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mtd: spi-nor: add support for TB bit in control register
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Some flashes like the Macronix MX25U3232F has the TB bit in the control
register and not in the status register. Unfortunately, this means that
we now have to read two registers and pass its contents to various
functions. It also means that these functions have to be renamed,
because they are all ending in _sr() but they don't exclusivly operate
on the status register anymore.

Signed-off-by: Michael Walle <michael@walle.cc>
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@mwalle
mwalle committed Nov 15, 2020
1 parent 1a56154 commit 7f3d4f7
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Showing 3 changed files with 73 additions and 29 deletions.
97 changes: 68 additions & 29 deletions drivers/mtd/spi-nor/core.c
View file
Expand Up @@ -1709,12 +1709,14 @@ static u8 spi_nor_get_sr_tb_mask(struct spi_nor *nor)
return SR_TB_BIT5;
}

static bool spi_nor_is_bottom_locked(struct spi_nor *nor, u8 sr)
static bool spi_nor_is_bottom_locked(struct spi_nor *nor, u8 sr, u8 cr)
{
u8 sr_tb_mask = spi_nor_get_sr_tb_mask(nor);

if (nor->flags & SNOR_F_HAS_SR_TB)
return sr & sr_tb_mask;
else if (nor->flags & SNOR_F_HAS_CR_TB)
return cr & CR_TB_BIT3;
else
return 0;
}
Expand All @@ -1725,6 +1727,8 @@ static bool spi_nor_has_writable_tb_bit(struct spi_nor *nor)
return false;
if (nor->flags & SNOR_F_HAS_SR_TB)
return true;
if (nor->flags & SNOR_F_HAS_CR_TB)
return true;
return false;
}

Expand All @@ -1744,8 +1748,8 @@ static u64 spi_nor_get_min_prot_length_sr(struct spi_nor *nor)
return nor->info->sector_size;
}

static void spi_nor_get_locked_range_sr(struct spi_nor *nor, u8 sr, loff_t *ofs,
uint64_t *len)
static void spi_nor_get_locked_range(struct spi_nor *nor, u8 sr, u8 cr,
loff_t *ofs, uint64_t *len)
{
struct mtd_info *mtd = &nor->mtd;
u64 min_prot_len;
Expand All @@ -1770,7 +1774,7 @@ static void spi_nor_get_locked_range_sr(struct spi_nor *nor, u8 sr, loff_t *ofs,
if (*len > mtd->size)
*len = mtd->size;

if (spi_nor_is_bottom_locked(nor, sr))
if (spi_nor_is_bottom_locked(nor, sr, cr))
*ofs = 0;
else
*ofs = mtd->size - *len;
Expand All @@ -1780,16 +1784,16 @@ static void spi_nor_get_locked_range_sr(struct spi_nor *nor, u8 sr, loff_t *ofs,
* Return 1 if the entire region is locked (if @locked is true) or unlocked (if
* @locked is false); 0 otherwise
*/
static int spi_nor_check_lock_status_sr(struct spi_nor *nor, loff_t ofs,
uint64_t len, u8 sr, bool locked)
static int spi_nor_check_lock_status(struct spi_nor *nor, loff_t ofs,
uint64_t len, u8 sr, u8 cr, bool locked)
{
loff_t lock_offs;
uint64_t lock_len;

if (!len)
return 1;

spi_nor_get_locked_range_sr(nor, sr, &lock_offs, &lock_len);
spi_nor_get_locked_range(nor, sr, cr, &lock_offs, &lock_len);

if (locked)
/* Requested range is a sub-range of locked range */
Expand All @@ -1799,16 +1803,16 @@ static int spi_nor_check_lock_status_sr(struct spi_nor *nor, loff_t ofs,
return (ofs >= lock_offs + lock_len) || (ofs + len <= lock_offs);
}

static int spi_nor_is_locked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
u8 sr)
static int spi_nor_is_range_locked(struct spi_nor *nor, loff_t ofs,
uint64_t len, u8 sr, u8 cr)
{
return spi_nor_check_lock_status_sr(nor, ofs, len, sr, true);
return spi_nor_check_lock_status(nor, ofs, len, sr, cr, true);
}

static int spi_nor_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
u8 sr)
static int spi_nor_is_range_unlocked(struct spi_nor *nor, loff_t ofs,
uint64_t len, u8 sr, u8 cr)
{
return spi_nor_check_lock_status_sr(nor, ofs, len, sr, false);
return spi_nor_check_lock_status(nor, ofs, len, sr, cr, false);
}

