You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
98 lines
4.3 KiB
98 lines
4.3 KiB
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.
|
|
|