clockdomains: add base OMAP2/3 clockdomain code

This patch creates an interface to the clockdomain registers in the
PRM/CM modules on OMAP2/3.  This interface is intended to be used by
PM code, e.g., pm.c; not by device drivers directly.

The patch also adds clockdomain usecount tracking.  This is intended
to be called whenever the first clock in a clockdomain is enabled, or
when the last enabled clock in a clockdomain is disabled.  If the
clockdomain is in software-supervised mode, the code will force-wakeup
or force-sleep the clockdomain.  If the clockdomain is in
hardware-supervised mode, the first clock enable will add sleep and
wakeup dependencies on a user-selectable set of parent domains (usually
MPU & IVA2), and the disable will remove them.

Each clockdomain will be defined in later patches as static
structures.  The clockdomain structures are linked into a list at boot
by clkdm_register(), similar to the OMAP clock code.

The patch adds a Kconfig option, CONFIG_OMAP_DEBUG_CLOCKDOMAIN, which
when enabled will emit verbose debug messages via pr_debug().
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/Makefile

@@ -4,7 +4,8 @@
 
 # Common support
 obj-y := irq.o id.o io.o memory.o control.o prcm.o clock.o mux.o \
-		devices.o serial.o gpmc.o timer-gp.o powerdomain.o
+		devices.o serial.o gpmc.o timer-gp.o powerdomain.o \
+		clockdomain.o
 
 # Functions loaded to SRAM
 obj-$(CONFIG_ARCH_OMAP2)		+= sram24xx.o

arch/arm/plat-omap/Kconfig

@@ -54,6 +54,18 @@ config OMAP_DEBUG_POWERDOMAIN
 	  for every powerdomain register write.  However, the
 	  extra detail costs some memory.
 
+config OMAP_DEBUG_CLOCKDOMAIN
+	bool "Emit debug messages from clockdomain layer"
+	depends on ARCH_OMAP2 || ARCH_OMAP3
+	default n
+	help
+	  Say Y here if you want to compile in clockdomain layer
+	  debugging messages for OMAP2/3.   These messages can
+	  provide more detail as to why some clockdomain calls
+	  may be failing, and will also emit a descriptive message
+	  for every clockdomain register write.  However, the
+	  extra detail costs some memory.
+
 config OMAP_RESET_CLOCKS
 	bool "Reset unused clocks during boot"
 	depends on ARCH_OMAP

include/asm-arm/arch-omap/clockdomain.h

+/*
+ * linux/include/asm-arm/arch-omap/clockdomain.h
+ *
+ * OMAP2/3 clockdomain framework functions
+ *
+ * Copyright (C) 2008 Texas Instruments, Inc.
+ * Copyright (C) 2008 Nokia Corporation
+ *
+ * Written by Paul Walmsley
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_ARM_ARCH_OMAP_CLOCKDOMAIN_H
+#define __ASM_ARM_ARCH_OMAP_CLOCKDOMAIN_H
+
+#include <asm/arch/powerdomain.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/cpu.h>
+
+/* Clockdomain capability flags */
+#define CLKDM_CAN_FORCE_SLEEP			(1 << 0)
+#define CLKDM_CAN_FORCE_WAKEUP			(1 << 1)
+#define CLKDM_CAN_ENABLE_AUTO			(1 << 2)
+#define CLKDM_CAN_DISABLE_AUTO			(1 << 3)
+
+#define CLKDM_CAN_HWSUP		(CLKDM_CAN_ENABLE_AUTO | CLKDM_CAN_DISABLE_AUTO)
+#define CLKDM_CAN_SWSUP		(CLKDM_CAN_FORCE_SLEEP | CLKDM_CAN_FORCE_WAKEUP)
+#define CLKDM_CAN_HWSUP_SWSUP	(CLKDM_CAN_SWSUP | CLKDM_CAN_HWSUP)
+
+/* OMAP24XX CM_CLKSTCTRL_*.AUTOSTATE_* register bit values */
+#define OMAP24XX_CLKSTCTRL_DISABLE_AUTO		0x0
+#define OMAP24XX_CLKSTCTRL_ENABLE_AUTO		0x1
+
+/* OMAP3XXX CM_CLKSTCTRL_*.CLKTRCTRL_* register bit values */
+#define OMAP34XX_CLKSTCTRL_DISABLE_AUTO		0x0
+#define OMAP34XX_CLKSTCTRL_FORCE_SLEEP		0x1
+#define OMAP34XX_CLKSTCTRL_FORCE_WAKEUP		0x2
+#define OMAP34XX_CLKSTCTRL_ENABLE_AUTO		0x3
+
+/*
+ * struct clkdm_pwrdm_autodep - a powerdomain that should have wkdeps
+ * and sleepdeps added when a powerdomain should stay active in hwsup mode;
+ * and conversely, removed when the powerdomain should be allowed to go
+ * inactive in hwsup mode.
+ */
+struct clkdm_pwrdm_autodep {
+
+	/* Name of the powerdomain to add a wkdep/sleepdep on */
+	const char *pwrdm_name;
+
+	/* Powerdomain pointer (looked up at clkdm_init() time) */
+	struct powerdomain *pwrdm;
+
+	/* OMAP chip types that this clockdomain dep is valid on */
+	const struct omap_chip_id omap_chip;
+
+};
+
+struct clockdomain {
+
+	/* Clockdomain name */
+	const char *name;
+
+	/* Powerdomain enclosing this clockdomain */
+	const char *pwrdm_name;
+
+	/* CLKTRCTRL/AUTOSTATE field mask in CM_CLKSTCTRL reg */
+	const u16 clktrctrl_mask;
+
+	/* Clockdomain capability flags */
+	const u8 flags;
+
+	/* OMAP chip types that this clockdomain is valid on */
+	const struct omap_chip_id omap_chip;
+
+	/* Usecount tracking */
+	atomic_t usecount;
+
+	/* Powerdomain pointer assigned at clkdm_register() */
+	struct powerdomain *pwrdm;
+
+	struct list_head node;
+
+};
+
+void clkdm_init(struct clockdomain **clkdms, struct clkdm_pwrdm_autodep *autodeps);
+int clkdm_register(struct clockdomain *clkdm);
+int clkdm_unregister(struct clockdomain *clkdm);
+struct clockdomain *clkdm_lookup(const char *name);
+
+void omap2_clkdm_allow_idle(struct clockdomain *clkdm);
+void omap2_clkdm_deny_idle(struct clockdomain *clkdm);
+
+int omap2_clkdm_wakeup(struct clockdomain *clkdm);
+int omap2_clkdm_sleep(struct clockdomain *clkdm);
+
+int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk);
+int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk);
+
+int clkdm_for_each(int (*fn)(struct clockdomain *clkdm));
+
+#endif