/*
Expand Down Expand Up @@ -1854,31 +1858,39 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
loff_t lock_len;
bool can_be_top, can_be_bottom;
bool use_top;
u8 control = 0;

ret = spi_nor_read_sr(nor, nor->bouncebuf);
if (ret)
return ret;

status_old = nor->bouncebuf[0];

if (nor->flags & SNOR_F_HAS_CR_TB) {
ret = spi_nor_read_cr(nor, nor->bouncebuf);
if (ret)
return ret;
control = nor->bouncebuf[0];
}

if (spi_nor_has_writable_tb_bit(nor))
can_be_top = can_be_bottom = true;
else if (spi_nor_is_bottom_locked(nor, status_old))
else if (spi_nor_is_bottom_locked(nor, status_old, control))
can_be_bottom = true;
else
can_be_top = true;

/* If nothing in our range is unlocked, we don't need to do anything */
if (spi_nor_is_locked_sr(nor, ofs, len, status_old))
if (spi_nor_is_range_locked(nor, ofs, len, status_old, control))
return 0;

/* If anything below us is unlocked, we can't use 'bottom' protection */
if (!spi_nor_is_locked_sr(nor, 0, ofs, status_old))
if (!spi_nor_is_range_locked(nor, 0, ofs, status_old, control))
can_be_bottom = false;

/* If anything above us is unlocked, we can't use 'top' protection */
if (!spi_nor_is_locked_sr(nor, ofs + len, mtd->size - (ofs + len),
status_old))
if (!spi_nor_is_range_locked(nor, ofs + len, mtd->size - (ofs + len),
status_old, control))
can_be_top = false;

if (!can_be_bottom && !can_be_top)
Expand Down Expand Up @@ -1916,7 +1928,13 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
/* Disallow further writes if WP pin is asserted */
status_new |= SR_SRWD;

/* Write the TB bit back if it is not OTP */
/*
* Write the TB bit back if it is not OTP.
*
* Please note that writeback of a TB bit in the control register is
* not implemented yet! As the time of this writing I'm not aware of
* any flashes which have a writable TB bit in the control register.
*/
if (!(nor->flags & SNOR_F_HAS_OTP_TB)) {
u8 tb_mask = spi_nor_get_sr_tb_mask(nor);

Expand Down Expand Up @@ -1952,31 +1970,39 @@ static int spi_nor_sr_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
loff_t lock_len;
bool can_be_top, can_be_bottom;
bool use_top;
u8 control = 0;

ret = spi_nor_read_sr(nor, nor->bouncebuf);
if (ret)
return ret;

status_old = nor->bouncebuf[0];

if (nor->flags & SNOR_F_HAS_CR_TB) {
ret = spi_nor_read_cr(nor, nor->bouncebuf);
if (ret)
return ret;
control = nor->bouncebuf[0];
}

if (spi_nor_has_writable_tb_bit(nor))
can_be_top = can_be_bottom = true;
else if (spi_nor_is_bottom_locked(nor, status_old))
else if (spi_nor_is_bottom_locked(nor, status_old, control))
can_be_bottom = true;
else
can_be_top = true;

/* If nothing in our range is locked, we don't need to do anything */
if (spi_nor_is_unlocked_sr(nor, ofs, len, status_old))
if (spi_nor_is_range_unlocked(nor, ofs, len, status_old, control))
return 0;

/* If anything below us is locked, we can't use 'top' protection */
if (!spi_nor_is_unlocked_sr(nor, 0, ofs, status_old))
if (!spi_nor_is_range_unlocked(nor, 0, ofs, status_old, control))
can_be_top = false;

