linux-stable.git/drivers/bus, branch v5.4.136 Linux kernel stable tree bus: ti-sysc: Fix flakey idling of uarts and stop using swsup_sidle_act 2021-06-10T11:37:08+00:00 Tony Lindgren tony@atomide.com 2021-05-25T06:08:23+00:00 0fa160a7574859192a1328a029c70d05b44a4c75 [ Upstream commit c8692ad416dcc420ce1b403596a425c8f4c2720b ] Looks like the swsup_sidle_act quirk handling is unreliable for serial ports. The serial ports just eventually stop idling until woken up and re-idled again. As the serial port not idling blocks any deeper SoC idle states, it's adds an annoying random flakeyness for power management. Let's just switch to swsup_sidle quirk instead like we already do for omap3 uarts. This means we manually idle the port instead of trying to use the hardware autoidle features when not in use. For more details on why the serial ports have been using swsup_idle_act, see commit 66dde54e978a ("ARM: OMAP2+: hwmod-data: UART IP needs software control to manage sidle modes"). It seems that the swsup_idle_act quirk handling is not enough though, and for example the TI Android kernel changed to using swsup_sidle with commit 77c34c84e1e0 ("OMAP4: HWMOD: UART1: disable smart-idle."). Fixes: b4a9a7a38917 ("bus: ti-sysc: Handle swsup idle mode quirks") Cc: Carl Philipp Klemm <philipp@uvos.xyz> Cc: Ivan Jelincic <parazyd@dyne.org> Cc: Merlijn Wajer <merlijn@wizzup.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Sebastian Reichel <sre@kernel.org> Cc: Sicelo A. Mhlongo <absicsz@gmail.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c8692ad416dcc420ce1b403596a425c8f4c2720b ]

Looks like the swsup_sidle_act quirk handling is unreliable for serial
ports. The serial ports just eventually stop idling until woken up and
re-idled again. As the serial port not idling blocks any deeper SoC idle
states, it's adds an annoying random flakeyness for power management.

Let's just switch to swsup_sidle quirk instead like we already do for
omap3 uarts. This means we manually idle the port instead of trying to
use the hardware autoidle features when not in use.

For more details on why the serial ports have been using swsup_idle_act,
see commit 66dde54e978a ("ARM: OMAP2+: hwmod-data: UART IP needs software
control to manage sidle modes"). It seems that the swsup_idle_act quirk
handling is not enough though, and for example the TI Android kernel
changed to using swsup_sidle with commit 77c34c84e1e0 ("OMAP4: HWMOD:
UART1: disable smart-idle.").

Fixes: b4a9a7a38917 ("bus: ti-sysc: Handle swsup idle mode quirks")
Cc: Carl Philipp Klemm <philipp@uvos.xyz>
Cc: Ivan Jelincic <parazyd@dyne.org>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sicelo A. Mhlongo <absicsz@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: qcom: Put child node before return 2021-05-14T07:44:19+00:00 Pan Bian bianpan2016@163.com 2021-01-21T11:49:07+00:00 3a76ec28824c01b57aa1f0927841d75e4f167cb8 [ Upstream commit ac6ad7c2a862d682bb584a4bc904d89fa7721af8 ] Put child node before return to fix potential reference count leak. Generally, the reference count of child is incremented and decremented automatically in the macro for_each_available_child_of_node() and should be decremented manually if the loop is broken in loop body. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Fixes: 335a12754808 ("bus: qcom: add EBI2 driver") Signed-off-by: Pan Bian <bianpan2016@163.com> Link: https://lore.kernel.org/r/20210121114907.109267-1-bianpan2016@163.com Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ac6ad7c2a862d682bb584a4bc904d89fa7721af8 ]

