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Subject[PATCH 1/3] genclk: add generic framework for managing clocks.
Provide a generic framework that platform may choose
to support clocks api. In particular this provides
platform-independant struct clk definition, a full
implementation of clocks api and a set of functions
for registering and unregistering clocks in a safe way.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
---
include/linux/generic_clk.h | 72 +++++++++++
init/Kconfig | 3 +
kernel/Makefile | 2 +
kernel/genclk/Makefile | 2 +
kernel/genclk/genclk.c | 264 ++++++++++++++++++++++++++++++++++++++++
kernel/genclk/genclk.h | 21 +++
kernel/genclk/genclk_debugfs.c | 97 +++++++++++++++
7 files changed, 461 insertions(+), 0 deletions(-)
create mode 100644 include/linux/generic_clk.h
create mode 100644 kernel/genclk/Makefile
create mode 100644 kernel/genclk/genclk.c
create mode 100644 kernel/genclk/genclk.h
create mode 100644 kernel/genclk/genclk_debugfs.c

diff --git a/include/linux/generic_clk.h b/include/linux/generic_clk.h
new file mode 100644
index 0000000..c211966
--- /dev/null
+++ b/include/linux/generic_clk.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2008 Dmitry Baryshkov
+ *
+ * This file is released under the GPL v2.
+ */
+
+#ifndef GENERIC_CLK_H
+#define GENERIC_CLK_H
+
+#include <linux/spinlock.h>
+#include <linux/kref.h>
+
+struct clk;
+struct device;
+
+/**
+ * struct clk_ops - generic clock management operations
+ * @can_get: checks whether passed device can get this clock
+ * @set_parent: reconfigures the clock to use specified parent
+ * @set_mode: enable or disable specified clock
+ * @get_rate: obtain the current clock rate of a specified clock
+ * @set_rate: set the clock rate for a specified clock
+ * @round_rate: adjust a reate to the exact rate a clock can provide
+ *
+ * This structure specifies clock operations that are used to configure
+ * specific clock.
+ */
+struct clk_ops {
+ int (*can_get)(struct clk *clk, struct device *dev);
+ int (*set_parent)(struct clk *clk, struct clk *parent);
+ int (*enable)(struct clk *clk);
+ void (*disable)(struct clk *clk);
+ unsigned long (*get_rate)(struct clk *clk);
+ long (*round_rate)(struct clk *clk, unsigned long hz, bool apply);
+};
+
+/*
+ * This is a part of struct clk that is used by generic_clk core.
+ * Don't ever touch it.
+ */
+struct clk_priv {
+ struct list_head node;
+#ifdef CONFIG_DEBUG_SPINLOCK
+ struct lock_class_key lock_key;
+#endif
+ spinlock_t lock;
+ struct kref ref;
+ int usage;
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *info;
+#endif
+};
+
+struct clk {
+ const char *name;
+ struct clk *parent;
+ struct clk_ops *ops;
+ void (*release)(struct clk *clk);
+
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *dir;
+#endif
+
+ struct clk_priv priv;
+};
+
+int clk_register(struct clk *clk);
+void clk_unregister(struct clk *clk);
+int clks_register(struct clk **clk, size_t num);
+void clks_unregister(struct clk **clk, size_t num);
+
+#endif
diff --git a/init/Kconfig b/init/Kconfig
index 6199d11..2b016ce 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -800,6 +800,9 @@ config PROC_PAGE_MONITOR
/proc/kpagecount, and /proc/kpageflags. Disabling these
interfaces will reduce the size of the kernel by approximately 4kb.

+config HAVE_GENERIC_CLOCKS
+ bool
+
endmenu # General setup

config SLABINFO
diff --git a/kernel/Makefile b/kernel/Makefile
index 1c9938a..3d9aa05 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -70,6 +70,8 @@ obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
obj-$(CONFIG_MARKERS) += marker.o
obj-$(CONFIG_LATENCYTOP) += latencytop.o

