[U-Boot] [PATCH v12 2/8] arm: add legacy linux clock framework support

[Kuo-Jung Su]

From: Kuo-Jung Su <dantesu at faraday-tech.com>

This ports the legacy linux clock framework from linux-3.10
(i.e., no common clock support)

Please check the list bellow for details:

1. CONFIG_CLKDEV_LOOKUP
   - Core clock management APIs
   - clk_get_sys(), clk_put(), clkdev_add(), clkdev_add_table()
     clkdev_alloc(), clkdev_drop(), clk_register_clkdev(),
     clk_register_clkdevs()

2. CONFIG_HAVE_MACH_CLKDEV (CONFIG_HAVE_ARCH_CLKDEV in U-Boot)
   - Use this to have machine specific structs & defines
     included in asm/clkdev.h

3. CONFIG_HAVE_CLK_PREPARE
   - This prepares the clock source for use
   - clk_prepare(), clk_unprepare()

Signed-off-by: Kuo-Jung Su <dantesu at faraday-tech.com>
CC: Albert Aribaud <albert.u.boot at aribaud.net>
CC: Wolfgang Denk <wd at denx.de>
---
Changes for v12:
	- Initial commit

 arch/arm/include/asm/clkdev.h |   29 ++++++
 drivers/Makefile              |    1 +
 drivers/clk/Makefile          |    8 ++
 drivers/clk/clkdev.c          |  207 +++++++++++++++++++++++++++++++++++++++++
 include/linux/clk.h           |  181 +++++++++++++++++++++++++++++++++++
 include/linux/clkdev.h        |   45 +++++++++
 6 files changed, 471 insertions(+)
 create mode 100644 arch/arm/include/asm/clkdev.h
 create mode 100644 drivers/clk/Makefile
 create mode 100644 drivers/clk/clkdev.c
 create mode 100644 include/linux/clk.h
 create mode 100644 include/linux/clkdev.h

