linux-toradex.git/drivers/firewire/core-device.c, branch v6.9-rc4

firewire: core: add memo about the caller of show functions for device attributes

2024-03-21T12:20:18+00:00

In the case of firewire core function, the caller of show functions for
device attributes is not only sysfs user, but also device initialization.

This commit adds memo about it against the typical assumption that the
functions are just dedicated to sysfs user.

Link: https://lore.kernel.org/lkml/20240318091759.678326-1-o-takashi@sakamocchi.jp/
Signed-off-by: Takashi Sakamoto

Revert "firewire: Kill unnecessary buf check in device_attribute.show"

2024-03-18T09:10:44+00:00

This reverts commit 4a2b06ca33763b363038d333274e212db6ff0de1.

The previous fix didn't consider callers from other than sysfs. Revert
it to fix the NULL dereference

 kernel:  ? sysfs_emit+0xb5/0xc0
 kernel:  show_immediate+0x13f/0x1d0 [firewire_core]
 kernel:  init_fw_attribute_group+0x81/0x150 [firewire_core]
 kernel:  create_units+0x119/0x160 [firewire_core]
 kernel:  fw_device_init+0x1a9/0x330 [firewire_core]
 kernel:  fw_device_workfn+0x12/0x20 [firewire_core]
 kernel:  process_one_work+0x16f/0x350
 kernel:  worker_thread+0x306/0x440
 kernel:  ? __pfx_worker_thread+0x10/0x10
 kernel:  kthread+0xf2/0x120
 kernel:  ? __pfx_kthread+0x10/0x10
 kernel:  ret_from_fork+0x47/0x70
 kernel:  ? __pfx_kthread+0x10/0x10
 kernel:  ret_from_fork_asm+0x1b/0x30
 kernel:  
 kernel: ---[ end trace 0000000000000000 ]---
 kernel: ------------[ cut here ]------------

Fixes: 4a2b06ca3376 ("firewire: Kill unnecessary buf check in device_attribute.show")
Reported-by: Takashi Sakamoto 
Signed-off-by: Li Zhijian 
Link: https://lore.kernel.org/lkml/625470f3-b196-43f7-9844-fa1cb6da99f8@fujitsu.com/
Signed-off-by: Takashi Sakamoto

firewire: core: fix build failure due to the caller of fw_csr_string()

2024-03-11T01:38:13+00:00

A commit 47dc55181dcb ("firewire: core: search descriptor leaf just after
vendor directory entry in root directory") for v6.8-rc3 and a commit
67a5a58c0443 ("firewire: Kill unnecessary buf check in
device_attribute.show") for v6.9 bring build failure in for-next tree due
to the change of the name of local variable.

This commit fixes it.

Reported-by: Stephen Rothwell 
Closes: https://lore.kernel.org/lkml/20240202111602.6f6e2c1a@canb.auug.org.au/
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202402022343.NkgsMITA-lkp@intel.com/
Link: https://lore.kernel.org/r/20240205060448.13881-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto

firewire: Convert snprintf/sprintf to sysfs_emit

2024-03-11T01:38:13+00:00

Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.

coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().

> drivers/firewire/core-device.c:326:8-16: WARNING: please use sysfs_emit or sysfs_emit_at

No functional change intended

Signed-off-by: Li Zhijian 
Link: https://lore.kernel.org/r/20240122053942.80648-2-lizhijian@fujitsu.com
Signed-off-by: Takashi Sakamoto

firewire: Kill unnecessary buf check in device_attribute.show

2024-03-11T01:38:13+00:00

Per Documentation/filesystems/sysfs.rst:
> sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the
> method.

So we can kill the unnecessary buf check safely.

Signed-off-by: Li Zhijian 
Link: https://lore.kernel.org/r/20240122053942.80648-1-lizhijian@fujitsu.com
Signed-off-by: Takashi Sakamoto

firewire: core: search descriptor leaf just after vendor directory entry in root directory

2024-02-01T11:53:18+00:00

It appears that Sony DVMC-DA1 has a quirk that the descriptor leaf entry
locates just after the vendor directory entry in root directory. This is
not conformant to the legacy layout of configuration ROM described in
Configuration ROM for AV/C Devices 1.0 (1394 Trading Association, Dec 2000,
TA Document 1999027).

This commit changes current implementation to parse configuration ROM for
device attributes so that the descriptor leaf entry can be detected for
the vendor name.

