ARM: tegra: Convert PMC to a driver

This commit converts the PMC support code to a platform driver. Because
the boot process needs to call into this driver very early, also set up
a minimal environment via an early initcall.

Signed-off-by: Thierry Reding <treding@nvidia.com>

2 files changed, 958 insertions, 0 deletions

diff --git a/drivers/soc/tegra/Makefile b/drivers/soc/tegra/Makefile
index db34987ed9dc..cdaad9d53a05 100644
--- a/drivers/soc/tegra/Makefile
+++ b/drivers/soc/tegra/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_ARCH_TEGRA) += fuse/
 
 obj-$(CONFIG_ARCH_TEGRA) += common.o
+obj-$(CONFIG_ARCH_TEGRA) += pmc.o
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
new file mode 100644
index 000000000000..a2c0ceb95f8f
--- /dev/null
+++ b/drivers/soc/tegra/pmc.c
@@ -0,0 +1,957 @@
+/*
+ * drivers/soc/tegra/pmc.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/clk/tegra.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/reset.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+
+#include <soc/tegra/common.h>
+#include <soc/tegra/fuse.h>
+#include <soc/tegra/pmc.h>
+
+#define PMC_CNTRL                       0x0
+#define  PMC_CNTRL_SYSCLK_POLARITY      (1 << 10)  /* sys clk polarity */
+#define  PMC_CNTRL_SYSCLK_OE            (1 << 11)  /* system clock enable */
+#define  PMC_CNTRL_SIDE_EFFECT_LP0      (1 << 14)  /* LP0 when CPU pwr gated */
+#define  PMC_CNTRL_CPU_PWRREQ_POLARITY  (1 << 15)  /* CPU pwr req polarity */
+#define  PMC_CNTRL_CPU_PWRREQ_OE        (1 << 16)  /* CPU pwr req enable */
+#define  PMC_CNTRL_INTR_POLARITY        (1 << 17)  /* inverts INTR polarity */
+
+#define DPD_SAMPLE                      0x020
+#define  DPD_SAMPLE_ENABLE              (1 << 0)
+#define  DPD_SAMPLE_DISABLE             (0 << 0)
+
+#define PWRGATE_TOGGLE                  0x30
+#define  PWRGATE_TOGGLE_START           (1 << 8)
+
+#define REMOVE_CLAMPING                 0x34
+
+#define PWRGATE_STATUS                  0x38
+
+#define PMC_SCRATCH0                    0x50
+#define  PMC_SCRATCH0_MODE_RECOVERY     (1 << 31)
+#define  PMC_SCRATCH0_MODE_BOOTLOADER   (1 << 30)
+#define  PMC_SCRATCH0_MODE_RCM          (1 << 1)
+#define  PMC_SCRATCH0_MODE_MASK         (PMC_SCRATCH0_MODE_RECOVERY | \
+                                         PMC_SCRATCH0_MODE_BOOTLOADER | \
+                                         PMC_SCRATCH0_MODE_RCM)
+
+#define PMC_CPUPWRGOOD_TIMER            0xc8
+#define PMC_CPUPWROFF_TIMER             0xcc
+
+#define PMC_SCRATCH41                   0x140
+
+#define IO_DPD_REQ                      0x1b8
+#define  IO_DPD_REQ_CODE_IDLE           (0 << 30)
+#define  IO_DPD_REQ_CODE_OFF            (1 << 30)
+#define  IO_DPD_REQ_CODE_ON             (2 << 30)
+#define  IO_DPD_REQ_CODE_MASK           (3 << 30)
+
+#define IO_DPD_STATUS                   0x1bc
+#define IO_DPD2_REQ                     0x1c0
+#define IO_DPD2_STATUS                  0x1c4
+#define SEL_DPD_TIM                     0x1c8
+
+#define GPU_RG_CNTRL                    0x2d4
+
+struct tegra_pmc_soc {
+        unsigned int num_powergates;
+        const char *const *powergates;
+        unsigned int num_cpu_powergates;
+        const u8 *cpu_powergates;
+};
+
+/**
+ * struct tegra_pmc - NVIDIA Tegra PMC
+ * @base: pointer to I/O remapped register region
+ * @clk: pointer to pclk clock
+ * @rate: currently configured rate of pclk
+ * @suspend_mode: lowest suspend mode available
+ * @cpu_good_time: CPU power good time (in microseconds)
