[PATCH] sh: Simplistic clock framework

This adds a relatively simplistic clock framework for sh.  The initial goal
behind this is to clean up the arch/sh/kernel/time.c mess and to get the CPU
subtype-specific frequency setting and calculation code moved somewhere more
sensible.

This only deals with the core clocks at the moment, though it's trivial for
other drivers to define their own clocks as desired.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 287 insertions, 0 deletions

diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c
new file mode 100644
index 000000000000..989e7fdd524d
--- /dev/null
+++ b/arch/sh/kernel/cpu/clock.c
@@ -0,0 +1,287 @@
+/*
+ * arch/sh/kernel/cpu/clock.c - SuperH clock framework
+ *
+ *  Copyright (C) 2005  Paul Mundt
+ *
+ * This clock framework is derived from the OMAP version by:
+ *
+ *	Copyright (C) 2004 Nokia Corporation
+ *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/kref.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/clock.h>
+#include <asm/timer.h>
+
+static LIST_HEAD(clock_list);
+static DEFINE_SPINLOCK(clock_lock);
+static DECLARE_MUTEX(clock_list_sem);
+
+/*
+ * Each subtype is expected to define the init routines for these clocks,
+ * as each subtype (or processor family) will have these clocks at the
+ * very least. These are all provided through the CPG, which even some of
+ * the more quirky parts (such as ST40, SH4-202, etc.) still have.
+ *
+ * The processor-specific code is expected to register any additional
+ * clock sources that are of interest.
+ */
+static struct clk master_clk = {
+	.name		= "master_clk",
+	.flags		= CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+#ifdef CONFIG_SH_PCLK_FREQ_BOOL
+	.rate		= CONFIG_SH_PCLK_FREQ,
+#endif
+};
+
+static struct clk module_clk = {
+	.name		= "module_clk",
+	.parent		= &master_clk,
+	.flags		= CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+};
+
+static struct clk bus_clk = {
+	.name		= "bus_clk",
+	.parent		= &master_clk,
+	.flags		= CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+};
+
+static struct clk cpu_clk = {
+	.name		= "cpu_clk",
+	.parent		= &master_clk,
+	.flags		= CLK_ALWAYS_ENABLED,
+};
+
+/*
+ * The ordering of these clocks matters, do not change it.
+ */
+static struct clk *onchip_clocks[] = {
+	&master_clk,
+	&module_clk,
+	&bus_clk,
+	&cpu_clk,
+};
+
+static void propagate_rate(struct clk *clk)
+{
+	struct clk *clkp;
+
+	list_for_each_entry(clkp, &clock_list, node) {
+		if (likely(clkp->parent != clk))
+			continue;
+		if (likely(clkp->ops && clkp->ops->recalc))
+			clkp->ops->recalc(clkp);
+	}
+}
+
+int __clk_enable(struct clk *clk)
+{
+	/*
+	 * See if this is the first time we're enabling the clock, some
+	 * clocks that are always enabled still require "special"
+	 * initialization. This is especially true if the clock mode
+	 * changes and the clock needs to hunt for the proper set of
+	 * divisors to use before it can effectively recalc.
+	 */
+	if (unlikely(atomic_read(&clk->kref.refcount) == 1))
+		if (clk->ops && clk->ops->init)
+			clk->ops->init(clk);
+
+	if (clk->flags & CLK_ALWAYS_ENABLED)
+		return 0;
+
+	if (likely(clk->ops && clk->ops->enable))
+		clk->ops->enable(clk);
+
+	kref_get(&clk->kref);
+	return 0;
+}
+
+int clk_enable(struct clk *clk)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&clock_lock, flags);
+	ret = __clk_enable(clk);
+	spin_unlock_irqrestore(&clock_lock, flags);
+
+	return ret;
+}
+
+static void clk_kref_release(struct kref *kref)
