coresight: Add helper for setting csdev->mode

Now that mode is in struct coresight_device, sets can be wrapped. This
also allows us to add a sanity check that there have been no concurrent
modifications of mode. Currently all usages of local_set() were inside
the device's spin locks so this new warning shouldn't be triggered.

coresight_take_mode() could maybe have been used in place of adding
the warning, but there may be use cases which set the mode to the same
mode which are valid but would fail in coresight_take_mode() because
it requires the device to only be in the disabled state.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-13-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Add a helper for getting csdev->mode

Now that mode is in struct coresight_device accesses can be wrapped.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-12-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Remove atomic type from refcnt

Refcnt is only ever accessed from either inside the coresight_mutex, or
the device's spinlock, making the atomic type and atomic_dec_return()
calls confusing and unnecessary. The only point of synchronisation
outside of these two types of locks is already done with a compare and
swap on 'mode', which a comment has been added for.

There was one instance of refcnt being used outside of a lock in TPIU,
but that can easily be fixed by making it the same as all the other
devices and adding a spinlock. Potentially in the future all the
refcounting and locking can be moved up into the core code, and all the
mostly duplicate code from the individual devices can be removed.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-8-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Move mode to struct coresight_device

Most devices use mode, so move the mode definition out of the individual
devices and up to the Coresight device. This will allow the core code to
also know the mode which will be useful in a later commit.

This also fixes the inconsistency of the documentation of the mode field
on the individual device types. For example ETB10 had "this ETB is being
used".

Two devices didn't require an atomic mode type, so these usages have
been converted to atomic_get() and atomic_set() only to make it compile,
but the documentation of the field in struct coresight_device explains
this type of usage.

In the future, manipulation of the mode could be completely moved out of
the individual devices and into the core code because it's almost all
duplicate code, and this change is a step towards that.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-5-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Fix uninitialized struct warnings

These warnings would be hit with the following W=1 build change so
initialize all structs properly.

Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231123120459.287578-2-james.clark@arm.com

coresight: ultrasoc-smb: Use guards to cleanup

Use guards to reduce gotos and simplify control flow.

Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-5-hejunhao3@huawei.com

coresight: ultrasoc-smb: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231116173301.708873-14-u.kleine-koenig@pengutronix.de

coresight: ultrasoc-smb: Fix uninitialized before use buf_hw_base

In smb_reset_buffer, the sdb->buf_hw_base variable is uninitialized
before use, which initializes it in smb_init_data_buffer. And the SMB
regiester are set in smb_config_inport.
So move the call after smb_config_inport.

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-4-hejunhao3@huawei.com

coresight: ultrasoc-smb: Config SMB buffer before register sink

The SMB dirver register the enable/disable sysfs interface in function
smb_register_sink(), however the buffer depends on the following
configuration to work well. So it'll be possible for user to access an
unreset one.

Move the config buffer operation to before register_sink().
Ignore the return value, if smb_config_inport() fails. That will
cause the hardwares disable trace path to fail, should not affect
SMB driver remove. So we make smb_remove() return success,

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-3-hejunhao3@huawei.com

coresight: ultrasoc-smb: Fix sleep while close preempt in enable_smb

When we to enable the SMB by perf, the perf sched will call perf_ctx_lock()
to close system preempt in event_function_call(). But SMB::enable_smb() use
mutex to lock the critical section, which may sleep.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 153023, name: perf
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
softirqs last enabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 2 PID: 153023 Comm: perf Kdump: loaded Tainted: G W O 6.5.0-rc4+ #1

Call trace:
...
__mutex_lock+0xbc/0xa70
mutex_lock_nested+0x34/0x48
smb_update_buffer+0x58/0x360 [ultrasoc_smb]
etm_event_stop+0x204/0x2d8 [coresight]
etm_event_del+0x1c/0x30 [coresight]
event_sched_out+0x17c/0x3b8
group_sched_out.part.0+0x5c/0x208
__perf_event_disable+0x15c/0x210
event_function+0xe0/0x230
remote_function+0xb4/0xe8
generic_exec_single+0x160/0x268
smp_call_function_single+0x20c/0x2a0
event_function_call+0x20c/0x220
_perf_event_disable+0x5c/0x90
perf_event_for_each_child+0x58/0xc0
_perf_ioctl+0x34c/0x1250
perf_ioctl+0x64/0x98
...

Use spinlock to replace mutex to control driver data access to one at a
time. The function copy_to_user() may sleep, it cannot be in a spinlock
context, so we can't simply replace it in smb_read(). But we can ensure
that only one user gets the SMB device fd by smb_open(), so remove the
locks from smb_read() and buffer synchronization is guaranteed by the user.

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-2-hejunhao3@huawei.com

coresight: Make refcount a property of the connection

This removes the need to do an additional lookup for the total number
of ports used and also removes the need to allocate an array of
refcounts which is just another representation of a connection array.

This was only used for link type devices, for regular devices a single
refcount on the coresight device is used.

There is a both an input and output refcount in case two link type
devices are connected together so that they don't overwrite each other's
counts.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-11-james.clark@arm.com

coresight: Use enum type for cs_mode wherever possible

mode is stored as a local_t, but it is also passed around a lot as a
plain u32, so use the correct type wherever local_t isn't currently
used. This helps a little bit with readability.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-3-james.clark@arm.com

coresight: ultrasoc-smb: fix return value check in smb_init_data_buffer()

platform_get_resource() returns NULL pointer not PTR_ERR(), replace
the IS_ERR() check with NULL pointer check.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230118074920.1772141-1-yangyingliang@huawei.com

drivers/coresight: Add UltraSoc System Memory Buffer driver

Add driver for UltraSoc SMB(System Memory Buffer) device.
SMB provides a way to buffer messages from ETM, and store
these "CPU instructions trace" in system memory.
The SMB device is identifier as ACPI HID "HISI03A1". Device
system memory address resources are allocated using the _CRS
method and buffer modes is the circular buffer mode.

SMB is developed by UltraSoc technology, which is acquired by
Siemens, and we still use "UltraSoc" to name driver.

Signed-off-by: Qi Liu <liuqi115@huawei.com>
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Tested-by: JunHao He <hejunhao3@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230114101302.62320-2-hejunhao3@huawei.com