From 8599395d34f2dd7b77bef42da1d99798e7a3d58f Mon Sep 17 00:00:00 2001
From: Leonardo Bras <leobras.c@gmail.com>
Date: Tue, 17 Aug 2021 03:39:27 -0300
Subject: [PATCH] powerpc/pseries/iommu: Find existing DDW with given property
 name

References: bsc#1212091 ltc#199106
Patch-mainline: v5.15-rc1
Git-commit: 8599395d34f2dd7b77bef42da1d99798e7a3d58f

At the moment pseries stores information about created directly mapped
DDW window in DIRECT64_PROPNAME.

With the objective of implementing indirect DMA mapping with DDW, it's
necessary to have another propriety name to make sure kexec'ing into older
kernels does not break, as it would if we reuse DIRECT64_PROPNAME.

In order to have this, find_existing_ddw_windows() needs to be able to
look for different property names.

Extract find_existing_ddw_windows() into find_existing_ddw_windows_named()
and calls it with current property name.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210817063929.38701-10-leobras.c@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/platforms/pseries/iommu.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 901f290999d0..e11c00b2dc1e 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -910,24 +910,21 @@ static struct direct_window *ddw_list_new_entry(struct device_node *pdn,
 	return window;
 }
 
-static int find_existing_ddw_windows(void)
+static void find_existing_ddw_windows_named(const char *name)
 {
 	int len;
 	struct device_node *pdn;
 	struct direct_window *window;
-	const struct dynamic_dma_window_prop *direct64;
-
-	if (!firmware_has_feature(FW_FEATURE_LPAR))
-		return 0;
+	const struct dynamic_dma_window_prop *dma64;
 
-	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, DIRECT64_PROPNAME);
+	for_each_node_with_property(pdn, name) {
+		dma64 = of_get_property(pdn, name, &len);
+		if (!dma64 || len < sizeof(*dma64)) {
+			remove_ddw(pdn, true, name);
 			continue;
 		}
 
-		window = ddw_list_new_entry(pdn, direct64);
+		window = ddw_list_new_entry(pdn, dma64);
 		if (!window)
 			break;
 
@@ -935,6 +932,14 @@ static int find_existing_ddw_windows(void)
 		list_add(&window->list, &direct_window_list);
 		spin_unlock(&direct_window_list_lock);
 	}
+}
+
+static int find_existing_ddw_windows(void)
+{
+	if (!firmware_has_feature(FW_FEATURE_LPAR))
+		return 0;
+
+	find_existing_ddw_windows_named(DIRECT64_PROPNAME);
 
 	return 0;
 }
-- 
2.41.0