ARM: shmobile: Add shared SCU CPU Hotplug code

Add CPU Hotplug functions for SCU equipped mach-shmobile SoCs.

The functions shmobile_smp_scu_cpu_die() together with
shmobile_smp_scu_cpu_kill() perform basic shutdown and
allows checking of shutdown status. These are written
to work together with SMP boot code in  headsmp-scu.S.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/arch/arm/mach-shmobile/include/mach/common.h b/arch/arm/mach-shmobile/include/mach/common.h
index 42761f4fb171d96952dd025e836f02eb6b0fc548..04209d5c0338f52bc0e9b4c3ede98193d98c47dd 100644 (file)
--- a/arch/arm/mach-shmobile/include/mach/common.h
+++ b/arch/arm/mach-shmobile/include/mach/common.h
@@ -14,6 +14,8 @@ extern void shmobile_boot_scu(void);
 extern void shmobile_smp_scu_prepare_cpus(unsigned int max_cpus);
 extern int shmobile_smp_scu_boot_secondary(unsigned int cpu,
                                           struct task_struct *idle);
+extern void shmobile_smp_scu_cpu_die(unsigned int cpu);
+extern int shmobile_smp_scu_cpu_kill(unsigned int cpu);
 struct clk;
 extern int shmobile_clk_init(void);
 extern void shmobile_handle_irq_intc(struct pt_regs *);

diff --git a/arch/arm/mach-shmobile/platsmp-scu.c b/arch/arm/mach-shmobile/platsmp-scu.c
index 8f478e4d4964cecf034e200e6b258fae1859f2f0..7a0c066df686a83eec8e9c5309e60a35b0145ee8 100644 (file)
--- a/arch/arm/mach-shmobile/platsmp-scu.c
+++ b/arch/arm/mach-shmobile/platsmp-scu.c
@@ -7,9 +7,11 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/smp.h>
+#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include <asm/smp_scu.h>
 #include <mach/common.h>
@@ -29,3 +31,46 @@ int shmobile_smp_scu_boot_secondary(unsigned int cpu, struct task_struct *idle)
        /* do nothing for now */
        return 0;
 }
+
+#ifdef CONFIG_HOTPLUG_CPU
+void shmobile_smp_scu_cpu_die(unsigned int cpu)
+{
+       dsb();
+       flush_cache_all();
+
+       /* disable cache coherency */
+       scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
+
+       /* Endless loop until reset */
+       while (1)
+               cpu_do_idle();
+}
+
+static int shmobile_smp_scu_psr_core_disabled(int cpu)
+{
+       unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
+
+       if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
+               return 1;
+
+       return 0;
+}
+
+int shmobile_smp_scu_cpu_kill(unsigned int cpu)
+{
+       int k;
+
+       /* this function is running on another CPU than the offline target,
+        * here we need wait for shutdown code in platform_cpu_die() to
+        * finish before asking SoC-specific code to power off the CPU core.
+        */
+       for (k = 0; k < 1000; k++) {
+               if (shmobile_smp_scu_psr_core_disabled(cpu))
+                       return 1;
+
+               mdelay(1);
+       }
+
+       return 0;
+}
+#endif