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On many older systems using SW sequencer the PREOP_OPTYPE register contains two preopcodes as following: PREOP_OPTYPE=0xf2785006 The last two bytes are the opcodes decoded to: 0x50 - Write enable for volatile status register 0x06 - Write enable The former is used to modify volatile bits in the status register. For non-volatile bits the latter is needed. Preopcodes are used in SW sequencer to send one command "atomically" without anything else interfering the transfer. The sequence that gets executed is: - Send preopcode (write enable) from PREOP_OPTYPE register - Send the actual SPI command - Poll busy bit in the status register (0x05, RDSR) Commit8c473dd61b("spi-nor: intel-spi: Don't assume OPMENU0/1 to be programmed by BIOS") enabled atomic sequence handling but because both preopcodes are programmed, the following happens: if (preop >> 8) val |= SSFSTS_CTL_SPOP; Since on these systems preop >> 8 == 0x50 we end up picking volatile write enable instead. Because of this the actual write command is pretty much NOP unless there is a WREN latched in the chip already. Furthermore we should not really just assume that WREN was issued in previous call to intel_spi_write_reg() because that might not be the case. This updates driver to first check that the opcode is actually available in PREOP_OPTYPE register and if not return error back to the spi-nor core (if the controller is not locked we program it now). In addition we save the opcode to ispi->atomic_preopcode field which is checked in next call to intel_spi_sw_cycle() to actually enable atomic sequence using the requested preopcode. Fixes:8c473dd61b("spi-nor: intel-spi: Don't assume OPMENU0/1 to be programmed by BIOS") Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: stable@vger.kernel.org Reviewed-by: Marek Vasut <marek.vasut@gmail.com> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Linux kernel
============
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