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Diffstat (limited to 'Documentation/fmc/fmc-chardev.txt')
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diff --git a/Documentation/fmc/fmc-chardev.txt b/Documentation/fmc/fmc-chardev.txt deleted file mode 100644 index d9ccb278e597..000000000000 --- a/Documentation/fmc/fmc-chardev.txt +++ /dev/null @@ -1,64 +0,0 @@ -fmc-chardev -=========== - -This is a simple generic driver, that allows user access by means of a -character device (actually, one for each mezzanine it takes hold of). - -The char device is created as a misc device. Its name in /dev (as -created by udev) is the same name as the underlying FMC device. Thus, -the name can be a silly fmc-0000 look-alike if the device has no -identifiers nor bus_id, a more specific fmc-0400 if the device has a -bus-specific address but no associated name, or something like -fdelay-0400 if the FMC core can rely on both a mezzanine name and a bus -address. - -Currently the driver only supports read and write: you can lseek to the -desired address and read or write a register. - -The driver assumes all registers are 32-bit in size, and only accepts a -single read or write per system call. However, as a result of Unix read -and write semantics, users can simply fread or fwrite bigger areas in -order to dump or store bigger memory areas. - -There is currently no support for mmap, user-space interrupt management -and DMA buffers. They may be added in later versions, if the need -arises. - -The example below shows raw access to a SPEC card programmed with its -golden FPGA file, that features an SDB structure at offset 256 - i.e. -64 words. The mezzanine's EEPROM in this case is not programmed, so the -default name is fmc-<bus><devfn>, and there are two cards in the system: - - spusa.root# insmod fmc-chardev.ko - [ 1073.339332] spec 0000:02:00.0: Driver has no ID: matches all - [ 1073.345051] spec 0000:02:00.0: Created misc device "fmc-0200" - [ 1073.350821] spec 0000:04:00.0: Driver has no ID: matches all - [ 1073.356525] spec 0000:04:00.0: Created misc device "fmc-0400" - spusa.root# ls -l /dev/fmc* - crw------- 1 root root 10, 58 Nov 20 19:23 /dev/fmc-0200 - crw------- 1 root root 10, 57 Nov 20 19:23 /dev/fmc-0400 - spusa.root# dd bs=4 skip=64 count=1 if=/dev/fmc-0200 2> /dev/null | od -t x1z - 0000000 2d 42 44 53 >-BDS< - 0000004 - -The simple program tools/fmc-mem in this package can access an FMC char -device and read or write a word or a whole area. Actually, the program -is not specific to FMC at all, it just uses lseek, read and write. - -Its first argument is the device name, the second the offset, the third -(if any) the value to write and the optional last argument that must -begin with "+" is the number of bytes to read or write. In case of -repeated reading data is written to stdout; repeated writes read from -stdin and the value argument is ignored. - -The following examples show reading the SDB magic number and the first -SDB record from a SPEC device programmed with its golden image: - - spusa.root# ./fmc-mem /dev/fmc-0200 100 - 5344422d - spusa.root# ./fmc-mem /dev/fmc-0200 100 +40 | od -Ax -t x1z - 000000 2d 42 44 53 00 01 02 00 00 00 00 00 00 00 00 00 >-BDS............< - 000010 00 00 00 00 ff 01 00 00 00 00 00 00 51 06 00 00 >............Q...< - 000020 c9 42 a5 e6 02 00 00 00 11 05 12 20 2d 34 42 57 >.B......... -4BW< - 000030 73 6f 72 43 72 61 62 73 49 53 47 2d 00 20 20 20 >sorCrabsISG-. < - 000040 |