ARM: shmobile: R-Mobile: Add DT support for PM domains

Populate the PM domains from DT, and provide support to hook up devices
to their respective PM domain.

The always-on power area (e.g. C5 on r8a7740) is created as a PM domain
without software control, to allow Run-Time management of module clocks
for hardware blocks inside this area.

Special cases like PM domains containing CPUs, the console device, or
Coresight-ETM, are handled by scanning the DT topology.

As long as the ARM debug/perf code doesn't use resource management with
runtime PM support, the power area containing Coresight-ETM (e.g. D4 on
r8a7740) must be kept powered to avoid a crash during resume from s2ram
(dbg_cpu_pm_notify() calls reset_ctrl_regs() unconditionally, causing an
undefined instruction oops).

Initialization is done from core_initcall(), as the
"renesas,intc-irqpin" driver uses postcore_initcall().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

3 files changed, 218 insertions, 4 deletions

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index d107b9386bda..894c68760060 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -7,6 +7,7 @@ config PM_RCAR
 
 config PM_RMOBILE
         bool
+        select PM_GENERIC_DOMAINS
 
 config ARCH_RCAR_GEN1
         bool
@@ -23,7 +24,7 @@ config ARCH_RCAR_GEN2
 
 config ARCH_RMOBILE
         bool
-        select PM_RMOBILE if PM && !ARCH_SHMOBILE_MULTI
+        select PM_RMOBILE if PM
         select SYS_SUPPORTS_SH_CMT
         select SYS_SUPPORTS_SH_TMU
 
diff --git a/arch/arm/mach-shmobile/pm-rmobile.c b/arch/arm/mach-shmobile/pm-rmobile.c
index a4fcd2cae718..85a7fdd9823b 100644
--- a/arch/arm/mach-shmobile/pm-rmobile.c
+++ b/arch/arm/mach-shmobile/pm-rmobile.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2012  Renesas Solutions Corp.
  * Copyright (C) 2012  Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ * Copyright (C) 2014  Glider bvba
  *
  * based on pm-sh7372.c
  *  Copyright (C) 2011 Magnus Damm
@@ -13,10 +14,16 @@
  */
 #include <linux/console.h>
 #include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_clock.h>
+#include <linux/slab.h>
+
 #include <asm/io.h>
+
 #include "pm-rmobile.h"
 
 /* SYSC */
@@ -30,8 +37,12 @@
 static int rmobile_pd_power_down(struct generic_pm_domain *genpd)
 {
         struct rmobile_pm_domain *rmobile_pd = to_rmobile_pd(genpd);
-        unsigned int mask = 1 << rmobile_pd->bit_shift;
+        unsigned int mask;
+
+        if (rmobile_pd->bit_shift == ~0)
+                return -EBUSY;
 
+        mask = 1 << rmobile_pd->bit_shift;
         if (rmobile_pd->suspend) {
                 int ret = rmobile_pd->suspend();
 
@@ -61,10 +72,14 @@ static int rmobile_pd_power_down(struct generic_pm_domain *genpd)
 static int __rmobile_pd_power_up(struct rmobile_pm_domain *rmobile_pd,
                                  bool do_resume)
 {
-        unsigned int mask = 1 << rmobile_pd->bit_shift;
+        unsigned int mask;
         unsigned int retry_count;
         int ret = 0;
 
+        if (rmobile_pd->bit_shift == ~0)
+                return 0;
+
+        mask = 1 << rmobile_pd->bit_shift;
         if (__raw_readl(rmobile_pd->base + PSTR) & mask)
                 goto out;
 
@@ -148,6 +163,8 @@ static void rmobile_init_pm_domain(struct rmobile_pm_domain *rmobile_pd)
         __rmobile_pd_power_up(rmobile_pd, false);
 }
 
