ARM: Add the clock framework for Telechips TCC8xxx processors.

This adds definitions and low-level functions to handle clocks in
TCC8xxx processors.

Signed-off-by: "Hans J. Koch" <hjk@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 256 insertions, 11 deletions

diff --git a/arch/arm/plat-tcc/Makefile b/arch/arm/plat-tcc/Makefile
index 3f2e4fe70d5..eceabc869b8 100644
--- a/arch/arm/plat-tcc/Makefile
+++ b/arch/arm/plat-tcc/Makefile
@@ -1,3 +1,3 @@
 # "Telechips Platform Common Modules"
 
-obj-y := system.o
+obj-y := clock.o system.o
diff --git a/arch/arm/plat-tcc/clock.c b/arch/arm/plat-tcc/clock.c
new file mode 100644
index 00000000000..f3ced10d527
--- /dev/null
+++ b/arch/arm/plat-tcc/clock.c
@@ -0,0 +1,179 @@
+/*
+ * Clock framework for Telechips SoCs
+ * Based on arch/arm/plat-mxc/clock.c
+ *
+ * Copyright (C) 2004 - 2005 Nokia corporation
+ * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
+ * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
+ * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ * Copyright 2010 Hans J. Koch, hjk@linutronix.de
+ *
+ * Licensed under the terms of the GPL v2.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+
+#include <mach/clock.h>
+#include <mach/hardware.h>
+
+static DEFINE_MUTEX(clocks_mutex);
+
+/*-------------------------------------------------------------------------
+ * Standard clock functions defined in include/linux/clk.h
+ *-------------------------------------------------------------------------*/
+
+static void __clk_disable(struct clk *clk)
+{
+	BUG_ON(clk->refcount == 0);
+
+	if (!(--clk->refcount) && clk->disable) {
+		/* Unconditionally disable the clock in hardware */
+		clk->disable(clk);
+		/* recursively disable parents */
+		if (clk->parent)
+			__clk_disable(clk->parent);
+	}
+}
+
+static int __clk_enable(struct clk *clk)
+{
+	int ret = 0;
+
+	if (clk->refcount++ == 0 && clk->enable) {
+		if (clk->parent)
+			ret = __clk_enable(clk->parent);
+		if (ret)
+			return ret;
+		else
+			return clk->enable(clk);
+	}
+
+	return 0;
+}
+
+/* This function increments the reference count on the clock and enables the
+ * clock if not already enabled. The parent clock tree is recursively enabled
+ */
+int clk_enable(struct clk *clk)
+{
+	int ret = 0;
+
+	if (!clk)
+		return -EINVAL;
+
+	mutex_lock(&clocks_mutex);
+	ret = __clk_enable(clk);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_enable);
+
+/* This function decrements the reference count on the clock and disables
+ * the clock when reference count is 0. The parent clock tree is
+ * recursively disabled
+ */
+void clk_disable(struct clk *clk)
+{
+	if (!clk)
+		return;
+
+	mutex_lock(&clocks_mutex);
+	__clk_disable(clk);
+	mutex_unlock(&clocks_mutex);
+}
+EXPORT_SYMBOL_GPL(clk_disable);
+
+/* Retrieve the *current* clock rate. If the clock itself
+ * does not provide a special calculation routine, ask
+ * its parent and so on, until one is able to return
+ * a valid clock rate
+ */
+unsigned long clk_get_rate(struct clk *clk)
+{
+	if (!clk)
+		return 0UL;
+
+	if (clk->get_rate)
+		return clk->get_rate(clk);
+
+	return clk_get_rate(clk->parent);
+}
+EXPORT_SYMBOL_GPL(clk_get_rate);
+
+/* Round the requested clock rate to the nearest supported
+ * rate that is less than or equal to the requested rate.
+ * This is dependent on the clock's current parent.
+ */
+long clk_round_rate(struct clk *clk, unsigned long rate)
+{
+	if (!clk)
+		return 0;
+	if (!clk->round_rate)
+		return 0;
+
+	return clk->round_rate(clk, rate);
+}
+EXPORT_SYMBOL_GPL(clk_round_rate);
+
+/* Set the clock to the requested clock rate. The rate must
+ * match a supported rate exactly based on what clk_round_rate returns
+ */
+int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	int ret = -EINVAL;
+
+	if (!clk)
+		return ret;
+	if (!clk->set_rate || !rate)
+		return ret;
+
+	mutex_lock(&clocks_mutex);
+	ret = clk->set_rate(clk, rate);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_set_rate);
+
+/* Set the clock's parent to another clock source */
+int clk_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct clk *old;
+	int ret = -EINVAL;
+
+	if (!clk)
+		return ret;
+	if (!clk->set_parent || !parent)
+		return ret;
+
+	mutex_lock(&clocks_mutex);
+	old = clk->parent;
+	if (clk->refcount)
+		__clk_enable(parent);
+	ret = clk->set_parent(clk, parent);
+	if (ret)
+		old = parent;
+	if (clk->refcount)
+		__clk_disable(old);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_set_parent);
+
+/* Retrieve the clock's parent clock source */
+struct clk *clk_get_parent(struct clk *clk)
+{
+	if (!clk)
+		return NULL;
+
+	return clk->parent;
+}
+EXPORT_SYMBOL_GPL(clk_get_parent);
diff --git a/arch/arm/plat-tcc/include/mach/clkdev.h b/arch/arm/plat-tcc/include/mach/clkdev.h
new file mode 100644
index 00000000000..04b37a89801
--- /dev/null
+++ b/arch/arm/plat-tcc/include/mach/clkdev.h
@@ -0,0 +1,7 @@
+#ifndef __ASM_MACH_CLKDEV_H
+#define __ASM_MACH_CLKDEV_H
+
+#define __clk_get(clk) ({ 1; })
+#define __clk_put(clk) do { } while (0)
+
+#endif
diff --git a/arch/arm/plat-tcc/include/mach/clock.h b/arch/arm/plat-tcc/include/mach/clock.h
new file mode 100644
index 00000000000..a12f58ad71a
--- /dev/null
+++ b/arch/arm/plat-tcc/include/mach/clock.h
@@ -0,0 +1,48 @@
+/*
+ * Low level clock header file for Telechips TCC architecture
+ * (C) 2010 Hans J. Koch <hjk@linutronix.de>
+ *
+ * Licensed under the GPL v2.
+ */
+
+#ifndef __ASM_ARCH_TCC_CLOCK_H__
+#define __ASM_ARCH_TCC_CLOCK_H__
+
+#ifndef __ASSEMBLY__
+
+struct clk {
+	struct clk *parent;
+	/* id number of a root clock, 0 for normal clocks */
+	int root_id;
+	/* Reference count of clock enable/disable */
+	int refcount;
+	/* Address of associated BCLKCTRx register. Must be set. */
+	void __iomem *bclkctr;
+	/* Bit position for BCLKCTRx. Must be set. */
+	int bclk_shift;
+	/* Address of ACLKxxx register, if any. */
+	void __iomem *aclkreg;
+	/* get the current clock rate (always a fresh value) */
+	unsigned long (*get_rate) (struct clk *);
+	/* Function ptr to set the clock to a new rate. The rate must match a
+	   supported rate returned from round_rate. Leave blank if clock is not
+	   programmable */
+	int (*set_rate) (struct clk *, unsigned long);
+	/* Function ptr to round the requested clock rate to the nearest
+	   supported rate that is less than or equal to the requested rate. */
+	unsigned long (*round_rate) (struct clk *, unsigned long);
+	/* Function ptr to enable the clock. Leave blank if clock can not
+	   be gated. */
+	int (*enable) (struct clk *);
+	/* Function ptr to disable the clock. Leave blank if clock can not
+	   be gated. */
+	void (*disable) (struct clk *);
+	/* Function ptr to set the parent clock of the clock. */
+	int (*set_parent) (struct clk *, struct clk *);
+};
+
+int clk_register(struct clk *clk);
+void clk_unregister(struct clk *clk);
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_ARCH_MXC_CLOCK_H__ */
diff --git a/arch/arm/plat-tcc/include/mach/tcc8k-regs.h b/arch/arm/plat-tcc/include/mach/tcc8k-regs.h
index f3243ebea46..1d942829533 100644
--- a/arch/arm/plat-tcc/include/mach/tcc8k-regs.h
+++ b/arch/arm/plat-tcc/include/mach/tcc8k-regs.h
@@ -30,13 +30,13 @@
 #define EXT_MEM_CTRL_BASE	0xf0000000
 #define EXT_MEM_CTRL_SIZE	SZ_4K
 