+ * @cpu_off_time: CPU power off time (in microsecends)
+ * @core_osc_time: core power good OSC time (in microseconds)
+ * @core_pmu_time: core power good PMU time (in microseconds)
+ * @core_off_time: core power off time (in microseconds)
+ * @corereq_high: core power request is active-high
+ * @sysclkreq_high: system clock request is active-high
+ * @combined_req: combined power request for CPU & core
+ * @cpu_pwr_good_en: CPU power good signal is enabled
+ * @lp0_vec_phys: physical base address of the LP0 warm boot code
+ * @lp0_vec_size: size of the LP0 warm boot code
+ * @powergates_lock: mutex for power gate register access
+ */
+struct tegra_pmc {
+        void __iomem *base;
+        struct clk *clk;
+
+        const struct tegra_pmc_soc *soc;
+
+        unsigned long rate;
+
+        enum tegra_suspend_mode suspend_mode;
+        u32 cpu_good_time;
+        u32 cpu_off_time;
+        u32 core_osc_time;
+        u32 core_pmu_time;
+        u32 core_off_time;
+        bool corereq_high;
+        bool sysclkreq_high;
+        bool combined_req;
+        bool cpu_pwr_good_en;
+        u32 lp0_vec_phys;
+        u32 lp0_vec_size;
+
+        struct mutex powergates_lock;
+};
+
+static struct tegra_pmc *pmc = &(struct tegra_pmc) {
+        .base = NULL,
+        .suspend_mode = TEGRA_SUSPEND_NONE,
+};
+
+static u32 tegra_pmc_readl(unsigned long offset)
+{
+        return readl(pmc->base + offset);
+}
+
+static void tegra_pmc_writel(u32 value, unsigned long offset)
+{
+        writel(value, pmc->base + offset);
+}
+
+/**
+ * tegra_powergate_set() - set the state of a partition
+ * @id: partition ID
+ * @new_state: new state of the partition
+ */
+static int tegra_powergate_set(int id, bool new_state)
+{
+        bool status;
+
+        mutex_lock(&pmc->powergates_lock);
+
+        status = tegra_pmc_readl(PWRGATE_STATUS) & (1 << id);
+
+        if (status == new_state) {
+                mutex_unlock(&pmc->powergates_lock);
+                return 0;
+        }
+
+        tegra_pmc_writel(PWRGATE_TOGGLE_START | id, PWRGATE_TOGGLE);
+
+        mutex_unlock(&pmc->powergates_lock);
+
+        return 0;
+}
+
+/**
+ * tegra_powergate_power_on() - power on partition
+ * @id: partition ID
+ */
+int tegra_powergate_power_on(int id)
+{
+        if (!pmc->soc || id < 0 || id >= pmc->soc->num_powergates)
+                return -EINVAL;
+
+        return tegra_powergate_set(id, true);
+}
+
+/**
+ * tegra_powergate_power_off() - power off partition
+ * @id: partition ID
+ */
+int tegra_powergate_power_off(int id)
+{
+        if (!pmc->soc || id < 0 || id >= pmc->soc->num_powergates)
+                return -EINVAL;
+
+        return tegra_powergate_set(id, false);
+}
+EXPORT_SYMBOL(tegra_powergate_power_off);
+
+/**
+ * tegra_powergate_is_powered() - check if partition is powered
+ * @id: partition ID
+ */
+int tegra_powergate_is_powered(int id)
+{
+        u32 status;
+
+        if (!pmc->soc || id < 0 || id >= pmc->soc->num_powergates)
+                return -EINVAL;
+
+        status = tegra_pmc_readl(PWRGATE_STATUS) & (1 << id);
+        return !!status;
+}
+
+/**
+ * tegra_powergate_remove_clamping() - remove power clamps for partition
+ * @id: partition ID
+ */
+int tegra_powergate_remove_clamping(int id)
+{
+        u32 mask;
+
+        if (!pmc->soc || id < 0 || id >= pmc->soc->num_powergates)
+                return -EINVAL;
+
+        /*
+         * The Tegra124 GPU has a separate register (with different semantics)
+         * to remove clamps.
