linux/sound/firewire
Takashi Sakamoto 407359d44e ALSA: firewire-motu: export meter information to userspace as float value
In command DSP models, one meter information consists of 4 bytes for
IEEE 764 floating point (binary32). In previous patch, it is exported
to userspace as 32 bit storage since the storage is also handled in
ALSA firewire-motu driver as well in kernel space in which floating point
arithmetic is not preferable. On the other hand, ALSA firewire-motu driver
doesn't perform floating point calculation. The driver just gather meter
information from isochronous packets and fill structure fields for
userspace.

In 'header' target of Kbuild, UAPI headers are processed before installed.
In this timing, #ifdef macro with __KERNEL__ is removed. This mechanism
is useful in the case so that the 32 bit storage can be accessible as u32
type in kernel space and float type in user space. We can see the same
usage in ''struct acct_v3' in 'include/uapi/linux/acct.h'.

This commit is for the above idea. Additionally, due to message
protocol, meter information is filled with 0xffffffff in the end of
period but 0xffffffff is invalid as binary32. To avoid confusion in
userspace application, the last two elements are left without any
assignment.

Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20211027125529.54295-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-10-28 09:10:41 +02:00
..
bebob ALSA: bebob: correct duplicated entries with TerraTec OUI 2021-07-05 19:31:12 +02:00
dice ALSA: dice: cease from delayed card registration 2021-06-07 17:14:14 +02:00
digi00x ALSA: firewire-digi00x: cease from delayed card registration 2021-06-07 17:14:29 +02:00
fireface ALSA: fireface: cease from delayed card registration 2021-06-07 17:14:48 +02:00
fireworks ALSA: fireworks: fulfil device entries 2021-06-12 09:33:09 +02:00
motu ALSA: firewire-motu: export meter information to userspace as float value 2021-10-28 09:10:41 +02:00
oxfw ALSA: oxfw: fix transmission method for Loud models based on OXFW971 2021-09-13 07:31:58 +02:00
tascam ALSA: firewire-tascam: cease from delayed card registration 2021-06-07 17:14:36 +02:00
amdtp-am824.c ALSA: firewire-lib/motu: use int type for the value of bitwise OR with enumerator-constant 2021-05-18 12:21:52 +02:00
amdtp-am824.h ALSA: firewire-lib/motu: use int type for the value of bitwise OR with enumerator-constant 2021-05-18 12:21:52 +02:00
amdtp-stream-trace.h ALSA: firewire-lib: replace in_interrupt() with in_softirq() 2021-06-12 09:31:41 +02:00
amdtp-stream.c ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found 2021-06-25 09:38:11 +02:00
amdtp-stream.h ALSA: firewire-lib: obsolete workqueue for period update 2021-06-10 09:50:37 +02:00
cmp.c ALSA: firewire: fix kernel-doc 2020-07-07 12:09:32 +02:00
cmp.h ALSA: firewire-lib: split allocation of isochronous resources from establishment of connection 2019-06-17 08:18:36 +02:00
fcp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 345 2019-06-05 17:37:08 +02:00
fcp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
isight.c ALSA: firewire: Drop superfluous ioctl PCM ops 2019-12-11 07:25:27 +01:00
iso-resources.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 345 2019-06-05 17:37:08 +02:00
iso-resources.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig ALSA: bebob: add support for ToneWeal FW66 2021-06-20 08:42:27 +02:00
lib.c ALSA: firewire-lib: delete unused kernel API 2021-06-07 17:14:54 +02:00
lib.h ALSA: firewire-lib: delete unused kernel API 2021-06-07 17:14:54 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
packets-buffer.c ALSA: firewire: fix a memory leak bug 2019-08-08 11:12:26 +02:00
packets-buffer.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00