i2c: core: Disable client irq on reboot/shutdown

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

If an i2c client receives an interrupt during reboot or shutdown it may
be too late to service it by making an i2c transaction on the bus
because the i2c controller has already been shutdown. This can lead to
system hangs if the i2c controller tries to make a transfer that is
doomed to fail because the access to the i2c pins is already shut down,
or an iommu translation has been torn down so i2c controller register
access doesn't work.

Let's simply disable the irq if there isn't a shutdown callback for an
i2c client when there is an irq associated with the device. This will
make sure that irqs don't come in later than the time that we can handle
it. We don't do this if the i2c client device already has a shutdown
callback because presumably they're doing the right thing and quieting
the device so irqs don't come in after the shutdown callback returns.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[swboyd@chromium.org: Dropped newline, added commit text]
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---

Dmitry, please add Signed-off-by

This supersedes https://lore.kernel.org/r/20210510220012.2003285-1-swboyd@chromium.org

 drivers/i2c/i2c-core-base.c | 2 ++
 1 file changed, 2 insertions(+)


base-commit: 8124c8a6b35386f73523d27eacb71b5364a68c4c

Hi Stephen,

I love your patch! Yet something to improve:

[auto build test ERROR on 8124c8a6b35386f73523d27eacb71b5364a68c4c]

url:    https://github.com/0day-ci/linux/commits/Stephen-Boyd/i2c-core-Disable-client-irq-on-reboot-shutdown/20210605-052848
base:   8124c8a6b35386f73523d27eacb71b5364a68c4c
config: nios2-randconfig-s031-20210604 (attached as .config)
compiler: nios2-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://github.com/0day-ci/linux/commit/2fb1417bc9d82a335db5ed8a1446be74bffae440
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Stephen-Boyd/i2c-core-Disable-client-irq-on-reboot-shutdown/20210605-052848
        git checkout 2fb1417bc9d82a335db5ed8a1446be74bffae440
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=nios2 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/i2c/i2c-core-base.c: In function 'i2c_device_shutdown':
>> drivers/i2c/i2c-core-base.c:631:3: error: implicit declaration of function 'disable_irq'; did you mean 'disable_srat'? [-Werror=implicit-function-declaration]
     631 |   disable_irq(client->irq);
         |   ^~~~~~~~~~~
         |   disable_srat
   cc1: some warnings being treated as errors


vim +631 drivers/i2c/i2c-core-base.c

   619	
   620	static void i2c_device_shutdown(struct device *dev)
   621	{
   622		struct i2c_client *client = i2c_verify_client(dev);
   623		struct i2c_driver *driver;
   624	
   625		if (!client || !dev->driver)
   626			return;
   627		driver = to_i2c_driver(dev->driver);
   628		if (driver->shutdown)
   629			driver->shutdown(client);
   630		else if (client->irq > 0)
 > 631			disable_irq(client->irq);
   632	}
   633	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Quoting kernel test robot (2021-06-04 16:01:32)
> Hi Stephen,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on 8124c8a6b35386f73523d27eacb71b5364a68c4c]
>
> url:    https://github.com/0day-ci/linux/commits/Stephen-Boyd/i2c-core-Disable-client-irq-on-reboot-shutdown/20210605-052848
> base:   8124c8a6b35386f73523d27eacb71b5364a68c4c
> config: nios2-randconfig-s031-20210604 (attached as .config)
> compiler: nios2-linux-gcc (GCC) 9.3.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # apt-get install sparse
>         # sparse version: v0.6.3-341-g8af24329-dirty
>         # https://github.com/0day-ci/linux/commit/2fb1417bc9d82a335db5ed8a1446be74bffae440
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Stephen-Boyd/i2c-core-Disable-client-irq-on-reboot-shutdown/20210605-052848
>         git checkout 2fb1417bc9d82a335db5ed8a1446be74bffae440
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=nios2
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>    drivers/i2c/i2c-core-base.c: In function 'i2c_device_shutdown':
> >> drivers/i2c/i2c-core-base.c:631:3: error: implicit declaration of function 'disable_irq'; did you mean 'disable_srat'? [-Werror=implicit-function-declaration]

Must need interrupt.h, which I must have got implicitly somehow.

>      631 |   disable_irq(client->irq);
>          |   ^~~~~~~~~~~
>          |   disable_srat