Commit 6e973d2c authored by Pawel Moll's avatar Pawel Moll Committed by Mike Turquette

clk: vexpress: Add separate SP810 driver

Factor out the SP810 clocking code into a separate driver,
selecting better (faster) parent at clk_prepare() time.
This is to avoid problems with clocking infrastructure
initialisation order, in particular to avoid dependency
of fixed clock being initialized before SP810. It also
makes vexpress platform OF-based clock initialisation code
unnecessary.
Signed-off-by: default avatarPawel Moll <pawel.moll@arm.com>
Tested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: add .unprepare, FIXME comment, cleaned up code]
parent 476ba5ff
......@@ -21,6 +21,8 @@
#include <linux/regulator/fixed.h>
#include <linux/regulator/machine.h>
#include <linux/vexpress.h>
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <asm/arch_timer.h>
#include <asm/mach-types.h>
......@@ -433,7 +435,7 @@ static void __init v2m_dt_timer_init(void)
{
struct device_node *node = NULL;
vexpress_clk_of_init();
of_clk_init(NULL);
do {
node = of_find_compatible_node(node, NULL, "arm,sp804");
......@@ -441,6 +443,10 @@ static void __init v2m_dt_timer_init(void)
if (node) {
pr_info("Using SP804 '%s' as a clock & events source\n",
node->full_name);
WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
"timclken1"), "v2m-timer0", "sp804"));
WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
"timclken2"), "v2m-timer1", "sp804"));
v2m_sp804_init(of_iomap(node, 0),
irq_of_parse_and_map(node, 0));
}
......
......@@ -3,5 +3,5 @@ obj-$(CONFIG_ICST) += clk-icst.o
obj-$(CONFIG_ARCH_INTEGRATOR) += clk-integrator.o
obj-$(CONFIG_INTEGRATOR_IMPD1) += clk-impd1.o
obj-$(CONFIG_ARCH_REALVIEW) += clk-realview.o
obj-$(CONFIG_ARCH_VEXPRESS) += clk-vexpress.o
obj-$(CONFIG_ARCH_VEXPRESS) += clk-vexpress.o clk-sp810.o
obj-$(CONFIG_VEXPRESS_CONFIG) += clk-vexpress-osc.o
/*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Copyright (C) 2013 ARM Limited
*/
#include <linux/amba/sp810.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_address.h>
#define to_clk_sp810_timerclken(_hw) \
container_of(_hw, struct clk_sp810_timerclken, hw)
struct clk_sp810;
struct clk_sp810_timerclken {
struct clk_hw hw;
struct clk *clk;
struct clk_sp810 *sp810;
int channel;
};
struct clk_sp810 {
struct device_node *node;
int refclk_index, timclk_index;
void __iomem *base;
spinlock_t lock;
struct clk_sp810_timerclken timerclken[4];
struct clk *refclk;
struct clk *timclk;
};
static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
u32 val = readl(timerclken->sp810->base + SCCTRL);
return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
}
static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
unsigned long flags = 0;
if (WARN_ON(index > 1))
return -EINVAL;
spin_lock_irqsave(&sp810->lock, flags);
val = readl(sp810->base + SCCTRL);
val &= ~(1 << shift);
val |= index << shift;
writel(val, sp810->base + SCCTRL);
spin_unlock_irqrestore(&sp810->lock, flags);
return 0;
}
/*
* FIXME - setting the parent every time .prepare is invoked is inefficient.
