/*
 * CPU frequency scaling for Broadcom SoCs with AVS firmware that
 * supports DVS or DVFS
 *
 * Copyright (c) 2016 Broadcom
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

/*
 * "AVS" is the name of a firmware developed at Broadcom. It derives
 * its name from the technique called "Adaptive Voltage Scaling".
 * Adaptive voltage scaling was the original purpose of this firmware.
 * The AVS firmware still supports "AVS mode", where all it does is
 * adaptive voltage scaling. However, on some newer Broadcom SoCs, the
 * AVS Firmware, despite its unchanged name, also supports DFS mode and
 * DVFS mode.
 *
 * In the context of this document and the related driver, "AVS" by
 * itself always means the Broadcom firmware and never refers to the
 * technique called "Adaptive Voltage Scaling".
 *
 * The Broadcom STB AVS CPUfreq driver provides voltage and frequency
 * scaling on Broadcom SoCs using AVS firmware with support for DFS and
 * DVFS. The AVS firmware is running on its own co-processor. The
 * driver supports both uniprocessor (UP) and symmetric multiprocessor
 * (SMP) systems which share clock and voltage across all CPUs.
 *
 * Actual voltage and frequency scaling is done solely by the AVS
 * firmware. This driver does not change frequency or voltage itself.
 * It provides a standard CPUfreq interface to the rest of the kernel
 * and to userland. It interfaces with the AVS firmware to effect the
 * requested changes and to report back the current system status in a
 * way that is expected by existing tools.
 */

#include <linux/cpufreq.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/semaphore.h>

#ifdef CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#endif

/* Max number of arguments AVS calls take */
#define AVS_MAX_CMD_ARGS        4
/*
 * This macro is used to generate AVS parameter register offsets. For
 * x >= AVS_MAX_CMD_ARGS, it returns 0 to protect against accidental memory
 * access outside of the parameter range. (Offset 0 is the first parameter.)
 */
#define AVS_PARAM_MULT(x)       ((x) < AVS_MAX_CMD_ARGS ? (x) : 0)

/* AVS Mailbox Register offsets */
#define AVS_MBOX_COMMAND        0x00
#define AVS_MBOX_STATUS         0x04
#define AVS_MBOX_VOLTAGE0       0x08
#define AVS_MBOX_TEMP0          0x0c
#define AVS_MBOX_PV0            0x10
#define AVS_MBOX_MV0            0x14
#define AVS_MBOX_PARAM(x)       (0x18 + AVS_PARAM_MULT(x) * sizeof(u32))
#define AVS_MBOX_REVISION       0x28
#define AVS_MBOX_PSTATE         0x2c
#define AVS_MBOX_HEARTBEAT      0x30
#define AVS_MBOX_MAGIC          0x34
#define AVS_MBOX_SIGMA_HVT      0x38
#define AVS_MBOX_SIGMA_SVT      0x3c
#define AVS_MBOX_VOLTAGE1       0x40
#define AVS_MBOX_TEMP1          0x44
#define AVS_MBOX_PV1            0x48
#define AVS_MBOX_MV1            0x4c
#define AVS_MBOX_FREQUENCY      0x50

/* AVS Commands */
#define AVS_CMD_AVAILABLE       0x00
#define AVS_CMD_DISABLE         0x10
#define AVS_CMD_ENABLE          0x11
#define AVS_CMD_S2_ENTER        0x12
#define AVS_CMD_S2_EXIT         0x13
#define AVS_CMD_BBM_ENTER       0x14
#define AVS_CMD_BBM_EXIT        0x15
#define AVS_CMD_S3_ENTER        0x16
#define AVS_CMD_S3_EXIT         0x17
#define AVS_CMD_BALANCE         0x18
/* PMAP and P-STATE commands */
#define AVS_CMD_GET_PMAP        0x30
#define AVS_CMD_SET_PMAP        0x31
#define AVS_CMD_GET_PSTATE      0x40
#define AVS_CMD_SET_PSTATE      0x41

/* Different modes AVS supports (for GET_PMAP/SET_PMAP) */
#define AVS_MODE_AVS            0x0
#define AVS_MODE_DFS            0x1
#define AVS_MODE_DVS            0x2
#define AVS_MODE_DVFS           0x3