+#ifdef CONFIG_ARCH_SHMOBILE_LEGACY
+
 void rmobile_init_domains(struct rmobile_pm_domain domains[], int num)
 {
         int j;
@@ -180,3 +197,199 @@ void rmobile_add_devices_to_domains(struct pm_domain_device data[],
                 rmobile_add_device_to_domain_td(data[j].domain_name,
                                                 data[j].pdev, &latencies);
 }
+
+#else /* !CONFIG_ARCH_SHMOBILE_LEGACY */
+
+static int rmobile_pd_suspend_cpu(void)
+{
+        /*
+         * This domain contains the CPU core and therefore it should
+         * only be turned off if the CPU is not in use.
+         */
+        return -EBUSY;
+}
+
+static int rmobile_pd_suspend_console(void)
+{
+        /*
+         * Serial consoles make use of SCIF hardware located in this domain,
+         * hence keep the power domain on if "no_console_suspend" is set.
+         */
+        return console_suspend_enabled ? 0 : -EBUSY;
+}
+
+static int rmobile_pd_suspend_debug(void)
+{
+        /*
+         * This domain contains the Coresight-ETM hardware block and
+         * therefore it should only be turned off if the debug module is
+         * not in use.
+         */
+        return -EBUSY;
+}
+
+#define MAX_NUM_CPU_PDS         8
+
+static unsigned int num_cpu_pds __initdata;
+static struct device_node *cpu_pds[MAX_NUM_CPU_PDS] __initdata;
+static struct device_node *console_pd __initdata;
+static struct device_node *debug_pd __initdata;
+
+static void __init get_special_pds(void)
+{
+        struct device_node *np, *pd;
+        unsigned int i;
+
+        /* PM domains containing CPUs */
+        for_each_node_by_type(np, "cpu") {
+                pd = of_parse_phandle(np, "power-domains", 0);
+                if (!pd)
+                        continue;
+
+                for (i = 0; i < num_cpu_pds; i++)
+                        if (pd == cpu_pds[i])
+                                break;
+
+                if (i < num_cpu_pds) {
+                        of_node_put(pd);
+                        continue;
+                }
+
+                if (num_cpu_pds == MAX_NUM_CPU_PDS) {
+                        pr_warn("Too many CPU PM domains\n");
+                        of_node_put(pd);
+                        continue;
+                }
+
+                cpu_pds[num_cpu_pds++] = pd;
+        }
+
+        /* PM domain containing console */
+        if (of_stdout)
+                console_pd = of_parse_phandle(of_stdout, "power-domains", 0);
+
+        /* PM domain containing Coresight-ETM */
+        np = of_find_compatible_node(NULL, NULL, "arm,coresight-etm3x");
+        if (np) {
+                debug_pd = of_parse_phandle(np, "power-domains", 0);
+                of_node_put(np);
+        }
+}
+
+static void __init put_special_pds(void)
+{
+        unsigned int i;
+
+        for (i = 0; i < num_cpu_pds; i++)
+                of_node_put(cpu_pds[i]);
+        of_node_put(console_pd);
+        of_node_put(debug_pd);
+}
+
+static bool __init pd_contains_cpu(const struct device_node *pd)
+{
+        unsigned int i;
+
+        for (i = 0; i < num_cpu_pds; i++)
+                if (pd == cpu_pds[i])
+                        return true;
+
+        return false;
+}
+
+static void __init rmobile_setup_pm_domain(struct device_node *np,
+                                           struct rmobile_pm_domain *pd)
+{
+        const char *name = pd->genpd.name;
+
+        if (pd_contains_cpu(np)) {
+                pr_debug("PM domain %s contains CPU\n", name);
+                pd->gov = &pm_domain_always_on_gov;
+                pd->suspend = rmobile_pd_suspend_cpu;
+        } else if (np == console_pd) {
+                pr_debug("PM domain %s contains serial console\n", name);
+                pd->gov = &pm_domain_always_on_gov;
+                pd->suspend = rmobile_pd_suspend_console;
+        } else if (np == debug_pd) {
+                pr_debug("PM domain %s contains Coresight-ETM\n", name);
+                pd->gov = &pm_domain_always_on_gov;
+                pd->suspend = rmobile_pd_suspend_debug;
+        }
+
+        rmobile_init_pm_domain(pd);
+}
+
+static int __init rmobile_add_pm_domains(void __iomem *base,
+                                         struct device_node *parent,
+                                         struct generic_pm_domain *genpd_parent)
+{
+        struct device_node *np;
+
+        for_each_child_of_node(parent, np) {
+                struct rmobile_pm_domain *pd;
+                u32 idx = ~0;
+
+                if (of_property_read_u32(np, "reg", &idx)) {
+                        /* always-on domain */
+                }
+
+                pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+                if (!pd)
+                        return -ENOMEM;
+
+                pd->genpd.name = np->name;
+                pd->base = base;
+                pd->bit_shift = idx;
+
+                rmobile_setup_pm_domain(np, pd);
+                if (genpd_parent)
+                        pm_genpd_add_subdomain(genpd_parent, &pd->genpd);
+                of_genpd_add_provider_simple(np, &pd->genpd);
+
+                rmobile_add_pm_domains(base, np, &pd->genpd);
+        }
+        return 0;
+}
+
+static int __init rmobile_init_pm_domains(void)
+{
+        struct device_node *np, *pmd;
+        bool scanned = false;
+        void __iomem *base;
+        int ret = 0;
+
+        for_each_compatible_node(np, NULL, "renesas,sysc-rmobile") {
+                base = of_iomap(np, 0);
+                if (!base) {
+                        pr_warn("%s cannot map reg 0\n", np->full_name);
+                        continue;
+                }
+
+                pmd = of_get_child_by_name(np, "pm-domains");
+                if (!pmd) {
+                        pr_warn("%s lacks pm-domains node\n", np->full_name);
+                        continue;
+                }
+
+                if (!scanned) {
+                        /* Find PM domains containing special blocks */
+                        get_special_pds();
+                        scanned = true;
+                }
+
+                ret = rmobile_add_pm_domains(base, pmd, NULL);
+                of_node_put(pmd);
+                if (ret) {
+                        of_node_put(np);
+                        break;
+                }
+        }
+
+        put_special_pds();
+
+        return ret;
+}
+
+core_initcall(rmobile_init_pm_domains);
+
+#endif /* !CONFIG_ARCH_SHMOBILE_LEGACY */
diff --git a/arch/arm/mach-shmobile/pm-rmobile.h b/arch/arm/mach-shmobile/pm-rmobile.h
index 0602130bb260..53219786f539 100644
--- a/arch/arm/mach-shmobile/pm-rmobile.h
+++ b/arch/arm/mach-shmobile/pm-rmobile.h
@@ -37,7 +37,7 @@ struct pm_domain_device {
         struct platform_device *pdev;
 };
 
-#ifdef CONFIG_PM_RMOBILE
+#if defined(CONFIG_PM_RMOBILE) && defined(CONFIG_ARCH_SHMOBILE_LEGACY)
 extern void rmobile_init_domains(struct rmobile_pm_domain domains[], int num);
 extern void rmobile_add_device_to_domain_td(const char *domain_name,
                                             struct platform_device *pdev,