diff --git a/arch/arm/include/asm/clkdev.h b/arch/arm/include/asm/clkdev.h
new file mode 100644
index 0000000..2b605aa
--- /dev/null
+++ b/arch/arm/include/asm/clkdev.h
@@ -0,0 +1,29 @@
+/*
+ *  arch/arm/include/asm/clkdev.h
+ *
+ *  Copyright (C) 2008 Russell King.
+ *
+ * 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.
+ *
+ * Helper for the clk API to assist looking up a struct clk.
+ */
+#ifndef __ASM_CLKDEV_H
+#define __ASM_CLKDEV_H
+
+#ifdef CONFIG_HAVE_ARCH_CLKDEV
+#include <asm/arch/clkdev.h>
+#else
+#define __clk_get(clk)	({ 1; })
+#define __clk_put(clk)	do { } while (0)
+#endif
+
+#include <malloc.h>
+
+static inline struct clk_lookup_alloc *__clkdev_alloc(size_t size)
+{
+	return calloc(1, size);
+}
+
+#endif
diff --git a/drivers/Makefile b/drivers/Makefile
index 5d03f37..b1aba5e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_BIOSEMU) += bios_emulator/
 obj-y += block/
 obj-$(CONFIG_BOOTCOUNT_LIMIT) += bootcount/
+obj-y += clk/
 obj-y += crypto/
 obj-$(CONFIG_FPGA) += fpga/
 obj-y += hwmon/
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
new file mode 100644
index 0000000..d1479d2
--- /dev/null
+++ b/drivers/clk/Makefile
@@ -0,0 +1,8 @@
+#
+# (C) Copyright 2000-2007
+# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
new file mode 100644
index 0000000..5f2921e
--- /dev/null
+++ b/drivers/clk/clkdev.c
@@ -0,0 +1,207 @@
+/*
+ * drivers/clk/clkdev.c
+ *
+ *  Copyright (C) 2008 Russell King.
+ *
+ * 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.
+ *
+ * Helper for the clk API to assist looking up a struct clk.
+ */
+#include <common.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+
+static LIST_HEAD(clocks);
+
+/*
+ * Find the correct struct clk for the device and connection ID.
+ * We do slightly fuzzy matching here:
+ *  An entry with a NULL ID is assumed to be a wildcard.
+ *  If an entry has a device ID, it must match
+ *  If an entry has a connection ID, it must match
+ * Then we take the most specific entry - with the following
+ * order of precedence: dev+con > dev only > con only.
+ */
+static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
+{
+	struct clk_lookup *p, *cl = NULL;
+	int match, best_found = 0, best_possible = 0;
+
+	if (dev_id)
+		best_possible += 2;
+	if (con_id)
+		best_possible += 1;
+
+	list_for_each_entry(p, &clocks, node) {
+		match = 0;
+		if (p->dev_id) {
+			if (!dev_id || strcmp(p->dev_id, dev_id))
+				continue;
+			match += 2;
+		}
+		if (p->con_id) {
+			if (!con_id || strcmp(p->con_id, con_id))
+				continue;
+			match += 1;
+		}
+
+		if (match > best_found) {
+			cl = p;
+			if (match != best_possible)
+				best_found = match;
+			else
+				break;
+		}
+	}
+	return cl;
+}
+
+struct clk *clk_get_sys(const char *dev_id, const char *con_id)
+{
+	struct clk_lookup *cl;
+
+	cl = clk_find(dev_id, con_id);
+	if (cl && !__clk_get(cl->clk))
+		cl = NULL;
+
+	return cl ? cl->clk : ERR_PTR(-ENOENT);
+}
+
+void clk_put(struct clk *clk)
+{
+	__clk_put(clk);
+}
+
+void clkdev_add(struct clk_lookup *cl)
+{
+	list_add_tail(&cl->node, &clocks);
+}
+
+void clkdev_add_table(struct clk_lookup *cl, size_t num)
+{
+	while (num--) {
+		list_add_tail(&cl->node, &clocks);
+		cl++;
+	}
+}
+
+#define MAX_DEV_ID	20
+#define MAX_CON_ID	16
+
+struct clk_lookup_alloc {
+	struct clk_lookup cl;
+	char dev_id[MAX_DEV_ID];
+	char con_id[MAX_CON_ID];
+};
+
+static struct clk_lookup *vclkdev_alloc(struct clk *clk, const char *con_id,
+	const char *dev_fmt, va_list ap)
+{
+	struct clk_lookup_alloc *cla;
+
+	cla = __clkdev_alloc(sizeof(*cla));
+	if (!cla)
+		return NULL;
+
+	cla->cl.clk = clk;
+	if (con_id) {
+		strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
+		cla->cl.con_id = cla->con_id;
+	}
+
+	if (dev_fmt) {
+		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
+		cla->cl.dev_id = cla->dev_id;
+	}
+
+	return &cla->cl;
+}
+
+struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
+	const char *dev_fmt, ...)
+{
+	struct clk_lookup *cl;
+	va_list ap;
+
+	va_start(ap, dev_fmt);
+	cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
+	va_end(ap);
+
+	return cl;
+}
+
+/*
+ * clkdev_drop - remove a clock dynamically allocated
+ */
+void clkdev_drop(struct clk_lookup *cl)
+{
+	list_del(&cl->node);
+	free(cl);
+}
+
+/**
+ * clk_register_clkdev - register one clock lookup for a struct clk
+ * @clk: struct clk to associate with all clk_lookups
+ * @con_id: connection ID string on device
+ * @dev_id: format string describing device name
+ *
+ * con_id or dev_id may be NULL as a wildcard, just as in the rest of
+ * clkdev.
+ *
+ * To make things easier for mass registration, we detect error clks
+ * from a previous clk_register() call, and return the error code for
+ * those.  This is to permit this function to be called immediately
+ * after clk_register().
+ */
+int clk_register_clkdev(struct clk *clk, const char *con_id,
+	const char *dev_fmt, ...)
+{
+	struct clk_lookup *cl;
+	va_list ap;
+
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	va_start(ap, dev_fmt);
+	cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
+	va_end(ap);
+
+	if (!cl)
+		return -ENOMEM;
+
+	clkdev_add(cl);
+
+	return 0;
+}
+
+/**
+ * clk_register_clkdevs - register a set of clk_lookup for a struct clk
+ * @clk: struct clk to associate with all clk_lookups
+ * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
+ * @num: number of clk_lookup structures to register
+ *
+ * To make things easier for mass registration, we detect error clks
+ * from a previous clk_register() call, and return the error code for
+ * those.  This is to permit this function to be called immediately
+ * after clk_register().
+ */
+int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
+{
+	unsigned i;
+
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	for (i = 0; i < num; i++, cl++) {
+		cl->clk = clk;
+		clkdev_add(cl);
+	}
+
