dma: xilinx_dpdma: Fix locking

There are several places where either chan->lock or chan->vchan.lock was
not held. Add appropriate locking. This fixes lockdep warnings like

[ 31.077578] ------------[ cut here ]------------
[ 31.077831] WARNING: CPU: 2 PID: 40 at drivers/dma/xilinx/xilinx_dpdma.c:834 xilinx_dpdma_chan_queue_transfer+0x274/0x5e0
[ 31.077953] Modules linked in:
[ 31.078019] CPU: 2 PID: 40 Comm: kworker/u12:1 Not tainted 6.6.20+ #98
[ 31.078102] Hardware name: xlnx,zynqmp (DT)
[ 31.078169] Workqueue: events_unbound deferred_probe_work_func
[ 31.078272] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 31.078377] pc : xilinx_dpdma_chan_queue_transfer+0x274/0x5e0
[ 31.078473] lr : xilinx_dpdma_chan_queue_transfer+0x270/0x5e0
[ 31.078550] sp : ffffffc083bb2e10
[ 31.078590] x29: ffffffc083bb2e10 x28: 0000000000000000 x27: ffffff880165a168
[ 31.078754] x26: ffffff880164e920 x25: ffffff880164eab8 x24: ffffff880164d480
[ 31.078920] x23: ffffff880165a148 x22: ffffff880164e988 x21: 0000000000000000
[ 31.079132] x20: ffffffc082aa3000 x19: ffffff880164e880 x18: 0000000000000000
[ 31.079295] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[ 31.079453] x14: 0000000000000000 x13: ffffff8802263dc0 x12: 0000000000000001
[ 31.079613] x11: 0001ffc083bb2e34 x10: 0001ff880164e98f x9 : 0001ffc082aa3def
[ 31.079824] x8 : 0001ffc082aa3dec x7 : 0000000000000000 x6 : 0000000000000516
[ 31.079982] x5 : ffffffc7f8d43000 x4 : ffffff88003c9c40 x3 : ffffffffffffffff
[ 31.080147] x2 : ffffffc7f8d43000 x1 : 00000000000000c0 x0 : 0000000000000000
[ 31.080307] Call trace:
[ 31.080340] xilinx_dpdma_chan_queue_transfer+0x274/0x5e0
[ 31.080518] xilinx_dpdma_issue_pending+0x11c/0x120
[ 31.080595] zynqmp_disp_layer_update+0x180/0x3ac
[ 31.080712] zynqmp_dpsub_plane_atomic_update+0x11c/0x21c
[ 31.080825] drm_atomic_helper_commit_planes+0x20c/0x684
[ 31.080951] drm_atomic_helper_commit_tail+0x5c/0xb0
[ 31.081139] commit_tail+0x234/0x294
[ 31.081246] drm_atomic_helper_commit+0x1f8/0x210
[ 31.081363] drm_atomic_commit+0x100/0x140
[ 31.081477] drm_client_modeset_commit_atomic+0x318/0x384
[ 31.081634] drm_client_modeset_commit_locked+0x8c/0x24c
[ 31.081725] drm_client_modeset_commit+0x34/0x5c
[ 31.081812] __drm_fb_helper_restore_fbdev_mode_unlocked+0x104/0x168
[ 31.081899] drm_fb_helper_set_par+0x50/0x70
[ 31.081971] fbcon_init+0x538/0xc48
[ 31.082047] visual_init+0x16c/0x23c
[ 31.082207] do_bind_con_driver.isra.0+0x2d0/0x634
[ 31.082320] do_take_over_console+0x24c/0x33c
[ 31.082429] do_fbcon_takeover+0xbc/0x1b0
[ 31.082503] fbcon_fb_registered+0x2d0/0x34c
[ 31.082663] register_framebuffer+0x27c/0x38c
[ 31.082767] __drm_fb_helper_initial_config_and_unlock+0x5c0/0x91c
[ 31.082939] drm_fb_helper_initial_config+0x50/0x74
[ 31.083012] drm_fbdev_dma_client_hotplug+0xb8/0x108
[ 31.083115] drm_client_register+0xa0/0xf4
[ 31.083195] drm_fbdev_dma_setup+0xb0/0x1cc
[ 31.083293] zynqmp_dpsub_drm_init+0x45c/0x4e0
[ 31.083431] zynqmp_dpsub_probe+0x444/0x5e0
[ 31.083616] platform_probe+0x8c/0x13c
[ 31.083713] really_probe+0x258/0x59c
[ 31.083793] __driver_probe_device+0xc4/0x224
[ 31.083878] driver_probe_device+0x70/0x1c0
[ 31.083961] __device_attach_driver+0x108/0x1e0
[ 31.084052] bus_for_each_drv+0x9c/0x100
[ 31.084125] __device_attach+0x100/0x298
[ 31.084207] device_initial_probe+0x14/0x20
[ 31.084292] bus_probe_device+0xd8/0xdc
[ 31.084368] deferred_probe_work_func+0x11c/0x180
[ 31.084451] process_one_work+0x3ac/0x988
[ 31.084643] worker_thread+0x398/0x694
[ 31.084752] kthread+0x1bc/0x1c0
[ 31.084848] ret_from_fork+0x10/0x20
[ 31.084932] irq event stamp: 64549
[ 31.084970] hardirqs last enabled at (64548): [<ffffffc081adf35c>] _raw_spin_unlock_irqrestore+0x80/0x90
[ 31.085157] hardirqs last disabled at (64549): [<ffffffc081adf010>] _raw_spin_lock_irqsave+0xc0/0xdc
[ 31.085277] softirqs last enabled at (64503): [<ffffffc08001071c>] __do_softirq+0x47c/0x500
[ 31.085390] softirqs last disabled at (64498): [<ffffffc080017134>] ____do_softirq+0x10/0x1c
[ 31.085501] ---[ end trace 0000000000000000 ]---

