All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] ARM: mvebu: convert secondary CPU clock sync to hotplug state
@ 2018-06-18 15:32 Lucas Stach
  2018-06-27  9:19 ` Gregory CLEMENT
  0 siblings, 1 reply; 2+ messages in thread
From: Lucas Stach @ 2018-06-18 15:32 UTC (permalink / raw)
  To: linux-arm-kernel

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>
---
 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

^ permalink raw reply related	[flat|nested] 2+ messages in thread
* [PATCH] ARM: mvebu: convert secondary CPU clock sync to hotplug state
  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
  0 siblings, 0 replies; 2+ messages in thread
From: Gregory CLEMENT @ 2018-06-27  9:19 UTC (permalink / raw)
  To: linux-arm-kernel

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

^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2018-06-27  9:19 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
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 is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.