The spi-nor core will convert the address mode to 4-btye, without checking whether 4-byte address is supported or not. For example, the 16M s25fs128s1 can work under both 3-byte and 4-byte address and provides a 4bait table. The spi-nor will drive the flash under 4-byte address mode after parsing the 4bait and will cause it unusable on platforms doesn't support 4-byte.

Add checking of 4-byte address support when parsing the 4bait table, stop converting the address mode if it's not supported.

The issue maybe addressed by moving the address mode set and 4-byte operation check out of paring 4bait table[1], but fix this with this patch to make the flash work properly on some platform first.

[1] https://lore.kernel.org/linux-mtd/20210129111649.jypytpp7dkywthwh@ti.com/

Signed-off-by: Yicong Yang yangyicong@hisilicon.com --- Change since v1: - address the comments from Pratyush

Link: https://lore.kernel.org/linux-mtd/20210129111649.jypytpp7dkywthwh@ti.com/

drivers/mtd/spi-nor/sfdp.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c index 6ee7719..46ce389 100644 --- a/drivers/mtd/spi-nor/sfdp.c +++ b/drivers/mtd/spi-nor/sfdp.c @@ -940,6 +940,25 @@ static int spi_nor_parse_smpt(struct spi_nor *nor, return ret; }

+static int spi_nor_spimem_check_4byte_addr(struct spi_nor *nor, + const struct spi_nor_read_command *read) +{ + struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 0), + SPI_MEM_OP_ADDR(4, 0, 1), + SPI_MEM_OP_DUMMY(0, 1), + SPI_MEM_OP_DATA_IN(0, NULL, 1)); + + spi_nor_spimem_setup_op(nor, &op, read->proto); + + op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) * + op.dummy.buswidth / 8; + + if (!spi_mem_supports_op(nor->spimem, &op)) + return -EOPNOTSUPP; + + return 0; +} + /** * spi_nor_parse_4bait() - parse the 4-Byte Address Instruction Table * @nor: pointer to a 'struct spi_nor'. @@ -1061,6 +1080,33 @@ static int spi_nor_parse_4bait(struct spi_nor *nor, goto out;

/* + * Check whether the 4-byte address is supported before converting + * the instruction set to 4-byte. + */ + if (nor->spimem) { + bool support = false; + + for (i = 0; i < SNOR_CMD_READ_MAX; i++) { + struct spi_nor_read_command read_cmd; + + memcpy(&read_cmd, &params->reads[i], sizeof(read_cmd)); + + read_cmd.opcode = spi_nor_convert_3to4_read(read_cmd.opcode); + if (!spi_nor_spimem_check_4byte_addr(nor, &read_cmd)) { + support = true; + break; + } + } + + /* + * No supported 4-byte instruction is found, stop parsing the + * 4bait table. + */ + if (!support) + goto out; + } + + /* * Discard all operations from the 4-byte instruction set which are * not supported by this memory. */