+{
+	/* Nothing to do */
+}
+
+void __clk_disable(struct clk *clk)
+{
+	if (clk->flags & CLK_ALWAYS_ENABLED)
+		return;
+
+	kref_put(&clk->kref, clk_kref_release);
+}
+
+void clk_disable(struct clk *clk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&clock_lock, flags);
+	__clk_disable(clk);
+	spin_unlock_irqrestore(&clock_lock, flags);
+}
+
+int clk_register(struct clk *clk)
+{
+	down(&clock_list_sem);
+
+	list_add(&clk->node, &clock_list);
+	kref_init(&clk->kref);
+
+	up(&clock_list_sem);
+
+	return 0;
+}
+
+void clk_unregister(struct clk *clk)
+{
+	down(&clock_list_sem);
+	list_del(&clk->node);
+	up(&clock_list_sem);
+}
+
+inline unsigned long clk_get_rate(struct clk *clk)
+{
+	return clk->rate;
+}
+
+int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	int ret = -EOPNOTSUPP;
+
+	if (likely(clk->ops && clk->ops->set_rate)) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&clock_lock, flags);
+		ret = clk->ops->set_rate(clk, rate);
+		spin_unlock_irqrestore(&clock_lock, flags);
+	}
+
+	if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
+		propagate_rate(clk);
+
+	return ret;
+}
+
+void clk_recalc_rate(struct clk *clk)
+{
+	if (likely(clk->ops && clk->ops->recalc)) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&clock_lock, flags);
+		clk->ops->recalc(clk);
+		spin_unlock_irqrestore(&clock_lock, flags);
+	}
+
+	if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
+		propagate_rate(clk);
+}
+
+struct clk *clk_get(const char *id)
+{
+	struct clk *p, *clk = ERR_PTR(-ENOENT);
+
+	down(&clock_list_sem);
+	list_for_each_entry(p, &clock_list, node) {
+		if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
+			clk = p;
+			break;
+		}
+	}
+	up(&clock_list_sem);
+
+	return clk;
+}
+
+void clk_put(struct clk *clk)
+{
+	if (clk && !IS_ERR(clk))
+		module_put(clk->owner);
+}
+
+void __init __attribute__ ((weak))
+arch_init_clk_ops(struct clk_ops **ops, int type)
+{
+}
+
+int __init clk_init(void)
+{
+	int i, ret = 0;
+
+	if (unlikely(!master_clk.rate))
+		/*
+		 * NOTE: This will break if the default divisor has been
+		 * changed.
+		 *
+		 * No one should be changing the default on us however,
+		 * expect that a sane value for CONFIG_SH_PCLK_FREQ will
+		 * be defined in the event of a different divisor.
+		 */
+		master_clk.rate = get_timer_frequency() * 4;
+
+	for (i = 0; i < ARRAY_SIZE(onchip_clocks); i++) {
+		struct clk *clk = onchip_clocks[i];
+
+		arch_init_clk_ops(&clk->ops, i);
+		ret |= clk_register(clk);
+		clk_enable(clk);
+	}
+
+	/* Kick the child clocks.. */
+	propagate_rate(&master_clk);
+	propagate_rate(&bus_clk);
+
+	return ret;
+}
+
+int show_clocks(struct seq_file *m)
+{
+	struct clk *clk;
+
+	list_for_each_entry_reverse(clk, &clock_list, node) {
+		unsigned long rate = clk_get_rate(clk);
+
+		/*
+		 * Don't bother listing dummy clocks with no ancestry
+		 * that only support enable and disable ops.
+		 */
+		if (unlikely(!rate && !clk->parent))
+			continue;
+
+		seq_printf(m, "%-12s\t: %ld.%02ldMHz\n", clk->name,
+			   rate / 1000000, (rate % 1000000) / 10000);
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(clk_register);
+EXPORT_SYMBOL_GPL(clk_unregister);
+EXPORT_SYMBOL_GPL(clk_get);
+EXPORT_SYMBOL_GPL(clk_put);
+EXPORT_SYMBOL_GPL(clk_enable);
+EXPORT_SYMBOL_GPL(clk_disable);
+EXPORT_SYMBOL_GPL(__clk_enable);
+EXPORT_SYMBOL_GPL(__clk_disable);
+EXPORT_SYMBOL_GPL(clk_get_rate);
+EXPORT_SYMBOL_GPL(clk_set_rate);
+EXPORT_SYMBOL_GPL(clk_recalc_rate);