+obj-$(CONFIG_HAVE_GENERIC_CLOCKS) += genclk/
+
ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
# needed for x86 only. Why this used to be enabled for all architectures is beyond
diff --git a/kernel/genclk/Makefile b/kernel/genclk/Makefile
new file mode 100644
index 0000000..39df420
--- /dev/null
+++ b/kernel/genclk/Makefile
@@ -0,0 +1,2 @@
+obj-y := genclk.o
+obj-$(CONFIG_DEBUG_FS) += genclk_debugfs.o
diff --git a/kernel/genclk/genclk.c b/kernel/genclk/genclk.c
new file mode 100644
index 0000000..c76ab49
--- /dev/null
+++ b/kernel/genclk/genclk.c
@@ -0,0 +1,264 @@
+/*
+ * Generic clocks API implementation
+ *
+ * Copyright (c) 2008 Dmitry Baryshkov
+ *
+ * This file is released under the GPL v2.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/generic_clk.h>
+#include <linux/spinlock.h>
+
+#include "genclk.h"
+
+LIST_HEAD(clocks);
+DEFINE_SPINLOCK(clocks_lock);
+
+static int clk_can_get_def(struct clk *clk, struct device *dev)
+{
+ return 1;
+}
+
+static unsigned long clk_get_rate_def(struct clk *clk)
+{
+ return 0;
+}
+
+static long clk_round_rate_def(struct clk *clk, unsigned long hz, bool apply)
+{
+ long rate = clk->ops->get_rate(clk);
+
+ if (apply && hz != rate)
+ return -EINVAL;
+
+ return rate;
+}
+
+static void clk_release(struct kref *ref)
+{
+ struct clk *clk = container_of(ref, struct clk, priv.ref);
+
+ BUG_ON(!clk->release);
+
+ if (clk->parent)
+ kref_get(&clk->parent->priv.ref);
+
+ clk->release(clk);
+}
+EXPORT_SYMBOL(clk_round_rate);
+
+struct clk* clk_get_parent(struct clk *clk)
+{
+ struct clk *parent;
+
+ spin_lock(&clk->priv.lock);
+
+ parent = clk->parent;
+ kref_get(&parent->priv.ref);
+
+ spin_unlock(&clk->priv.lock);
+
+ return parent;
+}
+EXPORT_SYMBOL(clk_get_parent);
+
+int clk_set_parent(struct clk *clk, struct clk *parent)
+{
+ int rc = -EINVAL;
+ struct clk *old;
+
+ spin_lock(&clk->priv.lock);
+
+ if (!clk->ops->set_parent)
+ goto out;
+
+ old = clk->parent;
+
+ rc = clk->ops->set_parent(clk, parent);
+ if (rc)
+ goto out;
+
+ kref_get(&parent->priv.ref);
+ clk->parent = parent;
+
+ clk_debugfs_reparent(clk, old, parent);
+
+ kref_put(&old->priv.ref, clk_release);
+
+out:
+ spin_unlock(&clk->priv.lock);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_set_parent);
+
+int clk_register(struct clk *clk)
+{
+ int rc;
+
+ BUG_ON(!clk->ops);
+ BUG_ON(!clk->ops->enable || !clk->ops->disable);
+
+ if (!clk->ops->can_get)
+ clk->ops->can_get = clk_can_get_def;
+ if (!clk->ops->get_rate)
+ clk->ops->get_rate = clk_get_rate_def;
+ if (!clk->ops->round_rate)
+ clk->ops->round_rate = clk_round_rate_def;
+
+ kref_init(&clk->priv.ref);
+#ifdef CONFIG_DEBUG_SPINLOCK
+ __spin_lock_init(&clk->priv.lock, "&clk->priv.lock", &clk->priv.lock_key);
+#else
+ spin_lock_init(&clk->priv.lock);
+#endif
+
+ spin_lock(&clocks_lock);
+ if (clk->parent)
+ kref_get(&clk->parent->priv.ref);
+ list_add_tail(&clk->priv.node, &clocks);
+
+ rc = clk_debugfs_init(clk);
+ if (rc) {
+ list_del(&clk->priv.node);
+ kref_put(&clk->priv.ref, clk_release);
+ }
+
+ spin_unlock(&clocks_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(clk_register);
+
+void clk_unregister(struct clk *clk)
+{
+ spin_lock(&clocks_lock);
+ clk_debugfs_clean(clk);
+ list_del(&clk->priv.node);
+ kref_put(&clk->priv.ref, clk_release);
+ spin_unlock(&clocks_lock);
+}
+EXPORT_SYMBOL(clk_unregister);
+
+int clks_register(struct clk **clk, size_t num)
+{
+ int i;
+ int rc;
+ for (i = 0; i < num; i++) {
+ rc = clk_register(clk[i]);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(clks_register);
+
+void clks_unregister(struct clk **clk, size_t num)
+{
+ int i;
+ for (i = 0; i < num; i++)
+ clk_unregister(clk[i]);
+}
+EXPORT_SYMBOL(clks_unregister);
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+ struct clk *clk = NULL, *p;
+
+ spin_lock(&clocks_lock);
+ list_for_each_entry(p, &clocks, priv.node)
+ if (strcmp(id, p->name) == 0 && p->ops->can_get(p, dev)) {
+ clk = p;
+ kref_get(&clk->priv.ref);
+ break;
+ }
+
+ spin_unlock(&clocks_lock);
+
+ return clk;
+}
+EXPORT_SYMBOL(clk_get);
+
+void clk_put(struct clk *clk)
+{
+ kref_put(&clk->priv.ref, clk_release);
+}
+EXPORT_SYMBOL(clk_put);
+
+int clk_enable(struct clk *clk)
+{
