Eric Lee / smarc-fsl-linux-kernel

Blame view

Documentation/mtd/intel-spi.txt 3.15 KB
edit raw normal view history
8afda8b26   Mika Westerberg   spi-nor: Add supp... 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
  Upgrading BIOS using intel-spi
  ------------------------------
  
  Many Intel CPUs like Baytrail and Braswell include SPI serial flash host
  controller which is used to hold BIOS and other platform specific data.
  Since contents of the SPI serial flash is crucial for machine to function,
  it is typically protected by different hardware protection mechanisms to
  avoid accidental (or on purpose) overwrite of the content.
  
  Not all manufacturers protect the SPI serial flash, mainly because it
  allows upgrading the BIOS image directly from an OS.
  
  The intel-spi driver makes it possible to read and write the SPI serial
  flash, if certain protection bits are not set and locked. If it finds
  any of them set, the whole MTD device is made read-only to prevent
  partial overwrites. By default the driver exposes SPI serial flash
  contents as read-only but it can be changed from kernel command line,
  passing "intel-spi.writeable=1".
  
  Please keep in mind that overwriting the BIOS image on SPI serial flash
  might render the machine unbootable and requires special equipment like
  Dediprog to revive. You have been warned!
  
  Below are the steps how to upgrade MinnowBoard MAX BIOS directly from
  Linux.
  
   1) Download and extract the latest Minnowboard MAX BIOS SPI image
      [1]. At the time writing this the latest image is v92.
  
   2) Install mtd-utils package [2]. We need this in order to erase the SPI
      serial flash. Distros like Debian and Fedora have this prepackaged with
      name "mtd-utils".
  
   3) Add "intel-spi.writeable=1" to the kernel command line and reboot
      the board (you can also reload the driver passing "writeable=1" as
      module parameter to modprobe).
  
   4) Once the board is up and running again, find the right MTD partition
      (it is named as "BIOS"):
  
      # cat /proc/mtd
      dev:    size   erasesize  name
      mtd0: 00800000 00001000 "BIOS"
  
      So here it will be /dev/mtd0 but it may vary.
  
   5) Make backup of the existing image first:
  
      # dd if=/dev/mtd0ro of=bios.bak
      16384+0 records in
      16384+0 records out
      8388608 bytes (8.4 MB) copied, 10.0269 s, 837 kB/s
  
   6) Verify the backup
  
      # sha1sum /dev/mtd0ro bios.bak
      fdbb011920572ca6c991377c4b418a0502668b73  /dev/mtd0ro
      fdbb011920572ca6c991377c4b418a0502668b73  bios.bak
  
      The SHA1 sums must match. Otherwise do not continue any further!
  
   7) Erase the SPI serial flash. After this step, do not reboot the
      board! Otherwise it will not start anymore.
  
      # flash_erase /dev/mtd0 0 0
      Erasing 4 Kibyte @ 7ff000 -- 100 % complete
  
   8) Once completed without errors you can write the new BIOS image:
  
      # dd if=MNW2MAX1.X64.0092.R01.1605221712.bin of=/dev/mtd0
  
   9) Verify that the new content of the SPI serial flash matches the new
      BIOS image:
  
      # sha1sum /dev/mtd0ro MNW2MAX1.X64.0092.R01.1605221712.bin
      9b4df9e4be2057fceec3a5529ec3d950836c87a2  /dev/mtd0ro
      9b4df9e4be2057fceec3a5529ec3d950836c87a2 MNW2MAX1.X64.0092.R01.1605221712.bin
  
      The SHA1 sums should match.
  
   10) Now you can reboot your board and observe the new BIOS starting up
       properly.
  
  References
  ----------
  
  [1] https://firmware.intel.com/sites/default/files/MinnowBoard.MAX_.X64.92.R01.zip
  [2] http://www.linux-mtd.infradead.org/