ALSA: hda: Skip event processing for unregistered codecs

When codec is unbound but not yet removed, in the eyes of
snd_hdac_bus_process_unsol_events() it is still a valid target to
delegate work to. Such behaviour may lead to use-after-free errors.
Address by verifying if codec is actually registered.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220706120230.427296-6-cezary.rojewski@intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: add link_power op to hdac_bus_ops

The extended HDA bus (hdac_ext) provides interfaces for more
fine-grained control of individual links than what plain HDA
provides for. Links can be powered off when they are not used and if
all links are released, controller can shut down the command DMA.

These interfaces are currently not used by common HDA codec drivers.
When a HDA codec is runtime suspended, it calls snd_hdac_codec_link_down(),
but there is no link to the HDA extended bus, and on controller side
the links are shut down only when all codecs are suspended.

This patch adds link_power() to hdac_bus ops. Controllers using the HDA
extended core, can use this to plug in snd_hdac_ext_bus_link_power() to
implement more fine-grained control of link power.

No change is needed for plain HDA controllers nor to existing HDA
codec drivers.

Co-developed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210205184630.1938761-2-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: avoid reset of sdo_limit

By default 'sdo_limit' is initialized with a default value of '8'
as per spec. This is overridden in cases where a different value is
required. However this is getting reset when snd_hdac_bus_init_chip()
is called again, which happens during runtime PM cycle.

Avoid this reset by moving 'sdo_limit' setup to 'snd_hdac_bus_init()'
function which would be called only once.

Fixes: 67ae482a59e9 ("ALSA: hda: add member to store ratio for stripe control")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1597851130-6765-1-git-send-email-spujar@nvidia.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Unexport some local helper functions

snd_hdac_bus_queue_event() and snd_hdac_bus_exec_verb() are used only
internally in HD-audio core. Let's drop the exports and move the
declarations into local.h.

Link: https://lore.kernel.org/r/20200516062854.22141-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Fix potential race in unsol event handler

The unsol event handling code has a loop retrieving the read/write
indices and the arrays without locking while the append to the array
may happen concurrently. This may lead to some inconsistency.
Although there hasn't been any proof of this bad results, it's still
safer to protect the racy accesses.

This patch adds the spinlock protection around the unsol handling loop
for addressing it. Here we take bus->reg_lock as the writer side
snd_hdac_bus_queue_event() is also protected by that lock.

Link: https://lore.kernel.org/r/20200516062556.30951-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Update kernel-doc function parameter descriptions

Make W=1 throws a lot of warnings, with multiple misalignments between
function params and their descriptions.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200113205638.27338-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Use standard waitqueue for RIRB wakeup

The HD-audio CORB/RIRB communication was programmed in a way that was
documented in the reference in decades ago, which is essentially a
polling in the waiter side. It's working fine but costs CPU cycles on
some platforms that support only slow communications. Also, for some
platforms that had unreliable communications, we put longer wait time
(2 ms), which accumulate quite long time if you execute many verbs in
a shot (e.g. at the initialization or resume phase).

This patch attempts to improve the situation by introducing the
standard waitqueue in the RIRB waiter side instead of polling. The
test results on my machine show significant improvements. The time
spent for "cat /proc/asound/card*/codec#*" were changed like:

* Intel SKL + Realtek codec
before the patch:
0.00user 0.04system 0:00.10elapsed 40.0%CPU
after the patch:
0.00user 0.01system 0:00.10elapsed 10.0%CPU

* Nvidia GP107GL + Nvidia HDMI codec
before the patch:
0.00user 0.00system 0:02.76elapsed 0.0%CPU
after the patch:
0.00user 0.00system 0:00.01elapsed 17.0%CPU

So, for Intel chips, the total time is same, while the total time is
greatly reduced (from 2.76 to 0.01s) for Nvidia chips.
The only negative data here is the increase of CPU time for Nvidia,
but this is the unavoidable cost for faster wakeups, supposedly.

Link: https://lore.kernel.org/r/20191210145727.22054-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Unexport a few more stuff

Drop EXPORT_SYMBOL*() from a few more stuff in HD-audio core that
aren't used outside. Particular the unsol event handler can be
staticized now because the recent change removed all external
callers.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Drop export of snd_hdac_bus_add/remove_device()

snd_hdac_bus_add_device() and snd_hdac_remove_device() are called only
internally in hda-core. Let's drop the exports of them and move the
declarations into local.h.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: readl/writel need linux/io.h

Fixes: 19abfefd4c76 ("ALSA: hda: Direct MMIO accesses")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Direct MMIO accesses

HD-audio drivers access to the mmio registers indirectly via the
corresponding bus->io_ops callbacks. This is because some platform
(notably Tegra SoC) requires the word-aligned access. But it's rather
a rare case, and other platforms suffer from the penalties by indirect
calls unnecessarily.