+         */
+        if (tegra_get_chip_id() == TEGRA124) {
+                if (id == TEGRA_POWERGATE_3D) {
+                        tegra_pmc_writel(0, GPU_RG_CNTRL);
+                        return 0;
+                }
+        }
+
+        /*
+         * 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);
+
+        tegra_pmc_writel(mask, REMOVE_CLAMPING);
+
+        return 0;
+}
+EXPORT_SYMBOL(tegra_powergate_remove_clamping);
+
+/**
+ * tegra_powergate_sequence_power_up() - power up partition
+ * @id: partition ID
+ * @clk: clock for partition
+ * @rst: reset for partition
+ *
+ * Must be called with clk disabled, and returns with clk enabled.
+ */
+int tegra_powergate_sequence_power_up(int id, struct clk *clk,
+                                      struct reset_control *rst)
+{
+        int ret;
+
+        reset_control_assert(rst);
+
+        ret = tegra_powergate_power_on(id);
+        if (ret)
+                goto err_power;
+
+        ret = clk_prepare_enable(clk);
+        if (ret)
+                goto err_clk;
+
+        usleep_range(10, 20);
+
+        ret = tegra_powergate_remove_clamping(id);
+        if (ret)
+                goto err_clamp;
+
+        usleep_range(10, 20);
+        reset_control_deassert(rst);
+
+        return 0;
+
+err_clamp:
+        clk_disable_unprepare(clk);
+err_clk:
+        tegra_powergate_power_off(id);
+err_power:
+        return ret;
+}
+EXPORT_SYMBOL(tegra_powergate_sequence_power_up);
+
+#ifdef CONFIG_SMP
+/**
+ * tegra_get_cpu_powergate_id() - convert from CPU ID to partition ID
+ * @cpuid: CPU partition ID
+ *
+ * Returns the partition ID corresponding to the CPU partition ID or a
+ * negative error code on failure.
+ */
+static int tegra_get_cpu_powergate_id(int cpuid)
+{
+        if (pmc->soc && cpuid > 0 && cpuid < pmc->soc->num_cpu_powergates)
+                return pmc->soc->cpu_powergates[cpuid];
+
+        return -EINVAL;
+}
+
+/**
+ * tegra_pmc_cpu_is_powered() - check if CPU partition is powered
+ * @cpuid: CPU partition ID
+ */
+bool tegra_pmc_cpu_is_powered(int cpuid)
+{
+        int id;
+
+        id = tegra_get_cpu_powergate_id(cpuid);
+        if (id < 0)
+                return false;
+
+        return tegra_powergate_is_powered(id);
+}
+
+/**
+ * tegra_pmc_cpu_power_on() - power on CPU partition
+ * @cpuid: CPU partition ID
+ */
+int tegra_pmc_cpu_power_on(int cpuid)
+{
+        int id;
+
+        id = tegra_get_cpu_powergate_id(cpuid);
+        if (id < 0)
+                return id;
+
+        return tegra_powergate_set(id, true);
+}
+
+/**
+ * tegra_pmc_cpu_remove_clamping() - remove power clamps for CPU partition
+ * @cpuid: CPU partition ID
+ */
+int tegra_pmc_cpu_remove_clamping(int cpuid)
+{
+        int id;
+
+        id = tegra_get_cpu_powergate_id(cpuid);
+        if (id < 0)
+                return id;
+
+        return tegra_powergate_remove_clamping(id);
+}
+#endif /* CONFIG_SMP */
+
+/**
+ * tegra_pmc_restart() - reboot the system
+ * @mode: which mode to reboot in
+ * @cmd: reboot command
+ */
+void tegra_pmc_restart(enum reboot_mode mode, const char *cmd)
+{
+        u32 value;
+
+        value = tegra_pmc_readl(PMC_SCRATCH0);
+        value &= ~PMC_SCRATCH0_MODE_MASK;
+
+        if (cmd) {
+                if (strcmp(cmd, "recovery") == 0)
+                        value |= PMC_SCRATCH0_MODE_RECOVERY;
+
+                if (strcmp(cmd, "bootloader") == 0)
