diff mbox

[v3,4/5] ARM: kernel: add logical mappings look-up

Message ID 1352983614-22924-5-git-send-email-lorenzo.pieralisi@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Lorenzo Pieralisi Nov. 15, 2012, 12:46 p.m. UTC 
In ARM SMP systems the MPIDR register ([23:0] bits) is used to uniquely
identify CPUs.

In order to retrieve the logical CPU index corresponding to a given
MPIDR value and guarantee a consistent translation throughout the kernel,
this patch adds a look-up based on the MPIDR[23:0] so that kernel subsystems
can use it whenever the logical cpu index corresponding to a given MPIDR
value is needed.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm/include/asm/smp_plat.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Nicolas Pitre Nov. 19, 2012, 3:14 a.m. UTC | #1 
On Thu, 15 Nov 2012, Lorenzo Pieralisi wrote:

> In ARM SMP systems the MPIDR register ([23:0] bits) is used to uniquely
> identify CPUs.
> 
> In order to retrieve the logical CPU index corresponding to a given
> MPIDR value and guarantee a consistent translation throughout the kernel,
> this patch adds a look-up based on the MPIDR[23:0] so that kernel subsystems
> can use it whenever the logical cpu index corresponding to a given MPIDR
> value is needed.
> 
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Acked-by: Will Deacon <will.deacon@arm.com>

Acked-by: Nicolas Pitre <nico@linaro.org>

> ---
>  arch/arm/include/asm/smp_plat.h | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h
> index 558d6c8..aaa61b6 100644
> --- a/arch/arm/include/asm/smp_plat.h
> +++ b/arch/arm/include/asm/smp_plat.h
> @@ -5,6 +5,9 @@
>  #ifndef __ASMARM_SMP_PLAT_H
>  #define __ASMARM_SMP_PLAT_H
>  
> +#include <linux/cpumask.h>
> +#include <linux/err.h>
> +
>  #include <asm/cputype.h>
>  
>  /*
> @@ -48,5 +51,19 @@ static inline int cache_ops_need_broadcast(void)
>   */
>  extern int __cpu_logical_map[];
>  #define cpu_logical_map(cpu)	__cpu_logical_map[cpu]
> +/*
> + * Retrieve logical cpu index corresponding to a given MPIDR[23:0]
> + *  - mpidr: MPIDR[23:0] to be used for the look-up
> + *
> + * Returns the cpu logical index or -EINVAL on look-up error
> + */
> +static inline int get_logical_index(u32 mpidr)
> +{
> +	int cpu;
> +	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
> +		if (cpu_logical_map(cpu) == mpidr)
> +			return cpu;
> +	return -EINVAL;
> +}
>  
>  #endif
> -- 
> 1.7.12
> 
>
diff mbox

Patch

diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h
index 558d6c8..aaa61b6 100644
--- a/arch/arm/include/asm/smp_plat.h
+++ b/arch/arm/include/asm/smp_plat.h
@@ -5,6 +5,9 @@ 
 #ifndef __ASMARM_SMP_PLAT_H
 #define __ASMARM_SMP_PLAT_H
 
+#include <linux/cpumask.h>
+#include <linux/err.h>
+
 #include <asm/cputype.h>
 
 /*
@@ -48,5 +51,19 @@  static inline int cache_ops_need_broadcast(void)
  */
 extern int __cpu_logical_map[];
 #define cpu_logical_map(cpu)	__cpu_logical_map[cpu]
+/*
+ * Retrieve logical cpu index corresponding to a given MPIDR[23:0]
+ *  - mpidr: MPIDR[23:0] to be used for the look-up
+ *
+ * Returns the cpu logical index or -EINVAL on look-up error
+ */
+static inline int get_logical_index(u32 mpidr)
+{
+	int cpu;
+	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
+		if (cpu_logical_map(cpu) == mpidr)
+			return cpu;
+	return -EINVAL;
+}
 
 #endif