From: gregory.clement@bootlin•com (Gregory CLEMENT)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: mvebu: convert secondary CPU clock sync to hotplug state
Date: Wed, 27 Jun 2018 11:19:52 +0200 [thread overview]
Message-ID: <87lgb08u2v.fsf@bootlin.com> (raw)
In-Reply-To: <20180618153230.32182-1-l.stach@pengutronix.de> (Lucas Stach's message of "Mon, 18 Jun 2018 17:32:30 +0200")
Hi Lucas,
On lun., juin 18 2018, Lucas Stach <l.stach@pengutronix•de> wrote:
> The current call site in boot_secondary is causing sleep in invalid context
> warnings, as this part of the code is running with interrrupts disabled and
> some of the calls into the clock framework might sleep on a mutex.
>
> Convert the secondary CPU clock sync to a hotplug state, which allows to
> call it from a sleepable context.
>
> Signed-off-by: Lucas Stach <l.stach@pengutronix•de>
Tested on Aramda XP DB and applied on mvebu/arm
Thanks,
Gregory
> ---
> arch/arm/mach-mvebu/platsmp.c | 49 ++++++++++++++++-------------------
> include/linux/cpuhotplug.h | 1 +
> 2 files changed, 24 insertions(+), 26 deletions(-)
>
> diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c
> index 4ffbbd217e82..c130497dc6cc 100644
> --- a/arch/arm/mach-mvebu/platsmp.c
> +++ b/arch/arm/mach-mvebu/platsmp.c
> @@ -35,6 +35,8 @@
> #define AXP_BOOTROM_BASE 0xfff00000
> #define AXP_BOOTROM_SIZE 0x100000
>
> +static struct clk *boot_cpu_clk;
> +
> static struct clk *get_cpu_clk(int cpu)
> {
> struct clk *cpu_clk;
> @@ -48,30 +50,6 @@ static struct clk *get_cpu_clk(int cpu)
> return cpu_clk;
> }
>
> -static void set_secondary_cpu_clock(unsigned int cpu)
> -{
> - int thiscpu;
> - unsigned long rate;
> - struct clk *cpu_clk;
> -
> - thiscpu = get_cpu();
> -
> - cpu_clk = get_cpu_clk(thiscpu);
> - if (!cpu_clk)
> - goto out;
> - clk_prepare_enable(cpu_clk);
> - rate = clk_get_rate(cpu_clk);
> -
> - cpu_clk = get_cpu_clk(cpu);
> - if (!cpu_clk)
> - goto out;
> - clk_set_rate(cpu_clk, rate);
> - clk_prepare_enable(cpu_clk);
> -
> -out:
> - put_cpu();
> -}
> -
> static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
> {
> int ret, hw_cpu;
> @@ -79,7 +57,6 @@ static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
> pr_info("Booting CPU %d\n", cpu);
>
> hw_cpu = cpu_logical_map(cpu);
> - set_secondary_cpu_clock(hw_cpu);
> mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);
>
> /*
> @@ -122,6 +99,19 @@ static void __init armada_xp_smp_init_cpus(void)
> panic("Invalid number of CPUs in DT\n");
> }
>
> +static int armada_xp_sync_secondary_clk(unsigned int cpu)
> +{
> + struct clk *cpu_clk = get_cpu_clk(cpu);
> +
> + if (!cpu_clk || !boot_cpu_clk)
> + return 0;
> +
> + clk_prepare_enable(cpu_clk);
> + clk_set_rate(cpu_clk, clk_get_rate(boot_cpu_clk));
> +
> + return 0;
> +}
> +
> static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
> {
> struct device_node *node;
> @@ -131,6 +121,14 @@ static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
> flush_cache_all();
> set_cpu_coherent();
>
> + boot_cpu_clk = get_cpu_clk(smp_processor_id());
> + if (boot_cpu_clk) {
> + clk_prepare_enable(boot_cpu_clk);
> + cpuhp_setup_state_nocalls(CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
> + "arm/mvebu/sync_clocks:online",
> + armada_xp_sync_secondary_clk, NULL);
> + }
> +
> /*
> * In order to boot the secondary CPUs we need to ensure
> * the bootROM is mapped at the correct address.
> @@ -223,7 +221,6 @@ static int mv98dx3236_boot_secondary(unsigned int cpu, struct task_struct *idle)
> int ret, hw_cpu;
>
> hw_cpu = cpu_logical_map(cpu);
> - set_secondary_cpu_clock(hw_cpu);
> mv98dx3236_resume_set_cpu_boot_addr(hw_cpu,
> armada_xp_secondary_startup);
>
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 8796ba387152..fa54e5fbea38 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -143,6 +143,7 @@ enum cpuhp_state {
> CPUHP_AP_SMPBOOT_THREADS,
> CPUHP_AP_X86_VDSO_VMA_ONLINE,
> CPUHP_AP_IRQ_AFFINITY_ONLINE,
> + CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
> CPUHP_AP_PERF_ONLINE,
> CPUHP_AP_PERF_X86_ONLINE,
> CPUHP_AP_PERF_X86_UNCORE_ONLINE,
> --
> 2.17.1
>
--
Gregory Clement, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com
prev parent reply other threads:[~2018-06-27 9:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 15:32 [PATCH] ARM: mvebu: convert secondary CPU clock sync to hotplug state Lucas Stach
2018-06-27 9:19 ` Gregory CLEMENT [this message]
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