* This is better handled by a dedicated clock tree configuration mechanism at
* init-time. Revisit this later when such a mechanism exists
*/
static int clk_sp810_timerclken_prepare(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
struct clk *old_parent = __clk_get_parent(hw->clk);
struct clk *new_parent;
if (!sp810->refclk)
sp810->refclk = of_clk_get(sp810->node, sp810->refclk_index);
if (!sp810->timclk)
sp810->timclk = of_clk_get(sp810->node, sp810->timclk_index);
if (WARN_ON(IS_ERR(sp810->refclk) || IS_ERR(sp810->timclk)))
return -ENOENT;
/* Select fastest parent */
if (clk_get_rate(sp810->refclk) > clk_get_rate(sp810->timclk))
new_parent = sp810->refclk;
else
new_parent = sp810->timclk;
/* Switch the parent if necessary */
if (old_parent != new_parent) {
clk_prepare(new_parent);
clk_set_parent(hw->clk, new_parent);
clk_unprepare(old_parent);
}
return 0;
}
static void clk_sp810_timerclken_unprepare(struct clk_hw *hw)
{
struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
struct clk_sp810 *sp810 = timerclken->sp810;
clk_put(sp810->timclk);
clk_put(sp810->refclk);
}
static const struct clk_ops clk_sp810_timerclken_ops = {
.prepare = clk_sp810_timerclken_prepare,
.unprepare = clk_sp810_timerclken_unprepare,
.get_parent = clk_sp810_timerclken_get_parent,
.set_parent = clk_sp810_timerclken_set_parent,
};
struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
void *data)
{
struct clk_sp810 *sp810 = data;
if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
ARRAY_SIZE(sp810->timerclken)))
return NULL;
return sp810->timerclken[clkspec->args[0]].clk;
}
void __init clk_sp810_of_setup(struct device_node *node)
{
struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
const char *parent_names[2];
char name[12];
struct clk_init_data init;
int i;
if (!sp810) {
pr_err("Failed to allocate memory for SP810!\n");
return;
}
sp810->refclk_index = of_property_match_string(node, "clock-names",
"refclk");
parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index);
sp810->timclk_index = of_property_match_string(node, "clock-names",
"timclk");
parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index);
if (parent_names[0] <= 0 || parent_names[1] <= 0) {
pr_warn("Failed to obtain parent clocks for SP810!\n");
return;
}
sp810->node = node;
sp810->base = of_iomap(node, 0);
spin_lock_init(&sp810->lock);
init.name = name;
init.ops = &clk_sp810_timerclken_ops;
init.flags = CLK_IS_BASIC;
init.parent_names = parent_names;
init.num_parents = ARRAY_SIZE(parent_names);
for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
sp810->timerclken[i].sp810 = sp810;
sp810->timerclken[i].channel = i;
sp810->timerclken[i].hw.init = &init;
sp810->timerclken[i].clk = clk_register(NULL,
&sp810->timerclken[i].hw);
WARN_ON(IS_ERR(sp810->timerclken[i].clk));
}
of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
}
CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
......@@ -15,8 +15,6 @@
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/vexpress.h>
static struct clk *vexpress_sp810_timerclken[4];
......@@ -86,50 +84,3 @@ void __init vexpress_clk_init(void __iomem *sp810_base)
WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
"v2m-timer1", "sp804"));
}
#if defined(CONFIG_OF)
struct clk *vexpress_sp810_of_get(struct of_phandle_args *clkspec, void *data)
{
if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
ARRAY_SIZE(vexpress_sp810_timerclken)))
return NULL;
return vexpress_sp810_timerclken[clkspec->args[0]];
}
void __init vexpress_clk_of_init(void)
{
struct device_node *node;
struct clk *clk;
struct clk *refclk, *timclk;
of_clk_init(NULL);
node = of_find_compatible_node(NULL, NULL, "arm,sp810");
vexpress_sp810_init(of_iomap(node, 0));
of_clk_add_provider(node, vexpress_sp810_of_get, NULL);
/* Select "better" (faster) parent for SP804 timers */
refclk = of_clk_get_by_name(node, "refclk");
timclk = of_clk_get_by_name(node, "timclk");
if (!WARN_ON(IS_ERR(refclk) || IS_ERR(timclk))) {
int i = 0;
if (clk_get_rate(refclk) > clk_get_rate(timclk))
clk = refclk;
else
clk = timclk;
for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i],
clk));
}
WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
"v2m-timer0", "sp804"));
WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
"v2m-timer1", "sp804"));
}
#endif
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