u-boot/arch/arm/mach-tegra/powergate.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
*/
#include <common.h>
#include <errno.h>
#include <asm/io.h>
#include <asm/types.h>
#include <asm/arch/powergate.h>
#include <asm/arch/tegra.h>
#define PWRGATE_TOGGLE 0x30
#define PWRGATE_TOGGLE_START (1 << 8)
#define REMOVE_CLAMPING 0x34
#define PWRGATE_STATUS 0x38
static int tegra_powergate_set(enum tegra_powergate id, bool state)
{
u32 value, mask = state ? (1 << id) : 0, old_mask;
unsigned long start, timeout = 25;
value = readl(NV_PA_PMC_BASE + PWRGATE_STATUS);
old_mask = value & (1 << id);
if (mask == old_mask)
return 0;
writel(PWRGATE_TOGGLE_START | id, NV_PA_PMC_BASE + PWRGATE_TOGGLE);
start = get_timer(0);
while (get_timer(start) < timeout) {
value = readl(NV_PA_PMC_BASE + PWRGATE_STATUS);
if ((value & (1 << id)) == mask)
return 0;
}
return -ETIMEDOUT;
}
int tegra_powergate_power_on(enum tegra_powergate id)
{
return tegra_powergate_set(id, true);
}
int tegra_powergate_power_off(enum tegra_powergate id)
{
return tegra_powergate_set(id, false);
}
static int tegra_powergate_remove_clamping(enum tegra_powergate id)
{
unsigned long value;
/*
* The REMOVE_CLAMPING register has the bits for the PCIE and VDEC
* partitions reversed. This was originally introduced on Tegra20 but
* has since been carried forward for backwards-compatibility.
*/
if (id == TEGRA_POWERGATE_VDEC)
value = 1 << TEGRA_POWERGATE_PCIE;
else if (id == TEGRA_POWERGATE_PCIE)
value = 1 << TEGRA_POWERGATE_VDEC;
else
value = 1 << id;
writel(value, NV_PA_PMC_BASE + REMOVE_CLAMPING);
return 0;
}
int tegra_powergate_sequence_power_up(enum tegra_powergate id,
enum periph_id periph)
{
int err;
reset_set_enable(periph, 1);
err = tegra_powergate_power_on(id);
if (err < 0)
return err;
clock_enable(periph);
udelay(10);
err = tegra_powergate_remove_clamping(id);
if (err < 0)
return err;
udelay(10);
reset_set_enable(periph, 0);
return 0;
}