linux-stable.git/include/linux/soundwire/sdw.h, branch v6.0

soundwire: peripheral: remove useless ops pointer

2022-07-06T07:04:21+00:00

Now that we are using the ops structure directly from the driver,
there are no users left of this ops pointer.

Signed-off-by: Pierre-Louis Bossart 
Reviewed-by: Rander Wang 
Reviewed-by: Ranjani Sridharan 
Reviewed-by: Bard Liao 
Reviewed-by: Péter Ujfalusi 
Link: https://lore.kernel.org/r/20220621225641.221170-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul

soundwire: revisit driver bind/unbind and callbacks

2022-07-06T07:04:21+00:00

In the SoundWire probe, we store a pointer from the driver ops into
the 'slave' structure. This can lead to kernel oopses when unbinding
codec drivers, e.g. with the following sequence to remove machine
driver and codec driver.

/sbin/modprobe -r snd_soc_sof_sdw
/sbin/modprobe -r snd_soc_rt711

The full details can be found in the BugLink below, for reference the
two following examples show different cases of driver ops/callbacks
being invoked after the driver .remove().

kernel: BUG: kernel NULL pointer dereference, address: 0000000000000150
kernel: Workqueue: events cdns_update_slave_status_work [soundwire_cadence]
kernel: RIP: 0010:mutex_lock+0x19/0x30
kernel: Call Trace:
kernel: ? sdw_handle_slave_status+0x426/0xe00 [soundwire_bus 94ff184bf398570c3f8ff7efe9e32529f532e4ae]
kernel: ? newidle_balance+0x26a/0x400
kernel: ? cdns_update_slave_status_work+0x1e9/0x200 [soundwire_cadence 1bcf98eebe5ba9833cd433323769ac923c9c6f82]

kernel: BUG: unable to handle page fault for address: ffffffffc07654c8
kernel: Workqueue: pm pm_runtime_work
kernel: RIP: 0010:sdw_bus_prep_clk_stop+0x6f/0x160 [soundwire_bus]
kernel: Call Trace:
kernel:
kernel: sdw_cdns_clock_stop+0xb5/0x1b0 [soundwire_cadence 1bcf98eebe5ba9833cd433323769ac923c9c6f82]
kernel: intel_suspend_runtime+0x5f/0x120 [soundwire_intel aca858f7c87048d3152a4a41bb68abb9b663a1dd]
kernel: ? dpm_sysfs_remove+0x60/0x60

This was not detected earlier in Intel tests since the tests first
remove the parent PCI device and shut down the bus. The sequence
above is a corner case which keeps the bus operational but without a
driver bound.

While trying to solve this kernel oopses, it became clear that the
existing SoundWire bus does not deal well with the unbind case.

Commit 528be501b7d4a ("soundwire: sdw_slave: add probe_complete structure and new fields")
added a 'probed' status variable and a 'probe_complete'
struct completion. This status is however not reset on remove and
likewise the 'probe complete' is not re-initialized, so the
bind/unbind/bind test cases would fail. The timeout used before the
'update_status' callback was also a bad idea in hindsight, there
should really be no timing assumption as to if and when a driver is
bound to a device.

An initial draft was based on device_lock() and device_unlock() was
tested. This proved too complicated, with deadlocks created during the
suspend-resume sequences, which also use the same device_lock/unlock()
as the bind/unbind sequences. On a CometLake device, a bad DSDT/BIOS
caused spurious resumes and the use of device_lock() caused hangs
during suspend. After multiple weeks or testing and painful
reverse-engineering of deadlocks on different devices, we looked for
alternatives that did not interfere with the device core.

A bus notifier was used successfully to keep track of DRIVER_BOUND and
DRIVER_UNBIND events. This solved the bind-unbind-bind case in tests,
but it can still be defeated with a theoretical corner case where the
memory is freed by a .remove while the callback is in use. The
notifier only helps make sure the driver callbacks are valid, but not
that the memory allocated in probe remains valid while the callbacks
are invoked.

This patch suggests the introduction of a new 'sdw_dev_lock' mutex
protecting probe/remove and all driver callbacks. Since this mutex is
'local' to SoundWire only, it does not interfere with existing locks
and does not create deadlocks. In addition, this patch removes the
'probe_complete' completion, instead we directly invoke the
'update_status' from the probe routine. That removes any sort of
timing dependency and a much better support for the device/driver
model, the driver could be bound before the bus started, or eons after
the bus started and the hardware would be properly initialized in all
cases.

BugLink: https://github.com/thesofproject/linux/issues/3531
Fixes: 56d4fe31af77 ("soundwire: Add MIPI DisCo property helpers")
Fixes: 528be501b7d4a ("soundwire: sdw_slave: add probe_complete structure and new fields")
Signed-off-by: Pierre-Louis Bossart
Reviewed-by: Rander Wang
Reviewed-by: Ranjani Sridharan
Reviewed-by: Bard Liao
Reviewed-by: Péter Ujfalusi
Link: https://lore.kernel.org/r/20220621225641.221170-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul

soundwire: add flag to ignore all command/control for mockup devices

2021-08-02T05:38:22+00:00

SoundWire mockup devices don't take part in the command/control
protocol, so all commands will complete with -ENODATA or
Command_Ignored results. With a flag, we can suppress such errors in
the bus management and make it appear as if all read/writes succeed.

