[PATCH v2 1/2] ARM: topology: Use a clock if possible to get the CPU frequency
Russell King - ARM Linux
linux at arm.linux.org.uk
Mon Jun 30 03:29:34 PDT 2014
On Mon, Jun 30, 2014 at 12:12:22PM +0200, Maxime Ripard wrote:
> The Cortex-A7 and Cortex-A15 based SoCs need a clock-frequency property in the
> topology code.
>
> Allow to use a clock to provide the same information.
>
> Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
This looks fine to me, but I don't know this code. Maybe Vincent Guittot
should be on the To: list (added)?
> ---
> arch/arm/kernel/topology.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index 9d853189028b..268443d88094 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -11,6 +11,7 @@
> * for more details.
> */
>
> +#include <linux/clk.h>
> #include <linux/cpu.h>
> #include <linux/cpumask.h>
> #include <linux/export.h>
> @@ -100,8 +101,8 @@ static void __init parse_dt_topology(void)
> GFP_NOWAIT);
>
> for_each_possible_cpu(cpu) {
> - const u32 *rate;
> - int len;
> + struct clk *clk;
> + u32 rate = 0;
>
> /* too early to use cpu->of_node */
> cn = of_get_cpu_node(cpu, NULL);
> @@ -117,14 +118,24 @@ static void __init parse_dt_topology(void)
> if (cpu_eff->compatible == NULL)
> continue;
>
> - rate = of_get_property(cn, "clock-frequency", &len);
> - if (!rate || len != 4) {
> - pr_err("%s missing clock-frequency property\n",
> - cn->full_name);
> + clk = of_clk_get(cn, 0);
> + if (!IS_ERR(clk))
> + rate = clk_get_rate(clk);
> + else
> + of_property_read_u32(cn, "clock-frequency", &rate);
> +
> + if (!rate) {
> + pr_err("%s missing clocks or clock-frequency properties\n",
> + cn->full_name);
> + continue;
> + }
> +
> + if (!rate) {
> + pr_err("%s invalid CPU frequency", cn->full_name);
> continue;
> }
>
> - capacity = ((be32_to_cpup(rate)) >> 20) * cpu_eff->efficiency;
> + capacity = ((rate) >> 20) * cpu_eff->efficiency;
>
> /* Save min capacity of the system */
> if (capacity < min_capacity)
> --
> 2.0.0
>
--
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