driver-api/mtd/spi-nor.rst

5 How to propose a new flash addition
6 -----------------------------------
9 Serial Flash Discoverable Parameter (SFDP) standard. SFDP describes
10 the functional and feature capabilities of serial flash devices in a
11 standard set of internal read-only parameter tables.
14 flash's parameters and settings. If the flash defines the SFDP tables
15 it's likely that you won't need a flash entry at all, and instead
16 rely on the generic flash driver which probes the flash solely based
17 on its SFDP data. All one has to do is to specify the "jedec,spi-nor"
20 There are cases however where you need to define an explicit flash
21 entry. This typically happens when the flash has settings or support
23 when the flash contains mangled SFDP data. If the later, one needs
28 -----------------------------
31 section, after the ``---`` marker.
33 1) Specify the controller that you used to test the flash and specify
34    the frequency at which the flash was operated, e.g.::
36     This flash is populated on the X board and was tested at Y
41     root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/partname
43     root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/jedec_id
45     root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/manufacturer
47     root@1:~# xxd -p /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
69     root@1:~# sha256sum /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
70 …0461876f189ac97f93e68a05fa6428c6650b3b7baf736a921e5898ed1  /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
72    Please dump the SFDP tables using ``xxd -p``. It enables us to do
74    ``xxd -rp``. Dumping the SFDP data with ``hexdump -Cv`` is accepted,
79     root@1:~# cat /sys/kernel/debug/spi-nor/spi0.0/capabilities
80     Supported read modes by the flash
81      1S-1S-1S
83       mode cycles	0
85      1S-1S-1S (fast read)
87       mode cycles	0
89      1S-1S-2S
91       mode cycles	0
93      1S-2S-2S
95       mode cycles	4
97      1S-1S-4S
99       mode cycles	0
101      1S-4S-4S
103       mode cycles	2
105      4S-4S-4S
107       mode cycles	2
110     Supported page program modes by the flash
111      1S-1S-1S
114     root@1:~# cat /sys/kernel/debug/spi-nor/spi0.0/params
131      read		1S-4S-4S
132      write		1S-1S-1S
133      register		1S-1S-1S
144      ------------------+------------+----------
145      00000000-00007fff |     [01  ] |
146      00008000-0000ffff |     [0 2 ] |
147      00010000-007effff |     [0  3] |
148      007f0000-007f7fff |     [0 2 ] |
149      007f8000-007fffff |     [01  ] |
151 4) Use `mtd-utils <https://git.infradead.org/mtd-utils.git>`__
160     Erased 2097152 bytes from address 0x00000000 in flash
163     Copied 2097152 bytes from address 0x00000000 in flash to spi_read
174     Copied 2097152 bytes from spi_test to address 0x00000000 in flash
177     Copied 2097152 bytes from address 0x00000000 in flash to spi_read
183    If the flash comes erased by default and the previous erase was ignored,
187     Erased 2097152 bytes from address 0x00000000 in flash
190     Copied 2097152 bytes from address 0x00000000 in flash to spi_read