[drm-intel:for-linux-next-gt 3/3] drivers/gpu/drm/i915/gem/i915_gem_stolen.c:943:32: sparse: sparse: Using plain integer as NULL pointer

[kernel test robot]

tree:   git://anongit.freedesktop.org/drm-intel for-linux-next-gt
head:   05da7d9f717bcb03c457379fa8a61c1689dab86c
commit: 05da7d9f717bcb03c457379fa8a61c1689dab86c [3/3] drm/i915/gem: Downgrade stolen lmem setup warning
config: x86_64-randconfig-122-20240614 (https://download.01.org/0day-ci/archive/20240615/202406150232.r9Of4ebo-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240615/202406150232.r9Of4ebo-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406150232.r9Of4ebo-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/gpu/drm/i915/gem/i915_gem_stolen.c:943:32: sparse: sparse: Using plain integer as NULL pointer

vim +943 drivers/gpu/drm/i915/gem/i915_gem_stolen.c

   889	
   890	struct intel_memory_region *
   891	i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
   892				   u16 instance)
   893	{
   894		struct intel_uncore *uncore = &i915->uncore;
   895		struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
   896		resource_size_t dsm_size, dsm_base, lmem_size;
   897		struct intel_memory_region *mem;
   898		resource_size_t io_start, io_size;
   899		resource_size_t min_page_size;
   900		int ret;
   901	
   902		if (WARN_ON_ONCE(instance))
   903			return ERR_PTR(-ENODEV);
   904	
   905		if (!i915_pci_resource_valid(pdev, GEN12_LMEM_BAR))
   906			return ERR_PTR(-ENXIO);
   907	
   908		if (HAS_LMEMBAR_SMEM_STOLEN(i915) || IS_DG1(i915)) {
   909			lmem_size = pci_resource_len(pdev, GEN12_LMEM_BAR);
   910		} else {
   911			resource_size_t lmem_range;
   912	
   913			lmem_range = intel_gt_mcr_read_any(to_gt(i915), XEHP_TILE0_ADDR_RANGE) & 0xFFFF;
   914			lmem_size = lmem_range >> XEHP_TILE_LMEM_RANGE_SHIFT;
   915			lmem_size *= SZ_1G;
   916		}
   917	
   918		if (HAS_LMEMBAR_SMEM_STOLEN(i915)) {
   919			/*
   920			 * MTL dsm size is in GGC register.
   921			 * Also MTL uses offset to GSMBASE in ptes, so i915
   922			 * uses dsm_base = 8MBs to setup stolen region, since
   923			 * DSMBASE = GSMBASE + 8MB.
   924			 */
   925			ret = mtl_get_gms_size(uncore);
   926			if (ret < 0) {
   927				drm_err(&i915->drm, "invalid MTL GGC register setting\n");
   928				return ERR_PTR(ret);
   929			}
   930	
   931			dsm_base = SZ_8M;
   932			dsm_size = (resource_size_t)(ret * SZ_1M);
   933	
   934			GEM_BUG_ON(pci_resource_len(pdev, GEN12_LMEM_BAR) != SZ_256M);
   935			GEM_BUG_ON((dsm_base + dsm_size) > lmem_size);
   936		} else {
   937			/* Use DSM base address instead for stolen memory */
   938			dsm_base = intel_uncore_read64(uncore, GEN6_DSMBASE) & GEN11_BDSM_MASK;
   939			if (lmem_size < dsm_base) {
   940				drm_dbg(&i915->drm,
   941					"Disabling stolen memory support due to OOB placement: lmem_size = %lli vs dsm_base = %lli\n",
   942					lmem_size, dsm_base);
 > 943				return 0;
   944			}
   945			dsm_size = ALIGN_DOWN(lmem_size - dsm_base, SZ_1M);
   946		}
   947	
   948		if (i915_direct_stolen_access(i915)) {
   949			drm_dbg(&i915->drm, "Using direct DSM access\n");
   950			io_start = intel_uncore_read64(uncore, GEN6_DSMBASE) & GEN11_BDSM_MASK;
   951			io_size = dsm_size;
   952		} else if (pci_resource_len(pdev, GEN12_LMEM_BAR) < lmem_size) {
   953			io_start = 0;
   954			io_size = 0;
   955		} else {
   956			io_start = pci_resource_start(pdev, GEN12_LMEM_BAR) + dsm_base;
   957			io_size = dsm_size;
   958		}
   959	
   960		min_page_size = HAS_64K_PAGES(i915) ? I915_GTT_PAGE_SIZE_64K :
   961							I915_GTT_PAGE_SIZE_4K;
   962	
   963		mem = intel_memory_region_create(i915, dsm_base, dsm_size,
   964						 min_page_size,
   965						 io_start, io_size,
   966						 type, instance,
   967						 &i915_region_stolen_lmem_ops);
   968		if (IS_ERR(mem))
   969			return mem;
   970	
   971		intel_memory_region_set_name(mem, "stolen-local");
   972	
   973		mem->private = true;
   974	
   975		return mem;
   976	}
   977	

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