Hi Rob,
On Sun, Mar 19, 2023 at 4:00 PM Rob Herring <robh@xxxxxxxxxx> wrote:
> Replace open coded CPU nodes reading of "reg" and translation to logical
> ID with of_cpu_node_to_id().
>
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Thanks for your patch!
> --- a/arch/arm/mach-shmobile/platsmp-apmu.c
> +++ b/arch/arm/mach-shmobile/platsmp-apmu.c
> @@ -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 +218,27 @@ static void apmu_parse_dt(void (*fn)(struct resource *res, int cpu, int bit))
>
> for (bit = 0; bit < CONFIG_NR_CPUS; bit++) {
This loops over all CPUs....
> 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 && of_cpu_node_to_id(np_cpu) == 0) {
As of_cpu_node_to_id() uses for_each_possible_cpu(), you're
converting an O(n) operation to O(n²). I'm sure this can be done
more efficiently, using for_each_possible_cpu() as the outer loop?
Meh, cpu_logical_map() also loops over all CPUs, so it was already
O(n²)... Still, we should do better...
> + 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)
> + continue;
> +
> + index = of_cpu_node_to_id(np_cpu);
Likewise.
> + if ((index >= 0) &&
> + !of_address_to_resource(np_apmu, 0, &res))
> + fn(&res, index, bit);
> +
> + of_node_put(np_cpu);
> }
> }
> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