+ int rc = 0;
+
+ spin_lock(&clk->priv.lock);
+
+ clk->priv.usage++;
+ if (clk->priv.usage == 1)
+ rc = clk->ops->enable(clk);
+
+ if (rc)
+ clk->priv.usage--;
+
+ spin_unlock(&clk->priv.lock);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_enable);
+
+void clk_disable(struct clk *clk)
+{
+ spin_lock(&clk->priv.lock);
+
+ WARN_ON(clk->priv.usage <= 0);
+
+ clk->priv.usage--;
+ if (clk->priv.usage == 0)
+ clk->ops->disable(clk);
+
+ spin_unlock(&clk->priv.lock);
+}
+EXPORT_SYMBOL(clk_disable);
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+ unsigned long hz;
+
+ spin_lock(&clk->priv.lock);
+
+ hz = clk->ops->get_rate(clk);
+
+ spin_unlock(&clk->priv.lock);
+
+ return hz;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+int clk_set_rate(struct clk *clk, unsigned long hz)
+{
+ long rc;
+
+ spin_lock(&clk->priv.lock);
+
+ rc = clk->ops->round_rate(clk, hz, 1);
+
+ spin_unlock(&clk->priv.lock);
+
+ return rc < 0 ? rc : 0;
+}
+EXPORT_SYMBOL(clk_set_rate);
+
+long clk_round_rate(struct clk *clk, unsigned long hz)
+{
+ long rc;
+
+ spin_lock(&clk->priv.lock);
+
+ rc = clk->ops->round_rate(clk, hz, 0);
+
+ spin_unlock(&clk->priv.lock);
+
+ return rc;
+}
+
diff --git a/kernel/genclk/genclk.h b/kernel/genclk/genclk.h
new file mode 100644
index 0000000..5b8d12c
--- /dev/null
+++ b/kernel/genclk/genclk.h
@@ -0,0 +1,21 @@
+#ifndef GENCLK_H
+#define GENCLK_H
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+
+extern struct list_head clocks;
+extern spinlock_t clocks_lock;
+
+#ifdef CONFIG_DEBUG_FS
+int clk_debugfs_init(struct clk *clk);
+void clk_debugfs_clean(struct clk *clk);
+void clk_debugfs_reparent(struct clk *clk, struct clk *old, struct clk *new);
+#else
+#define clk_debugfs_init(clk) ({0;})
+#define clk_debugfs_clean(clk) do {} while (0);
+#define clk_debugfs_reparent(clk, old, new) do {} while (0);
+#endif
+
+
+#endif
diff --git a/kernel/genclk/genclk_debugfs.c b/kernel/genclk/genclk_debugfs.c
new file mode 100644
index 0000000..b8acd38
--- /dev/null
+++ b/kernel/genclk/genclk_debugfs.c
@@ -0,0 +1,97 @@
+/*
+ * Generic clocks API implementation
+ *
+ * Copyright (c) 2008 Dmitry Baryshkov
+ *
+ * This file is released under the GPL v2.
+ */
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/clk.h>
+#include <linux/generic_clk.h>
+
+#include "genclk.h"
+
+static struct dentry *clkdir;
+
+static int genclk_show(struct seq_file *s, void *data)
+{
+ struct clk *clk = s->private;
+
+ BUG_ON(!clk);
+
+ seq_printf(s, "set_parent=%savailable\nusage=%d/%d\nrate=%10lu Hz\n",
+ clk->ops && clk->ops->set_parent ? "" : "not ",
+ clk->priv.usage, atomic_read(&clk->priv.ref.refcount),
+ clk_get_rate(clk));
+
+ return 0;
+}
+
+static int genclk_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, genclk_show, inode->i_private);
+}
+
+static struct file_operations genclk_operations = {
+ .open = genclk_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+int clk_debugfs_init(struct clk *clk)
+{
+ struct dentry *dir;
+ struct dentry *info;
+
+ /*
+ * We initialise it here, because this call can be executed from within arch code,
+ * so specifyint correct initialisation place is a bit tricky
+ */
+ if (!clkdir)
+ clkdir = debugfs_create_dir("clocks", NULL);
+
+ dir = debugfs_create_dir(clk->name,
+ clk->parent ? clk->parent->dir : clkdir);
+
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ info = debugfs_create_file("info", S_IFREG | S_IRUGO,
+ dir, clk, &genclk_operations);
+
+ if (IS_ERR(info)) {
+ debugfs_remove(dir);
+ return PTR_ERR(info);
+ }
+
+ clk->dir = dir;
+ clk->priv.info = info;
+
+ return 0;
+}
+
+void clk_debugfs_clean(struct clk *clk)
+{
+ if (clk->priv.info)
+ debugfs_remove(clk->priv.info);
+ clk->priv.info = NULL;
+
+ if (clk->dir)
+ debugfs_remove(clk->dir);
+ clk->dir = NULL;
+}
+
+void clk_debugfs_reparent(struct clk *clk, struct clk *old, struct clk *new)
+{
+ struct dentry *oldd = old ? old->dir : clkdir;
+ struct dentry *newd = new ? new->dir : clkdir;
+ struct dentry *dir = debugfs_rename(oldd, clk->dir, newd, clk->name);
+
+ if (IS_ERR(dir))
+ WARN_ON(1);
+ else
+ clk->dir = dir;
+}
+
--
1.5.6

--
With best wishes
Dmitry



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