drm/xe/vram: Use PCI rebar helpers in resize_vram_bar()

PCI core provides pci_rebar_size_supported() and pci_rebar_size_to_bytes();
use them in resize_vram_bar() to simplify code.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20251113180053.27944-8-ilpo.jarvinen@linux.intel.com

Author: ij-intel

drivers/gpu/drm/xe/xe_vram.c

@@ -24,8 +24,6 @@
 #include "xe_vram.h"
 #include "xe_vram_types.h"
 
-#define BAR_SIZE_SHIFT 20
-
 static void
 _resize_bar(struct xe_device *xe, int resno, resource_size_t size)
 {
@@ -71,25 +69,22 @@ static void resize_vram_bar(struct xe_device *xe)
 
 	/* set to a specific size? */
 	if (force_vram_bar_size) {
-		u32 bar_size_bit;
-
-		rebar_size = force_vram_bar_size * (resource_size_t)SZ_1M;
+		rebar_size = pci_rebar_bytes_to_size(force_vram_bar_size *
+						     (resource_size_t)SZ_1M);
 
-		bar_size_bit = bar_size_mask & BIT(pci_rebar_bytes_to_size(rebar_size));
-
-		if (!bar_size_bit) {
+		if (!pci_rebar_size_supported(pdev, LMEM_BAR, rebar_size)) {
 			drm_info(&xe->drm,
 				 "Requested size: %lluMiB is not supported by rebar sizes: 0x%x. Leaving default: %lluMiB\n",
-				 (u64)rebar_size >> 20, bar_size_mask, (u64)current_size >> 20);
+				 (u64)pci_rebar_size_to_bytes(rebar_size) >> 20,
+				 bar_size_mask, (u64)current_size >> 20);
 			return;
 		}
 
-		rebar_size = 1ULL << (__fls(bar_size_bit) + BAR_SIZE_SHIFT);
-
+		rebar_size = pci_rebar_size_to_bytes(rebar_size);
 		if (rebar_size == current_size)
 			return;
 	} else {
-		rebar_size = 1ULL << (__fls(bar_size_mask) + BAR_SIZE_SHIFT);
+		rebar_size = pci_rebar_size_to_bytes(__fls(bar_size_mask));
 
 		/* only resize if larger than current */
 		if (rebar_size <= current_size)