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ARM: sh-mobile: Use of_cpu_node_to_id() to read CPU node 'reg'

PATCH In review Rob Herring 2 participants 2 messages Mar 27, 2023 – Mar 30, 2023

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PATCH v2 1/1 ARM: sh-mobile: Use of_cpu_node_to_id() to read CPU node 'reg'

Replace open coded CPU nodes reading of "reg" and translation to logical ID with of_cpu_node_to_id().

The original code called of_parse_phandle() CONFIG_NR_CPUS times regardless of the length of 'cpus'. Optimize the loop to bail out once of_parse_phandle() fails as the end of 'cpus' property has been reached.

---
v2:
- Optimize the number of loop iterations

---
 arch/arm/mach-shmobile/platsmp-apmu.c | 36 ++++++++++++---------------
 1 file changed, 16 insertions(+), 20 deletions(-)
arch/arm/mach-shmobile/platsmp-apmu.c +16 -20
index e771ce70e132..ec6f421c0f4d 100644
@@ -10,6 +10,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
+#include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/smp.h>
 #include <linux/suspend.h>
@@ -210,7 +211,6 @@ static void apmu_parse_dt(void (*fn)(struct resource *res, int cpu, int bit))
 	struct device_node *np_apmu, *np_cpu;
 	struct resource res;
 	int bit, index;
-	u32 id;
 
 	for_each_matching_node(np_apmu, apmu_ids) {
 		/* only enable the cluster that includes the boot CPU */
@@ -218,33 +218,29 @@ static void apmu_parse_dt(void (*fn)(struct resource *res, int cpu, int bit))
 
 		for (bit = 0; bit < CONFIG_NR_CPUS; bit++) {
 			np_cpu = of_parse_phandle(np_apmu, "cpus", bit);
-			if (np_cpu) {
-				if (!of_property_read_u32(np_cpu, "reg", &id)) {
-					if (id == cpu_logical_map(0)) {
-						is_allowed = true;
-						of_node_put(np_cpu);
-						break;
-					}
-
-				}
+			if (!np_cpu)
+				break;
+			if (of_cpu_node_to_id(np_cpu) == 0) {
+				is_allowed = true;
 				of_node_put(np_cpu);
+				break;
 			}
+			of_node_put(np_cpu);
 		}
 		if (!is_allowed)
 			continue;
 
 		for (bit = 0; bit < CONFIG_NR_CPUS; bit++) {
 			np_cpu = of_parse_phandle(np_apmu, "cpus", bit);
-			if (np_cpu) {
-				if (!of_property_read_u32(np_cpu, "reg", &id)) {
-					index = get_logical_index(id);
-					if ((index >= 0) &&
-					    !of_address_to_resource(np_apmu,
-								    0, &res))
-						fn(&res, index, bit);
-				}
-				of_node_put(np_cpu);
-			}
+			if (!np_cpu)
+				break;
+
+			index = of_cpu_node_to_id(np_cpu);
+			if ((index >= 0) &&
+			    !of_address_to_resource(np_apmu, 0, &res))
+				fn(&res, index, bit);
+
+			of_node_put(np_cpu);
 		}
 	}
 }
Signature · 1 line
2.39.2
Reviewed-by Tested-by on v2 1/1
#1 lore raw

Hi Rob,

Quoted 11 lines · Rob Herring

Replace open coded CPU nodes reading of "reg" and translation to logical ID with of_cpu_node_to_id().

The original code called of_parse_phandle() CONFIG_NR_CPUS times regardless of the length of 'cpus'. Optimize the loop to bail out once of_parse_phandle() fails as the end of 'cpus' property has been reached.

---
v2:
- Optimize the number of loop iterations

Thanks for the update!

I have tested this on:
- R-Car H2: 4xCA15 + 4xCA7, booted from either CA15 or CA7,
- R-Car M2-W: 2xCA15,
- R-Car E2: 2xCA7.

i.e. will queue in renesas-devel for v6.4.

Gr{oetje,eeting}s,

Geert

Signature · 5 lines
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds