MIPS: Cavium: Add CPU hotplugging code.

Thanks to Cavium Inc. for the code contribution and help.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 233 insertions, 1 deletions

diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
index 24e0ad63980..0b891a9c625 100644
--- a/arch/mips/cavium-octeon/smp.c
+++ b/arch/mips/cavium-octeon/smp.c
@@ -5,6 +5,7 @@
  *
  * Copyright (C) 2004-2008 Cavium Networks
  */
+#include <linux/cpu.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/smp.h>
@@ -19,10 +20,16 @@
 
 #include <asm/octeon/octeon.h>
 
+#include "octeon_boot.h"
+
 volatile unsigned long octeon_processor_boot = 0xff;
 volatile unsigned long octeon_processor_sp;
 volatile unsigned long octeon_processor_gp;
 
+#ifdef CONFIG_HOTPLUG_CPU
+static unsigned int InitTLBStart_addr;
+#endif
+
 static irqreturn_t mailbox_interrupt(int irq, void *dev_id)
 {
         const int coreid = cvmx_get_core_num();
@@ -67,8 +74,28 @@ static inline void octeon_send_ipi_mask(cpumask_t mask, unsigned int action)
 }
 
 /**
- * Detect available CPUs, populate phys_cpu_present_map
+ * Detect available CPUs, populate cpu_possible_map
  */
+static void octeon_smp_hotplug_setup(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+        uint32_t labi_signature;
+
+        labi_signature =
+                cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                        LABI_ADDR_IN_BOOTLOADER +
+                                        offsetof(struct linux_app_boot_info,
+                                                    labi_signature)));
+        if (labi_signature != LABI_SIGNATURE)
+                pr_err("The bootloader version on this board is incorrect\n");
+        InitTLBStart_addr =
+                cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                   LABI_ADDR_IN_BOOTLOADER +
+                                           offsetof(struct linux_app_boot_info,
+                                                    InitTLBStart_addr)));
+#endif
+}
+
 static void octeon_smp_setup(void)
 {
         const int coreid = cvmx_get_core_num();
@@ -91,6 +118,9 @@ static void octeon_smp_setup(void)
                         cpus++;
                 }
         }
+        cpu_present_map = cpu_possible_map;
+
+        octeon_smp_hotplug_setup();
 }
 
 /**
@@ -128,6 +158,17 @@ static void octeon_init_secondary(void)
         const int coreid = cvmx_get_core_num();
         union cvmx_ciu_intx_sum0 interrupt_enable;
 
