--- /dev/null
+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;
+@@ -1164,7 +1216,7 @@ 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) },
+
+@@ -1220,6 +1272,9 @@ 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;
+
+@@ -1244,6 +1299,18 @@ 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;
+ }
+@@ -1345,6 +1412,10 @@ 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;
+@@ -1392,6 +1463,7 @@ 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;
+ }
+@@ -2808,8 +2880,10 @@ 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);
projects / openwrt / staging / kaloz.git / blobdiff