fmc: Delete the FMC subsystem

The FMC subsystem was created in 2012 with the ambition to
drive development of drivers for this hardware upstream.

The current implementation has architectural flaws and would
need to be revamped using real hardware to something that can
reuse existing kernel abstractions in the subsystems for e.g.
I2C, FPGA and GPIO.

We have concluded that for the mainline kernel it will be
better to delete the subsystem and start over with a clean
slate when/if an active maintainer steps up.

For details see:
https://lkml.org/lkml/2018/10/29/534

Suggested-by: Federico Vaga <federico.vaga@cern.ch>
Cc: Pat Riehecky <riehecky@fnal.gov>
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 0 insertions, 64 deletions

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