powerpc/pseries/iommu: Update remove_dma_window() to accept property name

Update remove_dma_window() so it can be used to remove DDW with a given
property name.

This enables the creation of new property names for DDW, so we can
have different usage for it, like indirect mapping.

Also, add return values to it so we can check if the property was found
while removing the active DDW. This allows skipping the remaining property
names while reducing the impact of multiple property names.
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210817063929.38701-9-leobras.c@gmail.com

arch/powerpc/platforms/pseries/iommu.c

@@ -844,31 +844,33 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
 	__remove_dma_window(np, ddw_avail, liobn);
 }
 
-static void remove_ddw(struct device_node *np, bool remove_prop)
+static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_name)
 {
 	struct property *win;
 	u32 ddw_avail[DDW_APPLICABLE_SIZE];
 	int ret = 0;
 
+	win = of_find_property(np, win_name, NULL);
+	if (!win)
+		return -EINVAL;
+
 	ret = of_property_read_u32_array(np, "ibm,ddw-applicable",
 					 &ddw_avail[0], DDW_APPLICABLE_SIZE);
 	if (ret)
-		return;
+		return 0;
 
-	win = of_find_property(np, DIRECT64_PROPNAME, NULL);
-	if (!win)
-		return;
 
 	if (win->length >= sizeof(struct dynamic_dma_window_prop))
 		remove_dma_window(np, ddw_avail, win);
 
 	if (!remove_prop)
-		return;
+		return 0;
 
 	ret = of_remove_property(np, win);
 	if (ret)
 		pr_warn("%pOF: failed to remove direct window property: %d\n",
 			np, ret);
+	return 0;
 }
 
 static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift)
@@ -921,7 +923,7 @@ static int find_existing_ddw_windows(void)
 	for_each_node_with_property(pdn, DIRECT64_PROPNAME) {
 		direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
 		if (!direct64 || len < sizeof(*direct64)) {
-			remove_ddw(pdn, true);
+			remove_ddw(pdn, true, DIRECT64_PROPNAME);
 			continue;
 		}
 
@@ -1565,7 +1567,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
 		 * we have to remove the property when releasing
 		 * the device node.
 		 */
-		remove_ddw(np, false);
+		remove_ddw(np, false, DIRECT64_PROPNAME);
 		if (pci && pci->table_group)
 			iommu_pseries_free_group(pci->table_group,
 					np->full_name);