[U-Boot] [PATCH 1/2] SPI Flash: add support of sst26wf* flash series

[Eugeniy Paltsev]

sst26wf flash series block protection implementation differs
from other SST series, so add implementation for sst26wf
lock/unlock/is_locked functions.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
---
 drivers/mtd/spi/spi_flash.c | 188 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 188 insertions(+)

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 294d9f9..ec3f5bc 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -842,6 +842,184 @@ int stm_unlock(struct spi_flash *flash, u32 ofs, size_t len)
 }
 #endif
 
+#if defined(CONFIG_SPI_FLASH_SST)
+#define SST26_CMD_READ_BPR		0x72
+#define SST26_CMD_WRITE_BPR		0x42
+
+#define BLOCK_64K_SZ			0x10000
+#define MAX_BPR_REG_LEN			(18 + 1)
+#define SST26WF_BOUND_REG_SIZE		((32 + 4 * 8) * 1024)
+
+bool sst26_check_bpr(u32 bpr_size, u8 *cmd, u32 bit)
+{
+	return !!(cmd[bpr_size - (bit / 8) - 1] & BIT(bit % 8));
+}
+
+bool sst26_clear_bpr(u32 bpr_size, u8 *cmd, u32 bit)
+{
+	cmd[bpr_size - (bit / 8) - 1] &= ~BIT(bit % 8);
+	return false;
+}
+
+bool sst26_set_bpr(u32 bpr_size, u8 *cmd, u32 bit)
+{
+	cmd[bpr_size - (bit / 8) - 1] |= BIT(bit % 8);
+	return false;
+}
+
+enum lock_ctl {
+	CTL_LOCK,
+	CTL_UNLOCK,
+	CTL_CHECK
+};
+
+/*
+ * 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)
+ */
+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[MAX_BPR_REG_LEN] = {};
+	int ret;
+
+	bool (* bpr_bit_process) (u32 bpr_size, u8 *, u32);
+
+	/* Check length and offset for 64k alignment */
+	if ((ofs & 0xFFFF) || (len & 0xFFFF))
+		return -EINVAL;
+
+	if (ofs + len > flash->size)
+		return -EINVAL;
+
+	/* SST26 family has only 16 Mbit, 32 Mbit and 64 Mbit IC */
+	if (flash->size != 0x200000 &&
+	    flash->size != 0x400000 &&
+	    flash->size != 0x800000)
+		return -EINVAL;
+
+	bpr_size = 2 + (flash->size / BLOCK_64K_SZ / 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;
+	}
+
+	if (ctl == CTL_LOCK)
+		bpr_bit_process = sst26_set_bpr;
+	else if (ctl == CTL_UNLOCK)
+		bpr_bit_process = sst26_clear_bpr;
+	else
+		bpr_bit_process = sst26_check_bpr;
+
+	rptr_64k = min_t(u32, ofs + len , flash->size - SST26WF_BOUND_REG_SIZE);
+	lptr_64k = max_t(u32, ofs, SST26WF_BOUND_REG_SIZE);
+
+	upper_64k = ((ofs + len) > (flash->size - SST26WF_BOUND_REG_SIZE));
+	lower_64k = (ofs < SST26WF_BOUND_REG_SIZE);
+
+	/* Lower bits in block-protection register are about 64k region */
+	bpr_ptr = lptr_64k / BLOCK_64K_SZ - 1;
+
+	/* Process 64K blocks region */
+	while (lptr_64k < rptr_64k) {
+		if (bpr_bit_process(bpr_size, bpr_buff, bpr_ptr))
+			return 1;
+
+		bpr_ptr++;
+		lptr_64k += BLOCK_64K_SZ;
+	}
+
+	/* 32K and 8K region bits in BPR are after 64k region bits */
+	bpr_ptr = (flash->size - 2 * SST26WF_BOUND_REG_SIZE) / BLOCK_64K_SZ;
+
+	/* Process lower 32K block region */
+	if (lower_64k)
+		if (bpr_bit_process(bpr_size, bpr_buff, bpr_ptr))
+			return 1;
+
+	bpr_ptr++;
+
+	/* Process upper 32K block region */
+	if (upper_64k)
+		if (bpr_bit_process(bpr_size, bpr_buff, bpr_ptr))
+			return 1;
+
+	bpr_ptr++;
+
+	/* Process lower 8K block region */
+	for (i = 0; i < 4; i++) {
+		if (lower_64k)
+			if (bpr_bit_process(bpr_size, bpr_buff, bpr_ptr))
+				return 1;
+
+		/* In 8K area BPR has both read and write protection bits */
+		bpr_ptr += 2;
+	}
+
+	/* Process upper 8K block region */
+	for (i = 0; i < 4; i++) {
+		if (upper_64k)
+			if (bpr_bit_process(bpr_size, bpr_buff, bpr_ptr))
+				return 1;
+
+		/* 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 == 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;
+}
+
+int sst26_unlock(struct spi_flash *flash, u32 ofs, size_t len)
+{
+	return sst26_lock_ctl(flash, ofs, len, CTL_UNLOCK);
+}
+
+int sst26_lock(struct spi_flash *flash, u32 ofs, size_t len)
+{
+	return sst26_lock_ctl(flash, ofs, len, CTL_LOCK);
+}
+
+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 & 0xFFFF;
+	len = len & 0xFFFF ? (len & ~0xFFFF) + BLOCK_64K_SZ : len;
+
+	return sst26_lock_ctl(flash, ofs, len, CTL_CHECK);
+}
+#endif
 
 #ifdef CONFIG_SPI_FLASH_MACRONIX
 static int macronix_quad_enable(struct spi_flash *flash)
@@ -1033,6 +1211,16 @@ int spi_flash_scan(struct spi_flash *flash)
 	}
 #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 &&
+	    (JEDEC_ID(info) >> 8) == 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;
-- 
2.9.3