drm/ttm: fix DMA32 handling in the global page pool

When we have mixed DMA32 and non DMA32 device in one system
it could otherwise happen that the DMA32 device gets pages
it can't work with.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.freedesktop.org/patch/401317/

drivers/gpu/drm/ttm/ttm_pool.c

@@ -63,6 +63,9 @@ static atomic_long_t allocated_pages;
 static struct ttm_pool_type global_write_combined[MAX_ORDER];
 static struct ttm_pool_type global_uncached[MAX_ORDER];
 
+static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER];
+static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
+
 static spinlock_t shrinker_lock;
 static struct list_head shrinker_list;
 static struct shrinker mm_shrinker;
@@ -290,8 +293,14 @@ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool,
 #ifdef CONFIG_X86
 	switch (caching) {
 	case ttm_write_combined:
+		if (pool->use_dma32)
+			return &global_dma32_write_combined[order];
+
 		return &global_write_combined[order];
 	case ttm_uncached:
+		if (pool->use_dma32)
+			return &global_dma32_uncached[order];
+
 		return &global_uncached[order];
 	default:
 		break;
@@ -570,6 +579,11 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
 	seq_puts(m, "uc\t:");
 	ttm_pool_debugfs_orders(global_uncached, m);
 
+	seq_puts(m, "wc 32\t:");
+	ttm_pool_debugfs_orders(global_dma32_write_combined, m);
+	seq_puts(m, "uc 32\t:");
+	ttm_pool_debugfs_orders(global_dma32_uncached, m);
+
 	for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) {
 		seq_puts(m, "DMA ");
 		switch (i) {
@@ -640,6 +654,11 @@ int ttm_pool_mgr_init(unsigned long num_pages)
 		ttm_pool_type_init(&global_write_combined[i], NULL,
 				   ttm_write_combined, i);
 		ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
+
+		ttm_pool_type_init(&global_dma32_write_combined[i], NULL,
+				   ttm_write_combined, i);
+		ttm_pool_type_init(&global_dma32_uncached[i], NULL,
+				   ttm_uncached, i);
 	}
 
 	mm_shrinker.count_objects = ttm_pool_shrinker_count;
@@ -660,6 +679,9 @@ void ttm_pool_mgr_fini(void)
 	for (i = 0; i < MAX_ORDER; ++i) {
 		ttm_pool_type_fini(&global_write_combined[i]);
 		ttm_pool_type_fini(&global_uncached[i]);
+
+		ttm_pool_type_fini(&global_dma32_write_combined[i]);
+		ttm_pool_type_fini(&global_dma32_uncached[i]);
 	}
 
 	unregister_shrinker(&mm_shrinker);