Re: [PATCH 1/8] ARM: SCU: Add common routines for secondary CPUbootup

From: Russell King - ARM Linux
Date: Tue Nov 30 2010 - 19:26:08 EST

On Tue, Nov 30, 2010 at 11:32:04PM +0000, Russell King - ARM Linux wrote:
> Note that I'll go with factoring this out into arch/arm/kernel/smp_scu.c
> for the time being, but I'm not convinced about the other parts yet.

IOW, something like the attached. I've gone a little further and removed
the now unnecessary scu_enable() and scu_get_core_count() global functions,
making scu_enable() static, and eliminating scu_get_core_count() entirely.

arch/arm/include/asm/smp_scu.h | 4 +-
arch/arm/kernel/smp_scu.c | 65 +++++++++++++++++++++++++++++++------
arch/arm/mach-omap2/omap-smp.c | 61 ++--------------------------------
arch/arm/mach-realview/platsmp.c | 66 ++------------------------------------
arch/arm/mach-s5pv310/platsmp.c | 58 ++-------------------------------
arch/arm/mach-tegra/platsmp.c | 37 +--------------------
arch/arm/mach-ux500/platsmp.c | 48 ++--------------------------
arch/arm/mach-vexpress/platsmp.c | 58 ++-------------------------------
8 files changed, 76 insertions(+), 321 deletions(-)

diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
index 2376835..9807fb4 100644
--- a/arch/arm/include/asm/smp_scu.h
+++ b/arch/arm/include/asm/smp_scu.h
@@ -1,7 +1,7 @@
#ifndef __ASMARM_ARCH_SCU_H
#define __ASMARM_ARCH_SCU_H

-unsigned int scu_get_core_count(void __iomem *);
-void scu_enable(void __iomem *);
+void scu_init_cpus(void __iomem *);
+void scu_prepare_cpus(void __iomem *, unsigned int);

#endif
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
index 9ab4149..6c949b4 100644
--- a/arch/arm/kernel/smp_scu.c
+++ b/arch/arm/kernel/smp_scu.c
@@ -11,6 +11,7 @@
#include <linux/init.h>
#include <linux/io.h>

+#include <asm/localtimer.h>
#include <asm/smp_scu.h>
#include <asm/cacheflush.h>

@@ -21,18 +22,9 @@
#define SCU_FPGA_REVISION 0x10

/*
- * Get the number of CPU cores from the SCU configuration
- */
-unsigned int __init scu_get_core_count(void __iomem *scu_base)
-{
- unsigned int ncores = __raw_readl(scu_base + SCU_CONFIG);
- return (ncores & 0x03) + 1;
-}
-
-/*
* Enable the SCU
*/
-void __init scu_enable(void __iomem *scu_base)
+static void __init scu_enable(void __iomem *scu_base)
{
u32 scu_ctrl;

@@ -50,3 +42,56 @@ void __init scu_enable(void __iomem *scu_base)
*/
flush_cache_all();
}
+
+void scu_init_cpus(void __iomem *scu_base)
+{
+ unsigned int i, ncores = 1;
+
+ if (scu_base)
+ ncores += __raw_readl(scu_base + SCU_CONFIG) & 0x03;
+
+ if (ncores > NR_CPUS) {
+ pr_warning("SMP: no. of cores (%d) greater than configured maximum of %d - clipping\n",
+ ncores, NR_CPUS);
+ ncores = NR_CPUS;
+ }
+
+ for (i = 0; i < ncores; i++)
+ set_cpu_possible(i, true);
+}
+
+void scu_prepare_cpus(void __iomem *scu_base, unsigned int max_cpus)
+{
+ unsigned int ncores = num_possible_cpus();
+ unsigned int cpu = smp_processor_id();
+ int i;
+
+ smp_store_cpu_info(cpu);
+
+ /*
+ * are we trying to boot more cores than exist?
+ */
+ if (max_cpus > ncores)
+ max_cpus = ncores;
+
+ /*
+ * Initialise the present map, which describes the set of CPUs
+ * actually populated at the present time.
+ */
+ for (i = 0; i < max_cpus; i++)
+ set_cpu_present(i, true);
+
+ /*
+ * Initialise the SCU if there are more than one CPU and let
+ * them know where to start.
+ */
+ if (max_cpus > 1) {
+ /*
+ * Enable the local timer or broadcast device for the
+ * boot CPU, but only if we have more than one CPU.
+ */
+ percpu_timer_setup();
+
+ scu_enable(scu_base);
+ }
+}
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index 56a8bce..05cc85e 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -21,7 +21,6 @@
#include <linux/io.h>

