[PATCH 3/4] drm/mgag200: Add IRQ support

[kernel test robot]

Hi Jocelyn,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 457391b0380335d5e9a5babdec90ac53928b23b4]

url:    https://github.com/intel-lab-lkp/linux/commits/Jocelyn-Falempe/drm-mgag200-Rename-constant-MGAREG_Status-to-MGAREG_STATUS/20230505-204705
base:   457391b0380335d5e9a5babdec90ac53928b23b4
patch link:    https://lore.kernel.org/r/20230505124337.854845-4-jfalempe%40redhat.com
patch subject: [PATCH 3/4] drm/mgag200: Add IRQ support
config: s390-allyesconfig (https://download.01.org/0day-ci/archive/20230505/202305052227.4o72gpi8-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/cbbd69ea02ffdcee64621b76bf22cb360d943294
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Jocelyn-Falempe/drm-mgag200-Rename-constant-MGAREG_Status-to-MGAREG_STATUS/20230505-204705
        git checkout cbbd69ea02ffdcee64621b76bf22cb360d943294
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/gpu/drm/mgag200/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202305052227.4o72gpi8-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/mgag200/mgag200_drv.c:113:13: warning: no previous prototype for 'mgag200_driver_irq_handler' [-Wmissing-prototypes]
     113 | irqreturn_t mgag200_driver_irq_handler(int irq, void *arg)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/mgag200/mgag200_drv.c:129:6: warning: no previous prototype for 'mgag200_init_irq' [-Wmissing-prototypes]
     129 | void mgag200_init_irq(struct mga_device *mdev)
         |      ^~~~~~~~~~~~~~~~
>> drivers/gpu/drm/mgag200/mgag200_drv.c:137:6: warning: no previous prototype for 'mgag200_enable_irq' [-Wmissing-prototypes]
     137 | void mgag200_enable_irq(struct mga_device *mdev)
         |      ^~~~~~~~~~~~~~~~~~


vim +/mgag200_driver_irq_handler +113 drivers/gpu/drm/mgag200/mgag200_drv.c

   112	
 > 113	irqreturn_t mgag200_driver_irq_handler(int irq, void *arg)
   114	{
   115		struct mga_device *mdev = (struct mga_device *) arg;
   116		u32 status;
   117	
   118		status = RREG32(MGAREG_STATUS);
   119	
   120		if (status & MGAIRQ_SOFTRAP) {
   121			WREG32(MGAREG_ICLEAR, MGAIRQ_SOFTRAP);
   122			mdev->dma_in_use = 0;
   123			wake_up(&mdev->waitq);
   124			return IRQ_HANDLED;
   125		}
   126		return IRQ_NONE;
   127	}
   128	
 > 129	void mgag200_init_irq(struct mga_device *mdev)
   130	{
   131		/* Disable *all* interrupts */
   132		WREG32(MGAREG_IEN, 0);
   133		/* Clear bits if they're already high */
   134		WREG32(MGAREG_ICLEAR, 0xf);
   135	}
   136	
 > 137	void mgag200_enable_irq(struct mga_device *mdev)
   138	{
   139		/* Enable only Softrap IRQ */
   140		WREG32(MGAREG_IEN, MGAIRQ_SOFTRAP);
   141	}
   142	

-- 
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https://github.com/intel/lkp-tests