spi: stm32-qspi: Optimize FIFO accesses using u16 or u32

FIFO accesses uses u8 only for read/write.
In order to optimize throughput, add u16 or u32 read/write
accesses when possible.

Running mtd_speedtest on a 4MB sNOR partition using a
stm32mp257f-ev1 board gives the following results:

           before        after   gain
Read :  5773 KiB/s  22170 KiB/s   384%
Write:   796 KiB/s    890 KiB/s    12%

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://patch.msgid.link/20251208-upstream_qspi_ospi_updates-v2-6-62526c9467dc@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Patrice Chotard 2025-12-08 08:29:13 +01:00 • committed by Mark Brown
commit 1ca9128164
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