Signed-off-by: Pierre-Louis Bossart 
Reviewed-by: Rander Wang 
Signed-off-by: Bard Liao 
Link: https://lore.kernel.org/r/20210714032209.11284-7-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul

Merge tag 'char-misc-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2021-07-05T20:42:16+00:00

Pull char / misc driver updates from Greg KH:
 "Here is the big set of char / misc and other driver subsystem updates
  for 5.14-rc1. Included in here are:

   - habanalabs driver updates

   - fsl-mc driver updates

   - comedi driver updates

   - fpga driver updates

   - extcon driver updates

   - interconnect driver updates

   - mei driver updates

   - nvmem driver updates

   - phy driver updates

   - pnp driver updates

   - soundwire driver updates

   - lots of other tiny driver updates for char and misc drivers

  This is looking more and more like the "various driver subsystems
  mushed together" tree...

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (292 commits)
  mcb: Use DEFINE_RES_MEM() helper macro and fix the end address
  PNP: moved EXPORT_SYMBOL so that it immediately followed its function/variable
  bus: mhi: pci-generic: Add missing 'pci_disable_pcie_error_reporting()' calls
  bus: mhi: Wait for M2 state during system resume
  bus: mhi: core: Fix power down latency
  intel_th: Wait until port is in reset before programming it
  intel_th: msu: Make contiguous buffers uncached
  intel_th: Remove an unused exit point from intel_th_remove()
  stm class: Spelling fix
  nitro_enclaves: Set Bus Master for the NE PCI device
  misc: ibmasm: Modify matricies to matrices
  misc: vmw_vmci: return the correct errno code
  siox: Simplify error handling via dev_err_probe()
  fpga: machxo2-spi: Address warning about unused variable
  lkdtm/heap: Add init_on_alloc tests
  selftests/lkdtm: Enable various testable CONFIGs
  lkdtm: Add CONFIG hints in errors where possible
  lkdtm: Enable DOUBLE_FAULT on all architectures
  lkdtm/heap: Add vmalloc linear overflow test
  lkdtm/bugs: XFAIL UNALIGNED_LOAD_STORE_WRITE
  ...

soundwire: export sdw_update() and sdw_update_no_pm()

2021-06-21T12:00:42+00:00

We currently export sdw_read() and sdw_write() but the sdw_update()
and sdw_update_no_pm() are currently available only to the bus
code. This was missed in an earlier contribution.

Export both functions so that codec drivers can perform
read-modify-write operations without duplicating the code.

Fixes: b04c975e654c ('soundwire: bus: use sdw_update_no_pm when initializing a device')
Signed-off-by: Pierre-Louis Bossart 
Reviewed-by: Bard Liao 
Reviewed-by: Péter Ujfalusi 
Acked-By: Vinod Koul 
Link: https://lore.kernel.org/r/20210614180815.153711-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown

soundwire: bus: Make sdw_nwrite() data pointer argument const

2021-06-20T11:16:14+00:00

Idiomatically, write functions should take const pointers to the
data buffer, as they don't change the data. They are also likely
to be called from functions that receive a const data pointer.

Internally the pointer is passed to function/structs shared with
the read functions, requiring a cast, but this is an implementation
detail that should be hidden by the public API.

Signed-off-by: Richard Fitzgerald 
Link: https://lore.kernel.org/r/20210616145901.29402-1-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul

soundwire: add missing kernel-doc description

2021-05-11T12:20:32+00:00

For some reason we never added a description for the clk_stop
callback.

Signed-off-by: Pierre-Louis Bossart 
Reviewed-by: Guennadi Liakhovetski 
Reviewed-by: Rander Wang 
Signed-off-by: Bard Liao 
Link: https://lore.kernel.org/r/20210511030048.25622-3-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul

soundwire: bus: only use CLOCK_STOP_MODE0 and fix confusions

2021-05-11T12:20:32+00:00

Existing devices and implementations only support the required
CLOCK_STOP_MODE0. All the code related to CLOCK_STOP_MODE1 has not
been tested and is highly questionable, with a clear confusion between
CLOCK_STOP_MODE1 and the simple clock stop state machine.

This patch removes all usages of CLOCK_STOP_MODE1 - which has no
impact on any solution - and fixes the use of the simple clock stop
state machine. The resulting code should be a lot more symmetrical and
easier to maintain.

Note that CLOCK_STOP_MODE1 is not supported in the SoundWire Device
Class specification so it's rather unlikely that we need to re-add
this mode later.

Signed-off-by: Pierre-Louis Bossart 
Reviewed-by: Guennadi Liakhovetski 
Reviewed-by: Rander Wang 
Signed-off-by: Bard Liao 
Link: https://lore.kernel.org/r/20210511030048.25622-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul

soundwire: add static port mapping support

2021-04-06T04:52:02+00:00

Some of the SoundWire device ports are statically mapped to Controller
ports during design, however there is no way to expose this information
to the controller. Controllers like Qualcomm ones use this info to setup
static bandwidth parameters for those ports.

A generic port allocation is not possible in this cases!
So this patch adds a new member m_port_map to struct sdw_slave to expose
this static map.

Signed-off-by: Srinivas Kandagatla 
Reviewed-by: Pierre-Louis Bossart 
Link: https://lore.kernel.org/r/20210315165650.13392-2-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul

soundwire: export sdw_compare_devid, sdw_extract_slave_id and sdw_slave_add

2021-03-30T17:25:07+00:00

Exporting these three functions makes sense as it can be used by
other controllers like Qualcomm during auto-enumeration!

Reported-by: kernel test robot 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20210330144719.13284-8-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul