The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Ludovic Desroches<ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200507190046.GA15298@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Ludovic Desroches<ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200507190038.GA15272@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200508210707.GA24136@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
In case of dmatest is built-in and no channel was configured test
doesn't run with:
dmatest: Could not start test, no channels configured
Even though description to "channel" parameter claims that default is
any.
Add default channel back as it used to be rather than reject test with
no channel configuration.
Fixes: d53513d5dc ("dmaengine: dmatest: Add support for multi channel testing)
Reported-by: Dijil Mohan <Dijil.Mohan@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Link: https://lore.kernel.org/r/20200429071522.58148-1-vladimir.murzin@arm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When the kernel is built with lockdep support and the owl-dma driver is
used, the following message is shown:
[ 2.496939] INFO: trying to register non-static key.
[ 2.501889] the code is fine but needs lockdep annotation.
[ 2.507357] turning off the locking correctness validator.
[ 2.512834] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.3+ #15
[ 2.519084] Hardware name: Generic DT based system
[ 2.523878] Workqueue: events_freezable mmc_rescan
[ 2.528681] [<801127f0>] (unwind_backtrace) from [<8010da58>] (show_stack+0x10/0x14)
[ 2.536420] [<8010da58>] (show_stack) from [<8080fbe8>] (dump_stack+0xb4/0xe0)
[ 2.543645] [<8080fbe8>] (dump_stack) from [<8017efa4>] (register_lock_class+0x6f0/0x718)
[ 2.551816] [<8017efa4>] (register_lock_class) from [<8017b7d0>] (__lock_acquire+0x78/0x25f0)
[ 2.560330] [<8017b7d0>] (__lock_acquire) from [<8017e5e4>] (lock_acquire+0xd8/0x1f4)
[ 2.568159] [<8017e5e4>] (lock_acquire) from [<80831fb0>] (_raw_spin_lock_irqsave+0x3c/0x50)
[ 2.576589] [<80831fb0>] (_raw_spin_lock_irqsave) from [<8051b5fc>] (owl_dma_issue_pending+0xbc/0x120)
[ 2.585884] [<8051b5fc>] (owl_dma_issue_pending) from [<80668cbc>] (owl_mmc_request+0x1b0/0x390)
[ 2.594655] [<80668cbc>] (owl_mmc_request) from [<80650ce0>] (mmc_start_request+0x94/0xbc)
[ 2.602906] [<80650ce0>] (mmc_start_request) from [<80650ec0>] (mmc_wait_for_req+0x64/0xd0)
[ 2.611245] [<80650ec0>] (mmc_wait_for_req) from [<8065aa10>] (mmc_app_send_scr+0x10c/0x144)
[ 2.619669] [<8065aa10>] (mmc_app_send_scr) from [<80659b3c>] (mmc_sd_setup_card+0x4c/0x318)
[ 2.628092] [<80659b3c>] (mmc_sd_setup_card) from [<80659f0c>] (mmc_sd_init_card+0x104/0x430)
[ 2.636601] [<80659f0c>] (mmc_sd_init_card) from [<8065a3e0>] (mmc_attach_sd+0xcc/0x16c)
[ 2.644678] [<8065a3e0>] (mmc_attach_sd) from [<8065301c>] (mmc_rescan+0x3ac/0x40c)
[ 2.652332] [<8065301c>] (mmc_rescan) from [<80143244>] (process_one_work+0x2d8/0x780)
[ 2.660239] [<80143244>] (process_one_work) from [<80143730>] (worker_thread+0x44/0x598)
[ 2.668323] [<80143730>] (worker_thread) from [<8014b5f8>] (kthread+0x148/0x150)
[ 2.675708] [<8014b5f8>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20)
[ 2.682912] Exception stack(0xee8fdfb0 to 0xee8fdff8)
[ 2.687954] dfa0: 00000000 00000000 00000000 00000000
[ 2.696118] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2.704277] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
The obvious fix would be to use 'spin_lock_init()' on 'pchan->lock'
before attempting to call 'spin_lock_irqsave()' in 'owl_dma_get_pchan()'.
However, according to Manivannan Sadhasivam, 'pchan->lock' was supposed
to only protect 'pchan->vchan' while 'od->lock' does a similar job in
'owl_dma_terminate_pchan()'.
