Re: [PATCH 17/23] mtd: spi-nor: Fix clearing of QE bit on lock()/unlock()

[Vignesh Raghavendra]

Hi Tudor

[...]

On 17-Sep-19 9:25 PM, tudor.amba...@microchip.com wrote:
> +static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 
> status_new,
> +                                         u8 mask)
> +{
> +     int ret;
> +     u8 *sr_cr = nor->bouncebuf;
> +     u8 cr_written;
> +
> +     /* Make sure we don't overwrite the contents of Status Register 2. */
> +     if (!(nor->flags & SNOR_F_NO_READ_CR)) {

Assuming SNOR_F_NO_READ_CR is not set...

> +             ret = spi_nor_read_cr(nor, &sr_cr[1]);
> +             if (ret)
> +                     return ret;
> +     } else if (nor->flash.quad_enable) {
> +             /*
> +              * If the Status Register 2 Read command (35h) is not
> +              * supported, we should at least be sure we don't
> +              * change the value of the SR2 Quad Enable bit.
> +              *
> +              * We can safely assume that when the Quad Enable method is
> +              * set, the value of the QE bit is one, as a consequence of the
> +              * nor->flash.quad_enable() call.
> +              *
> +              * We can safely assume that the Quad Enable bit is present in
> +              * the Status Register 2 at BIT(1). According to the JESD216
> +              * revB standard, BFPT DWORDS[15], bits 22:20, the 16-bit
> +              * Write Status (01h) command is available just for the cases
> +              * in which the QE bit is described in SR2 at BIT(1).
> +              */
> +             sr_cr[1] = CR_QUAD_EN_SPAN;
> +     } else {
> +             sr_cr[1] = 0;
> +     }
> +

CR_QUAD_EN_SPAN will not be in sr_cr[1] when we reach here. So code
won't enable quad mode.


> +     sr_cr[0] = status_new;
> +
> +     ret = spi_nor_write_sr(nor, sr_cr, 2);
> +     if (ret)
> +             return ret;
> +
> +     cr_written = sr_cr[1];
> +
> +     ret = spi_nor_read_sr(nor, &sr_cr[0]);
> +     if (ret)
> +             return ret;
> +
> +     if ((sr_cr[0] & mask) != (status_new & mask)) {
> +             dev_err(nor->dev, "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_written != sr_cr[1]) {
> +             dev_err(nor->dev, "Read back test failed\n");
> +             return -EIO;
> +     }
> +
> +     return 0;
> +}
> +

Regards
Vignesh