ARM: realview: add an DT SMP boot method

This adds an SMP boot method for the ARM RealView reference
designs. We also select HAVE_SMP by default and make it use
SMP_ON_UP so we only need to support one single kernel across
the RealView reference designs when using DT.

The RealViews need to have the SCU (Snoop Control Unit)
activated on boot, and this is now done by looking up its
address from the device tree and initializing it and counting
the available cores.

The RealViews boot by using a magic address register in the
system controller (SYS_FLAGS) to store the boot address,
the ROM will then read this register to the PC when the CPUs
are taken out of WFI. This code uses a handle to the syscon
regmap to access this register.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index 3a07a87fef2087550cb24f0c4aff5f8e2fecab21..19af9157f094bd7039ca6c6fa29a06b161b97169 100644 (file)
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -190,6 +190,7 @@ nodes to be present and contain the properties described below.
                            "allwinner,sun6i-a31"
                            "allwinner,sun8i-a23"
                            "arm,psci"
+                           "arm,realview-smp"
                            "brcm,brahma-b15"
                            "marvell,armada-375-smp"
                            "marvell,armada-380-smp"

diff --git a/arch/arm/mach-realview/Kconfig b/arch/arm/mach-realview/Kconfig
index edbc925e42c2698692edbb19536e076995b7579d..7316fff0f3bae16a3197d98b2182dc4f48683c5a 100644 (file)
--- a/arch/arm/mach-realview/Kconfig
+++ b/arch/arm/mach-realview/Kconfig
@@ -5,11 +5,13 @@ config REALVIEW_DT
        bool "Support RealView(R) Device Tree based boot"
        select ARM_GIC
        select CLK_SP810
+       select HAVE_SMP
        select ICST
        select MFD_SYSCON
        select POWER_RESET
        select POWER_RESET_VERSATILE
        select POWER_SUPPLY
+       select SMP_ON_UP
        select SOC_REALVIEW
        select USE_OF
        help

diff --git a/arch/arm/mach-realview/Makefile b/arch/arm/mach-realview/Makefile
index e07fdf7ae8a7e61948f268942e4cc5f01238ec81..a46fa694cf07f0e65e925ca210ce03172e6bf119 100644 (file)
--- a/arch/arm/mach-realview/Makefile
+++ b/arch/arm/mach-realview/Makefile
@@ -3,7 +3,7 @@
 #
 
 obj-y                                  := core.o
-obj-$(CONFIG_REALVIEW_DT)              += realview-dt.o
+obj-$(CONFIG_REALVIEW_DT)              += realview-dt.o platsmp-dt.o
 obj-$(CONFIG_MACH_REALVIEW_EB)         += realview_eb.o
 obj-$(CONFIG_MACH_REALVIEW_PB11MP)     += realview_pb11mp.o
 obj-$(CONFIG_MACH_REALVIEW_PB1176)     += realview_pb1176.o

diff --git a/arch/arm/mach-realview/platsmp-dt.c b/arch/arm/mach-realview/platsmp-dt.c
new file mode 100644 (file)
index 0000000..6558539
--- /dev/null
+++ b/arch/arm/mach-realview/platsmp-dt.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2015 Linus Walleij
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/smp.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#include <plat/platsmp.h>
+
+#include "core.h"
+
+#define REALVIEW_SYS_FLAGSSET_OFFSET   0x30
+
+static const struct of_device_id realview_scu_match[] = {
+       { .compatible = "arm,arm11mp-scu", },
+       { .compatible = "arm,cortex-a9-scu", },
+       { .compatible = "arm,cortex-a5-scu", },
+       { }
+};
+
+static const struct of_device_id realview_syscon_match[] = {
+        { .compatible = "arm,core-module-integrator", },
+        { .compatible = "arm,realview-eb-syscon", },
+        { .compatible = "arm,realview-pb11mp-syscon", },
+        { .compatible = "arm,realview-pbx-syscon", },
+        { },
+};
+
+static void __init realview_smp_prepare_cpus(unsigned int max_cpus)
+{
+       struct device_node *np;
+       void __iomem *scu_base;
+       struct regmap *map;
+       unsigned int ncores;
+       int i;
+
+       np = of_find_matching_node(NULL, realview_scu_match);
+       if (!np) {
+               pr_err("PLATSMP: No SCU base address\n");
+               return;
+       }
+       scu_base = of_iomap(np, 0);
+       of_node_put(np);
+       if (!scu_base) {
+               pr_err("PLATSMP: No SCU remap\n");
+               return;
+       }
+
+       scu_enable(scu_base);
+       ncores = scu_get_core_count(scu_base);
+       pr_info("SCU: %d cores detected\n", ncores);
+       for (i = 0; i < ncores; i++)
+               set_cpu_possible(i, true);
+       iounmap(scu_base);
+
+       /* The syscon contains the magic SMP start address registers */
+       np = of_find_matching_node(NULL, realview_syscon_match);
+       if (!np) {
+               pr_err("PLATSMP: No syscon match\n");
+               return;
+       }
+       map = syscon_node_to_regmap(np);
+       if (IS_ERR(map)) {
+               pr_err("PLATSMP: No syscon regmap\n");
+               return;
+       }
+       /* Put the boot address in this magic register */
+       regmap_write(map, REALVIEW_SYS_FLAGSSET_OFFSET,
+                    virt_to_phys(versatile_secondary_startup));
+}
+
+struct smp_operations realview_dt_smp_ops __initdata = {
+       .smp_prepare_cpus       = realview_smp_prepare_cpus,
+       .smp_secondary_init     = versatile_secondary_init,
+       .smp_boot_secondary     = versatile_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+       .cpu_die                = realview_cpu_die,
+#endif
+};
+CPU_METHOD_OF_DECLARE(realview_smp, "arm,realview-smp", &realview_dt_smp_ops);