> -	if (ret)
> -		return ret;
> -
> -	sr_written = sr_cr[0];
> -
> -	ret = spi_nor_read_sr(nor, sr_cr);
> -	if (ret)
> -		return ret;
> -
> -	if (sr_written != sr_cr[0]) {
> -		dev_err(nor->dev, "SR: Read back test failed\n");
> -		return -EIO;
> -	}
> -
> -	sr_written = sr_cr[1];
> -
> -	/* Read back and check it. */
> -	ret = spi_nor_read_cr(nor, &sr_cr[1]);
> -	if (ret)
> -		return ret;
> -
> -	if (sr_cr[1] != sr_written) {
> -		dev_dbg(nor->dev, "CR: Read back test failed\n");
> -		return -EIO;
> -	}
> -
> -	return 0;
> +	return spi_nor_write_16bit_cr_and_check(nor, nor->bouncebuf[0]);
>  }
>  
>  /**
> @@ -2235,7 +2206,7 @@ static int spi_nor_clear_sr_bp(struct spi_nor *nor)
>   *
>   * Read-modify-write function that clears the Block Protection bits from the
>   * Status Register without affecting other bits. The function is tightly
> - * coupled with the spansion_read_cr_quad_enable() function. Both assume that
> + * coupled with the spi_nor_sr2_bit1_quad_enable() function. Both assume that
>   * the Write Register with 16 bits, together with the Read Configuration
>   * Register (35h) instructions are supported.
>   *
> @@ -3753,7 +3724,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>  		 * supported.
>  		 */
>  		nor->flags |= SNOR_F_HAS_16BIT_SR | SNOR_F_NO_READ_CR;
> -		params->quad_enable = spansion_no_read_cr_quad_enable;
> +		params->quad_enable = spi_nor_sr2_bit1_quad_enable;
>  		break;
>  
>  	case BFPT_DWORD15_QER_SR1_BIT6:
> @@ -3775,7 +3746,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>  		 */
>  		nor->flags |= SNOR_F_HAS_16BIT_SR;
>  
> -		params->quad_enable = spansion_read_cr_quad_enable;
> +		params->quad_enable = spi_nor_sr2_bit1_quad_enable;
>  		break;
>  
>  	default:
> @@ -4738,7 +4709,7 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
>  	u8 i, erase_mask;
>  
>  	/* Initialize legacy flash parameters and settings. */
> -	params->quad_enable = spansion_read_cr_quad_enable;
> +	params->quad_enable = spi_nor_sr2_bit1_quad_enable;
>  	params->set_4byte = spansion_set_4byte;
>  	params->setup = spi_nor_default_setup;
>  	/* Default to 16-bit Write Status (01h) Command */
> @@ -4955,7 +4926,7 @@ static int spi_nor_init(struct spi_nor *nor)
>  	int err;
>  
>  	if (nor->clear_sr_bp) {
> -		if (nor->params.quad_enable == spansion_read_cr_quad_enable)
> +		if (nor->params.quad_enable == spi_nor_sr2_bit1_quad_enable)
>  			nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
>  
>  		err = nor->clear_sr_bp(nor);
> 

-- 
Regards
Vignesh