+                        value |= PMC_SCRATCH0_MODE_BOOTLOADER;
+
+                if (strcmp(cmd, "forced-recovery") == 0)
+                        value |= PMC_SCRATCH0_MODE_RCM;
+        }
+
+        tegra_pmc_writel(value, PMC_SCRATCH0);
+
+        value = tegra_pmc_readl(0);
+        value |= 0x10;
+        tegra_pmc_writel(value, 0);
+}
+
+static int powergate_show(struct seq_file *s, void *data)
+{
+        unsigned int i;
+
+        seq_printf(s, " powergate powered\n");
+        seq_printf(s, "------------------\n");
+
+        for (i = 0; i < pmc->soc->num_powergates; i++) {
+                if (!pmc->soc->powergates[i])
+                        continue;
+
+                seq_printf(s, " %9s %7s\n", pmc->soc->powergates[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 tegra_powergate_debugfs_init(void)
+{
+        struct dentry *d;
+
+        d = debugfs_create_file("powergate", S_IRUGO, NULL, NULL,
+                                &powergate_fops);
+        if (!d)
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int tegra_io_rail_prepare(int id, unsigned long *request,
+                                 unsigned long *status, unsigned int *bit)
+{
+        unsigned long rate, value;
+        struct clk *clk;
+
+        *bit = id % 32;
+
+        /*
+         * There are two sets of 30 bits to select IO rails, but bits 30 and
+         * 31 are control bits rather than IO rail selection bits.
+         */
+        if (id > 63 || *bit == 30 || *bit == 31)
+                return -EINVAL;
+
+        if (id < 32) {
+                *status = IO_DPD_STATUS;
+                *request = IO_DPD_REQ;
+        } else {
+                *status = IO_DPD2_STATUS;
+                *request = IO_DPD2_REQ;
+        }
+
+        clk = clk_get_sys(NULL, "pclk");
+        if (IS_ERR(clk))
+                return PTR_ERR(clk);
+
+        rate = clk_get_rate(clk);
+        clk_put(clk);
+
+        tegra_pmc_writel(DPD_SAMPLE_ENABLE, DPD_SAMPLE);
+
+        /* must be at least 200 ns, in APB (PCLK) clock cycles */
+        value = DIV_ROUND_UP(1000000000, rate);
+        value = DIV_ROUND_UP(200, value);
+        tegra_pmc_writel(value, SEL_DPD_TIM);
+
+        return 0;
+}
+
+static int tegra_io_rail_poll(unsigned long offset, unsigned long mask,
+                              unsigned long val, unsigned long timeout)
+{
+        unsigned long value;
+
+        timeout = jiffies + msecs_to_jiffies(timeout);
+
+        while (time_after(timeout, jiffies)) {
+                value = tegra_pmc_readl(offset);
+                if ((value & mask) == val)
+                        return 0;
+
+                usleep_range(250, 1000);
+        }
+
+        return -ETIMEDOUT;
+}
+
+static void tegra_io_rail_unprepare(void)
+{
+        tegra_pmc_writel(DPD_SAMPLE_DISABLE, DPD_SAMPLE);
+}
+
+int tegra_io_rail_power_on(int id)
+{
+        unsigned long request, status, value;
+        unsigned int bit, mask;
+        int err;
+
+        err = tegra_io_rail_prepare(id, &request, &status, &bit);
+        if (err < 0)
+                return err;
+
+        mask = 1 << bit;
+
+        value = tegra_pmc_readl(request);
+        value |= mask;
+        value &= ~IO_DPD_REQ_CODE_MASK;
+        value |= IO_DPD_REQ_CODE_OFF;
+        tegra_pmc_writel(value, request);
+
+        err = tegra_io_rail_poll(status, mask, 0, 250);
