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Diffstat (limited to 'Documentation/fmc/fmc-write-eeprom.txt')
| -rw-r--r-- | Documentation/fmc/fmc-write-eeprom.txt | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/Documentation/fmc/fmc-write-eeprom.txt b/Documentation/fmc/fmc-write-eeprom.txt deleted file mode 100644 index e0a9712156aa..000000000000 --- a/Documentation/fmc/fmc-write-eeprom.txt +++ /dev/null @@ -1,98 +0,0 @@ -fmc-write-eeprom -================ - -This module is designed to load a binary file from /lib/firmware and to -write it to the internal EEPROM of the mezzanine card. This driver uses -the `busid' generic parameter. - -Overwriting the EEPROM is not something you should do daily, and it is -expected to only happen during manufacturing. For this reason, the -module makes it unlikely for the random user to change a working EEPROM. - -However, since the EEPROM may include application-specific information -other than the identification, later versions of this packages added -write-support through sysfs. See *note Accessing the EEPROM::. - -To avoid damaging the EEPROM content, the module takes the following -measures: - - * It accepts a `file=' argument (within /lib/firmware) and if no - such argument is received, it doesn't write anything to EEPROM - (i.e. there is no default file name). - - * If the file name ends with `.bin' it is written verbatim starting - at offset 0. - - * If the file name ends with `.tlv' it is interpreted as - type-length-value (i.e., it allows writev(2)-like operation). - - * If the file name doesn't match any of the patterns above, it is - ignored and no write is performed. - - * Only cards listed with `busid=' are written to. If no busid is - specified, no programming is done (and the probe function of the - driver will fail). - - -Each TLV tuple is formatted in this way: the header is 5 bytes, -followed by data. The first byte is `w' for write, the next two bytes -represent the address, in little-endian byte order, and the next two -represent the data length, in little-endian order. The length does not -include the header (it is the actual number of bytes to be written). - -This is a real example: that writes 5 bytes at position 0x110: - - spusa.root# od -t x1 -Ax /lib/firmware/try.tlv - 000000 77 10 01 05 00 30 31 32 33 34 - 00000a - spusa.root# insmod /tmp/fmc-write-eeprom.ko busid=0x0200 file=try.tlv - [19983.391498] spec 0000:03:00.0: write 5 bytes at 0x0110 - [19983.414615] spec 0000:03:00.0: write_eeprom: success - -Please note that you'll most likely want to use SDBFS to build your -EEPROM image, at least if your mezzanines are being used in the White -Rabbit environment. For this reason the TLV format is not expected to -be used much and is not expected to be developed further. - -If you want to try reflashing fake EEPROM devices, you can use the -fmc-fakedev.ko module (see *note fmc-fakedev::). Whenever you change -the image starting at offset 0, it will deregister and register again -after two seconds. Please note, however, that if fmc-write-eeprom is -still loaded, the system will associate it to the new device, which -will be reprogrammed and thus will be unloaded after two seconds. The -following example removes the module after it reflashed fakedev the -first time. - - spusa.root# insmod fmc-fakedev.ko - [ 72.984733] fake-fmc: Manufacturer: fake-vendor - [ 72.989434] fake-fmc: Product name: fake-design-for-testing - spusa.root# insmod fmc-write-eeprom.ko busid=0 file=fdelay-eeprom.bin; \ - rmmod fmc-write-eeprom - [ 130.874098] fake-fmc: Matching a generic driver (no ID) - [ 130.887845] fake-fmc: programming 6155 bytes - [ 130.894567] fake-fmc: write_eeprom: success - [ 132.895794] fake-fmc: Manufacturer: CERN - [ 132.899872] fake-fmc: Product name: FmcDelay1ns4cha - - -Accessing the EEPROM -===================== - -The bus creates a sysfs binary file called eeprom for each mezzanine it -knows about: - - spusa.root# cd /sys/bus/fmc/devices; ls -l */eeprom - -r--r--r-- 1 root root 8192 Feb 21 12:30 FmcAdc100m14b4cha-0800/eeprom - -r--r--r-- 1 root root 8192 Feb 21 12:30 FmcDelay1ns4cha-0200/eeprom - -r--r--r-- 1 root root 8192 Feb 21 12:30 FmcDio5cha-0400/eeprom - -Everybody can read the files and the superuser can also modify it, but -the operation may on the carrier driver, if the carrier is unable to -access the I2C bus. For example, the spec driver can access the bus -only with its golden gateware: after a mezzanine driver reprogrammed -the FPGA with a custom circuit, the carrier is unable to access the -EEPROM and returns ENOTSUPP. - -An alternative way to write the EEPROM is the mezzanine driver -fmc-write-eeprom (See *note fmc-write-eeprom::), but the procedure is -more complex. |