[RFC PATCH 0/3] mtd: spi-nor: Rework flash parameter initialization

[Takahiro.Kuwano at infineon.com]

> Hi,
> 
> > Hi Michael,
> >
> > On 01/06/2026 at 14:52:42 +02, Michael Walle <mwalle at kernel.org> wrote:
> >
> > > Try to simplify the flash initialization and get rid of the legacy
> > > handling. As default, all the flags of the in-kernel database are
> > > taken and amended with the SFDP data.
> > >
> > > This might have the consequence that all the flashes now get a
> > > RDSFPD opcode which might be an unknown opcode. But that was already
> > > the case for any flashes which were unknown to the linux kernel. So
> > > far, there was not a single complaint.
> > >
> > > See patch 3 for more information. If feedback is positive, this is
> > > intended to be applied to the spi-nor tree after the next merge
> > > window, so it will sit around in -next for quite some time and get
> > > some testing.
> > >
> > > That being said, I've just did a quick test on my boards. Please
> > > give it a test on your boards.
> >
> > Interesting cleanup, thanks for pushing it. I'll run some tests with
> > some old and newer SFDP based flashes. I do not have chips without SFDP
> > though.
> >
> I do have some non-SFDP chips (S25FL-S). Will get back to you with test
> result.

With my AMD Zynq-7000 & Infineon internal SPI controller, s25fl128s0,
s25fl128s1, and s25fl256s0 work fine.

Here is the test log of s25fl256s0:

zynq> cat /sys/bus/spi/devices/spi0.0/spi-nor/partname
s25fl256s0

zynq> cat /sys/bus/spi/devices/spi0.0/spi-nor/jedec_id
0102194d0080

zynq> cat /sys/bus/spi/devices/spi0.0/spi-nor/manufacturer
spansion

zynq> xxd -p /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
xxd: /sys/bus/spi/devices/spi0.0/spi-nor/sfdp: No such file or directory
xxd: /sys/bus/spi/devices/spi0.0/spi-nor/sfdp: Bad file descriptor

zynq> md5sum /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
md5sum: can't open '/sys/bus/spi/devices/spi0.0/spi-nor/sfdp': No such file or directory

zynq> test_spi.sh
2+0 records in
2+0 records out
2097152 bytes (2.0MB) copied, 0.074296 seconds, 26.9MB/s
Erased 2097152 bytes from address 0x00000000 in flash
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
0000000 ffff ffff ffff ffff ffff ffff ffff ffff
*
0200000
4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5  spi_read
Copied 2097152 bytes from spi_test to address 0x00000000 in flash
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
1565a9e729e432053d204d569952d5ee6d669e0ace84a88d681b20e4600df356  spi_read
1565a9e729e432053d204d569952d5ee6d669e0ace84a88d681b20e4600df356  spi_test
Erased 2097152 bytes from address 0x00000000 in flash
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5  spi_read
1565a9e729e432053d204d569952d5ee6d669e0ace84a88d681b20e4600df356  spi_test

zynq> cat /sys/kernel/debug/spi-nor/spi0.0/params
name            s25fl256s0
id              01 02 19 4d 00 80
size            32.0 MiB
write size      1
page size       256
address nbytes  4
flags           4B_OPCODES | HAS_16BIT_SR

opcodes
 read           0x6c
  dummy cycles  8
 erase          0xdc
 program        0x12
 8D extension   none

protocols
 read           1S-1S-4S
 write          1S-1S-1S
 register       1S-1S-1S

erase commands
 d8 (256 KiB) [0]
 c7 (32.0 MiB)

sector map
 region (in hex)   | erase mask | overlaid
 ------------------+------------+----------
 00000000-01ffffff |     [0   ] | no

zynq> cat /sys/kernel/debug/spi-nor/spi0.0/capabilities
Supported read modes by the flash
 1S-1S-1S
  opcode        0x03
  mode cycles   0
  dummy cycles  0
 1S-1S-1S (fast read)
  opcode        0x0b
  mode cycles   0
  dummy cycles  8
 1S-1S-2S
  opcode        0x3b
  mode cycles   0
  dummy cycles  8
 1S-1S-4S
  opcode        0x6b
  mode cycles   0
  dummy cycles  8

Supported page program modes by the flash
 1S-1S-1S
  opcode        0x02