ARM: mach-shmobile: Runtime PM prototype

From: Magnus Damm <[email protected]>

This is a simple prototype that enables Runtime PM on SH-Mobile ARM processors. Only clocks are managed at this point. Needs more work, especially WRT the shared ARM bits.

Signed-off-by Magnus Damm <[email protected]>

---

 arch/arm/include/asm/device.h         |    3 
 arch/arm/mach-shmobile/Kconfig        |    2 
 arch/arm/mach-shmobile/Makefile       |    2 
 arch/arm/mach-shmobile/clock-sh7372.c |    2 
 arch/arm/mach-shmobile/pm_runtime.c   |  109 +++++++++++++++++++++++++++++++++
 5 files changed, 116 insertions(+), 2 deletions(-)

arch/arm/include/asm/device.h +3 -0

@@ -13,6 +13,9 @@ struct dev_archdata {
 };
 
 struct pdev_archdata {
+#ifdef CONFIG_ARCH_SHMOBILE
+	struct clk *clk;
+#endif
 };
 
 #endif

arch/arm/mach-shmobile/Kconfig +2 -0

@@ -25,6 +25,8 @@ config ARCH_SH7372
 	select COMMON_CLKDEV
 	select SH_CLK_CPG
 	select GENERIC_CLOCKEVENTS
+	select PM
+	select PM_RUNTIME
 
 comment "SH-Mobile Board Type"
 

arch/arm/mach-shmobile/Makefile +1 -1

@@ -3,7 +3,7 @@
 #
 
 # Common objects
-obj-y				:= timer.o console.o clock.o
+obj-y				:= timer.o console.o clock.o pm_runtime.o
 
 # CPU objects
 obj-$(CONFIG_ARCH_SH7367)	+= setup-sh7367.o clock-sh7367.o intc-sh7367.o

arch/arm/mach-shmobile/clock-sh7372.c +1 -1

@@ -274,7 +274,7 @@ static struct clk mstp_clks[MSTP_NR] = {
 	[MSTP201] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR2, 1, 0), /* SCIFA3 */
 	[MSTP200] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR2, 0, 0), /* SCIFA4 */
 	[MSTP329] = MSTP(&r_clk, SMSTPCR3, 29, 0), /* CMT10 */
-	[MSTP328] = MSTP(&div6_clks[DIV6_SPU], SMSTPCR3, 28, CLK_ENABLE_ON_INIT), /* FSIA */
+	[MSTP328] = MSTP(&div6_clks[DIV6_SPU], SMSTPCR3, 28, 0), /* FSIA */
 	[MSTP323] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR3, 23, 0), /* IIC1 */
 	[MSTP322] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR3, 22, 0), /* USB0 */
 	[MSTP314] = MSTP(&div4_clks[DIV4_HP], SMSTPCR3, 14, 0), /* SDHI0 */

arch/arm/mach-shmobile/pm_runtime.c new file +109 -1

@@ -0,0 +1,109 @@
+/*
+ * 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.
+ */
+//#define DEBUG
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/clk.h>
+#include <linux/sh_clk.h>
+
+static struct clk uninitialized_clock;
+
+static void platform_pm_init_once(struct platform_device *pdev)
+{
+	if (pdev->archdata.clk = &uninitialized_clock) {
+		pdev->archdata.clk = clk_get(&pdev->dev, NULL);
+		dev_info(&pdev->dev, "clocks managed by runtime pm\n");
+	}
+}
+
+static void platform_pm_init_bug(struct platform_device *pdev)
+{
+	if (pdev->archdata.clk = &uninitialized_clock) {
+		pdev->archdata.clk = NULL;
+		dev_info(&pdev->dev, "incorrect runtime pm usage\n");
+	}
+}
+
+int platform_pm_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	dev_dbg(dev, "platform_pm_runtime_suspend()\n");
+
+	platform_pm_init_bug(pdev);
+
+	if (pdev->archdata.clk)
+		clk_disable(pdev->archdata.clk);
+
+	return 0;
+}
+
+int platform_pm_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	dev_dbg(dev, "platform_pm_runtime_resume()\n");
+
+	platform_pm_init_once(pdev);
+
+	if (pdev->archdata.clk)
+		clk_enable(pdev->archdata.clk);
+
+	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 platform_device *pdev = to_platform_device(dev);
+
+	dev_dbg(dev, "platform_bus_notify() %ld !\n", action);
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		pdev->archdata.clk = &uninitialized_clock;
+
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+		if (pdev->archdata.clk &&
+		    pdev->archdata.clk != &uninitialized_clock)
+			clk_put(pdev->archdata.clk);
+
+		pdev->archdata.clk = NULL;
+		break;
+	}
+
+
+	return 0;
+}
+
+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);
--

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Quoted 8 lines · Magnus Damm

From: Magnus Damm <[email protected]>

This is a simple prototype that enables Runtime PM on SH-Mobile ARM processors. Only clocks are managed at this point. Needs more work, especially WRT the shared ARM bits.

Signed-off-by Magnus Damm <[email protected]>

I think, something like this is needed on top of your patch:

+       if (dev->driver && dev->driver->pm && dev->driver->pm->runtime_suspend)
+               ret = dev->driver->pm->runtime_suspend(dev);
+       else
+               ret = 0;

+       if (dev->driver && dev->driver->pm && dev->driver->pm->runtime_resume)
+               ret = dev->driver->pm->runtime_resume(dev);
+       else
+               ret = 0;

I.e., you also have to call driver runtime-pm methofs, similarly to how it is done on SuperH. Otherwise, e.g., lcdcfb doesn't work.