Fixes: 7cbb0c63de3f ("dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/r/20240308210034.3634938-2-sean.anderson@linux.dev
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: xdma: Workaround truncation compilation error

Increase length to be copied to be large enough to overcome the
following compilation error. The buf is large enough for this purpose.

drivers/dma/xilinx/xilinx_dpdma.c: In function ‘xilinx_dpdma_debugfs_desc_done_irq_read’:
drivers/dma/xilinx/xilinx_dpdma.c:313:39: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
313 | snprintf(buf, out_str_len, "%d",
| ^
drivers/dma/xilinx/xilinx_dpdma.c:313:9: note: ‘snprintf’ output between 2 and 6 bytes into a destination of size 5
313 | snprintf(buf, out_str_len, "%d",
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
314 | dpdma_debugfs.xilinx_dpdma_irq_done_count);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20231222094017.731917-1-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: xilinx_dpdma: 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() is renamed to .remove().

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

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230919133207.1400430-59-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: use strscpy to replace strlcpy

The strlcpy should not be used because it doesn't limit the source
length. Preferred is strscpy.

Signed-off-by: XueBing Chen <chenxuebing@jari.cn>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/39aa840f.e31.181ed9461c2.Coremail.chenxuebing@jari.cn
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx_dpdma: Omit superfluous error message in xilinx_dpdma_probe()

In the function xilinx_dpdma_probe(), when get irq failed,
the function platform_get_irq() logs an error message,
so remove redundant message here.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20220519130855.7664-1-tangbin@cmss.chinamobile.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx_dpdma: stop using slave_id field

The display driver wants to pass a custom flag to the DMA engine driver,
which it started doing by using the slave_id field that was traditionally
used for a different purpose.

As there is no longer a correct use for the slave_id field, it should
really be removed, and the remaining users changed over to something
different.

The new mechanism for passing nonstandard settings is using the
.peripheral_config field, so use that to pass a newly defined structure
here, making it clear that this will not work in portable drivers.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211122222203.4103644-10-arnd@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: remove debugfs #ifdef

The ptdma driver has added debugfs support, but this fails to build
when debugfs is disabled:

drivers/dma/ptdma/ptdma-debugfs.c: In function 'ptdma_debugfs_setup':
drivers/dma/ptdma/ptdma-debugfs.c:93:54: error: 'struct dma_device' has no member named 'dbg_dev_root'
93 | debugfs_create_file("info", 0400, pt->dma_dev.dbg_dev_root, pt,
| ^
drivers/dma/ptdma/ptdma-debugfs.c:96:55: error: 'struct dma_device' has no member named 'dbg_dev_root'
96 | debugfs_create_file("stats", 0400, pt->dma_dev.dbg_dev_root, pt,
| ^
drivers/dma/ptdma/ptdma-debugfs.c:102:52: error: 'struct dma_device' has no member named 'dbg_dev_root'
102 | debugfs_create_dir("q", pt->dma_dev.dbg_dev_root);
| ^

Remove the #ifdef in the header, as this only saves a few bytes,
but would require ugly #ifdefs in each driver using it.
Simplify the other user while we're at it.