#include <asm/cacheflush.h>
-#include <asm/localtimer.h>
#include <asm/smp_scu.h>
#include <mach/hardware.h>
#include <mach/omap4-common.h>
@@ -29,16 +28,6 @@
/* SCU base address */
static void __iomem *scu_base;

-/*
- * Use SCU config register to count number of cores
- */
-static inline unsigned int get_core_count(void)
-{
- if (scu_base)
- return scu_get_core_count(scu_base);
- return 1;
-}
-
static DEFINE_SPINLOCK(boot_lock);

void __cpuinit platform_secondary_init(unsigned int cpu)
@@ -118,59 +107,17 @@ void __init smp_init_cpus(void)
scu_base = ioremap(OMAP44XX_SCU_BASE, SZ_256);
BUG_ON(!scu_base);

- ncores = get_core_count();
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
+ scu_init_cpus(scu_base);
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = get_core_count();
- unsigned int cpu = smp_processor_id();
- int i;
-
- /* sanity check */
- if (ncores == 0) {
- printk(KERN_ERR
- "OMAP4: strange core count of 0? Default to 1\n");
- ncores = 1;
- }
-
- if (ncores > NR_CPUS) {
- printk(KERN_WARNING
- "OMAP4: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, NR_CPUS);
- ncores = NR_CPUS;
- }
- smp_store_cpu_info(cpu);
-
- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- if (max_cpus > 1) {
- /*
- * Enable the local timer or broadcast device for the
- * boot CPU, but only if we have more than one CPU.
- */
- percpu_timer_setup();
+ scu_prepare_cpus(scu_base, max_cpus);

+ if (num_present_cpus() > 1) {
/*
- * Initialise the SCU and wake up the secondary core using
- * wakeup_secondary().
+ * Wake up the secondary core using wakeup_secondary().
*/
- scu_enable(scu_base);
wakeup_secondary();
}
}
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c
index af3d909..43614f2 100644
--- a/arch/arm/mach-realview/platsmp.c
+++ b/arch/arm/mach-realview/platsmp.c
@@ -19,7 +19,6 @@
#include <asm/cacheflush.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>
-#include <asm/localtimer.h>
#include <asm/unified.h>

#include <mach/board-eb.h>
@@ -50,14 +49,6 @@ static void __iomem *scu_base_addr(void)
return (void __iomem *)0;
}

-static inline unsigned int get_core_count(void)
-{
- void __iomem *scu_base = scu_base_addr();
- if (scu_base)
- return scu_get_core_count(scu_base);
- return 1;
-}
-
static DEFINE_SPINLOCK(boot_lock);

void __cpuinit platform_secondary_init(unsigned int cpu)
@@ -158,64 +149,13 @@ static void __init poke_milo(void)
*/
void __init smp_init_cpus(void)
{
- unsigned int i, ncores = get_core_count();
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
+ scu_init_cpus(scu_base_addr());
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = get_core_count();
- unsigned int cpu = smp_processor_id();
- int i;
-
- /* sanity check */
- if (ncores == 0) {
- printk(KERN_ERR
- "Realview: strange CM count of 0? Default to 1\n");
-
- ncores = 1;
- }
-
- if (ncores > NR_CPUS) {
- printk(KERN_WARNING
- "Realview: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, NR_CPUS);
- ncores = NR_CPUS;
- }
-
- smp_store_cpu_info(cpu);
+ scu_prepare_cpus(scu_base_addr(), max_cpus);

- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- /*
- * Initialise the SCU if there are more than one CPU and let
- * them know where to start. Note that, on modern versions of
- * MILO, the "poke" doesn't actually do anything until each
- * individual core is sent a soft interrupt to get it out of
- * WFI
- */
- if (max_cpus > 1) {
- /*
- * Enable the local timer or broadcast device for the
- * boot CPU, but only if we have more than one CPU.
- */
- percpu_timer_setup();
-
- scu_enable(scu_base_addr());
+ if (num_present_cpus() > 1)
poke_milo();
- }
}
diff --git a/arch/arm/mach-s5pv310/platsmp.c b/arch/arm/mach-s5pv310/platsmp.c
index d474426..4da410a 100644
--- a/arch/arm/mach-s5pv310/platsmp.c
+++ b/arch/arm/mach-s5pv310/platsmp.c
@@ -22,7 +22,6 @@
#include <linux/io.h>

#include <asm/cacheflush.h>
-#include <asm/localtimer.h>
#include <asm/smp_scu.h>
#include <asm/unified.h>

@@ -124,69 +123,20 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)

void __init smp_init_cpus(void)
{
- void __iomem *scu_base = scu_base_addr();
- unsigned int i, ncores;
-
- ncores = scu_base ? scu_get_core_count(scu_base) : 1;
-
- /* sanity check */
- if (ncores == 0) {
- printk(KERN_ERR
- "S5PV310: strange CM count of 0? Default to 1\n");
-
- ncores = 1;
- }
-
- if (ncores > NR_CPUS) {
- printk(KERN_WARNING
- "S5PV310: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, NR_CPUS);
- ncores = NR_CPUS;
- }
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
+ scu_init_cpus(scu_base_addr());
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = num_possible_cpus();
- unsigned int cpu = smp_processor_id();
- int i;
-
- smp_store_cpu_info(cpu);
-
- /* are we trying to boot more cores than exist? */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- /*
- * Initialise the SCU if there are more than one CPU and let
- * them know where to start.
- */
- if (max_cpus > 1) {
- /*
- * Enable the local timer or broadcast device for the
- * boot CPU, but only if we have more than one CPU.
- */
- percpu_timer_setup();
-
- scu_enable(scu_base_addr());
+ scu_prepare_cpus(scu_base_addr(), max_cpus);

+ if (num_present_cpus() > 1) {
/*
* Write the address of secondary startup into the
* system-wide flags register. The boot monitor waits
* until it receives a soft interrupt, and then the
* secondary CPU branches to this address.
*/
- __raw_writel(BSYM(virt_to_phys(s5pv310_secondary_startup)), S5P_VA_SYSRAM);
+ __raw_writel(BSYM(virt_to_phys(s5pv310_secondary_startup)), S5P_VA_SYSRAM);
}
}
diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
index 1c0fd92..3b6bcca 100644
--- a/arch/arm/mach-tegra/platsmp.c
+++ b/arch/arm/mach-tegra/platsmp.c
@@ -22,7 +22,6 @@
#include <asm/cacheflush.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>
-#include <asm/localtimer.h>
#include <asm/smp_scu.h>