-#define CS1_BASE_VIRT		0xf7000000
-#define AHB_PERI_BASE_VIRT	0xf4000000
-#define APB0_PERI_BASE_VIRT	0xf1000000
-#define APB1_PERI_BASE_VIRT	0xf2000000
-#define EXT_MEM_CTRL_BASE_VIRT	0xf3000000
-#define INT_SRAM_BASE_VIRT	0xf5000000
-#define DATA_TCM_BASE_VIRT	0xf6000000
+#define CS1_BASE_VIRT		(void __iomem *)0xf7000000
+#define AHB_PERI_BASE_VIRT	(void __iomem *)0xf4000000
+#define APB0_PERI_BASE_VIRT	(void __iomem *)0xf1000000
+#define APB1_PERI_BASE_VIRT	(void __iomem *)0xf2000000
+#define EXT_MEM_CTRL_BASE_VIRT	(void __iomem *)0xf3000000
+#define INT_SRAM_BASE_VIRT	(void __iomem *)0xf5000000
+#define DATA_TCM_BASE_VIRT	(void __iomem *)0xf6000000
 
 #define __REG(x)     (*((volatile u32 *)(x)))
 
@@ -649,8 +649,7 @@
 #define PMGPIO_APB_OFFS		0x800
 
 /* Clock controller registers */
-#define CKC_BASE		(APB1_PERI_BASE_VIRT + 0x6000)
-#define CKC_BASE_PHYS		(APB1_PERI_BASE + 0x6000)
+#define CKC_BASE	((void __iomem *)(APB1_PERI_BASE_VIRT + 0x6000))
 
 #define CLKCTRL_OFFS		0x00
 #define PLL0CFG_OFFS		0x04
@@ -724,8 +723,20 @@
 /* SWRESET1 bits */
 #define SWRESET1_USBH1		(1 << 20)
 
-/* System clock sources */
+/* System clock sources.
+ * Note: These are the clock sources that serve as parents for
+ * all other clocks. They have no parents themselves.
+ *
+ * These values are used for struct clk->root_id. All clocks
+ * that are not system clock sources have this value set to
+ * CLK_SRC_NOROOT.
+ * The values for system clocks start with CLK_SRC_PLL0 == 0
+ * because this gives us exactly the values needed for the lower
+ * 4 bits of ACLK_* registers. Therefore, CLK_SRC_NOROOT is
+ * defined as -1 to not disturb the order.
+ */
 enum root_clks {
+	CLK_SRC_NOROOT = -1,
 	CLK_SRC_PLL0 = 0,
 	CLK_SRC_PLL1,
 	CLK_SRC_PLL0DIV,