Put child node before return to fix potential reference count leak.
Generally, the reference count of child is incremented and decremented
automatically in the macro for_each_available_child_of_node() and should
be decremented manually if the loop is broken in loop body.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Fixes: 335a12754808 ("bus: qcom: add EBI2 driver")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Link: https://lore.kernel.org/r/20210121114907.109267-1-bianpan2016@163.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: ti-sysc: Probe for l4_wkup and l4_cfg interconnect devices first 2021-05-11T12:04:04+00:00 Tony Lindgren tony@atomide.com 2021-03-08T09:35:07+00:00 ce64f57a0fe0771379a24341b55823a676681a84 [ Upstream commit 4700a00755fb5a4bb5109128297d6fd2d1272ee6 ] We want to probe l4_wkup and l4_cfg interconnect devices first to avoid issues with missing resources. Otherwise we attempt to probe l4_per devices first causing pointless deferred probe and also annoyingh renumbering of the MMC devices for example. Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4700a00755fb5a4bb5109128297d6fd2d1272ee6 ]

We want to probe l4_wkup and l4_cfg interconnect devices first to avoid
issues with missing resources. Otherwise we attempt to probe l4_per
devices first causing pointless deferred probe and also annoyingh
renumbering of the MMC devices for example.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: ti-sysc: Fix warning on unbind if reset is not deasserted 2021-04-10T11:34:30+00:00 Tony Lindgren tony@atomide.com 2021-02-18T11:06:57+00:00 422c68101110ab29ab9bed723bb837c1a36ce3f4 [ Upstream commit a7b5d7c4969aba8d1f04c29048906abaa71fb6a9 ] We currently get thefollowing on driver unbind if a reset is configured and asserted: WARNING: CPU: 0 PID: 993 at drivers/reset/core.c:432 reset_control_assert ... (reset_control_assert) from [<c0fecda8>] (sysc_remove+0x190/0x1e4) (sysc_remove) from [<c0a2bb58>] (platform_remove+0x24/0x3c) (platform_remove) from [<c0a292fc>] (__device_release_driver+0x154/0x214) (__device_release_driver) from [<c0a2a210>] (device_driver_detach+0x3c/0x8c) (device_driver_detach) from [<c0a27d64>] (unbind_store+0x60/0xd4) (unbind_store) from [<c0546bec>] (kernfs_fop_write_iter+0x10c/0x1cc) Let's fix it by checking the reset status. Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a7b5d7c4969aba8d1f04c29048906abaa71fb6a9 ]

We currently get thefollowing on driver unbind if a reset is configured
and asserted:

WARNING: CPU: 0 PID: 993 at drivers/reset/core.c:432 reset_control_assert
...
(reset_control_assert) from [<c0fecda8>] (sysc_remove+0x190/0x1e4)
(sysc_remove) from [<c0a2bb58>] (platform_remove+0x24/0x3c)
(platform_remove) from [<c0a292fc>] (__device_release_driver+0x154/0x214)
(__device_release_driver) from [<c0a2a210>] (device_driver_detach+0x3c/0x8c)
(device_driver_detach) from [<c0a27d64>] (unbind_store+0x60/0xd4)
(unbind_store) from [<c0546bec>] (kernfs_fop_write_iter+0x10c/0x1cc)

Let's fix it by checking the reset status.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: omap_l3_noc: mark l3 irqs as IRQF_NO_THREAD 2021-03-30T12:35:24+00:00 Grygorii Strashko grygorii.strashko@ti.com 2021-01-28T19:15:48+00:00 f259a7fdeb1241bafac7596c707fd2decff0f614 [ Upstream commit 7d7275b3e866cf8092bd12553ec53ba26864f7bb ] The main purpose of l3 IRQs is to catch OCP bus access errors and identify corresponding code places by showing call stack, so it's important to handle L3 interconnect errors as fast as possible. On RT these IRQs will became threaded and will be scheduled much more late from the moment actual error occurred so showing completely useless information. Hence, mark l3 IRQs as IRQF_NO_THREAD so they will not be forced threaded on RT or if force_irqthreads = true. Fixes: 0ee7261c9212 ("drivers: bus: Move the OMAP interconnect driver to drivers/bus/") Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7d7275b3e866cf8092bd12553ec53ba26864f7bb ]

The main purpose of l3 IRQs is to catch OCP bus access errors and identify
corresponding code places by showing call stack, so it's important to
handle L3 interconnect errors as fast as possible. On RT these IRQs will
became threaded and will be scheduled much more late from the moment actual
error occurred so showing completely useless information.