#include <mach/iomap.h>
@@ -115,42 +114,10 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
*/
void __init smp_init_cpus(void)
{
- unsigned int i, ncores = scu_get_core_count(scu_base);
-
- for (i = 0; i < ncores; i++)
- cpu_set(i, cpu_possible_map);
+ scu_init_cpus(scu_base);
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = scu_get_core_count(scu_base);
- unsigned int cpu = smp_processor_id();
- int i;
-
- smp_store_cpu_info(cpu);
-
- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- /*
- * Initialise the SCU if there are more than one CPU and let
- * them know where to start. Note that, on modern versions of
- * MILO, the "poke" doesn't actually do anything until each
- * individual core is sent a soft interrupt to get it out of
- * WFI
- */
- if (max_cpus > 1) {
- percpu_timer_setup();
- scu_enable(scu_base);
- }
+ scu_prepare_cpus(scu_base, max_cpus);
}
diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c
index b8987bd..8910c08 100644
--- a/arch/arm/mach-ux500/platsmp.c
+++ b/arch/arm/mach-ux500/platsmp.c
@@ -28,11 +28,6 @@
*/
volatile int __cpuinitdata pen_release = -1;

-static unsigned int __init get_core_count(void)
-{
- return scu_get_core_count(__io_address(UX500_SCU_BASE));
-}
-
static DEFINE_SPINLOCK(boot_lock);

void __cpuinit platform_secondary_init(unsigned int cpu)
@@ -126,55 +121,18 @@ static void __init wakeup_secondary(void)
*/
void __init smp_init_cpus(void)
{
- unsigned int i, ncores = get_core_count();
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
+ scu_init_cpus(__io_address(UX500_SCU_BASE));
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = get_core_count();
- unsigned int cpu = smp_processor_id();
- int i;
-
- /* sanity check */
- if (ncores == 0) {
- printk(KERN_ERR
- "U8500: strange CM count of 0? Default to 1\n");
- ncores = 1;
- }
-
- if (ncores > num_possible_cpus()) {
- printk(KERN_WARNING
- "U8500: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, num_possible_cpus());
- ncores = num_possible_cpus();
- }
-
- smp_store_cpu_info(cpu);
-
- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
+ scu_prepare_cpus(__io_address(UX500_SCU_BASE), max_cpus);

- if (max_cpus > 1) {
+ if (num_present_cpus() > 1) {
/*
* Enable the local timer or broadcast device for the
* boot CPU, but only if we have more than one CPU.
*/
- percpu_timer_setup();
- scu_enable(__io_address(UX500_SCU_BASE));
wakeup_secondary();
}
}
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index 276f916..ecedd5a 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -17,7 +17,6 @@
#include <linux/io.h>

#include <asm/cacheflush.h>
-#include <asm/localtimer.h>
#include <asm/smp_scu.h>
#include <asm/unified.h>

@@ -118,65 +117,14 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
*/
void __init smp_init_cpus(void)
{
- void __iomem *scu_base = scu_base_addr();
- unsigned int i, ncores;
-
- ncores = scu_base ? scu_get_core_count(scu_base) : 1;
-
- /* sanity check */
- if (ncores == 0) {
- printk(KERN_ERR
- "vexpress: strange CM count of 0? Default to 1\n");
-
- ncores = 1;
- }
-
- if (ncores > NR_CPUS) {
- printk(KERN_WARNING
- "vexpress: no. of cores (%d) greater than configured "
- "maximum of %d - clipping\n",
- ncores, NR_CPUS);
- ncores = NR_CPUS;
- }
-
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
+ scu_init_cpus(scu_base_addr());
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
- unsigned int ncores = num_possible_cpus();
- unsigned int cpu = smp_processor_id();
- int i;
-
- smp_store_cpu_info(cpu);
-
- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
-
- /*
- * Initialise the present map, which describes the set of CPUs
- * actually populated at the present time.
- */
- for (i = 0; i < max_cpus; i++)
- set_cpu_present(i, true);
-
- /*
- * Initialise the SCU if there are more than one CPU and let
- * them know where to start.
- */
- if (max_cpus > 1) {
- /*
- * Enable the local timer or broadcast device for the
- * boot CPU, but only if we have more than one CPU.
- */
- percpu_timer_setup();
-
- scu_enable(scu_base_addr());
+ scu_prepare_cpus(scu_base_addr(), max_cpus);

+ if (num_present_cpus() > 1) {
/*
* Write the address of secondary startup into the
* system-wide flags register. The boot monitor waits

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