Fixes: e2fb2e2a33fa ("dmaengine: ptdma: Add debugfs entries for PTDMA")
Fixes: 26cf132de6f7 ("dmaengine: Create debug directories for DMA devices")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20210920122017.205975-1-arnd@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Fix spacing around addr[i-1]

Use proper spacing for array calculation. Issue is reported by
checkpatch.pl --strict.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/ef7cde6f793bfa6f3dd0a8898bad13b6407479b0.1624446456.git.michal.simek@xilinx.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Use kernel type u32 over uint32_t

Use u32 kernel type instead of uint32_t. Issue is reported by
checkpatch.pl --strict.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/9569008794d519b487348bfeafbfd76c5da5755e.1624446336.git.michal.simek@xilinx.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: fix kernel-doc

Fix function name in xilinx/xilinx_dpdma.c comment to remove
a warning found by kernel-doc.

drivers/dma/xilinx/xilinx_dpdma.c:935: warning: expecting prototype for
xilinx_dpdma_chan_no_ostand(). Prototype was for
xilinx_dpdma_chan_notify_no_ostand() instead.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/1623222893-123227-1-git-send-email-yang.lee@linux.alibaba.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Print debug message when losing vsync race

The hardware retrigger is inherently racy with the vsync interrupt. This
isn't an issue as the hardware provides a way to detect a race loss and
handle it correctly. When debugging issues related to this, it's useful
to get a notification of the race loss. Add a debug message to do so.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Reviewed-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Link: https://lore.kernel.org/r/20210520152420.23986-4-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Print channel number in kernel log messages

To ease debugging, add the channel number to all kernel log messages
related to a particular channel.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Reviewed-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Link: https://lore.kernel.org/r/20210520152420.23986-3-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Limit descriptor IDs to 16 bits

While the descriptor ID is stored in a 32-bit field in the hardware
descriptor, only 16 bits are used by the hardware and are reported
through the XILINX_DPDMA_CH_DESC_ID register. Failure to handle the
wrap-around results in a descriptor ID mismatch after 65536 frames. Fix
it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Reviewed-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Link: https://lore.kernel.org/r/20210520152420.23986-5-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: initialize registers before request_irq

In some scenarios (kdump), dpdma hardware irqs has been enabled when
calling request_irq in probe function, and then the dpdma irq handler
xilinx_dpdma_irq_handler is invoked to access xdev->chan[i]. But at
this moment xdev->chan[i] hasn't been initialized.

We should ensure the dpdma controller to be in a consistent and
clean state before further initialization. So add dpdma_hw_init()
to do this.

Furthermore, in xilinx_dpdma_disable_irq, disable all interrupts
instead of error interrupts.

This patch is to fix the kdump kernel crash as below:

[ 3.696128] Unable to handle kernel NULL pointer dereference at virtual address 000000000000012c
[ 3.696710] xilinx-zynqmp-dpdma fd4c0000.dma-controller: Xilinx DPDMA engine is probed
[ 3.704900] Mem abort info:
[ 3.704902] ESR = 0x96000005
[ 3.704905] EC = 0x25: DABT (current EL), IL = 32 bits
[ 3.704907] SET = 0, FnV = 0
[ 3.704912] EA = 0, S1PTW = 0
[ 3.713800] ahci-ceva fd0c0000.ahci: supply ahci not found, using dummy regulator
[ 3.715585] Data abort info:
[ 3.715587] ISV = 0, ISS = 0x00000005
[ 3.715589] CM = 0, WnR = 0
[ 3.715592] [000000000000012c] user address but active_mm is swapper
[ 3.715596] Internal error: Oops: 96000005 [#1] SMP
[ 3.715599] Modules linked in:
[ 3.715608] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-12170-g60894882155f-dirty #77
[ 3.723937] Hardware name: ZynqMP ZCU102 Rev1.0 (DT)
[ 3.723942] pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
[ 3.723956] pc : xilinx_dpdma_irq_handler+0x418/0x560
[ 3.793049] lr : xilinx_dpdma_irq_handler+0x3d8/0x560
[ 3.798089] sp : ffffffc01186bdf0
[ 3.801388] x29: ffffffc01186bdf0 x28: ffffffc011836f28
[ 3.806692] x27: ffffff8023e0ac80 x26: 0000000000000080
[ 3.811996] x25: 0000000008000408 x24: 0000000000000003
[ 3.817300] x23: ffffffc01186be70 x22: ffffffc011291740
[ 3.822604] x21: 0000000000000000 x20: 0000000008000408
[ 3.827908] x19: 0000000000000000 x18: 0000000000000010
[ 3.833212] x17: 0000000000000000 x16: 0000000000000000
[ 3.838516] x15: 0000000000000000 x14: ffffffc011291740
[ 3.843820] x13: ffffffc02eb4d000 x12: 0000000034d4d91d
[ 3.849124] x11: 0000000000000040 x10: ffffffc0112d2d48
[ 3.854428] x9 : ffffffc0112d2d40 x8 : ffffff8021c00268
[ 3.859732] x7 : 0000000000000000 x6 : ffffffc011836000
[ 3.865036] x5 : 0000000000000003 x4 : 0000000000000000
[ 3.870340] x3 : 0000000000000001 x2 : 0000000000000000
[ 3.875644] x1 : 0000000000000000 x0 : 000000000000012c
[ 3.880948] Call trace:
[ 3.883382] xilinx_dpdma_irq_handler+0x418/0x560
[ 3.888079] __handle_irq_event_percpu+0x5c/0x178
[ 3.892774] handle_irq_event_percpu+0x34/0x98
[ 3.897210] handle_irq_event+0x44/0xb8
[ 3.901030] handle_fasteoi_irq+0xd0/0x190
[ 3.905117] generic_handle_irq+0x30/0x48
[ 3.909111] __handle_domain_irq+0x64/0xc0
[ 3.913192] gic_handle_irq+0x78/0xa0
[ 3.916846] el1_irq+0xc4/0x180
[ 3.919982] cpuidle_enter_state+0x134/0x2f8
[ 3.924243] cpuidle_enter+0x38/0x50
[ 3.927810] call_cpuidle+0x1c/0x40
[ 3.931290] do_idle+0x20c/0x270
[ 3.934502] cpu_startup_entry+0x28/0x58
[ 3.938410] rest_init+0xbc/0xcc
[ 3.941631] arch_call_rest_init+0x10/0x1c
[ 3.945718] start_kernel+0x51c/0x558

