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We need to track the flash's internal address mode as there are flashes that can operate with 4B opcodes but unfortunately do not have a 4B opcode correspondent for all the 3B opcodes. Such an example is the Infineon Semper chips which provide 4B opcodes for read/program/erase but do not provide 4B opcodes for Read/Write Any Register. These registers are indexed by address and require the internal address mode of the flash before Read/Write Any Register opcodes are issued. 4B opcodes are preferred over changing the flash's address mode to 4byte, as set_4byte_addr_mode could be done in a non-volatile way and could break the boot sequence. Thus we need to track the flash's internal address mode so that we can use 4B opcodes together with opcodes that don't have a 4B opcode correspondent. Track flash's internal address mode. addr_mode_nbytes is discovered when parsing BFPT. For the BFPT_DWORD1_ADDRESS_BYTES_3_OR_4 case, one could introduce a method that queries the flash's internal address mode at run-time (works for Winbond). If a run-time querying can not be accomplished or if SFDP is not defined at all, but the address mode is volatile and resets to a default known value at boot, one can change the default addr_mode_nbytes value of 3 by introducing a flash_info flag. If the address mode can not be queried, discovered and it is configured via a non-volatile register, we may introduce a dt property, but it will harm the generic approach of the jedec,spi-nor compatible. All this complexity is not needed now, so let it for future development. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Reviewed-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com> Reviewed-by: Michael Walle <michael@walle.cc> Link: https://lore.kernel.org/r/20220725092505.446315-6-tudor.ambarus@microchip.com |
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| .. | ||
| controllers | ||
| atmel.c | ||
| catalyst.c | ||
| core.c | ||
| core.h | ||
| debugfs.c | ||
| eon.c | ||
| esmt.c | ||
| everspin.c | ||
| fujitsu.c | ||
| gigadevice.c | ||
| intel.c | ||
| issi.c | ||
| Kconfig | ||
| macronix.c | ||
| Makefile | ||
| micron-st.c | ||
| otp.c | ||
| sfdp.c | ||
| sfdp.h | ||
| spansion.c | ||
| sst.c | ||
| swp.c | ||
| sysfs.c | ||
| winbond.c | ||
| xilinx.c | ||
| xmc.c | ||