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mtd: spi-nor: ignore errors in spi_nor_unlock_all()

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Just try to unlock the whole SPI-NOR flash array. Don't abort the
probing in case of an error. Justifications:
 (1) For some boards, this just works because
     spi_nor_write_16bit_sr_and_check() is broken and just checks the
     second half of the 16bit. Once that will be fixed, SPI probe will
     fail for boards which has hardware-write protected SPI-NOR flashes.
 (2) Until now, hardware write-protection was the only viable solution
     to use the block protection bits. This is because this very
     function spi_nor_unlock_all() will be called unconditionally on
     every linux boot. Therefore, this bits only makes sense in
     combination with the hardware write-protection. If we would fail
     the SPI probe on an error in spi_nor_unlock_all() we'd break
     virtually all users of the block protection bits.
 (3) We should try hard to keep the MTD working even if the flash might
     not be writable/erasable.

Fixes: 3e0930f109 ("mtd: spi-nor: Rework the disabling of block write protection")
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201203162959.29589-3-michael@walle.cc
This commit is contained in:
Michael Walle 2020-12-03 17:29:54 +01:00 committed by Vignesh Raghavendra
parent 989d4b72ba
commit bdb1a75e4b
1 changed files with 13 additions and 10 deletions
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23
drivers/mtd/spi-nor/core.c
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@ -3122,20 +3122,27 @@ static int spi_nor_quad_enable(struct spi_nor *nor)
}
/**
* spi_nor_unlock_all() - Unlocks the entire flash memory array.
* spi_nor_try_unlock_all() - Tries to unlock the entire flash memory array.
* @nor: pointer to a 'struct spi_nor'.
*
* Some SPI NOR flashes are write protected by default after a power-on reset
* cycle, in order to avoid inadvertent writes during power-up. Backward
* compatibility imposes to unlock the entire flash memory array at power-up
* by default.
*
* Unprotecting the entire flash array will fail for boards which are hardware
* write-protected. Thus any errors are ignored.
*/
static int spi_nor_unlock_all(struct spi_nor *nor)
static void spi_nor_try_unlock_all(struct spi_nor *nor)
{
if (nor->flags & SNOR_F_HAS_LOCK)
return spi_nor_unlock(&nor->mtd, 0, nor->params->size);
int ret;
return 0;
if (!(nor->flags & SNOR_F_HAS_LOCK))
return;
ret = spi_nor_unlock(&nor->mtd, 0, nor->params->size);
if (ret)
dev_dbg(nor->dev, "Failed to unlock the entire flash memory array\n");
}
static int spi_nor_init(struct spi_nor *nor)
@ -3154,11 +3161,7 @@ static int spi_nor_init(struct spi_nor *nor)
return err;
}
err = spi_nor_unlock_all(nor);
if (err) {
dev_dbg(nor->dev, "Failed to unlock the entire flash memory array\n");
return err;
}
spi_nor_try_unlock_all(nor);
if (nor->addr_width == 4 &&
nor->read_proto != SNOR_PROTO_8_8_8_DTR &&