+        if (err < 0)
+                return err;
+
+        tegra_io_rail_unprepare();
+
+        return 0;
+}
+EXPORT_SYMBOL(tegra_io_rail_power_on);
+
+int tegra_io_rail_power_off(int id)
+{
+        unsigned long request, status, value;
+        unsigned int bit, mask;
+        int err;
+
+        err = tegra_io_rail_prepare(id, &request, &status, &bit);
+        if (err < 0)
+                return err;
+
+        mask = 1 << bit;
+
+        value = tegra_pmc_readl(request);
+        value |= mask;
+        value &= ~IO_DPD_REQ_CODE_MASK;
+        value |= IO_DPD_REQ_CODE_ON;
+        tegra_pmc_writel(value, request);
+
+        err = tegra_io_rail_poll(status, mask, mask, 250);
+        if (err < 0)
+                return err;
+
+        tegra_io_rail_unprepare();
+
+        return 0;
+}
+EXPORT_SYMBOL(tegra_io_rail_power_off);
+
+#ifdef CONFIG_PM_SLEEP
+enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void)
+{
+        return pmc->suspend_mode;
+}
+
+void tegra_pmc_set_suspend_mode(enum tegra_suspend_mode mode)
+{
+        if (mode < TEGRA_SUSPEND_NONE || mode >= TEGRA_MAX_SUSPEND_MODE)
+                return;
+
+        pmc->suspend_mode = mode;
+}
+
+void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode)
+{
+        unsigned long long rate = 0;
+        u32 value;
+
+        switch (mode) {
+        case TEGRA_SUSPEND_LP1:
+                rate = 32768;
+                break;
+
+        case TEGRA_SUSPEND_LP2:
+                rate = clk_get_rate(pmc->clk);
+                break;
+
+        default:
+                break;
+        }
+
+        if (WARN_ON_ONCE(rate == 0))
+                rate = 100000000;
+
+        if (rate != pmc->rate) {
+                u64 ticks;
+
+                ticks = pmc->cpu_good_time * rate + USEC_PER_SEC - 1;
+                do_div(ticks, USEC_PER_SEC);
+                tegra_pmc_writel(ticks, PMC_CPUPWRGOOD_TIMER);
+
+                ticks = pmc->cpu_off_time * rate + USEC_PER_SEC - 1;
+                do_div(ticks, USEC_PER_SEC);
+                tegra_pmc_writel(ticks, PMC_CPUPWROFF_TIMER);
+
+                wmb();
+
+                pmc->rate = rate;
+        }
+
+        value = tegra_pmc_readl(PMC_CNTRL);
+        value &= ~PMC_CNTRL_SIDE_EFFECT_LP0;
+        value |= PMC_CNTRL_CPU_PWRREQ_OE;
+        tegra_pmc_writel(value, PMC_CNTRL);
+}
+#endif
+
+static int tegra_pmc_parse_dt(struct tegra_pmc *pmc, struct device_node *np)
+{
+        u32 value, values[2];
+
+        if (of_property_read_u32(np, "nvidia,suspend-mode", &value)) {
+        } else {
+                switch (value) {
+                case 0:
+                        pmc->suspend_mode = TEGRA_SUSPEND_LP0;
+                        break;
+
+                case 1:
+                        pmc->suspend_mode = TEGRA_SUSPEND_LP1;
+                        break;
+
+                case 2:
+                        pmc->suspend_mode = TEGRA_SUSPEND_LP2;
+                        break;
+
+                default:
+                        pmc->suspend_mode = TEGRA_SUSPEND_NONE;
+                        break;
+                }
+        }
+
+        pmc->suspend_mode = tegra_pm_validate_suspend_mode(pmc->suspend_mode);
+
+        if (of_property_read_u32(np, "nvidia,cpu-pwr-good-time", &value))
+                pmc->suspend_mode = TEGRA_SUSPEND_NONE;
+
+        pmc->cpu_good_time = value;
+
