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authorJungseung Lee <js07.lee@samsung.com>2020-03-18 15:06:13 +0300
committerTudor Ambarus <tudor.ambarus@microchip.com>2020-03-24 12:43:28 +0300
commit2d284768b49bcf1c643c08a201ff2161041178ef (patch)
tree90bb26bd07740c47c6c73c839a27306dd50882c1 /drivers/mtd
parentb0e2d252f9280835a24e007dcd6feaef5a8809cd (diff)
downloadlinux-2d284768b49bcf1c643c08a201ff2161041178ef.tar.xz
mtd: spi-nor: Add generic formula for SR block protection handling
The current mainline locking was restricted and could only be applied to flashes that have 3 block protection bits and fixed locking ratio. A new method of normalization was reached at the end of the discussion [1]. (1) - if bp slot is insufficient. (2) - if bp slot is sufficient. if (bp_slots_needed > bp_slots) // (1) min_prot_length = sector_size << (bp_slots_needed - bp_slots); else // (2) min_prot_length = sector_size; This patch changes logic to handle block protection based on min_prot_length. It is suitable for the overall flashes with exception of some corner cases (see EON and catalyst) and easy to extend and apply for the case of 2bit or 4bit block protection. [1] http://lists.infradead.org/pipermail/linux-mtd/2020-February/093934.html Signed-off-by: Jungseung Lee <js07.lee@samsung.com> Reviewed-by: Michael Walle <michael@walle.cc> Tested-by: Michael Walle <michael@walle.cc> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/spi-nor/core.c72
1 files changed, 41 insertions, 31 deletions
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index bc57b1b5ec62..8146d82afe61 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1536,29 +1536,51 @@ erase_err:
return ret;
}
+static u64 spi_nor_get_min_prot_length_sr(struct spi_nor *nor)
+{
+ unsigned int bp_slots, bp_slots_needed;
+ u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
+
+ /* Reserved one for "protect none" and one for "protect all". */
+ bp_slots = (mask >> SR_BP_SHIFT) + 1 - 2;
+ bp_slots_needed = ilog2(nor->info->n_sectors);
+
+ if (bp_slots_needed > bp_slots)
+ return nor->info->sector_size <<
+ (bp_slots_needed - bp_slots);
+ else
+ 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)
{
struct mtd_info *mtd = &nor->mtd;
+ u64 min_prot_len;
u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
u8 tb_mask = SR_TB_BIT5;
- int pow;
+ u8 bp = (sr & mask) >> SR_BP_SHIFT;
if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
tb_mask = SR_TB_BIT6;
- if (!(sr & mask)) {
+ if (!bp) {
/* No protection */
*ofs = 0;
*len = 0;
- } else {
- pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
- *len = mtd->size >> pow;
- if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
- *ofs = 0;
- else
- *ofs = mtd->size - *len;
+ return;
}
+
+ min_prot_len = spi_nor_get_min_prot_length_sr(nor);
+ *len = min_prot_len << (bp - 1);
+
+ if (*len > mtd->size)
+ *len = mtd->size;
+
+ if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
+ *ofs = 0;
+ else
+ *ofs = mtd->size - *len;
}
/*
@@ -1631,6 +1653,7 @@ static int spi_nor_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
struct mtd_info *mtd = &nor->mtd;
+ u64 min_prot_len;
int ret, status_old, status_new;
u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
u8 tb_mask = SR_TB_BIT5;
@@ -1673,20 +1696,12 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
tb_mask = SR_TB_BIT6;
- /*
- * Need smallest pow such that:
- *
- * 1 / (2^pow) <= (len / size)
- *
- * so (assuming power-of-2 size) we do:
- *
- * pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
- */
if (lock_len == mtd->size) {
val = mask;
} else {
- pow = ilog2(mtd->size) - ilog2(lock_len);
- val = mask - (pow << SR_BP_SHIFT);
+ min_prot_len = spi_nor_get_min_prot_length_sr(nor);
+ pow = ilog2(lock_len) - ilog2(min_prot_len) + 1;
+ val = pow << SR_BP_SHIFT;
if (val & ~mask)
return -EINVAL;
@@ -1723,6 +1738,7 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
static int spi_nor_sr_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
struct mtd_info *mtd = &nor->mtd;
+ u64 min_prot_len;
int ret, status_old, status_new;
u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
u8 tb_mask = SR_TB_BIT5;
@@ -1764,20 +1780,14 @@ static int spi_nor_sr_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
tb_mask = SR_TB_BIT6;
- /*
- * Need largest pow such that:
- *
- * 1 / (2^pow) >= (len / size)
- *
- * so (assuming power-of-2 size) we do:
- *
- * pow = floor(log2(size / len)) = log2(size) - ceil(log2(len))
- */
- pow = ilog2(mtd->size) - order_base_2(lock_len);
+
if (lock_len == 0) {
val = 0; /* fully unlocked */
} else {
- val = mask - (pow << SR_BP_SHIFT);
+ min_prot_len = spi_nor_get_min_prot_length_sr(nor);
+ pow = ilog2(lock_len) - ilog2(min_prot_len) + 1;
+ val = pow << SR_BP_SHIFT;
+
/* Some power-of-two sizes are not supported */
if (val & ~mask)
return -EINVAL;