$ config-rom-pretty-printer < Sony-DVMC-DA1.img
               ROM header and bus information block
               -----------------------------------------------------------------
1024  041ee7fb  bus_info_length 4, crc_length 30, crc 59387
1028  31333934  bus_name "1394"
1032  e0644000  irmc 1, cmc 1, isc 1, bmc 0, cyc_clk_acc 100, max_rec 4 (32)
1036  08004603  company_id 080046     |
1040  0014193c  device_id 12886219068  | EUI-64 576537731003586876

               root directory
               -----------------------------------------------------------------
1044  0006b681  directory_length 6, crc 46721
1048  03080046  vendor
1052  0c0083c0  node capabilities: per IEEE 1394
1056  8d00000a  --> eui-64 leaf at 1096
1060  d1000003  --> unit directory at 1072
1064  c3000005  --> vendor directory at 1084
1068  8100000a  --> descriptor leaf at 1108

               unit directory at 1072
               -----------------------------------------------------------------
1072  0002cdbf  directory_length 2, crc 52671
1076  1200a02d  specifier id
1080  13010000  version

               vendor directory at 1084
               -----------------------------------------------------------------
1084  00020cfe  directory_length 2, crc 3326
1088  17fa0000  model
1092  81000008  --> descriptor leaf at 1124

               eui-64 leaf at 1096
               -----------------------------------------------------------------
1096  0002c66e  leaf_length 2, crc 50798
1100  08004603  company_id 080046     |
1104  0014193c  device_id 12886219068  | EUI-64 576537731003586876

               descriptor leaf at 1108
               -----------------------------------------------------------------
1108  00039e26  leaf_length 3, crc 40486
1112  00000000  textual descriptor
1116  00000000  minimal ASCII
1120  536f6e79  "Sony"

               descriptor leaf at 1124
               -----------------------------------------------------------------
1124  0005001d  leaf_length 5, crc 29
1128  00000000  textual descriptor
1132  00000000  minimal ASCII
1136  44564d43  "DVMC"
1140  2d444131  "-DA1"
1144  00000000

Suggested-by: Adam Goldman 
Tested-by: Adam Goldman 
Link: https://lore.kernel.org/r/20240130100409.30128-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto

firewire: core: correct documentation of fw_csr_string() kernel API

2024-02-01T11:53:18+00:00

Against its current description, the kernel API can accepts all types of
directory entries.

This commit corrects the documentation.

Cc: stable@vger.kernel.org
Fixes: 3c2c58cb33b3 ("firewire: core: fw_csr_string addendum")
Link: https://lore.kernel.org/r/20240130100409.30128-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto

firewire: core: fill model field in modalias of unit device for legacy layout of configuration ROM

2024-01-10T09:37:13+00:00

As the last part of support for legacy layout of configuration ROM, this
commit traverses vendor directory as well as root directory when
constructing modalias for unit device. The change brings loss of backward
compatibility since it can fill model field ('mo') which is 0 at current
implementation in the case. However, we can be optimistic against
regression for unit drivers in kernel, due to some points:

1. ALSA drivers for audio and music units use the model fields to match
   device, however all of supported devices does not have such legacy
   layout.
2. the other unit drivers (e.g. sbp2) does not use the model field to
   match device.

The rest of concern is user space application. The most of applications
just take care of node device and does not use the modalias of unit
device, thus the change does not affect to them. But systemd project is
known to get affects from the change since it includes hwdb to take udev
to configure fw character device conveniently. I have a plan to work for
systemd so that the access permission of character device could be kept
across the change.

Suggested-by: Adam Goldman 
Link: https://lore.kernel.org/r/20231221134849.603857-9-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto

firewire: core: detect model name for legacy layout of configuration ROM

2024-01-08T00:36:56+00:00

As the part of support for legacy layout of configuration ROM, this
commit traverses vendor directory as well as root directory when showing
device attribute for node device. This change expects 'model_name'
attribute appears in node device, however it is probable to see the other
types of descriptor leaf if the vendor directory includes.

Suggested-by: Adam Goldman 
Link: https://lore.kernel.org/r/20231221134849.603857-8-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto

firewire: core: detect numeric model identifier for legacy layout of configuration ROM

2024-01-08T00:36:56+00:00

As the part of support for legacy layout of configuration ROM, this
commit traverses vendor directory as well as root directory when showing
device attribute for node device. This change expects 'model' attribute
appears in node device, however it is probable to see the other types of
immediate values if the vendor directory includes.

Suggested-by: Adam Goldman 
Link: https://lore.kernel.org/r/20231221134849.603857-7-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto