Blackfin: SMP: add PM/CPU hotplug support

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

7 files changed, 138 insertions, 13 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 0bd26dbca09f..c0d6d966adec 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -250,6 +250,11 @@ config NR_CPUS
         depends on SMP
         default 2 if BF561
 
+config HOTPLUG_CPU
+        bool "Support for hot-pluggable CPUs"
+        depends on SMP && HOTPLUG
+        default y
+
 config IRQ_PER_CPU
         bool
         depends on SMP
@@ -1130,7 +1135,6 @@ source "fs/Kconfig.binfmt"
 endmenu
 
 menu "Power management options"
-        depends on !SMP
 
 source "kernel/power/Kconfig"
 
diff --git a/arch/blackfin/include/asm/smp.h b/arch/blackfin/include/asm/smp.h
index 6a0fe94b84a6..29fb88219470 100644
--- a/arch/blackfin/include/asm/smp.h
+++ b/arch/blackfin/include/asm/smp.h
@@ -25,5 +25,12 @@ struct corelock_slot {
 
 void smp_icache_flush_range_others(unsigned long start,
                                    unsigned long end);
+#ifdef CONFIG_HOTPLUG_CPU
+void coreb_sleep(u32 sic_iwr0, u32 sic_iwr1, u32 sic_iwr2);
+void cpu_die(void);
+void platform_cpu_die(void);
+int __cpu_disable(void);
+int __cpu_die(unsigned int cpu);
+#endif
 
 #endif /* !__ASM_BLACKFIN_SMP_H */
diff --git a/arch/blackfin/mach-bf561/Makefile b/arch/blackfin/mach-bf561/Makefile
index 59e18afe28c6..b34029718318 100644
--- a/arch/blackfin/mach-bf561/Makefile
+++ b/arch/blackfin/mach-bf561/Makefile
@@ -6,3 +6,4 @@ obj-y := ints-priority.o dma.o
 
 obj-$(CONFIG_BF561_COREB) += coreb.o
 obj-$(CONFIG_SMP)  += smp.o secondary.o atomic.o
+obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
diff --git a/arch/blackfin/mach-bf561/hotplug.c b/arch/blackfin/mach-bf561/hotplug.c
new file mode 100644
index 000000000000..c95169b612dc
--- /dev/null
+++ b/arch/blackfin/mach-bf561/hotplug.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2007-2009 Analog Devices Inc.
+ *               Graff Yang <graf.yang@analog.com>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <asm/blackfin.h>
+#include <asm/smp.h>
+#define SIC_SYSIRQ(irq) (irq - (IRQ_CORETMR + 1))
+
+int hotplug_coreb;
+
+void platform_cpu_die(void)
+{
+        unsigned long iwr[2] = {0, 0};
+        unsigned long bank = SIC_SYSIRQ(IRQ_SUPPLE_0) / 32;
+        unsigned long bit = 1 << (SIC_SYSIRQ(IRQ_SUPPLE_0) % 32);
+
+        hotplug_coreb = 1;
+
+        iwr[bank] = bit;
+
+        /* disable core timer */
+        bfin_write_TCNTL(0);
+
+        /* clear ipi interrupt IRQ_SUPPLE_0 */
+        bfin_write_SICB_SYSCR(bfin_read_SICB_SYSCR() | (1 << (10 + 1)));
+        SSYNC();
+
+        coreb_sleep(iwr[0], iwr[1], 0);
+}
diff --git a/arch/blackfin/mach-bf561/secondary.S b/arch/blackfin/mach-bf561/secondary.S
index 8e6050369c06..4624eebbf9c4 100644
--- a/arch/blackfin/mach-bf561/secondary.S
+++ b/arch/blackfin/mach-bf561/secondary.S
@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <asm/blackfin.h>
 #include <asm/asm-offsets.h>
+#include <asm/trace.h>
 
 __INIT
 
@@ -62,6 +63,8 @@ ENTRY(_coreb_trampoline_start)
         M2 = r0;
         M3 = r0;
 
+        trace_buffer_init(p0,r0);
+
         /* Turn off the icache */
         p0.l = LO(IMEM_CONTROL);
         p0.h = HI(IMEM_CONTROL);
@@ -159,6 +162,41 @@ ENTRY(_coreb_trampoline_start)
 ENDPROC(_coreb_trampoline_start)
 ENTRY(_coreb_trampoline_end)
 
+.section ".text"
+ENTRY(_set_sicb_iwr)
+        P0.H = hi(SICB_IWR0);
+        P0.L = lo(SICB_IWR0);
+        P1.H = hi(SICB_IWR1);
+        P1.L = lo(SICB_IWR1);
+        [P0] = R0;
+        [P1] = R1;
+        SSYNC;
+        RTS;
+ENDPROC(_set_sicb_iwr)
+
+ENTRY(_coreb_sleep)
+        sp.l = lo(INITIAL_STACK);
+        sp.h = hi(INITIAL_STACK);
+        fp = sp;
+        usp = sp;
+
+        call _set_sicb_iwr;
+
+        CLI R2;
+        SSYNC;
+        IDLE;
+        STI R2;
+
+        R0 = IWR_DISABLE_ALL;
+        R1 = IWR_DISABLE_ALL;
+        call _set_sicb_iwr;
+
+        p0.h = hi(COREB_L1_CODE_START);
+        p0.l = lo(COREB_L1_CODE_START);
+        jump (p0);
+ENDPROC(_coreb_sleep)
+
+__CPUINIT
 ENTRY(_coreb_start)
         [--sp] = reti;
 
