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authorLinus Torvalds2014-04-01 16:13:21 -0700
committerLinus Torvalds2014-04-01 16:13:21 -0700
commit675c354a95d5375153b8bb80a0448cab916c7991 (patch)
tree88cbc5a5a31dd1c1016271006a8d56cfe0abf7bd /Documentation/fmc/fmc-write-eeprom.txt
parentc70929147a10fa4538886cb23b934b509c4c0e49 (diff)
parent1b3fa22e0234d613df967445cd34807e10fa54fa (diff)
Merge tag 'char-misc-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver patches from Greg KH: "Here's the big char/misc driver updates for 3.15-rc1. Lots of various things here, including the new mcb driver subsystem. All of these have been in linux-next for a while" * tag 'char-misc-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (118 commits) extcon: Move OF helper function to extcon core and change function name extcon: of: Remove unnecessary function call by using the name of device_node extcon: gpio: Use SIMPLE_DEV_PM_OPS macro extcon: palmas: Use SIMPLE_DEV_PM_OPS macro mei: don't use deprecated DEFINE_PCI_DEVICE_TABLE macro mei: amthif: fix checkpatch error mei: client.h fix checkpatch errors mei: use cl_dbg where appropriate mei: fix Unnecessary space after function pointer name mei: report consistently copy_from/to_user failures mei: drop pr_fmt macros mei: make me hw headers private to me hw. mei: fix memory leak of pending write cb objects mei: me: do not reset when less than expected data is received drivers: mcb: Fix build error discovered by 0-day bot cs5535-mfgpt: Simplify dependencies spmi: pm: drop bus-level PM suspend/resume routines spmi: pmic_arb: make selectable on ARCH_QCOM Drivers: hv: vmbus: Increase the limit on the number of pfns we can handle pch_phub: Report error writing MAC back to user ...
Diffstat (limited to 'Documentation/fmc/fmc-write-eeprom.txt')
-rw-r--r--Documentation/fmc/fmc-write-eeprom.txt77
1 files changed, 25 insertions, 52 deletions
diff --git a/Documentation/fmc/fmc-write-eeprom.txt b/Documentation/fmc/fmc-write-eeprom.txt
index 44a3bc678bf0..e0a9712156aa 100644
--- a/Documentation/fmc/fmc-write-eeprom.txt
+++ b/Documentation/fmc/fmc-write-eeprom.txt
@@ -9,7 +9,12 @@ 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.
-The module takes the following measures:
+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
@@ -70,56 +75,24 @@ first time.
[ 132.899872] fake-fmc: Product name: FmcDelay1ns4cha
-Writing to the EEPROM
+Accessing the EEPROM
=====================
-Once you have created a binary file for your EEPROM, you can write it
-to the storage medium using the fmc-write-eeprom (See *note
-fmc-write-eeprom::, while relying on a carrier driver. The procedure
-here shown here uses the SPEC driver
-(`http://www.ohwr.org/projects/spec-sw').
-
-The example assumes no driver is already loaded (actually, I unloaded
-them by hand as everything loads automatically at boot time after you
-installed the modules), and shows kernel messages together with
-commands. Here the prompt is spusa.root# and two SPEC cards are plugged
-in the system.
-
- spusa.root# insmod fmc.ko
- spusa.root# insmod spec.ko
- [13972.382818] spec 0000:02:00.0: probe for device 0002:0000
- [13972.392773] spec 0000:02:00.0: got file "fmc/spec-init.bin", 1484404 (0x16a674) bytes
- [13972.591388] spec 0000:02:00.0: FPGA programming successful
- [13972.883011] spec 0000:02:00.0: EEPROM has no FRU information
- [13972.888719] spec 0000:02:00.0: No device_id filled, using index
- [13972.894676] spec 0000:02:00.0: No mezzanine_name found
- [13972.899863] /home/rubini/wip/spec-sw/kernel/spec-gpio.c - spec_gpio_init
- [13972.906578] spec 0000:04:00.0: probe for device 0004:0000
- [13972.916509] spec 0000:04:00.0: got file "fmc/spec-init.bin", 1484404 (0x16a674) bytes
- [13973.115096] spec 0000:04:00.0: FPGA programming successful
- [13973.401798] spec 0000:04:00.0: EEPROM has no FRU information
- [13973.407474] spec 0000:04:00.0: No device_id filled, using index
- [13973.413417] spec 0000:04:00.0: No mezzanine_name found
- [13973.418600] /home/rubini/wip/spec-sw/kernel/spec-gpio.c - spec_gpio_init
- spusa.root# ls /sys/bus/fmc/devices
- fmc-0000 fmc-0001
- spusa.root# insmod fmc-write-eeprom.ko busid=0x0200 file=fdelay-eeprom.bin
- [14103.966259] spec 0000:02:00.0: Matching an generic driver (no ID)
- [14103.975519] spec 0000:02:00.0: programming 6155 bytes
- [14126.373762] spec 0000:02:00.0: write_eeprom: success
- [14126.378770] spec 0000:04:00.0: Matching an generic driver (no ID)
- [14126.384903] spec 0000:04:00.0: fmc_write_eeprom: no filename given: not programming
- [14126.392600] fmc_write_eeprom: probe of fmc-0001 failed with error -2
-
-Reading back the EEPROM
-=======================
-
-In order to read back the binary content of the EEPROM of your
-mezzanine device, the bus creates a read-only sysfs 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 Apr 9 16:53 FmcDelay1ns4cha-f001/eeprom
- -r--r--r-- 1 root root 8192 Apr 9 17:19 fake-design-for-testing-f002/eeprom
- -r--r--r-- 1 root root 8192 Apr 9 17:19 fake-design-for-testing-f003/eeprom
- -r--r--r-- 1 root root 8192 Apr 9 17:19 fmc-f004/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.