Therefore, this patch substitutes 'pchan->lock' with 'od->lock' and
removes the 'lock' attribute in 'owl_dma_pchan' struct.
Fixes: 47e20577c2 ("dmaengine: Add Actions Semi Owl family S900 DMA driver")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Link: https://lore.kernel.org/r/c6e6cdaca252b5364bd294093673951036488cf0.1588439073.git.cristian.ciocaltea@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Modify dw_edma_device_transfer() to also support the semantics of dma
device transfer for additional use cases involving pcitest utility as a
local initiator.
For its original use case, dw-edma supported the semantics of dma device
transfer from the perspective of a remote initiator who is located across
the PCIe bus from dma channel hardware.
To a remote initiator, DMA_DEV_TO_MEM means using a remote dma WRITE
channel to transfer from remote memory to local memory. A WRITE channel
would be employed on the remote device in order to move the contents of
remote memory to the bus destined for local memory.
To a remote initiator, DMA_MEM_TO_DEV means using a remote dma READ
channel to transfer from local memory to remote memory. A READ channel
would be employed on the remote device in order to move the contents of
local memory to the bus destined for remote memory.
>From the perspective of a local dma initiator who is co-located on the
same side of the PCIe bus as the dma channel hardware, the semantics of
dma device transfer are flipped.
To a local initiator, DMA_DEV_TO_MEM means using a local dma READ channel
to transfer from remote memory to local memory. A READ channel would be
employed on the local device in order to move the contents of remote
memory to the bus destined for local memory.
To a local initiator, DMA_MEM_TO_DEV means using a local dma WRITE channel
to transfer from local memory to remote memory. A WRITE channel would be
employed on the local device in order to move the contents of local memory
to the bus destined for remote memory.
To support local dma initiators, dw_edma_device_transfer() is modified to
now examine the direction field of struct dma_slave_config for the channel
which initiators can configure by calling dmaengine_slave_config().
If direction is configured as either DMA_DEV_TO_MEM or DMA_MEM_TO_DEV,
local initiator semantics are used. If direction is a value other than
DMA_DEV_TO_MEM nor DMA_MEM_TO_DEV, then remote initiator semantics are
used. This should maintain backward compatibility with the original use
case of dw-edma.
The dw-edma-test utility is an example of a remote initiator. From reading
its patch, dw-edma-test does not specifically set the direction field of
struct dma_slave_config. Since dw_edma_device_transfer() also does not
check the direction field of struct dma_slave_config, it seems safe to use
this convention in dw-edma to support both local and remote initiator
semantics.
Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
Link: https://lore.kernel.org/r/1588122633-1552-1-git-send-email-alan.mikhak@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The validation kernel doc script complains about undescribed
function parameters
.../dmaengine.c:155: warning: Function parameter or member 'dev' not descr ibed in 'dev_to_dma_chan'
.../dmaengine.c:251: warning: cannot understand function prototype: 'dma_cap_mask_t dma_cap_mask_all; '
.../dmaengine.c:257: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent '
.../dmaengine.c:264: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END]; '
.../dmaengine.c:304: warning: Function parameter or member 'chan' not described in 'dma_chan_is_local'
.../dmaengine.c:304: warning: Function parameter or member 'cpu' not described in 'dma_chan_is_local'
.../dmaengine.c:414: warning: Function parameter or member 'chan' not described in 'balance_ref_count'
.../dmaengine.c:447: warning: Function parameter or member 'chan' not described in 'dma_chan_get'
.../dmaengine.c:494: warning: Function parameter or member 'chan' not described in 'dma_chan_put'
Add descriptions to the function parameters and in some cases update
existing text as well.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200429122151.50989-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
If we do
% echo 1 > /sys/module/dmatest/parameters/run
[ 115.851124] dmatest: Could not start test, no channels configured
% echo dma8chan7 > /sys/module/dmatest/parameters/channel
[ 127.563872] dmatest: Added 1 threads using dma8chan7
% cat /sys/module/dmatest/parameters/wait
... !!! HANG !!! ...
The culprit is the commit 6138f967bc
("dmaengine: dmatest: Use fixed point div to calculate iops")
which makes threads not to run, but pending and being kicked off by writing
to the 'run' node. However, it forgot to consider 'wait' routine to avoid
above mentioned case.
In order to fix this, check for really running threads, i.e. with pending
and done flags unset.
