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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:32:52 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:32:52 +0000
commit4073723acb9cdcdbe4df9c0e0c376c65d1697e43 (patch)
treef41c17eac157b1223ce104845cf9b1e5a9e6a83d /arch/arm/mach-realview/platsmp.c
parent58daf18cdcab550262a5f4681e1f1e073e21965a (diff)
parent4ec3eb13634529c0bc7466658d84d0bbe3244aea (diff)
Merge branch 'misc' into devel
Conflicts: arch/arm/Kconfig arch/arm/common/Makefile arch/arm/kernel/Makefile arch/arm/kernel/smp.c
Diffstat (limited to 'arch/arm/mach-realview/platsmp.c')
-rw-r--r--arch/arm/mach-realview/platsmp.c114
1 files changed, 36 insertions, 78 deletions
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c
index 6da8a2e53c4..a22bf67f2f7 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>
@@ -37,6 +36,19 @@ extern void realview_secondary_startup(void);
*/
volatile int __cpuinitdata pen_release = -1;
+/*
+ * Write pen_release in a way that is guaranteed to be visible to all
+ * observers, irrespective of whether they're taking part in coherency
+ * or not. This is necessary for the hotplug code to work reliably.
+ */
+static void write_pen_release(int val)
+{
+ pen_release = val;
+ smp_wmb();
+ __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
+ outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
+}
+
static void __iomem *scu_base_addr(void)
{
if (machine_is_realview_eb_mp())
@@ -50,20 +62,10 @@ 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)
{
- trace_hardirqs_off();
-
/*
* if any interrupts are already enabled for the primary
* core (e.g. timer irq), then they will not have been enabled
@@ -75,8 +77,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
* let the primary processor know we're out of the
* pen, then head off into the C entry point
*/
- pen_release = -1;
- smp_wmb();
+ write_pen_release(-1);
/*
* Synchronise with the boot thread.
@@ -103,20 +104,14 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
* Note that "pen_release" is the hardware CPU ID, whereas
* "cpu" is Linux's internal ID.
*/
- pen_release = cpu;
- flush_cache_all();
+ write_pen_release(cpu);
/*
- * XXX
- *
- * This is a later addition to the booting protocol: the
- * bootMonitor now puts secondary cores into WFI, so
- * poke_milo() no longer gets the cores moving; we need
- * to send a soft interrupt to wake the secondary core.
- * Use smp_cross_call() for this, since there's little
- * point duplicating the code here
+ * Send the secondary CPU a soft interrupt, thereby causing
+ * the boot monitor to read the system wide flags register,
+ * and branch to the address found there.
*/
- smp_cross_call(cpumask_of(cpu));
+ smp_cross_call(cpumask_of(cpu), 1);
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
@@ -136,48 +131,18 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
return pen_release != -1 ? -ENOSYS : 0;
}
-static void __init poke_milo(void)
-{
- /* nobody is to be released from the pen yet */
- pen_release = -1;
-
- /*
- * Write the address of secondary startup into the system-wide flags
- * register. The BootMonitor waits for this register to become
- * non-zero.
- */
- __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)),
- __io_address(REALVIEW_SYS_FLAGSSET));
-
- mb();
-}
-
/*
* Initialise the CPU possible map early - this describes the CPUs
* which may be present or become present in the system.
*/
void __init smp_init_cpus(void)
{
- unsigned int i, ncores = get_core_count();
+ void __iomem *scu_base = scu_base_addr();
+ unsigned int i, ncores;
- for (i = 0; i < ncores; i++)
- set_cpu_possible(i, true);
-}
-
-void __init smp_prepare_cpus(unsigned int max_cpus)
-{
- unsigned int ncores = get_core_count();
- unsigned int cpu = smp_processor_id();
- int i;
+ ncores = scu_base ? scu_get_core_count(scu_base) : 1;
/* 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 "
@@ -186,13 +151,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
ncores = NR_CPUS;
}
- smp_store_cpu_info(cpu);
+ for (i = 0; i < ncores; i++)
+ set_cpu_possible(i, true);
+}
- /*
- * are we trying to boot more cores than exist?
- */
- if (max_cpus > ncores)
- max_cpus = ncores;
+void __init platform_smp_prepare_cpus(unsigned int max_cpus)
+{
+ int i;
/*
* Initialise the present map, which describes the set of CPUs
@@ -201,21 +166,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
for (i = 0; i < max_cpus; i++)
set_cpu_present(i, true);
+ scu_enable(scu_base_addr());
+
/*
- * 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
+ * Write the address of secondary startup into the
+ * system-wide flags register. The BootMonitor waits
+ * until it receives a soft interrupt, and then the
+ * secondary CPU branches to this address.
*/
- 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());
- poke_milo();
- }
+ __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)),
+ __io_address(REALVIEW_SYS_FLAGSSET));
}