+        if (of_property_read_u32(np, "nvidia,cpu-pwr-off-time", &value))
+                pmc->suspend_mode = TEGRA_SUSPEND_NONE;
+
+        pmc->cpu_off_time = value;
+
+        if (of_property_read_u32_array(np, "nvidia,core-pwr-good-time",
+                                       values, ARRAY_SIZE(values)))
+                pmc->suspend_mode = TEGRA_SUSPEND_NONE;
+
+        pmc->core_osc_time = values[0];
+        pmc->core_pmu_time = values[1];
+
+        if (of_property_read_u32(np, "nvidia,core-pwr-off-time", &value))
+                pmc->suspend_mode = TEGRA_SUSPEND_NONE;
+
+        pmc->core_off_time = value;
+
+        pmc->corereq_high = of_property_read_bool(np,
+                                "nvidia,core-power-req-active-high");
+
+        pmc->sysclkreq_high = of_property_read_bool(np,
+                                "nvidia,sys-clock-req-active-high");
+
+        pmc->combined_req = of_property_read_bool(np,
+                                "nvidia,combined-power-req");
+
+        pmc->cpu_pwr_good_en = of_property_read_bool(np,
+                                "nvidia,cpu-pwr-good-en");
+
+        if (of_property_read_u32_array(np, "nvidia,lp0-vec", values,
+                                       ARRAY_SIZE(values)))
+                if (pmc->suspend_mode == TEGRA_SUSPEND_LP0)
+                        pmc->suspend_mode = TEGRA_SUSPEND_LP1;
+
+        pmc->lp0_vec_phys = values[0];
+        pmc->lp0_vec_size = values[1];
+
+        return 0;
+}
+
+static void tegra_pmc_init(struct tegra_pmc *pmc)
+{
+        u32 value;
+
+        /* Always enable CPU power request */
+        value = tegra_pmc_readl(PMC_CNTRL);
+        value |= PMC_CNTRL_CPU_PWRREQ_OE;
+        tegra_pmc_writel(value, PMC_CNTRL);
+
+        value = tegra_pmc_readl(PMC_CNTRL);
+
+        if (pmc->sysclkreq_high)
+                value &= ~PMC_CNTRL_SYSCLK_POLARITY;
+        else
+                value |= PMC_CNTRL_SYSCLK_POLARITY;
+
+        /* configure the output polarity while the request is tristated */
+        tegra_pmc_writel(value, PMC_CNTRL);
+
+        /* now enable the request */
+        value = tegra_pmc_readl(PMC_CNTRL);
+        value |= PMC_CNTRL_SYSCLK_OE;
+        tegra_pmc_writel(value, PMC_CNTRL);
+}
+
+static int tegra_pmc_probe(struct platform_device *pdev)
+{
+        void __iomem *base = pmc->base;
+        struct resource *res;
+        int err;
+
+        err = tegra_pmc_parse_dt(pmc, pdev->dev.of_node);
+        if (err < 0)
+                return err;
+
+        /* take over the memory region from the early initialization */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        pmc->base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(pmc->base))
+                return PTR_ERR(pmc->base);
+
+        iounmap(base);
+
+        pmc->clk = devm_clk_get(&pdev->dev, "pclk");
+        if (IS_ERR(pmc->clk)) {
+                err = PTR_ERR(pmc->clk);
+                dev_err(&pdev->dev, "failed to get pclk: %d\n", err);
+                return err;
+        }
+
+        tegra_pmc_init(pmc);
+
+        if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+                err = tegra_powergate_debugfs_init();
+                if (err < 0)
+                        return err;
+        }
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_pmc_suspend(struct device *dev)
+{
+        tegra_pmc_writel(virt_to_phys(tegra_resume), PMC_SCRATCH41);
