diff options
Diffstat (limited to 'arch/arm/mach-tegra/powergate.c')
| -rw-r--r-- | arch/arm/mach-tegra/powergate.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/powergate.c b/arch/arm/mach-tegra/powergate.c new file mode 100644 index 00000000000..3cee9aa1f2c --- /dev/null +++ b/arch/arm/mach-tegra/powergate.c @@ -0,0 +1,212 @@ +/* + * 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 */ +int tegra_powergate_sequence_power_up(int id, struct clk *clk) +{ + int ret; + + 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 * const 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; + int err = -ENOMEM; + + d = debugfs_create_file("powergate", S_IRUGO, NULL, NULL, + &powergate_fops); + if (!d) + return -ENOMEM; + + return err; +} + +late_initcall(powergate_debugfs_init); + +#endif |