+#ifdef CONFIG_HOTPLUG_CPU
+        unsigned int cur_exception_base;
+
+        cur_exception_base = cvmx_read64_uint32(
+                CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                             LABI_ADDR_IN_BOOTLOADER +
+                             offsetof(struct linux_app_boot_info,
+                                      cur_exception_base)));
+        /* cur_exception_base is incremented in bootloader after setting */
+        write_c0_ebase((unsigned int)(cur_exception_base - EXCEPTION_BASE_INCR));
+#endif
         octeon_check_cpu_bist();
         octeon_init_cvmcount();
         /*
@@ -199,6 +240,193 @@ static void octeon_cpus_done(void)
 #endif
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+
+/* State of each CPU. */
+DEFINE_PER_CPU(int, cpu_state);
+
+extern void fixup_irqs(void);
+
+static DEFINE_SPINLOCK(smp_reserve_lock);
+
+static int octeon_cpu_disable(void)
+{
+        unsigned int cpu = smp_processor_id();
+
+        if (cpu == 0)
+                return -EBUSY;
+
+        spin_lock(&smp_reserve_lock);
+
+        cpu_clear(cpu, cpu_online_map);
+        cpu_clear(cpu, cpu_callin_map);
+        local_irq_disable();
+        fixup_irqs();
+        local_irq_enable();
+
+        flush_cache_all();
+        local_flush_tlb_all();
+
+        spin_unlock(&smp_reserve_lock);
+
+        return 0;
+}
+
+static void octeon_cpu_die(unsigned int cpu)
+{
+        int coreid = cpu_logical_map(cpu);
+        uint32_t avail_coremask;
+        struct cvmx_bootmem_named_block_desc *block_desc;
+
+#ifdef CONFIG_CAVIUM_OCTEON_WATCHDOG
+        /* Disable the watchdog */
+        cvmx_ciu_wdogx_t ciu_wdog;
+        ciu_wdog.u64 = cvmx_read_csr(CVMX_CIU_WDOGX(cpu));
+        ciu_wdog.s.mode = 0;
+        cvmx_write_csr(CVMX_CIU_WDOGX(cpu), ciu_wdog.u64);
+#endif
+
+        while (per_cpu(cpu_state, cpu) != CPU_DEAD)
+                cpu_relax();
+
+        /*
+         * This is a bit complicated strategics of getting/settig available
+         * cores mask, copied from bootloader
+         */
+        /* LINUX_APP_BOOT_BLOCK is initialized in bootoct binary */
+        block_desc = cvmx_bootmem_find_named_block(LINUX_APP_BOOT_BLOCK_NAME);
+
+        if (!block_desc) {
+                avail_coremask =
+                        cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                                   LABI_ADDR_IN_BOOTLOADER +
+                                                   offsetof
+                                                   (struct linux_app_boot_info,
+                                                    avail_coremask)));
+        } else {                       /* alternative, already initialized */
+               avail_coremask =
+                   cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                                   block_desc->base_addr +
+                                                  AVAIL_COREMASK_OFFSET_IN_LINUX_APP_BOOT_BLOCK));
+        }
+
+        avail_coremask |= 1 << coreid;
+
+        /* Setting avail_coremask for bootoct binary */
+        if (!block_desc) {
+                cvmx_write64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                                LABI_ADDR_IN_BOOTLOADER +
+                                                offsetof(struct linux_app_boot_info,
+                                                         avail_coremask)),
+                                   avail_coremask);
+        } else {
+                cvmx_write64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                                block_desc->base_addr +
+                                                AVAIL_COREMASK_OFFSET_IN_LINUX_APP_BOOT_BLOCK),
+                                   avail_coremask);
+        }
+
+        pr_info("Reset core %d. Available Coremask = %x \n", coreid,
+                avail_coremask);
+        cvmx_write_csr(CVMX_CIU_PP_RST, 1 << coreid);
+        cvmx_write_csr(CVMX_CIU_PP_RST, 0);
+}
+
+void play_dead(void)
+{
+        int coreid = cvmx_get_core_num();
+
+        idle_task_exit();
+        octeon_processor_boot = 0xff;
+        per_cpu(cpu_state, coreid) = CPU_DEAD;
+
+        while (1)       /* core will be reset here */
+                ;
+}
+
+extern void kernel_entry(unsigned long arg1, ...);
+
+static void start_after_reset(void)
+{
+        kernel_entry(0, 0, 0);  /* set a2 = 0 for secondary core */
+}
+
+int octeon_update_boot_vector(unsigned int cpu)
+{
+
+        int coreid = cpu_logical_map(cpu);
+        unsigned int avail_coremask;
+        struct cvmx_bootmem_named_block_desc *block_desc;
+        struct boot_init_vector *boot_vect =
+                (struct boot_init_vector *) cvmx_phys_to_ptr(0x0 +
+                                                  BOOTLOADER_BOOT_VECTOR);
+
+        block_desc = cvmx_bootmem_find_named_block(LINUX_APP_BOOT_BLOCK_NAME);
+
+        if (!block_desc) {
+                avail_coremask =
+                        cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                           LABI_ADDR_IN_BOOTLOADER +
+                                                offsetof(struct linux_app_boot_info,
+                                                avail_coremask)));
+        } else {                       /* alternative, already initialized */
+               avail_coremask =
+                   cvmx_read64_uint32(CVMX_ADD_SEG(CVMX_MIPS_SPACE_XKPHYS,
+                                                   block_desc->base_addr +
+                                                   AVAIL_COREMASK_OFFSET_IN_LINUX_APP_BOOT_BLOCK));
+        }
+
+        if (!(avail_coremask & (1 << coreid))) {
+                /* core not available, assume, that catched by simple-executive */
+                cvmx_write_csr(CVMX_CIU_PP_RST, 1 << coreid);
+                cvmx_write_csr(CVMX_CIU_PP_RST, 0);
+        }
+
+        boot_vect[coreid].app_start_func_addr =
+                (uint32_t) (unsigned long) start_after_reset;
+        boot_vect[coreid].code_addr = InitTLBStart_addr;
+
+        CVMX_SYNC;
+
+        cvmx_write_csr(CVMX_CIU_NMI, (1 << coreid) & avail_coremask);
+
+        return 0;
+}
+
+static int __cpuinit octeon_cpu_callback(struct notifier_block *nfb,
+        unsigned long action, void *hcpu)
+{
+        unsigned int cpu = (unsigned long)hcpu;
+
+        switch (action) {
+        case CPU_UP_PREPARE:
+                octeon_update_boot_vector(cpu);
+                break;
+        case CPU_ONLINE:
+                pr_info("Cpu %d online\n", cpu);
+                break;
+        case CPU_DEAD:
+                break;
+        }
+
+        return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata octeon_cpu_notifier = {
+        .notifier_call = octeon_cpu_callback,
+};
+
+static int __cpuinit register_cavium_notifier(void)
+{
+        register_hotcpu_notifier(&octeon_cpu_notifier);
+
+        return 0;
+}
+
+late_initcall(register_cavium_notifier);
+
+#endif  /* CONFIG_HOTPLUG_CPU */
+
 struct plat_smp_ops octeon_smp_ops = {
         .send_ipi_single        = octeon_send_ipi_single,
         .send_ipi_mask          = octeon_send_ipi_mask,
@@ -208,4 +436,8 @@ struct plat_smp_ops octeon_smp_ops = {
         .boot_secondary         = octeon_boot_secondary,
         .smp_setup              = octeon_smp_setup,
         .prepare_cpus           = octeon_prepare_cpus,
+#ifdef CONFIG_HOTPLUG_CPU
+        .cpu_disable            = octeon_cpu_disable,
+        .cpu_die                = octeon_cpu_die,
+#endif
 };