@@ -176,12 +214,20 @@ ENTRY(_coreb_start)
         sp = [p0];
         usp = sp;
         fp = sp;
+#ifdef CONFIG_HOTPLUG_CPU
+        p0.l = _hotplug_coreb;
+        p0.h = _hotplug_coreb;
+        r0 = [p0];
+        cc = BITTST(r0, 0);
+        if cc jump 3f;
+#endif
         sp += -12;
         call _init_pda
         sp += 12;
+#ifdef CONFIG_HOTPLUG_CPU
+3:
+#endif
         call _secondary_start_kernel;
 .L_exit:
         jump.s  .L_exit;
 ENDPROC(_coreb_start)
-
-__FINIT
diff --git a/arch/blackfin/mach-bf561/smp.c b/arch/blackfin/mach-bf561/smp.c
index 90369429ee66..3b9a4bf7dacc 100644
--- a/arch/blackfin/mach-bf561/smp.c
+++ b/arch/blackfin/mach-bf561/smp.c
@@ -65,6 +65,8 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
         bfin_write_SICB_IAR5(bfin_read_SICA_IAR5());
         bfin_write_SICB_IAR6(bfin_read_SICA_IAR6());
         bfin_write_SICB_IAR7(bfin_read_SICA_IAR7());
+        bfin_write_SICB_IWR0(IWR_DISABLE_ALL);
+        bfin_write_SICB_IWR1(IWR_DISABLE_ALL);
         SSYNC();
 
         /* Store CPU-private information to the cpu_data array. */
@@ -80,17 +82,18 @@ int __cpuinit platform_boot_secondary(unsigned int cpu, struct task_struct *idle
 {
         unsigned long timeout;
 
-        /* CoreB already running?! */
-        BUG_ON((bfin_read_SICA_SYSCR() & COREB_SRAM_INIT) == 0);
-
         printk(KERN_INFO "Booting Core B.\n");
 
         spin_lock(&boot_lock);
 
-        /* Kick CoreB, which should start execution from CORE_SRAM_BASE. */
-        SSYNC();
-        bfin_write_SICA_SYSCR(bfin_read_SICA_SYSCR() & ~COREB_SRAM_INIT);
-        SSYNC();
+        if ((bfin_read_SICA_SYSCR() & COREB_SRAM_INIT) == 0) {
+                /* CoreB already running, sending ipi to wakeup it */
+                platform_send_ipi_cpu(cpu, IRQ_SUPPLE_0);
+        } else {
+                /* Kick CoreB, which should start execution from CORE_SRAM_BASE. */
+                bfin_write_SICA_SYSCR(bfin_read_SICA_SYSCR() & ~COREB_SRAM_INIT);
+                SSYNC();
+        }
 
         timeout = jiffies + 1 * HZ;
         while (time_before(jiffies, timeout)) {
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index b343ab3764a1..efc47ffd066d 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -344,8 +344,11 @@ void smp_send_stop(void)
 
 int __cpuinit __cpu_up(unsigned int cpu)
 {
-        struct task_struct *idle;
         int ret;
+        static struct task_struct *idle;
+
+        if (idle)
+                free_task(idle);
 
         idle = fork_idle(cpu);
         if (IS_ERR(idle)) {
@@ -354,7 +357,6 @@ int __cpuinit __cpu_up(unsigned int cpu)
         }
 
         secondary_stack = task_stack_page(idle) + THREAD_SIZE;
-        smp_wmb();
 
         ret = platform_boot_secondary(cpu, idle);
 
@@ -413,7 +415,6 @@ void __cpuinit secondary_start_kernel(void)
         atomic_inc(&mm->mm_users);
         atomic_inc(&mm->mm_count);
         current->active_mm = mm;
-        BUG_ON(current->mm);    /* Can't be, but better be safe than sorry. */
 
         preempt_disable();
 
@@ -495,3 +496,34 @@ void resync_core_dcache(void)
 }
 EXPORT_SYMBOL(resync_core_dcache);
 #endif
+
+#ifdef CONFIG_HOTPLUG_CPU
+int __cpuexit __cpu_disable(void)
+{
+        unsigned int cpu = smp_processor_id();
+
+        if (cpu == 0)
+                return -EPERM;
+
+        set_cpu_online(cpu, false);
+        return 0;
+}
+
+static DECLARE_COMPLETION(cpu_killed);
+
+int __cpuexit __cpu_die(unsigned int cpu)
+{
+        return wait_for_completion_timeout(&cpu_killed, 5000);
+}
+
+void cpu_die(void)
+{
+        complete(&cpu_killed);
+
+        atomic_dec(&init_mm.mm_users);
+        atomic_dec(&init_mm.mm_count);
+
+        local_irq_disable();
+        platform_cpu_die();
+}
+#endif