ARM: mach-shmobile: r8a7779 SMP support V3

This patch contains r8a7779 SMP support V3 - now including
CPU hotplug offine and online support. The r8a7779 power
domain code is tied together with SMP glue code which allows
us to control the power domains via CPU hotplug.

At this point the kernel boots with the 4 Cortex-A9 cores in
SMP mode and all CPU cores except CPU0 can be hotplugged.

The code in platsmp.c is quite far from pretty, but it is
kept like that intentionally to avoid creating layers of
code that will go away in the near future anyway. The code
needs to be updated when some per-SoC handling code will be
added to the ARM architecture, see the following patch for
more information:
 "[RFC PATCH 0/3] Per SoC descriptor"

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 153 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/smp-r8a7779.c b/arch/arm/mach-shmobile/smp-r8a7779.c
new file mode 100644
index 00000000000..cc97ef892d1
--- /dev/null
+++ b/arch/arm/mach-shmobile/smp-r8a7779.c
@@ -0,0 +1,153 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile - r8a7779 portion
+ *
+ * Copyright (C) 2011  Renesas Solutions Corp.
+ * Copyright (C) 2011  Magnus Damm
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <mach/common.h>
+#include <mach/r8a7779.h>
+#include <asm/smp_scu.h>
+#include <asm/smp_twd.h>
+#include <asm/hardware/gic.h>
+
+#define AVECR 0xfe700040
+
+static struct r8a7779_pm_ch r8a7779_ch_cpu1 = {
+        .chan_offs = 0x40, /* PWRSR0 .. PWRER0 */
+        .chan_bit = 1, /* ARM1 */
+        .isr_bit = 1, /* ARM1 */
+};
+
+static struct r8a7779_pm_ch r8a7779_ch_cpu2 = {
+        .chan_offs = 0x40, /* PWRSR0 .. PWRER0 */
+        .chan_bit = 2, /* ARM2 */
+        .isr_bit = 2, /* ARM2 */
+};
+
+static struct r8a7779_pm_ch r8a7779_ch_cpu3 = {
+        .chan_offs = 0x40, /* PWRSR0 .. PWRER0 */
+        .chan_bit = 3, /* ARM3 */
+        .isr_bit = 3, /* ARM3 */
+};
+
+static struct r8a7779_pm_ch *r8a7779_ch_cpu[4] = {
+        [1] = &r8a7779_ch_cpu1,
+        [2] = &r8a7779_ch_cpu2,
+        [3] = &r8a7779_ch_cpu3,
+};
+
+static void __iomem *scu_base_addr(void)
+{
+        return (void __iomem *)0xf0000000;
+}
+
+static DEFINE_SPINLOCK(scu_lock);
+static unsigned long tmp;
+
+static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
+{
+        void __iomem *scu_base = scu_base_addr();
+
+        spin_lock(&scu_lock);
+        tmp = __raw_readl(scu_base + 8);
+        tmp &= ~clr;
+        tmp |= set;
+        spin_unlock(&scu_lock);
+
+        /* disable cache coherency after releasing the lock */
+        __raw_writel(tmp, scu_base + 8);
+}
+
+unsigned int __init r8a7779_get_core_count(void)
+{
+        void __iomem *scu_base = scu_base_addr();
+
+#ifdef CONFIG_HAVE_ARM_TWD
+        /* twd_base needs to be initialized before percpu_timer_setup() */
+        twd_base = (void __iomem *)0xf0000600;
+#endif
+
+        return scu_get_core_count(scu_base);
+}
+
+int r8a7779_platform_cpu_kill(unsigned int cpu)
+{
+        struct r8a7779_pm_ch *ch = NULL;
+        int ret = -EIO;
+
+        cpu = cpu_logical_map(cpu);
+
+        /* disable cache coherency */
+        modify_scu_cpu_psr(3 << (cpu * 8), 0);
+
+        if (cpu < ARRAY_SIZE(r8a7779_ch_cpu))
+                ch = r8a7779_ch_cpu[cpu];
+
+        if (ch)
+                ret = r8a7779_sysc_power_down(ch);
+
+        return ret ? ret : 1;
+}
+
+void __cpuinit r8a7779_secondary_init(unsigned int cpu)
+{
+        gic_secondary_init(0);
+}
+
+int __cpuinit r8a7779_boot_secondary(unsigned int cpu)
+{
+        struct r8a7779_pm_ch *ch = NULL;
+        int ret = -EIO;
+
+        cpu = cpu_logical_map(cpu);
+
+        /* enable cache coherency */
+        modify_scu_cpu_psr(0, 3 << (cpu * 8));
+
+        if (cpu < ARRAY_SIZE(r8a7779_ch_cpu))
+                ch = r8a7779_ch_cpu[cpu];
+
+        if (ch)
+                ret = r8a7779_sysc_power_up(ch);
+
+        return ret;
+}
+
+void __init r8a7779_smp_prepare_cpus(void)
+{
+        int cpu = cpu_logical_map(0);
+
+        scu_enable(scu_base_addr());
+
+        /* Map the reset vector (in headsmp.S) */
+        __raw_writel(__pa(shmobile_secondary_vector), __io(AVECR));
+
+        /* enable cache coherency on CPU0 */
+        modify_scu_cpu_psr(0, 3 << (cpu * 8));
+
+        r8a7779_pm_init();
+
+        /* power off secondary CPUs */
+        r8a7779_platform_cpu_kill(1);
+        r8a7779_platform_cpu_kill(2);
+        r8a7779_platform_cpu_kill(3);
+}