Hence, mark l3 IRQs as IRQF_NO_THREAD so they will not be forced threaded
on RT or if force_irqthreads = true.

Fixes: 0ee7261c9212 ("drivers: bus: Move the OMAP interconnect driver to drivers/bus/")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: fsl-mc: fix error return code in fsl_mc_object_allocate() 2020-12-30T10:51:23+00:00 Zhang Changzhong zhangchangzhong@huawei.com 2020-12-04T08:02:47+00:00 be4d879cb7c4b492d58aabb6fac4c06437e200b4 [ Upstream commit 3d70fb03711c37bc64e8e9aea5830f498835f6bf ] Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Fixes: 197f4d6a4a00 ("staging: fsl-mc: fsl-mc object allocator driver") Reported-by: Hulk Robot <hulkci@huawei.com> Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com> Link: https://lore.kernel.org/r/1607068967-31991-1-git-send-email-zhangchangzhong@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3d70fb03711c37bc64e8e9aea5830f498835f6bf ]

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 197f4d6a4a00 ("staging: fsl-mc: fsl-mc object allocator driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Link: https://lore.kernel.org/r/1607068967-31991-1-git-send-email-zhangchangzhong@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
mips: cdmm: fix use-after-free in mips_cdmm_bus_discover 2020-12-30T10:51:13+00:00 Qinglang Miao miaoqinglang@huawei.com 2020-11-20T07:48:47+00:00 5873beee8744d607793f49b854ed36e361f36289 [ Upstream commit f0e82242b16826077a2775eacfe201d803bb7a22 ] kfree(dev) has been called inside put_device so anther kfree would cause a use-after-free bug/ Fixes: 8286ae03308c ("MIPS: Add CDMM bus support") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> Acked-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f0e82242b16826077a2775eacfe201d803bb7a22 ]

kfree(dev) has been called inside put_device so anther
kfree would cause a use-after-free bug/

Fixes: 8286ae03308c ("MIPS: Add CDMM bus support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: ti-sysc: Fix bogus resetdone warning on enable for cpsw 2020-12-02T07:49:49+00:00 Tony Lindgren tony@atomide.com 2020-10-26T08:08:47+00:00 6f87d79ef40dcd43d95bd2db3c600b5bc7680c2d [ Upstream commit e7ae08d398e094e1305dee823435b1f996d39106 ] Bail out early from sysc_wait_softreset() just like we do in sysc_reset() if there's no sysstatus srst_shift to fix a bogus resetdone warning on enable as suggested by Grygorii Strashko <grygorii.strashko@ti.com>. We do not currently handle resets for modules that need writing to the sysstatus register. If we at some point add that, we also need to add SYSS_QUIRK_RESETDONE_INVERTED flag for cpsw as the sysstatus bit is low when reset is done as described in the am335x TRM "Table 14-202 SOFT_RESET Register Field Descriptions" Fixes: d46f9fbec719 ("bus: ti-sysc: Use optional clocks on for enable and wait for softreset bit") Suggested-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e7ae08d398e094e1305dee823435b1f996d39106 ]

Bail out early from sysc_wait_softreset() just like we do in sysc_reset()
if there's no sysstatus srst_shift to fix a bogus resetdone warning on
enable as suggested by Grygorii Strashko <grygorii.strashko@ti.com>.

We do not currently handle resets for modules that need writing to the
sysstatus register. If we at some point add that, we also need to add
SYSS_QUIRK_RESETDONE_INVERTED flag for cpsw as the sysstatus bit is low
when reset is done as described in the am335x TRM "Table 14-202
SOFT_RESET Register Field Descriptions"

Fixes: d46f9fbec719 ("bus: ti-sysc: Use optional clocks on for enable and wait for softreset bit")
Suggested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus/fsl_mc: Do not rely on caller to provide non NULL mc_io 2020-11-05T10:43:19+00:00 Diana Craciun diana.craciun@oss.nxp.com 2020-09-29T08:54:38+00:00 37464a8a7f68373536f76fd9dbaa5293a88f1823 [ Upstream commit 5026cf605143e764e1785bbf9158559d17f8d260 ] Before destroying the mc_io, check first that it was allocated. Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com> Link: https://lore.kernel.org/r/20200929085441.17448-11-diana.craciun@oss.nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 5026cf605143e764e1785bbf9158559d17f8d260 ]

Before destroying the mc_io, check first that it was
allocated.

Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
Link: https://lore.kernel.org/r/20200929085441.17448-11-diana.craciun@oss.nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bus: hisi_lpc: Fixup IO ports addresses to avoid use-after-free in host removal 2020-10-01T11:17:37+00:00 John Garry john.garry@huawei.com 2020-01-16T18:48:34+00:00 29c25e69492b9c3f2a930265c88dab5ea73eb3d8 [ Upstream commit a6dd255bdd7d00bbdbf78ba00bde9fc64f86c3a7 ] Some released ACPI FW for Huawei boards describes incorrect the port IO address range for child devices, in that it tells us the IO port max range is 0x3fff for each child device, which is not correct. The address range should be [e4:e8) or similar. With this incorrect upper range, the child device IO port resources overlap. As such, the kernel thinks that the LPC host serial device is a child of the IPMI device: root@(none)$ more /proc/ioports [...] 00ffc0e3-00ffffff : hisi-lpc-ipmi.0.auto 00ffc0e3-00ffc0e3 : ipmi_si 00ffc0e4-00ffc0e4 : ipmi_si 00ffc0e5-00ffc0e5 : ipmi_si 00ffc2f7-00ffffff : serial8250.1.auto 00ffc2f7-00ffc2fe : serial root@(none)$ They should both be siblings. Note that these are logical PIO addresses, which have a direct mapping from the FW IO port ranges. This shows up as a real issue when we enable CONFIG_KASAN and CONFIG_DEBUG_TEST_DRIVER_REMOVE - we see use-after-free warnings in the host removal path: ================================================================== BUG: KASAN: use-after-free in release_resource+0x38/0xc8 Read of size 8 at addr ffff0026accdbc38 by task swapper/0/1 CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc6-00001-g68e186e77b5c-dirty #1593 Hardware name: Huawei Taishan 2180 /D03, BIOS Hisilicon D03 IT20 Nemo 2.0 RC0 03/30/2018 Call trace: dump_backtrace+0x0/0x290 show_stack+0x14/0x20 dump_stack+0xf0/0x14c print_address_description.isra.9+0x6c/0x3b8 __kasan_report+0x12c/0x23c kasan_report+0xc/0x18 __asan_load8+0x94/0xb8 release_resource+0x38/0xc8 platform_device_del.part.10+0x80/0xe0 platform_device_unregister+0x20/0x38 hisi_lpc_acpi_remove_subdev+0x10/0x20 device_for_each_child+0xc8/0x128 hisi_lpc_acpi_remove+0x4c/0xa8 hisi_lpc_remove+0xbc/0xc0 platform_drv_remove+0x3c/0x68 really_probe+0x174/0x548 driver_probe_device+0x7c/0x148 device_driver_attach+0x94/0xa0 __driver_attach+0xa4/0x110 bus_for_each_dev+0xe8/0x158 driver_attach+0x30/0x40 bus_add_driver+0x234/0x2f0 driver_register+0xbc/0x1d0 __platform_driver_register+0x7c/0x88 hisi_lpc_driver_init+0x18/0x20 do_one_initcall+0xb4/0x258 kernel_init_freeable+0x248/0x2c0 kernel_init+0x10/0x118 ret_from_fork+0x10/0x1c ... The issue here is that the kernel created an incorrect parent-child resource dependency between two devices, and references the false parent node when deleting the second child device, when it had been deleted already. Fix up the child device resources from FW to create proper IO port resource relationships for broken FW. With this, the IO port layout looks more healthy: root@(none)$ more /proc/ioports [...] 00ffc0e3-00ffc0e7 : hisi-lpc-ipmi.0.auto 00ffc0e3-00ffc0e3 : ipmi_si 00ffc0e4-00ffc0e4 : ipmi_si 00ffc0e5-00ffc0e5 : ipmi_si 00ffc2f7-00ffc2ff : serial8250.1.auto 00ffc2f7-00ffc2fe : serial Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Wei Xu <xuwei5@hisilicon.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a6dd255bdd7d00bbdbf78ba00bde9fc64f86c3a7 ]