Fixes: 7cbb0c63de3f ("dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Link: https://lore.kernel.org/r/20210430064041.4058180-1-quanyang.wang@windriver.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Fix race condition in done IRQ

The active descriptor pointer is accessed from different contexts,
including different interrupt handlers, and its access must be protected
by the channel's lock. This wasn't done in the done IRQ handler. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20210307040629.29308-3-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Fix descriptor issuing on video group

When multiple channels are part of a video group, the transfer is
triggered only when all channels in the group are ready. The logic to do
so is incorrect, as it causes the descriptors for all channels but the
last one in a group to not being pushed to the hardware. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20210307040629.29308-2-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: convert tasklets to use new tasklet_setup() API

In preparation for unconditionally passing the
struct tasklet_struct pointer to all tasklet
callbacks, switch to using the new tasklet_setup()
and from_tasklet() to pass the tasklet pointer explicitly.

Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Allen Pais <apais@linux.microsoft.com>
Link: https://lore.kernel.org/r/20201006050458.221329-2-allen.lkml@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Make symbol 'dpdma_debugfs_reqs' static

The sparse tool complains as follows:

drivers/dma/xilinx/xilinx_dpdma.c:349:37: warning:
symbol 'dpdma_debugfs_reqs' was not declared. Should it be static?

This variable is not used outside of xilinx_dpdma.c, so this commit
marks it static.

Fixes: 1d220435cab3 ("dmaengine: xilinx: dpdma: Add debugfs support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Hyun Kwon <hyun.kwon@xilinx.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20200818112217.43816-1-weiyongjun1@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Add debugfs support

Expose statistics to debugfs when available. This helps debugging issues
with the DPDMA driver.

Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20200812171228.9751-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Fix kerneldoc warning

Document the struct xilinx_dpdma_chan desc field to fix a kerneldoc
undocumented member warning (which can be reproduced by compiling with
W=1).

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20200722161747.30048-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: add missing kernel doc

xilinx_dpdma_sw_desc_set_dma_addrs() documentation is missing describing
'xdev', so add it

drivers/dma/xilinx/xilinx_dpdma.c:313: warning: Function parameter or
member 'xdev' not described in 'xilinx_dpdma_sw_desc_set_dma_addrs'

Link: https://lore.kernel.org/r/20200718135201.191881-2-vkoul@kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: remove comparison of unsigned expression

xilinx_dpdma_config() channel id is unsigned int and compares with
ZYNQMP_DPDMA_VIDEO0 which is zero, so remove this comparison

drivers/dma/xilinx/xilinx_dpdma.c:1073:15: warning: comparison of
unsigned expression in ‘>= 0’ is always true [-Wtype-limits] if
(chan->id >= ZYNQMP_DPDMA_VIDEO0 && chan->id <= ZYNQMP_DPDMA_VIDEO2)

Link: https://lore.kernel.org/r/20200718135201.191881-1-vkoul@kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver

The ZynqMP DisplayPort subsystem includes a DMA engine called DPDMA with
6 DMa channels (4 for display and 2 for audio). This driver exposes the
DPDMA through the dmaengine API, to be used by audio (ALSA) and display
(DRM) drivers for the DisplayPort subsystem.

Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Tejas Upadhyay <tejasu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20200717013337.24122-4-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>