ARM: vexpress: Simplify SMP operations for DT-powered system

As all cores must be properly described in the Device Tree,
there is no point in getting their numbers from SCU on
A5/A9 platforms. This significantly simplifies the code,
removing the need for flat-tree scanning and early static
mapping.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>

3 files changed, 41 insertions, 126 deletions

diff --git a/arch/arm/mach-vexpress/core.h b/arch/arm/mach-vexpress/core.h
index bde4374ab6d5..152fad91b3ae 100644
--- a/arch/arm/mach-vexpress/core.h
+++ b/arch/arm/mach-vexpress/core.h
@@ -4,10 +4,9 @@
 /* Tile's peripherals static mappings should start here */
 #define V2T_PERIPH 0xf8200000
 
-void vexpress_dt_smp_map_io(void);
-
 bool vexpress_smp_init_ops(void);
 
 extern struct smp_operations    vexpress_smp_ops;
+extern struct smp_operations    vexpress_smp_dt_ops;
 
 extern void vexpress_cpu_die(unsigned int cpu);
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index 12a875182836..a1f3804fd5a5 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -12,8 +12,7 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
 #include <linux/io.h>
-#include <linux/of.h>
-#include <linux/of_fdt.h>
+#include <linux/of_address.h>
 #include <linux/vexpress.h>
 
 #include <asm/mcpm.h>
@@ -26,125 +25,13 @@
 
 #include "core.h"
 
-#if defined(CONFIG_OF)
-
-static enum {
-        GENERIC_SCU,
-        CORTEX_A9_SCU,
-} vexpress_dt_scu __initdata = GENERIC_SCU;
-
-static struct map_desc vexpress_dt_cortex_a9_scu_map __initdata = {
-        .virtual        = V2T_PERIPH,
-        /* .pfn set in vexpress_dt_init_cortex_a9_scu() */
-        .length         = SZ_128,
-        .type           = MT_DEVICE,
-};
-
-static void *vexpress_dt_cortex_a9_scu_base __initdata;
-
-const static char *vexpress_dt_cortex_a9_match[] __initconst = {
-        "arm,cortex-a5-scu",
-        "arm,cortex-a9-scu",
-        NULL
-};
-
-static int __init vexpress_dt_find_scu(unsigned long node,
-                const char *uname, int depth, void *data)
-{
-        if (of_flat_dt_match(node, vexpress_dt_cortex_a9_match)) {
-                phys_addr_t phys_addr;
-                __be32 *reg = of_get_flat_dt_prop(node, "reg", NULL);
-
-                if (WARN_ON(!reg))
-                        return -EINVAL;
-
-                phys_addr = be32_to_cpup(reg);
-                vexpress_dt_scu = CORTEX_A9_SCU;
-
-                vexpress_dt_cortex_a9_scu_map.pfn = __phys_to_pfn(phys_addr);
-                iotable_init(&vexpress_dt_cortex_a9_scu_map, 1);
-                vexpress_dt_cortex_a9_scu_base = ioremap(phys_addr, SZ_256);
-                if (WARN_ON(!vexpress_dt_cortex_a9_scu_base))
-                        return -EFAULT;
-        }
-
-        return 0;
-}
-
-void __init vexpress_dt_smp_map_io(void)
-{
-        if (initial_boot_params)
-                WARN_ON(of_scan_flat_dt(vexpress_dt_find_scu, NULL));
-}
-
-static void __init vexpress_dt_smp_init_cpus(void)
-{
-        int ncores = 0, i;
-
-        switch (vexpress_dt_scu) {
-        case GENERIC_SCU:
-                return;
-        case CORTEX_A9_SCU:
-                ncores = scu_get_core_count(vexpress_dt_cortex_a9_scu_base);
-                break;
-        default:
-                WARN_ON(1);
-                break;
-        }
-
-        if (ncores < 2)
-                return;
-
-        if (ncores > nr_cpu_ids) {
-                pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
-                                ncores, nr_cpu_ids);
-                ncores = nr_cpu_ids;
-        }
-
-        for (i = 0; i < ncores; ++i)
-                set_cpu_possible(i, true);
-}
-
-static void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
-{
-
-        switch (vexpress_dt_scu) {
-        case GENERIC_SCU:
-                break;
-        case CORTEX_A9_SCU:
-                scu_enable(vexpress_dt_cortex_a9_scu_base);
-                break;
-        default:
-                WARN_ON(1);
-                break;
-        }
-}
-
-#else
-
-static void __init vexpress_dt_smp_init_cpus(void)
-{
-        WARN_ON(1);
-}
-
-void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
-{
-        WARN_ON(1);
-}
-
-#endif
-
 /*
  * Initialise the CPU possible map early - this describes the CPUs
  * which may be present or become present in the system.
  */
 static void __init vexpress_smp_init_cpus(void)
 {
-        if (ct_desc)
-                ct_desc->init_cpu_map();
-        else
-                vexpress_dt_smp_init_cpus();
-
+        ct_desc->init_cpu_map();
 }
 
