clk-branch.c
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/*
* Copyright (c) 2013, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include "clk-branch.h"
static bool clk_branch_in_hwcg_mode(const struct clk_branch *br)
{
u32 val;
if (!br->hwcg_reg)
return 0;
regmap_read(br->clkr.regmap, br->hwcg_reg, &val);
return !!(val & BIT(br->hwcg_bit));
}
static bool clk_branch_check_halt(const struct clk_branch *br, bool enabling)
{
bool invert = (br->halt_check == BRANCH_HALT_ENABLE);
u32 val;
regmap_read(br->clkr.regmap, br->halt_reg, &val);
val &= BIT(br->halt_bit);
if (invert)
val = !val;
return !!val == !enabling;
}
#define BRANCH_CLK_OFF BIT(31)
#define BRANCH_NOC_FSM_STATUS_SHIFT 28
#define BRANCH_NOC_FSM_STATUS_MASK 0x7
#define BRANCH_NOC_FSM_STATUS_ON (0x2 << BRANCH_NOC_FSM_STATUS_SHIFT)
static bool clk_branch2_check_halt(const struct clk_branch *br, bool enabling)
{
u32 val;
u32 mask;
mask = BRANCH_NOC_FSM_STATUS_MASK << BRANCH_NOC_FSM_STATUS_SHIFT;
mask |= BRANCH_CLK_OFF;
regmap_read(br->clkr.regmap, br->halt_reg, &val);
if (enabling) {
val &= mask;
return (val & BRANCH_CLK_OFF) == 0 ||
val == BRANCH_NOC_FSM_STATUS_ON;
} else {
return val & BRANCH_CLK_OFF;
}
}
static int clk_branch_wait(const struct clk_branch *br, bool enabling,
bool (check_halt)(const struct clk_branch *, bool))
{
bool voted = br->halt_check & BRANCH_VOTED;
const char *name = __clk_get_name(br->clkr.hw.clk);
/* Skip checking halt bit if the clock is in hardware gated mode */
if (clk_branch_in_hwcg_mode(br))
return 0;
if (br->halt_check == BRANCH_HALT_DELAY || (!enabling && voted)) {
udelay(10);
} else if (br->halt_check == BRANCH_HALT_ENABLE ||
br->halt_check == BRANCH_HALT ||
(enabling && voted)) {
int count = 200;
while (count-- > 0) {
if (check_halt(br, enabling))
return 0;
udelay(1);
}
WARN(1, "%s status stuck at 'o%s'", name,
enabling ? "ff" : "n");
return -EBUSY;
}
return 0;
}
static int clk_branch_toggle(struct clk_hw *hw, bool en,
bool (check_halt)(const struct clk_branch *, bool))
{
struct clk_branch *br = to_clk_branch(hw);
int ret;
if (en) {
ret = clk_enable_regmap(hw);
if (ret)
return ret;
} else {
clk_disable_regmap(hw);
}
return clk_branch_wait(br, en, check_halt);
}
static int clk_branch_enable(struct clk_hw *hw)
{
return clk_branch_toggle(hw, true, clk_branch_check_halt);
}
static void clk_branch_disable(struct clk_hw *hw)
{
clk_branch_toggle(hw, false, clk_branch_check_halt);
}
const struct clk_ops clk_branch_ops = {
.enable = clk_branch_enable,
.disable = clk_branch_disable,
.is_enabled = clk_is_enabled_regmap,
};
EXPORT_SYMBOL_GPL(clk_branch_ops);
static int clk_branch2_enable(struct clk_hw *hw)
{
return clk_branch_toggle(hw, true, clk_branch2_check_halt);
}
static void clk_branch2_disable(struct clk_hw *hw)
{
clk_branch_toggle(hw, false, clk_branch2_check_halt);
}
const struct clk_ops clk_branch2_ops = {
.enable = clk_branch2_enable,
.disable = clk_branch2_disable,
.is_enabled = clk_is_enabled_regmap,
};
EXPORT_SYMBOL_GPL(clk_branch2_ops);
const struct clk_ops clk_branch_simple_ops = {
.enable = clk_enable_regmap,
.disable = clk_disable_regmap,
.is_enabled = clk_is_enabled_regmap,
};
EXPORT_SYMBOL_GPL(clk_branch_simple_ops);