This patch is an attempt to optimize and cleanup for this situation.
Now the special aligned access is used only when a new kconfig
CONFIG_SND_HDA_ALIGNED_MMIO is set. And the HD-audio core itself
provides the aligned MMIO access helpers instead of the driver side.
If Kconfig isn't set (as default), the standard helpers like readl()
or writel() are used directly.

A couple of places in ASoC Intel drivers have the access via io_ops
reg_writel(), and they are replaced with the direct writel() calls.

And now with this patch, the whole bus->io_ops becomes empty, so it's
dropped completely. The bus initialization functions are changed
accordingly as well to drop the whole bus->io_ops.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Remove page allocation redirection

The HD-audio core allocates and releases pages via driver's specific
dma_alloc_pages and dma_free_pages ops defined in bus->io_ops. This
was because some platforms require the uncached pages and the handling
of page flags had to be done locally in the driver code.

Since the recent change in ALSA core memory allocator, we can simply
pass SNDRV_DMA_TYPE_DEV_UC for the uncached pages, and the only
difference became about this type to be passed to the core allocator.
That is, it's good time for cleaning up the mess.

This patch changes the allocation code in HD-audio core to call the
core allocator directly so that we get rid of dma_alloc_pages and
dma_free_pages io_ops. If a driver needs the uncached pages, it has
to set bus->dma_type right after the bus initialization.

This is merely a code refactoring and shouldn't bring any behavior
changes.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ALSA: hda: Initialize ext-bus-specific fields in snd_hdac_bus_init(), too

Some fields in snd_hdac_bus are ext-bus specific, but they still
should be initialized in snd_hdac_bus_init() for consistency, at
least, for the ones that do need the explicit initialization like the
list head.

Also move the lock field to the more appropriate place and correct the
comment to reflect the recent change where it serves for both the
display power and the link management.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Fix racy display power access

snd_hdac_display_power() doesn't handle the concurrent calls carefully
enough, and it may lead to the doubly get_power or put_power calls,
when a runtime PM and an async work get called in racy way.

This patch addresses it by reusing the bus->lock mutex that has been
used for protecting the link state change in ext bus code, so that it
can protect against racy display state changes. The initialization of
bus->lock was moved from snd_hdac_ext_bus_init() to
snd_hdac_bus_init() as well accordingly.

Testcase: igt/i915_pm_rpm/module-reload #glk-dsi
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Fix racy display power access

snd_hdac_display_power() doesn't handle the concurrent calls carefully
enough, and it may lead to the doubly get_power or put_power calls,
when a runtime PM and an async work get called in racy way.

This patch addresses it by reusing the bus->lock mutex that has been
used for protecting the link state change in ext bus code, so that it
can protect against racy display state changes. The initialization of
bus->lock was moved from snd_hdac_ext_bus_init() to
snd_hdac_bus_init() as well accordingly.

Testcase: igt/i915_pm_rpm/module-reload #glk-dsi
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/s5h8swiunph.wl-tiwai@suse.de

ALSA: HDA: export process_unsol_events()

The SOF implementation does not rely on the hdac_bus library, however
for HDMI and HDaudio codec support it does need to deal with
unsolicited events. Instead of re-inventing the wheel, export this
symbol to reuse this part of the library directly.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda: Fix potential race at unregistration and unsol events

When the codec device is unregistered / freed, it may release the
resource while being used in an unsolicited event like the jack
detection work. This leads to use-after-free.

The fix here is to unregister the device at first, i.e. removing the
codec from the list, then flushing the pending works to assure that
all unsol events are gone. After this point, we're free from
accessing the codec via unsol events, thus can release the resources
gracefully.

The issue was spotted originally by Intel CI, but it couldn't be
reproduced reliably by its nature. So let's hope this fix really
addresses the whole issues.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196045
Reported-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda - Add / fix kernel doc comments

Give some readable comment in kernel doc style for each exported
function, as I promised in the previous meetings. While we're at it,
fix the wrong comments, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda - Add the controller helper codes to hda-core module

This patch adds the controller helper codes to hda-core library.
The I/O access ops are added to the bus ops. The CORB/RIRB, the basic
attributes like irq# and iomap address, some locks and the list of
streams are added to the bus object, together with the stream object
and its helpers.

Currently the codes are just copied from the legacy driver, so you can
find duplicated codes in both directories. Only constants are removed
from the original hda_controller.h. More integration work will follow
in the later patches.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda - Re-add tracepoints to HD-audio core driver

Now let's take the basic tracepoints back to the HD-audio driver.
The three bus tracepoints, hda_send_cmd, hda_get_response and
hda_unsol_event are revived but in a slightly different form.
Since we don't assign the card number there, print the bus device name
instead.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: hda - Move some codes up to hdac_bus struct

A few basic codes for communicating over HD-audio bus are moved to
struct hdac_bus now. It has only command and get_response ops in
addition to the unsolicited event handling.

Note that the codec-side tracing support is disabled temporarily
during this transition due to the code shuffling. It will be
re-enabled later once when all pieces are settled down.

Signed-off-by: Takashi Iwai <tiwai@suse.de>