It's pity the culprit commit hadn't updated documentation and tested all
possible scenarios.
Fixes: 6138f967bc ("dmaengine: dmatest: Use fixed point div to calculate iops")
Cc: Seraj Alijan <seraj.alijan@sondrel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200428113518.70620-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Under some circumstances, i.e. when test is still running and about to
time out and user runs, for example,
grep -H . /sys/module/dmatest/parameters/*
the iterations parameter is not respected and test is going on and on until
user gives
echo 0 > /sys/module/dmatest/parameters/run
This is not what expected.
The history of this bug is interesting. I though that the commit
2d88ce76eb ("dmatest: add a 'wait' parameter")
is a culprit, but looking closer to the code I think it simple revealed the
broken logic from the day one, i.e. in the commit
0a2ff57d6f ("dmaengine: dmatest: add a maximum number of test iterations")
which adds iterations parameter.
So, to the point, the conditional of checking the thread to be stopped being
first part of conjunction logic prevents to check iterations. Thus, we have to
always check both conditions to be able to stop after given iterations.
Since it wasn't visible before second commit appeared, I add a respective
Fixes tag.
Fixes: 2d88ce76eb ("dmatest: add a 'wait' parameter")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20200424161147.16895-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
DMA synchronization hook checks whether interrupt is raised by testing
corresponding bit in a hardware status register, and thus, clock should
be enabled in this case, otherwise CPU may hang if synchronization is
invoked while Runtime PM is in suspended state. This patch resumes the RPM
during of the DMA synchronization process in order to avoid potential
problems. It is a minor clean up of a previous commit, no real problem is
fixed by this patch because currently RPM is always in a resumed state
while DMA is synchronized, although this may change in the future.
Fixes: 6697255f23 ("dmaengine: tegra-apb: Improve DMA synchronization")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200426190835.21950-1-digetx@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Modify dw_edma_irq_request() to check if a struct msi_desc entry exists
before copying the contents of its struct msi_msg pointer.
Without this sanity check, __get_cached_msi_msg() crashes when invoked by
dw_edma_irq_request() running on a Linux-based PCIe endpoint device. MSI
interrupt are not received by PCIe endpoint devices. If irq_get_msi_desc()
returns null, then there is no cached struct msi_msg to be copied.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/1587607101-31914-1-git-send-email-alan.mikhak@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When the channel register code was changed to allow hotplug operations,
dynamic indexing wasn't taken into account. When channels are randomly
plugged and unplugged out of order, the serial indexing breaks. Convert
channel indexing to using IDA tracking in order to allow dynamic
assignment. The previous code does not cause any regression bug for
existing channel allocation besides idxd driver since the hotplug usage
case is only used by idxd at this point.
With this change, the chan->idr_ref is also not needed any longer. We can
have a device with no channels registered due to hot plug. The channel
device release code no longer should attempt to free the dma device id on
the last channel release.
Fixes: e81274cd6b ("dmaengine: add support to dynamic register/unregister of channels")
Reported-by: Yixin Zhang <yixin.zhang@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Yixin Zhang <yixin.zhang@intel.com>
Link: https://lore.kernel.org/r/158679961260.7674.8485924270472851852.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When a channel configuration fails, the status of the channel is set to
DEV_ERROR so that an attempt to submit it fails. However, this status
sticks until the heat end of the universe, making it impossible to
recover from the error.
Let's reset it when the channel is released so that further use of the
channel with correct configuration is not impacted.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200419164912.670973-5-lkundrak@v3.sk
Signed-off-by: Vinod Koul <vkoul@kernel.org>
With an invalid dma_slave_config set previously,
mmp_tdma_prep_dma_cyclic() would detect an error whilst configuring the
channel, but proceed happily on:
[ 120.756530] mmp-tdma d42a0800.adma: mmp_tdma: unknown burst size.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200419164912.670973-2-lkundrak@v3.sk
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Decouple dw-edma-core.c from struct pci_dev as a step toward integration
of dw-edma with pci-epf-test so the latter can initiate dma operations
locally from the endpoint side. A barrier to such integration is the
dependency of dw_edma_probe() and other functions in dw-edma-core.c on
struct pci_dev.
