mtd: sf: Add support of sst26wf* flash ICs protection ops
sst26wf flash series block protection implementation differs
from other SST series, so add specific implementation
flash_lock/flash_unlock/flash_is_locked functions for sst26wf
flash ICs.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 2e61685..5e5bd5d 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -16,6 +16,7 @@
#include <spi.h>
#include <spi_flash.h>
#include <linux/log2.h>
+#include <linux/sizes.h>
#include <dma.h>
#include "sf_internal.h"
@@ -541,6 +542,164 @@
}
#ifdef CONFIG_SPI_FLASH_SST
+static bool sst26_process_bpr(u32 bpr_size, u8 *cmd, u32 bit, enum lock_ctl ctl)
+{
+ switch (ctl) {
+ case SST26_CTL_LOCK:
+ cmd[bpr_size - (bit / 8) - 1] |= BIT(bit % 8);
+ break;
+ case SST26_CTL_UNLOCK:
+ cmd[bpr_size - (bit / 8) - 1] &= ~BIT(bit % 8);
+ break;
+ case SST26_CTL_CHECK:
+ return !!(cmd[bpr_size - (bit / 8) - 1] & BIT(bit % 8));
+ }
+
+ return false;
+}
+
+/*
+ * sst26wf016/sst26wf032/sst26wf064 have next block protection:
+ * 4x - 8 KByte blocks - read & write protection bits - upper addresses
+ * 1x - 32 KByte blocks - write protection bits
+ * rest - 64 KByte blocks - write protection bits
+ * 1x - 32 KByte blocks - write protection bits
+ * 4x - 8 KByte blocks - read & write protection bits - lower addresses
+ *
+ * We'll support only per 64k lock/unlock so lower and upper 64 KByte region
+ * will be treated as single block.
+ */
+
+/*
+ * Lock, unlock or check lock status of the flash region of the flash (depending
+ * on the lock_ctl value)
+ */
+static int sst26_lock_ctl(struct spi_flash *flash, u32 ofs, size_t len, enum lock_ctl ctl)
+{
+ u32 i, bpr_ptr, rptr_64k, lptr_64k, bpr_size;
+ bool lower_64k = false, upper_64k = false;
+ u8 cmd, bpr_buff[SST26_MAX_BPR_REG_LEN] = {};
+ int ret;
+
+ /* Check length and offset for 64k alignment */
+ if ((ofs & (SZ_64K - 1)) || (len & (SZ_64K - 1)))
+ return -EINVAL;
+
+ if (ofs + len > flash->size)
+ return -EINVAL;
+
+ /* SST26 family has only 16 Mbit, 32 Mbit and 64 Mbit IC */
+ if (flash->size != SZ_2M &&
+ flash->size != SZ_4M &&
+ flash->size != SZ_8M)
+ return -EINVAL;
+
+ bpr_size = 2 + (flash->size / SZ_64K / 8);
+
+ cmd = SST26_CMD_READ_BPR;
+ ret = spi_flash_read_common(flash, &cmd, 1, bpr_buff, bpr_size);
+ if (ret < 0) {
+ printf("SF: fail to read block-protection register\n");
+ return ret;
+ }
+
+ rptr_64k = min_t(u32, ofs + len , flash->size - SST26_BOUND_REG_SIZE);
+ lptr_64k = max_t(u32, ofs, SST26_BOUND_REG_SIZE);
+
+ upper_64k = ((ofs + len) > (flash->size - SST26_BOUND_REG_SIZE));
+ lower_64k = (ofs < SST26_BOUND_REG_SIZE);
+
+ /* Lower bits in block-protection register are about 64k region */
+ bpr_ptr = lptr_64k / SZ_64K - 1;
+
+ /* Process 64K blocks region */
+ while (lptr_64k < rptr_64k) {
+ if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
+ return EACCES;
+
+ bpr_ptr++;
+ lptr_64k += SZ_64K;
+ }
+
+ /* 32K and 8K region bits in BPR are after 64k region bits */
+ bpr_ptr = (flash->size - 2 * SST26_BOUND_REG_SIZE) / SZ_64K;
+
+ /* Process lower 32K block region */
+ if (lower_64k)
+ if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
+ return EACCES;
+
+ bpr_ptr++;
+
+ /* Process upper 32K block region */
+ if (upper_64k)
+ if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
+ return EACCES;
+
+ bpr_ptr++;
+
+ /* Process lower 8K block regions */
+ for (i = 0; i < SST26_BPR_8K_NUM; i++) {
+ if (lower_64k)
+ if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
+ return EACCES;
+
+ /* In 8K area BPR has both read and write protection bits */
+ bpr_ptr += 2;
+ }
+
+ /* Process upper 8K block regions */
+ for (i = 0; i < SST26_BPR_8K_NUM; i++) {
+ if (upper_64k)
+ if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
+ return EACCES;
+
+ /* In 8K area BPR has both read and write protection bits */
+ bpr_ptr += 2;
+ }
+
+ /* If we check region status we don't need to write BPR back */
+ if (ctl == SST26_CTL_CHECK)
+ return 0;
+
+ cmd = SST26_CMD_WRITE_BPR;
+ ret = spi_flash_write_common(flash, &cmd, 1, bpr_buff, bpr_size);
+ if (ret < 0) {
+ printf("SF: fail to write block-protection register\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int sst26_unlock(struct spi_flash *flash, u32 ofs, size_t len)
+{
+ return sst26_lock_ctl(flash, ofs, len, SST26_CTL_UNLOCK);
+}
+
+static int sst26_lock(struct spi_flash *flash, u32 ofs, size_t len)
+{
+ return sst26_lock_ctl(flash, ofs, len, SST26_CTL_LOCK);
+}
+
+/*
+ * Returns EACCES (positive value) if region is locked, 0 if region is unlocked,
+ * and negative on errors.
+ */
+static int sst26_is_locked(struct spi_flash *flash, u32 ofs, size_t len)
+{
+ /*
+ * is_locked function is used for check before reading or erasing flash
+ * region, so offset and length might be not 64k allighned, so adjust
+ * them to be 64k allighned as sst26_lock_ctl works only with 64k
+ * allighned regions.
+ */
+ ofs -= ofs & (SZ_64K - 1);
+ len = len & (SZ_64K - 1) ? (len & ~(SZ_64K - 1)) + SZ_64K : len;
+
+ return sst26_lock_ctl(flash, ofs, len, SST26_CTL_CHECK);
+}
+
static int sst_byte_write(struct spi_flash *flash, u32 offset, const void *buf)
{
struct spi_slave *spi = flash->spi;
@@ -1033,6 +1192,15 @@
}
#endif
+/* sst26wf series block protection implementation differs from other series */
+#if defined(CONFIG_SPI_FLASH_SST)
+ if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_SST && info->id[1] == 0x26) {
+ flash->flash_lock = sst26_lock;
+ flash->flash_unlock = sst26_unlock;
+ flash->flash_is_locked = sst26_is_locked;
+ }
+#endif
+
/* Compute the flash size */
flash->shift = (flash->dual_flash & SF_DUAL_PARALLEL_FLASH) ? 1 : 0;
flash->page_size = info->page_size;