+
+        return 0;
+}
+
+static int tegra_pmc_resume(struct device *dev)
+{
+        tegra_pmc_writel(0x0, PMC_SCRATCH41);
+
+        return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tegra_pmc_pm_ops, tegra_pmc_suspend, tegra_pmc_resume);
+
+static const char * const tegra20_powergates[] = {
+        [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 const struct tegra_pmc_soc tegra20_pmc_soc = {
+        .num_powergates = ARRAY_SIZE(tegra20_powergates),
+        .powergates = tegra20_powergates,
+        .num_cpu_powergates = 0,
+        .cpu_powergates = NULL,
+};
+
+static const char * const tegra30_powergates[] = {
+        [TEGRA_POWERGATE_CPU] = "cpu0",
+        [TEGRA_POWERGATE_3D] = "3d0",
+        [TEGRA_POWERGATE_VENC] = "venc",
+        [TEGRA_POWERGATE_VDEC] = "vdec",
+        [TEGRA_POWERGATE_PCIE] = "pcie",
+        [TEGRA_POWERGATE_L2] = "l2",
+        [TEGRA_POWERGATE_MPE] = "mpe",
+        [TEGRA_POWERGATE_HEG] = "heg",
+        [TEGRA_POWERGATE_SATA] = "sata",
+        [TEGRA_POWERGATE_CPU1] = "cpu1",
+        [TEGRA_POWERGATE_CPU2] = "cpu2",
+        [TEGRA_POWERGATE_CPU3] = "cpu3",
+        [TEGRA_POWERGATE_CELP] = "celp",
+        [TEGRA_POWERGATE_3D1] = "3d1",
+};
+
+static const u8 tegra30_cpu_powergates[] = {
+        TEGRA_POWERGATE_CPU,
+        TEGRA_POWERGATE_CPU1,
+        TEGRA_POWERGATE_CPU2,
+        TEGRA_POWERGATE_CPU3,
+};
+
+static const struct tegra_pmc_soc tegra30_pmc_soc = {
+        .num_powergates = ARRAY_SIZE(tegra30_powergates),
+        .powergates = tegra30_powergates,
+        .num_cpu_powergates = ARRAY_SIZE(tegra30_cpu_powergates),
+        .cpu_powergates = tegra30_cpu_powergates,
+};
+
+static const char * const tegra114_powergates[] = {
+        [TEGRA_POWERGATE_CPU] = "crail",
+        [TEGRA_POWERGATE_3D] = "3d",
+        [TEGRA_POWERGATE_VENC] = "venc",
+        [TEGRA_POWERGATE_VDEC] = "vdec",
+        [TEGRA_POWERGATE_MPE] = "mpe",
+        [TEGRA_POWERGATE_HEG] = "heg",
+        [TEGRA_POWERGATE_CPU1] = "cpu1",
+        [TEGRA_POWERGATE_CPU2] = "cpu2",
+        [TEGRA_POWERGATE_CPU3] = "cpu3",
+        [TEGRA_POWERGATE_CELP] = "celp",
+        [TEGRA_POWERGATE_CPU0] = "cpu0",
+        [TEGRA_POWERGATE_C0NC] = "c0nc",
+        [TEGRA_POWERGATE_C1NC] = "c1nc",
+        [TEGRA_POWERGATE_DIS] = "dis",
+        [TEGRA_POWERGATE_DISB] = "disb",
+        [TEGRA_POWERGATE_XUSBA] = "xusba",
+        [TEGRA_POWERGATE_XUSBB] = "xusbb",
+        [TEGRA_POWERGATE_XUSBC] = "xusbc",
+};
+
+static const u8 tegra114_cpu_powergates[] = {
+        TEGRA_POWERGATE_CPU0,
+        TEGRA_POWERGATE_CPU1,
+        TEGRA_POWERGATE_CPU2,
+        TEGRA_POWERGATE_CPU3,
+};
+
+static const struct tegra_pmc_soc tegra114_pmc_soc = {
+        .num_powergates = ARRAY_SIZE(tegra114_powergates),
+        .powergates = tegra114_powergates,
+        .num_cpu_powergates = ARRAY_SIZE(tegra114_cpu_powergates),
+        .cpu_powergates = tegra114_cpu_powergates,
+};
+
+static const char * const tegra124_powergates[] = {
+        [TEGRA_POWERGATE_CPU] = "crail",
+        [TEGRA_POWERGATE_3D] = "3d",
+        [TEGRA_POWERGATE_VENC] = "venc",
+        [TEGRA_POWERGATE_PCIE] = "pcie",
+        [TEGRA_POWERGATE_VDEC] = "vdec",
+        [TEGRA_POWERGATE_L2] = "l2",
+        [TEGRA_POWERGATE_MPE] = "mpe",
+        [TEGRA_POWERGATE_HEG] = "heg",
+        [TEGRA_POWERGATE_SATA] = "sata",
