OpenWrt – Rev 1
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mtd: spi-nor: add support for switching between 3-byte and 4-byte addressing on w25q256 flash
On some devices the flash chip needs to be in 3-byte addressing mode during
reboot, otherwise the boot loader will fail to start.
This mode however does not allow regular reads/writes onto the upper 16M
half. W25Q256 has separate read commands for reading from >16M, however
it does not have any separate write commands.
This patch changes the code to leave the chip in 3-byte mode most of the
time and only switch during erase/write cycles that go to >16M
addresses.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -89,6 +89,10 @@ struct flash_info {
#define NO_CHIP_ERASE BIT(12) /* Chip does not support chip erase */
#define SPI_NOR_SKIP_SFDP BIT(13) /* Skip parsing of SFDP tables */
#define USE_CLSR BIT(14) /* use CLSR command */
+#define SPI_NOR_4B_READ_OP BIT(15) /*
+ * Like SPI_NOR_4B_OPCODES, but for read
+ * op code only.
+ */
};
#define JEDEC_MFR(info) ((info)->id[0])
@@ -240,6 +244,15 @@ static inline u8 spi_nor_convert_3to4_er
ARRAY_SIZE(spi_nor_3to4_erase));
}
+static void spi_nor_set_4byte_read(struct spi_nor *nor,
+ const struct flash_info *info)
+{
+ nor->addr_width = 3;
+ nor->ext_addr = 0;
+ nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
+ nor->flags |= SNOR_F_4B_EXT_ADDR;
+}
+
static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
const struct flash_info *info)
{
@@ -467,6 +480,36 @@ static int spi_nor_erase_sector(struct s
return nor->write_reg(nor, nor->erase_opcode, buf, nor->addr_width);
}
+static int spi_nor_check_ext_addr(struct spi_nor *nor, u32 addr)
+{
+ bool ext_addr;
+ int ret;
+ u8 cmd;
+
+ if (!(nor->flags & SNOR_F_4B_EXT_ADDR))
+ return 0;
+
+ ext_addr = !!(addr & 0xff000000);
+ if (nor->ext_addr == ext_addr)
+ return 0;
+
+ cmd = ext_addr ? SPINOR_OP_EN4B : SPINOR_OP_EX4B;
+ write_enable(nor);
+ ret = nor->write_reg(nor, cmd, NULL, 0);
+ if (ret)
+ return ret;
+
+ cmd = 0;
+ ret = nor->write_reg(nor, SPINOR_OP_WREAR, &cmd, 1);
+ if (ret)
+ return ret;
+
+ nor->addr_width = 3 + ext_addr;
+ nor->ext_addr = ext_addr;
+ write_disable(nor);
+ return 0;
+}
+
/*
* Erase an address range on the nor chip. The address range may extend
* one or more erase sectors. Return an error is there is a problem erasing.
@@ -492,6 +535,10 @@ static int spi_nor_erase(struct mtd_info
if (ret)
return ret;
+ ret = spi_nor_check_ext_addr(nor, addr + len);
+ if (ret)
+ return ret;
+
/* whole-chip erase? */
if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
unsigned long timeout;
@@ -542,6 +589,7 @@ static int spi_nor_erase(struct mtd_info
write_disable(nor);
erase_err:
+ spi_nor_check_ext_addr(nor, 0);
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);
instr->state = ret ? MTD_ERASE_FAILED : MTD_ERASE_DONE;
@@ -834,7 +882,9 @@ static int spi_nor_lock(struct mtd_info
if (ret)
return ret;
+ spi_nor_check_ext_addr(nor, ofs + len);
ret = nor->flash_lock(nor, ofs, len);
+ spi_nor_check_ext_addr(nor, 0);
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
return ret;
@@ -849,7 +899,9 @@ static int spi_nor_unlock(struct mtd_inf
if (ret)
return ret;
+ spi_nor_check_ext_addr(nor, ofs + len);
ret = nor->flash_unlock(nor, ofs, len);
+ spi_nor_check_ext_addr(nor, 0);
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
return ret;
@@ -1177,7 +1229,7 @@ static const struct flash_info spi_nor_i
{ "w25q80", INFO(0xef5014, 0, 64 * 1024, 16, SECT_4K) },
{ "w25q80bl", INFO(0xef4014, 0, 64 * 1024, 16, SECT_4K) },
{ "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
- { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+ { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_READ_OP) },
{ "w25m512jv", INFO(0xef7119, 0, 64 * 1024, 1024,
SECT_4K | SPI_NOR_QUAD_READ | SPI_NOR_DUAL_READ) },
@@ -1237,6 +1289,9 @@ static int spi_nor_read(struct mtd_info
if (ret)
return ret;
+ if (nor->flags & SNOR_F_4B_EXT_ADDR)
+ nor->addr_width = 4;
+
while (len) {
loff_t addr = from;
@@ -1261,6 +1316,18 @@ static int spi_nor_read(struct mtd_info
ret = 0;
read_err:
+ if (nor->flags & SNOR_F_4B_EXT_ADDR) {
+ u8 val = 0;
+
+ if ((from + len) & 0xff000000) {
+ write_enable(nor);
+ nor->write_reg(nor, SPINOR_OP_WREAR, &val, 1);
+ write_disable(nor);
+ }
+
+ nor->addr_width = 3;
+ }
+
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
return ret;
}
@@ -1362,6 +1429,10 @@ static int spi_nor_write(struct mtd_info
if (ret)
return ret;
+ ret = spi_nor_check_ext_addr(nor, to + len);
+ if (ret < 0)
+ return ret;
+
for (i = 0; i < len; ) {
ssize_t written;
loff_t addr = to + i;
@@ -1402,6 +1473,7 @@ static int spi_nor_write(struct mtd_info
}
write_err:
+ spi_nor_check_ext_addr(nor, 0);
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
return ret;
}
@@ -2818,8 +2890,10 @@ int spi_nor_scan(struct spi_nor *nor, co
} else if (mtd->size > 0x1000000) {
/* enable 4-byte addressing if the device exceeds 16MiB */
nor->addr_width = 4;
- if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
- info->flags & SPI_NOR_4B_OPCODES)
+ if (info->flags & SPI_NOR_4B_READ_OP)
+ spi_nor_set_4byte_read(nor, info);
+ else if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
+ info->flags & SPI_NOR_4B_OPCODES)
spi_nor_set_4byte_opcodes(nor, info);
else
set_4byte(nor, info, 1);
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -102,6 +102,7 @@
/* Used for Macronix and Winbond flashes. */
#define SPINOR_OP_EN4B 0xb7 /* Enter 4-byte mode */
#define SPINOR_OP_EX4B 0xe9 /* Exit 4-byte mode */
+#define SPINOR_OP_WREAR 0xc5 /* Write extended address register */
/* Used for Spansion flashes only. */
#define SPINOR_OP_BRWR 0x17 /* Bank register write */
@@ -229,6 +230,7 @@ enum spi_nor_option_flags {
SNOR_F_S3AN_ADDR_DEFAULT = BIT(3),
SNOR_F_READY_XSR_RDY = BIT(4),
SNOR_F_USE_CLSR = BIT(5),
+ SNOR_F_4B_EXT_ADDR = BIT(6),
};
/**
@@ -280,6 +282,7 @@ struct spi_nor {
enum spi_nor_protocol reg_proto;
bool sst_write_second;
u32 flags;
+ u8 ext_addr;
u8 cmd_buf[SPI_NOR_MAX_CMD_SIZE];
int (*prepare)(struct spi_nor *nor, enum spi_nor_ops ops);