 static void __init vexpress_smp_prepare_cpus(unsigned int max_cpus)
@@ -153,10 +40,7 @@ static void __init vexpress_smp_prepare_cpus(unsigned int max_cpus)
          * Initialise the present map, which describes the set of CPUs
          * actually populated at the present time.
          */
-        if (ct_desc)
-                ct_desc->smp_enable(max_cpus);
-        else
-                vexpress_dt_smp_prepare_cpus(max_cpus);
+        ct_desc->smp_enable(max_cpus);
 
         /*
          * Write the address of secondary startup into the
@@ -194,3 +78,39 @@ bool __init vexpress_smp_init_ops(void)
 #endif
         return false;
 }
+
+#if defined(CONFIG_OF)
+
+static const struct of_device_id vexpress_smp_dt_scu_match[] __initconst = {
+        { .compatible = "arm,cortex-a5-scu", },
+        { .compatible = "arm,cortex-a9-scu", },
+        {}
+};
+
+static void __init vexpress_smp_dt_prepare_cpus(unsigned int max_cpus)
+{
+        struct device_node *scu = of_find_matching_node(NULL,
+                        vexpress_smp_dt_scu_match);
+
+        if (scu)
+                scu_enable(of_iomap(scu, 0));
+
+        /*
+         * 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.
+         */
+        vexpress_flags_set(virt_to_phys(versatile_secondary_startup));
+}
+
+struct smp_operations __initdata vexpress_smp_dt_ops = {
+        .smp_prepare_cpus       = vexpress_smp_dt_prepare_cpus,
+        .smp_secondary_init     = versatile_secondary_init,
+        .smp_boot_secondary     = versatile_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+        .cpu_die                = vexpress_cpu_die,
+#endif
+};
+
+#endif
diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
index d8a9fd7a695d..d8b419bcf3c3 100644
--- a/arch/arm/mach-vexpress/v2m.c
+++ b/arch/arm/mach-vexpress/v2m.c
@@ -400,10 +400,6 @@ void __init v2m_dt_map_io(void)
                 iotable_init(&v2m_rs1_io_desc, 1);
         else
                 iotable_init(v2m_io_desc, ARRAY_SIZE(v2m_io_desc));
-
-#if defined(CONFIG_SMP)
-        vexpress_dt_smp_map_io();
-#endif
 }
 
 void __init v2m_dt_init_early(void)
@@ -434,7 +430,7 @@ static const char * const v2m_dt_match[] __initconst = {
 
 DT_MACHINE_START(VEXPRESS_DT, "ARM-Versatile Express")
         .dt_compat      = v2m_dt_match,
-        .smp            = smp_ops(vexpress_smp_ops),
+        .smp            = smp_ops(vexpress_smp_dt_ops),
         .smp_init       = smp_init_ops(vexpress_smp_init_ops),
         .map_io         = v2m_dt_map_io,
         .init_early     = v2m_dt_init_early,