+        [TEGRA_POWERGATE_CPU1] = "cpu1",
+        [TEGRA_POWERGATE_CPU2] = "cpu2",
+        [TEGRA_POWERGATE_CPU3] = "cpu3",
+        [TEGRA_POWERGATE_CELP] = "celp",
+        [TEGRA_POWERGATE_CPU0] = "cpu0",
+        [TEGRA_POWERGATE_C0NC] = "c0nc",
+        [TEGRA_POWERGATE_C1NC] = "c1nc",
+        [TEGRA_POWERGATE_SOR] = "sor",
+        [TEGRA_POWERGATE_DIS] = "dis",
+        [TEGRA_POWERGATE_DISB] = "disb",
+        [TEGRA_POWERGATE_XUSBA] = "xusba",
+        [TEGRA_POWERGATE_XUSBB] = "xusbb",
+        [TEGRA_POWERGATE_XUSBC] = "xusbc",
+        [TEGRA_POWERGATE_VIC] = "vic",
+        [TEGRA_POWERGATE_IRAM] = "iram",
+};
+
+static const u8 tegra124_cpu_powergates[] = {
+        TEGRA_POWERGATE_CPU0,
+        TEGRA_POWERGATE_CPU1,
+        TEGRA_POWERGATE_CPU2,
+        TEGRA_POWERGATE_CPU3,
+};
+
+static const struct tegra_pmc_soc tegra124_pmc_soc = {
+        .num_powergates = ARRAY_SIZE(tegra124_powergates),
+        .powergates = tegra124_powergates,
+        .num_cpu_powergates = ARRAY_SIZE(tegra124_cpu_powergates),
+        .cpu_powergates = tegra124_cpu_powergates,
+};
+
+static const struct of_device_id tegra_pmc_match[] = {
+        { .compatible = "nvidia,tegra124-pmc", .data = &tegra124_pmc_soc },
+        { .compatible = "nvidia,tegra114-pmc", .data = &tegra114_pmc_soc },
+        { .compatible = "nvidia,tegra30-pmc", .data = &tegra30_pmc_soc },
+        { .compatible = "nvidia,tegra20-pmc", .data = &tegra20_pmc_soc },
+        { }
+};
+
+static struct platform_driver tegra_pmc_driver = {
+        .driver = {
+                .name = "tegra-pmc",
+                .suppress_bind_attrs = true,
+                .of_match_table = tegra_pmc_match,
+                .pm = &tegra_pmc_pm_ops,
+        },
+        .probe = tegra_pmc_probe,
+};
+module_platform_driver(tegra_pmc_driver);
+
+/*
+ * Early initialization to allow access to registers in the very early boot
+ * process.
+ */
+static int __init tegra_pmc_early_init(void)
+{
+        const struct of_device_id *match;
+        struct device_node *np;
+        struct resource regs;
+        bool invert;
+        u32 value;
+
+        if (!soc_is_tegra())
+                return 0;
+
+        np = of_find_matching_node_and_match(NULL, tegra_pmc_match, &match);
+        if (!np) {
+                pr_warn("PMC device node not found, disabling powergating\n");
+
+                regs.start = 0x7000e400;
+                regs.end = 0x7000e7ff;
+                regs.flags = IORESOURCE_MEM;
+
+                pr_warn("Using memory region %pR\n", &regs);
+        } else {
+                pmc->soc = match->data;
+        }
+
+        if (of_address_to_resource(np, 0, &regs) < 0) {
+                pr_err("failed to get PMC registers\n");
+                return -ENXIO;
+        }
+
+        pmc->base = ioremap_nocache(regs.start, resource_size(&regs));
+        if (!pmc->base) {
+                pr_err("failed to map PMC registers\n");
+                return -ENXIO;
+        }
+
+        mutex_init(&pmc->powergates_lock);
+
+        invert = of_property_read_bool(np, "nvidia,invert-interrupt");
+
+        value = tegra_pmc_readl(PMC_CNTRL);
+
+        if (invert)
+                value |= PMC_CNTRL_INTR_POLARITY;
+        else
+                value &= ~PMC_CNTRL_INTR_POLARITY;
+
+        tegra_pmc_writel(value, PMC_CNTRL);
+
+        return 0;
+}
+early_initcall(tegra_pmc_early_init);