ARM: Alpine: smp support

This patch introduces support for waking up secondary CPU cores on
Alpine platform.

Signed-off-by: Barak Wasserstrom <barak@annapurnalabs.com>
Signed-off-by: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

6 files changed, 186 insertions, 0 deletions

diff --git a/arch/arm/mach-alpine/Kconfig b/arch/arm/mach-alpine/Kconfig
index 44b9a8f4e5bb..79b26491a96c 100644
--- a/arch/arm/mach-alpine/Kconfig
+++ b/arch/arm/mach-alpine/Kconfig
@@ -4,5 +4,7 @@ config ARCH_ALPINE
         select ARM_GIC
         select GENERIC_IRQ_CHIP
         select HAVE_ARM_ARCH_TIMER
+        select HAVE_SMP
+        select MFD_SYSCON
         help
           This enables support for the Annapurna Labs Alpine V1 boards.
diff --git a/arch/arm/mach-alpine/Makefile b/arch/arm/mach-alpine/Makefile
index b7dbb12d89cd..b6674890be71 100644
--- a/arch/arm/mach-alpine/Makefile
+++ b/arch/arm/mach-alpine/Makefile
@@ -1 +1,2 @@
 obj-y                           += alpine_machine.o
+obj-$(CONFIG_SMP)               += platsmp.o alpine_cpu_pm.o
diff --git a/arch/arm/mach-alpine/alpine_cpu_pm.c b/arch/arm/mach-alpine/alpine_cpu_pm.c
new file mode 100644
index 000000000000..121c77c4b53c
--- /dev/null
+++ b/arch/arm/mach-alpine/alpine_cpu_pm.c
@@ -0,0 +1,70 @@
+/*
+ * Low-level power-management support for Alpine platform.
+ *
+ * Copyright (C) 2015 Annapurna Labs Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#include "alpine_cpu_pm.h"
+#include "alpine_cpu_resume.h"
+
+/* NB registers */
+#define AL_SYSFAB_POWER_CONTROL(cpu)    (0x2000 + (cpu)*0x100 + 0x20)
+
+static struct regmap *al_sysfabric;
+static struct al_cpu_resume_regs __iomem *al_cpu_resume_regs;
+static int wakeup_supported;
+
+int alpine_cpu_wakeup(unsigned int phys_cpu, uint32_t phys_resume_addr)
+{
+        if (!wakeup_supported)
+                return -ENOSYS;
+
+        /*
+         * Set CPU resume address -
+         * secure firmware running on boot will jump to this address
+         * after setting proper CPU mode, and initialiing e.g. secure
+         * regs (the same mode all CPUs are booted to - usually HYP)
+         */
+        writel(phys_resume_addr,
+               &al_cpu_resume_regs->per_cpu[phys_cpu].resume_addr);
+
+        /* Power-up the CPU */
+        regmap_write(al_sysfabric, AL_SYSFAB_POWER_CONTROL(phys_cpu), 0);
+
+        return 0;
+}
+
+void __init alpine_cpu_pm_init(void)
+{
+        struct device_node *np;
+        uint32_t watermark;
+
+        al_sysfabric = syscon_regmap_lookup_by_compatible("al,alpine-sysfabric-service");
+
+        np = of_find_compatible_node(NULL, NULL, "al,alpine-cpu-resume");
+        al_cpu_resume_regs = of_iomap(np, 0);
+
+        wakeup_supported = !IS_ERR(al_sysfabric) && al_cpu_resume_regs;
+
+        if (wakeup_supported) {
+                watermark = readl(&al_cpu_resume_regs->watermark);
+                wakeup_supported = (watermark & AL_CPU_RESUME_MAGIC_NUM_MASK)
+                                    == AL_CPU_RESUME_MAGIC_NUM;
+        }
+}
diff --git a/arch/arm/mach-alpine/alpine_cpu_pm.h b/arch/arm/mach-alpine/alpine_cpu_pm.h
new file mode 100644
index 000000000000..5179e697c492
--- /dev/null
+++ b/arch/arm/mach-alpine/alpine_cpu_pm.h
@@ -0,0 +1,26 @@
+/*
+ * Low-level power-management support for Alpine platform.
+ *
+ * Copyright (C) 2015 Annapurna Labs Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __ALPINE_CPU_PM_H__
+#define __ALPINE_CPU_PM_H__
+
+/* Alpine CPU Power Management Services Initialization */
+void alpine_cpu_pm_init(void);
+
+/* Wake-up a CPU */
+int alpine_cpu_wakeup(unsigned int phys_cpu, uint32_t phys_resume_addr);
+
+#endif /* __ALPINE_CPU_PM_H__ */
diff --git a/arch/arm/mach-alpine/alpine_cpu_resume.h b/arch/arm/mach-alpine/alpine_cpu_resume.h
new file mode 100644
index 000000000000..c80150c0d2d8
--- /dev/null
+++ b/arch/arm/mach-alpine/alpine_cpu_resume.h
@@ -0,0 +1,38 @@
+/*
+ * Annapurna labs cpu-resume register structure.
+ *
+ * Copyright (C) 2015 Annapurna Labs Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef ALPINE_CPU_RESUME_H_
+#define ALPINE_CPU_RESUME_H_
+
+/* Per-cpu regs */
+struct al_cpu_resume_regs_per_cpu {
+        uint32_t        flags;
+        uint32_t        resume_addr;
+};
+
+/* general regs */
+struct al_cpu_resume_regs {
+        /* Watermark for validating the CPU resume struct */
+        uint32_t watermark;
+        uint32_t flags;
+        struct al_cpu_resume_regs_per_cpu per_cpu[];
+};
+
+/* The expected magic number for validating the resume addresses */
+#define AL_CPU_RESUME_MAGIC_NUM         0xf0e1d200
+#define AL_CPU_RESUME_MAGIC_NUM_MASK    0xffffff00
+
+#endif /* ALPINE_CPU_RESUME_H_ */
diff --git a/arch/arm/mach-alpine/platsmp.c b/arch/arm/mach-alpine/platsmp.c
new file mode 100644
index 000000000000..f78429f48bd6
--- /dev/null
+++ b/arch/arm/mach-alpine/platsmp.c
@@ -0,0 +1,49 @@
+/*
+ * SMP operations for Alpine platform.
+ *
+ * Copyright (C) 2015 Annapurna Labs Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#include <asm/smp_plat.h>
+
+#include "alpine_cpu_pm.h"
+
+static int alpine_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+        phys_addr_t addr;
+
+        addr = virt_to_phys(secondary_startup);
+
+        if (addr > (phys_addr_t)(uint32_t)(-1)) {
+                pr_err("FAIL: resume address over 32bit (%pa)", &addr);
+                return -EINVAL;
+        }
+
+        return alpine_cpu_wakeup(cpu_logical_map(cpu), (uint32_t)addr);
+}
+
+static void __init alpine_smp_prepare_cpus(unsigned int max_cpus)
+{
+        alpine_cpu_pm_init();
+}
+
+static struct smp_operations alpine_smp_ops __initdata = {
+        .smp_prepare_cpus       = alpine_smp_prepare_cpus,
+        .smp_boot_secondary     = alpine_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(alpine_smp, "al,alpine-smp", &alpine_smp_ops);