dmaengine: ioatdma: use default_groups in kobj_type

There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field. Move the ioatdma sysfs code to use default_groups field which has
been the preferred way since aa30f47cf666 ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.

Cc: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20220104163330.1338824-1-gregkh@linuxfoundation.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 291

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope 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 the full gnu general public license is included in
this distribution in the file called copying

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
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 the full gnu general public license is included in
this distribution in the file called copying

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 57 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.515993066@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

dmaengine: ioatdma: Add intr_coalesce sysfs entry

We observed performance increase with DMA copy from memory
to MMIO by changing the interrupt coalescing value to 0.
The previous set value was projected on the C5xxx Xeon
platform and no longer holds true. Removing hard coded
value and providing a tune-able in sysfs in order to allow
user to tune this on a per channel basis. By default this
value will be set to 0.
Example of sysfs variable importing for interrupt coalescing
value from command line:
echo 5> /sys/devices/pci0000:00/0000:00:04.0/dma/dma0chan0/
quickdata/intr_coalesce

Reported-by: Nithin Sujir <nsujir@tintri.com>
Signed-off-by: Ujjal Singh <ujjal.singh@intel.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: ioatdma: move all sysfs related code

Move and fixup all sysfs related bits to sysfs.c file.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>