dmaengine: qcom: hidma: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Also, because there is no need to save the file dentry, remove the
variables that were saving them as they were never even being used once
set.

Cc: Sinan Kaya <okaya@kernel.org>
Cc: Andy Gross <agross@kernel.org>
Cc: David Brown <david.brown@linaro.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 and
only version 2 as published by the free software foundation this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 294 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.825281744@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

dmaengine: qcom_hidma: convert to DEFINE_SHOW_ATTRIBUTE

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: qcom_hidma: make pending_tre_count atomic

Getting ready for the MSI interrupts. The pending_tre_count is used
in the interrupt handler to make sure all outstanding requests are
serviced.

The driver will allocate 11 MSI interrupts. Each MSI interrupt can be
assigned to a different CPU. Then, we have a race condition for common
variables as they share the same interrupt handler with a different
cause bit and they can potentially be executed in parallel. Making this
variable atomic so that it can be updated from multiple processor
contexts.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: qcom_hidma: remove useless debugfs file removal

Since 'commit acc29fb8f792 ("debugfs: ->d_parent is never NULL or
negative")', HIDMA object removal is no longer working. This is due to
redundant debugfs remove call in hidma_debug_uninit.

debugfs_remove_recursive(dmadev->debugfs);
debugfs_remove_recursive(dmadev->stats);

The first remove is for the directory. Second remove is for the file under
the directory. The directory remove makes file remove invalid.

Unable to handle kernel NULL pointer dereference at virtual address

[<ffff00000889f480>] down_write+0x18/0x68
[<ffff00000831c220>] debugfs_remove_recursive+0x50/0x1c0
[<ffff00000848e0a8>] hidma_debug_uninit+0x20/0x30
[<ffff00000848c5d8>] hidma_remove+0x48/0x98
[<ffff000008511b6c>] platform_drv_remove+0x24/0x68
[<ffff00000850fac8>] __device_release_driver+0x80/0x118
[<ffff00000850fb84>] device_release_driver+0x24/0x38
[<ffff00000850e928>] unbind_store+0xe8/0x110
[<ffff00000850dd30>] drv_attr_store+0x20/0x30
[<ffff000008253a48>] sysfs_kf_write+0x48/0x58
[<ffff000008252dd8>] kernfs_fop_write+0xb0/0x1d8
[<ffff0000081dab3c>] __vfs_write+0x1c/0x110
[<ffff0000081db940>] vfs_write+0xa0/0x1b8
[<ffff0000081dcd34>] SyS_write+0x44/0xa0
[<ffff000008082ef0>] el0_svc_naked+0x24/0x28

Removing the second line.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: qcom_hidma: add debugfs hooks

Add debugfs hooks for debugging the execution behavior of the DMA
channel. The debugfs hooks get initialized by the probe function and
uninitialized by the remove function.

A stats file is created in debugfs. The stats file will show the
information about each HIDMA channel as well as each asynchronous job
queued and completed at a given time.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>