The Synopsys DesignWare dw-edma driver was designed to run on host side
of PCIe link to initiate DMA operations remotely using eDMA channels of
PCIe controller on the endpoint side. This can be inferred from seeing
that dw-edma uses struct pci_dev and accesses hardware registers of dma
channels across the bus using BAR0 and BAR2.
The ops field of struct dw_edma in dw-edma-core.h is currenty undefined:
const struct dw_edma_core_ops *ops;
However, the kernel builds without failure even when dw-edma driver is
enabled. Instead of removing the currently undefined and usued ops field,
define struct dw_edma_core_ops and use the ops field to decouple
dw-edma-core.c from struct pci_dev.
Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/1586971629-30196-1-git-send-email-alan.mikhak@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The DMA transfer might finish just after checking the state with
dma_cookie_status, but before the lock is acquired. Not checking
for an empty list in xilinx_dma_tx_status may result in reading
random data or data corruption when desc is written to. This can
be reliably triggered by using dma_sync_wait to wait for DMA
completion.
Signed-off-by: Sebastian von Ohr <vonohr@smaract.com>
Tested-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Link: https://lore.kernel.org/r/20200303130518.333-1-vonohr@smaract.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
If PCI_MSI is not set, building fais:
drivers/dma/hisi_dma.c: In function ‘hisi_dma_free_irq_vectors’:
drivers/dma/hisi_dma.c:138:2: error: implicit declaration of function ‘pci_free_irq_vectors’;
did you mean ‘pci_alloc_irq_vectors’? [-Werror=implicit-function-declaration]
pci_free_irq_vectors(data);
^~~~~~~~~~~~~~~~~~~~
Make HISI_DMA depends on PCI_MSI to fix this.
Fixes: e9f08b6525 ("dmaengine: hisilicon: Add Kunpeng DMA engine support")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20200328114133.17560-1-yuehaibing@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Pull dmaengine updates from Vinod Koul:
"Core:
- Some code cleanup and optimization in core by Andy
- Debugfs support for displaying dmaengine channels by Peter
Drivers:
- New driver for uniphier-xdmac controller
- Updates to stm32 dma, mdma and dmamux drivers and PM support
- More updates to idxd drivers
- Bunch of changes in tegra-apb driver and cleaning up of pm
functions
- Bunch of spelling fixes and Replace zero-length array patches
- Shutdown hook for fsl-dpaa2-qdma driver
- Support for interleaved transfers for ti-edma and virtualization
support for k3-dma driver
- Support for reset and updates in xilinx_dma driver
- Improvements and locking updates in at_hdma driver"
* tag 'dmaengine-5.7-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (89 commits)
dt-bindings: dma: renesas,usb-dmac: add r8a77961 support
dmaengine: uniphier-xdmac: Remove redandant error log for platform_get_irq
dmaengine: tegra-apb: Improve DMA synchronization
dmaengine: tegra-apb: Don't save/restore IRQ flags in interrupt handler
dmaengine: tegra-apb: mark PM functions as __maybe_unused
dmaengine: fix spelling mistake "exceds" -> "exceeds"
dmaengine: sprd: Set request pending flag when DMA controller is active
dmaengine: ppc4xx: Use scnprintf() for avoiding potential buffer overflow
dmaengine: idxd: remove global token limit check
dmaengine: idxd: reflect shadow copy of traffic class programming
dmaengine: idxd: Merge definition of dsa_batch_desc into dsa_hw_desc
dmaengine: Create debug directories for DMA devices
dmaengine: ti: k3-udma: Implement custom dbg_summary_show for debugfs
dmaengine: Add basic debugfs support
dmaengine: fsl-dpaa2-qdma: remove set but not used variable 'dpaa2_qdma'
dmaengine: ti: edma: fix null dereference because of a typo in pointer name
dmaengine: fsl-dpaa2-qdma: Adding shutdown hook
dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
dt-bindings: dmaengine: Add UniPhier external DMA controller bindings
dmaengine: ti: k3-udma: Implement support for atype (for virtualization)
...
Boot CPU0 always handles DMA interrupts and under some rare circumstances
it could stuck in uninterruptible state for a significant time (like in a
case of KASAN + NFS root). In this case sibling CPU, which waits for DMA
transfer completion, will get a DMA transfer timeout. In order to handle
this rare condition, interrupt status needs to be polled until interrupt
is handled.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200319212321.3297-2-digetx@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
