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/*
* drivers/powergate/tegra-powergate.c
*
* Copyright (c) 2010 Google, Inc
*
* Author:
* Colin Cross <ccross@google.com>
*
* 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/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <mach/clk.h>
#include <mach/iomap.h>
#include <mach/powergate.h>
#define PWRGATE_TOGGLE 0x30
#define PWRGATE_TOGGLE_START (1 << 8)
#define REMOVE_CLAMPING 0x34
#define PWRGATE_STATUS 0x38
static DEFINE_SPINLOCK(tegra_powergate_lock);
static void __iomem *pmc = IO_ADDRESS(TEGRA_PMC_BASE);
static u32 pmc_read(unsigned long reg)
{
return readl(pmc + reg);
}
static void pmc_write(u32 val, unsigned long reg)
{
writel(val, pmc + reg);
}
static int tegra_powergate_set(int id, bool new_state)
{
bool status;
unsigned long flags;
spin_lock_irqsave(&tegra_powergate_lock, flags);
status = pmc_read(PWRGATE_STATUS) & (1 << id);
if (status == new_state) {
spin_unlock_irqrestore(&tegra_powergate_lock, flags);
return -EINVAL;
}
pmc_write(PWRGATE_TOGGLE_START | id, PWRGATE_TOGGLE);
spin_unlock_irqrestore(&tegra_powergate_lock, flags);
return 0;
}
int tegra_powergate_power_on(int id)
{
if (id < 0 || id >= TEGRA_NUM_POWERGATE)
return -EINVAL;
return tegra_powergate_set(id, true);
}
int tegra_powergate_power_off(int id)
{
if (id < 0 || id >= TEGRA_NUM_POWERGATE)
return -EINVAL;
return tegra_powergate_set(id, false);
}
bool tegra_powergate_is_powered(int id)
{
u32 status;
if (id < 0 || id >= TEGRA_NUM_POWERGATE)
return -EINVAL;
status = pmc_read(PWRGATE_STATUS) & (1 << id);
return !!status;
}
int tegra_powergate_remove_clamping(int id)
{
u32 mask;
if (id < 0 || id >= TEGRA_NUM_POWERGATE)
return -EINVAL;
/*
* Tegra 2 has a bug where PCIE and VDE clamping masks are
* swapped relatively to the partition ids
*/
if (id == TEGRA_POWERGATE_VDEC)
mask = (1 << TEGRA_POWERGATE_PCIE);
else if (id == TEGRA_POWERGATE_PCIE)
mask = (1 << TEGRA_POWERGATE_VDEC);
else
mask = (1 << id);
pmc_write(mask, REMOVE_CLAMPING);
return 0;
}
/* Must be called with clk disabled, and returns with clk enabled */
static int tegra_powergate_reset_module(struct clk *clk)
{
int ret;
tegra_periph_reset_assert(clk);
udelay(10);
ret = clk_enable(clk);
if (ret)
return ret;
udelay(10);
tegra_periph_reset_deassert(clk);
return 0;
}
/* Must be called with clk disabled, and returns with clk enabled */
int tegra_powergate_sequence_power_up(int id, struct clk *clk)
{
int ret;
if (tegra_powergate_is_powered(id))
return tegra_powergate_reset_module(clk);
tegra_periph_reset_assert(clk);
ret = tegra_powergate_power_on(id);
if (ret)
goto err_power;
ret = clk_enable(clk);
if (ret)
goto err_clk;
udelay(10);
ret = tegra_powergate_remove_clamping(id);
if (ret)
goto err_clamp;
udelay(10);
tegra_periph_reset_deassert(clk);
return 0;
err_clamp:
clk_disable(clk);
err_clk:
tegra_powergate_power_off(id);
err_power:
return ret;
}
#ifdef CONFIG_DEBUG_FS
static const char *powergate_name[] = {
[TEGRA_POWERGATE_CPU] = "cpu",
[TEGRA_POWERGATE_3D] = "3d",
[TEGRA_POWERGATE_VENC] = "venc",
[TEGRA_POWERGATE_VDEC] = "vdec",
[TEGRA_POWERGATE_PCIE] = "pcie",
[TEGRA_POWERGATE_L2] = "l2",
[TEGRA_POWERGATE_MPE] = "mpe",
};
static int powergate_show(struct seq_file *s, void *data)
{
int i;
seq_printf(s, " powergate powered\n");
seq_printf(s, "------------------\n");
for (i = 0; i < TEGRA_NUM_POWERGATE; i++)
seq_printf(s, " %9s %7s\n", powergate_name[i],
tegra_powergate_is_powered(i) ? "yes" : "no");
return 0;
}
static int powergate_open(struct inode *inode, struct file *file)
{
return single_open(file, powergate_show, inode->i_private);
}
static const struct file_operations powergate_fops = {
.open = powergate_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init powergate_debugfs_init(void)
{
struct dentry *d;
d = debugfs_create_file("powergate", S_IRUGO, NULL, NULL,
&powergate_fops);
if (!d)
return -ENOMEM;
return 0;
}
late_initcall(powergate_debugfs_init);
#endif
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