/* If anything above us is locked, we can't use 'bottom' protection */
if (!spi_nor_is_unlocked_sr(nor, ofs + len, mtd->size - (ofs + len),
status_old))
if (!spi_nor_is_range_unlocked(nor, ofs + len, mtd->size - (ofs + len),
status_old, control))
can_be_bottom = false;

if (!can_be_bottom && !can_be_top)
Expand Down Expand Up @@ -2012,7 +2038,7 @@ static int spi_nor_sr_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if (lock_len == 0)
status_new &= ~SR_SRWD;

/* Write the TB bit back if it is not OTP */
/* Write the TB bit back if it is not OTP. See spi_nor_sr_lock(). */
if (!(nor->flags & SNOR_F_HAS_OTP_TB)) {
u8 tb_mask = spi_nor_get_sr_tb_mask(nor);

Expand Down Expand Up @@ -2043,12 +2069,21 @@ static int spi_nor_sr_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
static int spi_nor_sr_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
int ret;
u8 sr, cr = 0;

ret = spi_nor_read_sr(nor, nor->bouncebuf);
if (ret)
return ret;
sr = nor->bouncebuf[0];

if (nor->flags & SNOR_F_HAS_CR_TB) {
ret = spi_nor_read_cr(nor, nor->bouncebuf);
if (ret)
return ret;
cr = nor->bouncebuf[0];
}

return spi_nor_is_locked_sr(nor, ofs, len, nor->bouncebuf[0]);
return spi_nor_is_range_locked(nor, ofs, len, sr, cr);
}

static const struct spi_nor_locking_ops spi_nor_sr_locking_ops = {
Expand Down Expand Up @@ -3639,9 +3674,13 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
if (info->flags & USE_FSR)
nor->flags |= SNOR_F_USE_FSR;
if (info->flags & SPI_NOR_HAS_TB) {
nor->flags |= SNOR_F_HAS_SR_TB;
if (info->flags & SPI_NOR_TB_SR_BIT6)
nor->flags |= SNOR_F_HAS_SR_TB_BIT6;
if (info->flags & SPI_NOR_TB_CR)
nor->flags |= SNOR_F_HAS_CR_TB;
else {
nor->flags |= SNOR_F_HAS_SR_TB;
if (info->flags & SPI_NOR_TB_SR_BIT6)
nor->flags |= SNOR_F_HAS_SR_TB_BIT6;
}
}
if (info->flags & SPI_NOR_HAS_OTP_TB)
nor->flags |= SNOR_F_HAS_OTP_TB;
Expand Down
3 changes: 3 additions & 0 deletions drivers/mtd/spi-nor/core.h
View file
Expand Up @@ -29,6 +29,8 @@ enum spi_nor_option_flags {
SNOR_F_IO_MODE_EN_VOLATILE = BIT(14),
SNOR_F_SOFT_RESET = BIT(15),
SNOR_F_WP_IS_VOLATILE = BIT(16),
SNOR_F_HAS_OTP_TB = BIT(17),
SNOR_F_HAS_CR_TB = BIT(18),
};

struct spi_nor_read_command {
Expand Down Expand Up @@ -369,6 +371,7 @@ struct flash_info {
* a write-protected state.
*/
#define SPI_NOR_HAS_OTP_TB BIT(20) /* TB bit is one time programmable. */
#define SPI_NOR_TB_CR BIT(21) /* TB is in control register */

/* Part specific fixup hooks. */
const struct spi_nor_fixups *fixups;
Expand Down
2 changes: 2 additions & 0 deletions include/linux/mtd/spi-nor.h
View file
Expand Up @@ -146,6 +146,8 @@

#define SR_BP_SHIFT 2

#define CR_TB_BIT3 BIT(3)

/* Enhanced Volatile Configuration Register bits */
#define EVCR_QUAD_EN_MICRON BIT(7) /* Micron Quad I/O */

Expand Down

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