Some released ACPI FW for Huawei boards describes incorrect the port IO
address range for child devices, in that it tells us the IO port max range
is 0x3fff for each child device, which is not correct. The address range
should be [e4:e8) or similar. With this incorrect upper range, the child
device IO port resources overlap.

As such, the kernel thinks that the LPC host serial device is a child of
the IPMI device:

root@(none)$ more /proc/ioports
[...]
00ffc0e3-00ffffff : hisi-lpc-ipmi.0.auto
  00ffc0e3-00ffc0e3 : ipmi_si
  00ffc0e4-00ffc0e4 : ipmi_si
  00ffc0e5-00ffc0e5 : ipmi_si
  00ffc2f7-00ffffff : serial8250.1.auto
    00ffc2f7-00ffc2fe : serial
root@(none)$

They should both be siblings. Note that these are logical PIO addresses,
which have a direct mapping from the FW IO port ranges.

This shows up as a real issue when we enable CONFIG_KASAN and
CONFIG_DEBUG_TEST_DRIVER_REMOVE - we see use-after-free warnings in the
host removal path:

==================================================================
BUG: KASAN: use-after-free in release_resource+0x38/0xc8
Read of size 8 at addr ffff0026accdbc38 by task swapper/0/1

CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc6-00001-g68e186e77b5c-dirty #1593
Hardware name: Huawei Taishan 2180 /D03, BIOS Hisilicon D03 IT20 Nemo 2.0 RC0 03/30/2018
Call trace:
dump_backtrace+0x0/0x290
show_stack+0x14/0x20
dump_stack+0xf0/0x14c
print_address_description.isra.9+0x6c/0x3b8
__kasan_report+0x12c/0x23c
kasan_report+0xc/0x18
__asan_load8+0x94/0xb8
release_resource+0x38/0xc8
platform_device_del.part.10+0x80/0xe0
platform_device_unregister+0x20/0x38
hisi_lpc_acpi_remove_subdev+0x10/0x20
device_for_each_child+0xc8/0x128
hisi_lpc_acpi_remove+0x4c/0xa8
hisi_lpc_remove+0xbc/0xc0
platform_drv_remove+0x3c/0x68
really_probe+0x174/0x548
driver_probe_device+0x7c/0x148
device_driver_attach+0x94/0xa0
__driver_attach+0xa4/0x110
bus_for_each_dev+0xe8/0x158
driver_attach+0x30/0x40
bus_add_driver+0x234/0x2f0
driver_register+0xbc/0x1d0
__platform_driver_register+0x7c/0x88
hisi_lpc_driver_init+0x18/0x20
do_one_initcall+0xb4/0x258
kernel_init_freeable+0x248/0x2c0
kernel_init+0x10/0x118
ret_from_fork+0x10/0x1c

...

The issue here is that the kernel created an incorrect parent-child
resource dependency between two devices, and references the false parent
node when deleting the second child device, when it had been deleted
already.

Fix up the child device resources from FW to create proper IO port
resource relationships for broken FW.

With this, the IO port layout looks more healthy:

root@(none)$ more /proc/ioports
[...]
00ffc0e3-00ffc0e7 : hisi-lpc-ipmi.0.auto
  00ffc0e3-00ffc0e3 : ipmi_si
  00ffc0e4-00ffc0e4 : ipmi_si
  00ffc0e5-00ffc0e5 : ipmi_si
00ffc2f7-00ffc2ff : serial8250.1.auto
  00ffc2f7-00ffc2fe : serial

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>