+	return 0;
+}
diff --git a/include/linux/clk.h b/include/linux/clk.h
new file mode 100644
index 0000000..5f2ccbb
--- /dev/null
+++ b/include/linux/clk.h
@@ -0,0 +1,181 @@
+/*
+ *  linux/include/linux/clk.h
+ *
+ *  Copyright (C) 2004 ARM Limited.
+ *  Written by Deep Blue Solutions Limited.
+ *  Copyright (C) 2011-2012 Linaro Ltd <mturquette at linaro.org>
+ *
+ * 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 __LINUX_CLK_H
+#define __LINUX_CLK_H
+
+#include <linux/compiler.h>
+#include <linux/err.h>
+
+struct clk;
+
+/**
+ * clk_prepare - prepare a clock source
+ * @clk: clock source
+ *
+ * This prepares the clock source for use.
+ *
+ * Must not be called from within atomic context.
+ */
+#ifdef CONFIG_HAVE_CLK_PREPARE
+int clk_prepare(struct clk *clk);
+#else
+static inline int clk_prepare(struct clk *clk)
+{
+	return 0;
+}
+#endif
+
+/**
+ * clk_unprepare - undo preparation of a clock source
+ * @clk: clock source
+ *
+ * This undoes a previously prepared clock.  The caller must balance
+ * the number of prepare and unprepare calls.
+ *
+ * Must not be called from within atomic context.
+ */
+#ifdef CONFIG_HAVE_CLK_PREPARE
+void clk_unprepare(struct clk *clk);
+#else
+static inline void clk_unprepare(struct clk *clk)
+{
+}
+#endif
+
+/**
+ * clk_enable - inform the system when the clock source should be running.
+ * @clk: clock source
+ *
+ * If the clock can not be enabled/disabled, this should return success.
+ *
+ * May be called from atomic contexts.
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_enable(struct clk *clk);
+
+/**
+ * clk_disable - inform the system when the clock source is no longer required.
+ * @clk: clock source
+ *
+ * Inform the system that a clock source is no longer required by
+ * a driver and may be shut down.
+ *
+ * May be called from atomic contexts.
+ *
+ * Implementation detail: if the clock source is shared between
+ * multiple drivers, clk_enable() calls must be balanced by the
+ * same number of clk_disable() calls for the clock source to be
+ * disabled.
+ */
+void clk_disable(struct clk *clk);
+
+/**
+ * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
+ *		  This is only valid once the clock source has been enabled.
+ * @clk: clock source
+ */
+unsigned long clk_get_rate(struct clk *clk);
+
+/**
+ * clk_put	- "free" the clock source
+ * @clk: clock source
+ *
+ * Note: drivers must ensure that all clk_enable calls made on this
+ * clock source are balanced by clk_disable calls prior to calling
+ * this function.
+ *
+ * clk_put should not be called from within interrupt context.
+ */
+void clk_put(struct clk *clk);
+
+/*
+ * The remaining APIs are optional for machine class support.
+ */
+
+
+/**
+ * clk_round_rate - adjust a rate to the exact rate a clock can provide
+ * @clk: clock source
+ * @rate: desired clock rate in Hz
+ *
+ * Returns rounded clock rate in Hz, or negative errno.
+ */
+long clk_round_rate(struct clk *clk, unsigned long rate);
+
+/**
+ * clk_set_rate - set the clock rate for a clock source
+ * @clk: clock source
+ * @rate: desired clock rate in Hz
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_rate(struct clk *clk, unsigned long rate);
+
+/**
+ * clk_set_parent - set the parent clock source for this clock
+ * @clk: clock source
+ * @parent: parent clock source
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_parent(struct clk *clk, struct clk *parent);
+
+/**
+ * clk_get_parent - get the parent clock source for this clock
+ * @clk: clock source
+ *
+ * Returns struct clk corresponding to parent clock source, or
+ * valid IS_ERR() condition containing errno.
+ */
+struct clk *clk_get_parent(struct clk *clk);
+
+/**
+ * clk_get_sys - get a clock based upon the device name
+ * @dev_id: device name
+ * @con_id: connection ID
+ *
+ * Returns a struct clk corresponding to the clock producer, or
+ * valid IS_ERR() condition containing errno.  The implementation
+ * uses @dev_id and @con_id to determine the clock consumer, and
+ * thereby the clock producer. In contrast to clk_get() this function
+ * takes the device name instead of the device itself for identification.
+ *
+ * Drivers must assume that the clock source is not enabled.
+ *
+ * clk_get_sys should not be called from within interrupt context.
+ */
+struct clk *clk_get_sys(const char *dev_id, const char *con_id);
+
+/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
+static inline int clk_prepare_enable(struct clk *clk)
+{
+	int ret;
+
+	ret = clk_prepare(clk);
+	if (ret)
+		return ret;
+	ret = clk_enable(clk);
+	if (ret)
+		clk_unprepare(clk);
+
+	return ret;
+}
+
+/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
+static inline void clk_disable_unprepare(struct clk *clk)
+{
+	clk_disable(clk);
+	clk_unprepare(clk);
+}
+
+#endif
diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h
new file mode 100644
index 0000000..78f2ff4
--- /dev/null
+++ b/include/linux/clkdev.h
@@ -0,0 +1,45 @@
+/*
+ *  include/linux/clkdev.h
+ *
+ *  Copyright (C) 2008 Russell King.
+ *
+ * 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.
+ *
+ * Helper for the clk API to assist looking up a struct clk.
+ */
+#ifndef __CLKDEV_H
+#define __CLKDEV_H
+
+#include <linux/list.h>
+#include <asm/clkdev.h>
+
+struct clk;
+
+struct clk_lookup {
+	struct list_head node;
+	const char *dev_id;
+	const char *con_id;
+	struct clk *clk;
+};
+
+#define CLKDEV_INIT(d, n, c)	\
+	{			\
+		.dev_id = d,	\
+		.con_id = n,	\
+		.clk = c,	\
+	}
+
+struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
+	const char *dev_fmt, ...);
+
+void clkdev_add(struct clk_lookup *cl);
+void clkdev_drop(struct clk_lookup *cl);
+
+void clkdev_add_table(struct clk_lookup *, size_t);
+
+int clk_register_clkdev(struct clk *, const char *, const char *, ...);
+int clk_register_clkdevs(struct clk *, struct clk_lookup *, size_t);
+
+#endif
--
1.7.9.5