ARM: mach-shmobile: Runtime PM V3

This is the SH-Mobile ARM Runtime PM implementation V3.
Only clocks are managed at this point. If Runtime PM
is disabled then the clocks will be enabled before
->probe() and disabled after ->remove().

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

1 files changed, 169 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/pm_runtime.c b/arch/arm/mach-shmobile/pm_runtime.c
new file mode 100644
index 00000000000..94912d3944d
--- /dev/null
+++ b/arch/arm/mach-shmobile/pm_runtime.c
@@ -0,0 +1,169 @@
+/*
+ * arch/arm/mach-shmobile/pm_runtime.c
+ *
+ * Runtime PM support code for SuperH Mobile ARM
+ *
+ *  Copyright (C) 2009-2010 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/sh_clk.h>
+#include <linux/bitmap.h>
+
+#ifdef CONFIG_PM_RUNTIME
+#define BIT_ONCE 0
+#define BIT_ACTIVE 1
+#define BIT_CLK_ENABLED 2
+
+struct pm_runtime_data {
+	unsigned long flags;
+	struct clk *clk;
+};
+
+static void __devres_release(struct device *dev, void *res)
+{
+	struct pm_runtime_data *prd = res;
+
+	dev_dbg(dev, "__devres_release()\n");
+
+	if (test_bit(BIT_CLK_ENABLED, &prd->flags))
+		clk_disable(prd->clk);
+
+	if (test_bit(BIT_ACTIVE, &prd->flags))
+		clk_put(prd->clk);
+}
+
+static struct pm_runtime_data *__to_prd(struct device *dev)
+{
+	return devres_find(dev, __devres_release, NULL, NULL);
+}
+
+static void platform_pm_runtime_init(struct device *dev,
+				     struct pm_runtime_data *prd)
+{
+	if (prd && !test_and_set_bit(BIT_ONCE, &prd->flags)) {
+		prd->clk = clk_get(dev, NULL);
+		if (!IS_ERR(prd->clk)) {
+			set_bit(BIT_ACTIVE, &prd->flags);
+			dev_info(dev, "clocks managed by runtime pm\n");
+		}
+	}
+}
+
+static void platform_pm_runtime_bug(struct device *dev,
+				    struct pm_runtime_data *prd)
+{
+	if (prd && !test_and_set_bit(BIT_ONCE, &prd->flags))
+		dev_err(dev, "runtime pm suspend before resume\n");
+}
+
+int platform_pm_runtime_suspend(struct device *dev)
+{
+	struct pm_runtime_data *prd = __to_prd(dev);
+
+	dev_dbg(dev, "platform_pm_runtime_suspend()\n");
+
+	platform_pm_runtime_bug(dev, prd);
+
+	if (prd && test_bit(BIT_ACTIVE, &prd->flags)) {
+		clk_disable(prd->clk);
+		clear_bit(BIT_CLK_ENABLED, &prd->flags);
+	}
+
+	return 0;
+}
+
+int platform_pm_runtime_resume(struct device *dev)
+{
+	struct pm_runtime_data *prd = __to_prd(dev);
+
+	dev_dbg(dev, "platform_pm_runtime_resume()\n");
+
+	platform_pm_runtime_init(dev, prd);
+
+	if (prd && test_bit(BIT_ACTIVE, &prd->flags)) {
+		clk_enable(prd->clk);
+		set_bit(BIT_CLK_ENABLED, &prd->flags);
+	}
+
+	return 0;
+}
+
+int platform_pm_runtime_idle(struct device *dev)
+{
+	/* suspend synchronously to disable clocks immediately */
+	return pm_runtime_suspend(dev);
+}
+
+static int platform_bus_notify(struct notifier_block *nb,
+			       unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct pm_runtime_data *prd;
+
+	dev_dbg(dev, "platform_bus_notify() %ld !\n", action);
+
+	if (action == BUS_NOTIFY_BIND_DRIVER) {
+		prd = devres_alloc(__devres_release, sizeof(*prd), GFP_KERNEL);
+		if (prd)
+			devres_add(dev, prd);
+		else
+			dev_err(dev, "unable to alloc memory for runtime pm\n");
+	}
+
+	return 0;
+}
+
+#else /* CONFIG_PM_RUNTIME */
+
+static int platform_bus_notify(struct notifier_block *nb,
+			       unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct clk *clk;
+
+	dev_dbg(dev, "platform_bus_notify() %ld !\n", action);
+
+	switch (action) {
+	case BUS_NOTIFY_BIND_DRIVER:
+		clk = clk_get(dev, NULL);
+		if (!IS_ERR(clk)) {
+			clk_enable(clk);
+			clk_put(clk);
+			dev_info(dev, "runtime pm disabled, clock forced on\n");
+		}
+		break;
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		clk = clk_get(dev, NULL);
+		if (!IS_ERR(clk)) {
+			clk_disable(clk);
+			clk_put(clk);
+			dev_info(dev, "runtime pm disabled, clock forced off\n");
+		}
+		break;
+	}
+
+	return 0;
+}
+
+#endif /* CONFIG_PM_RUNTIME */
+
+static struct notifier_block platform_bus_notifier = {
+	.notifier_call = platform_bus_notify
+};
+
+static int __init sh_pm_runtime_init(void)
+{
+	bus_register_notifier(&platform_bus_type, &platform_bus_notifier);
+	return 0;
+}
+core_initcall(sh_pm_runtime_init);