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mtd: spi-nor: Check that BP bits are set properly

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Previously, the lock and unlock functions returned success even if the
BP bits were not actually updated in the status register due to
hardware write protection. Introduce write_sr_and_check() to write and
read back the status register to ensure the desired BP bits are
actually set as requested.

Signed-off-by: Joe Schultz <jschultz@xes-inc.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>
This commit is contained in:
Aaron Sierra 2017-12-05 12:13:44 -06:00 committed by Cyrille Pitchen
parent 20ccb993f2
commit 2666067fdb
1 changed files with 23 additions and 12 deletions
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35
drivers/mtd/spi-nor/spi-nor.c
View file

@ -566,6 +566,27 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
return ret;
}
/* Write status register and ensure bits in mask match written values */
static int write_sr_and_check(struct spi_nor *nor, u8 status_new, u8 mask)
{
int ret;
write_enable(nor);
ret = write_sr(nor, status_new);
if (ret)
return ret;
ret = spi_nor_wait_till_ready(nor);
if (ret)
return ret;
ret = read_sr(nor);
if (ret < 0)
return ret;
return ((ret & mask) != (status_new & mask)) ? -EIO : 0;
}
static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
uint64_t *len)
{
@ -664,7 +685,6 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
loff_t lock_len;
bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
bool use_top;
int ret;
status_old = read_sr(nor);
if (status_old < 0)
@ -728,11 +748,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if ((status_new & mask) < (status_old & mask))
return -EINVAL;
write_enable(nor);
ret = write_sr(nor, status_new);
if (ret)
return ret;
return spi_nor_wait_till_ready(nor);
return write_sr_and_check(nor, status_new, mask);
}
/*
@ -749,7 +765,6 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
loff_t lock_len;
bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
bool use_top;
int ret;
status_old = read_sr(nor);
if (status_old < 0)
@ -816,11 +831,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if ((status_new & mask) > (status_old & mask))
return -EINVAL;
write_enable(nor);
ret = write_sr(nor, status_new);
if (ret)
return ret;
return spi_nor_wait_till_ready(nor);
return write_sr_and_check(nor, status_new, mask);
}
/*