powerpc/ps3: Add dma_mask to ps3_dma_region

Commit f959dcd6 (dma-direct: Fix
potential NULL pointer dereference) added a null check on the
dma_mask pointer of the kernel's device structure.

Add a dma_mask variable to the ps3_dma_region structure and set
the device structure's dma_mask pointer to point to this new variable.

Fixes runtime errors like these:
# WARNING: Fixes tag on line 10 doesn't match correct format
# WARNING: Fixes tag on line 10 doesn't match correct format

  ps3_system_bus_match:349: dev=8.0(sb_01), drv=8.0(ps3flash): match
  WARNING: CPU: 0 PID: 1 at kernel/dma/mapping.c:151 .dma_map_page_attrs+0x34/0x1e0
  ps3flash sb_01: ps3stor_setup:193: map DMA region failed
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/562d0c9ea0100a30c3b186bcc7adb34b0bbd2cd7.1622746428.git.geoff@infradead.org

arch/powerpc/include/asm/ps3.h

@@ -71,6 +71,7 @@ struct ps3_dma_region_ops;
  * @bus_addr: The 'translated' bus address of the region.
  * @len: The length in bytes of the region.
  * @offset: The offset from the start of memory of the region.
+ * @dma_mask: Device dma_mask.
  * @ioid: The IOID of the device who owns this region
  * @chunk_list: Opaque variable used by the ioc page manager.
  * @region_ops: struct ps3_dma_region_ops - dma region operations
@@ -85,6 +86,7 @@ struct ps3_dma_region {
 	enum ps3_dma_region_type region_type;
 	unsigned long len;
 	unsigned long offset;
+	u64 dma_mask;
 
 	/* driver variables  (set by ps3_dma_region_create) */
 	unsigned long bus_addr;

arch/powerpc/platforms/ps3/mm.c

@@ -6,6 +6,7 @@
  *  Copyright 2006 Sony Corp.
  */
 
+#include <linux/dma-mapping.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
@@ -1118,6 +1119,7 @@ int ps3_dma_region_init(struct ps3_system_bus_device *dev,
 	enum ps3_dma_region_type region_type, void *addr, unsigned long len)
 {
 	unsigned long lpar_addr;
+	int result;
 
 	lpar_addr = addr ? ps3_mm_phys_to_lpar(__pa(addr)) : 0;
 
@@ -1129,6 +1131,16 @@ int ps3_dma_region_init(struct ps3_system_bus_device *dev,
 		r->offset -= map.r1.offset;
 	r->len = len ? len : ALIGN(map.total, 1 << r->page_size);
 
+	dev->core.dma_mask = &r->dma_mask;
+
+	result = dma_set_mask_and_coherent(&dev->core, DMA_BIT_MASK(32));
+
+	if (result < 0) {
+		dev_err(&dev->core, "%s:%d: dma_set_mask_and_coherent failed: %d\n",
+			__func__, __LINE__, result);
+		return result;
+	}
+
 	switch (dev->dev_type) {
 	case PS3_DEVICE_TYPE_SB:
 		r->region_ops =  (USE_DYNAMIC_DMA)