/*
 * PMAP parameter p1
 * unused:31-24, mdiv_p0:23-16, unused:15-14, pdiv:13-10 , ndiv_int:9-0
 */
#define NDIV_INT_SHIFT          0
#define NDIV_INT_MASK           0x3ff
#define PDIV_SHIFT              10
#define PDIV_MASK               0xf
#define MDIV_P0_SHIFT           16
#define MDIV_P0_MASK            0xff
/*
 * PMAP parameter p2
 * mdiv_p4:31-24, mdiv_p3:23-16, mdiv_p2:15:8, mdiv_p1:7:0
 */
#define MDIV_P1_SHIFT           0
#define MDIV_P1_MASK            0xff
#define MDIV_P2_SHIFT           8
#define MDIV_P2_MASK            0xff
#define MDIV_P3_SHIFT           16
#define MDIV_P3_MASK            0xff
#define MDIV_P4_SHIFT           24
#define MDIV_P4_MASK            0xff

/* Different P-STATES AVS supports (for GET_PSTATE/SET_PSTATE) */
#define AVS_PSTATE_P0           0x0
#define AVS_PSTATE_P1           0x1
#define AVS_PSTATE_P2           0x2
#define AVS_PSTATE_P3           0x3
#define AVS_PSTATE_P4           0x4
#define AVS_PSTATE_MAX          AVS_PSTATE_P4

/* CPU L2 Interrupt Controller Registers */
#define AVS_CPU_L2_SET0         0x04
#define AVS_CPU_L2_INT_MASK     BIT(31)

/* AVS Command Status Values */
#define AVS_STATUS_CLEAR        0x00
/* Command/notification accepted */
#define AVS_STATUS_SUCCESS      0xf0
/* Command/notification rejected */
#define AVS_STATUS_FAILURE      0xff
/* Invalid command/notification (unknown) */
#define AVS_STATUS_INVALID      0xf1
/* Non-AVS modes are not supported */
#define AVS_STATUS_NO_SUPP      0xf2
/* Cannot set P-State until P-Map supplied */
#define AVS_STATUS_NO_MAP       0xf3
/* Cannot change P-Map after initial P-Map set */
#define AVS_STATUS_MAP_SET      0xf4
/* Max AVS status; higher numbers are used for debugging */
#define AVS_STATUS_MAX          0xff

/* Other AVS related constants */
#define AVS_LOOP_LIMIT          10000
#define AVS_TIMEOUT             300 /* in ms; expected completion is < 10ms */
#define AVS_FIRMWARE_MAGIC      0xa11600d1

#define BRCM_AVS_CPUFREQ_PREFIX "brcmstb-avs"
#define BRCM_AVS_CPUFREQ_NAME   BRCM_AVS_CPUFREQ_PREFIX "-cpufreq"
#define BRCM_AVS_CPU_DATA       "brcm,avs-cpu-data-mem"
#define BRCM_AVS_CPU_INTR       "brcm,avs-cpu-l2-intr"
#define BRCM_AVS_HOST_INTR      "sw_intr"

struct pmap {
        unsigned int mode;
        unsigned int p1;
        unsigned int p2;
        unsigned int state;
};

struct private_data {
        void __iomem *base;
        void __iomem *avs_intr_base;
        struct device *dev;
#ifdef CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG
        struct dentry *debugfs;
#endif
        struct completion done;
        struct semaphore sem;
        struct pmap pmap;
};

#ifdef CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG

enum debugfs_format {
        DEBUGFS_NORMAL,
        DEBUGFS_FLOAT,
        DEBUGFS_REV,
};

struct debugfs_data {
        struct debugfs_entry *entry;
        struct private_data *priv;
};

struct debugfs_entry {
        char *name;
        u32 offset;
        fmode_t mode;
        enum debugfs_format format;
};

#define DEBUGFS_ENTRY(name, mode, format)       { \
        #name, AVS_MBOX_##name, mode, format \
}

/*
 * These are used for debugfs only. Otherwise we use AVS_MBOX_PARAM() directly.
 */
#define AVS_MBOX_PARAM1         AVS_MBOX_PARAM(0)
#define AVS_MBOX_PARAM2         AVS_MBOX_PARAM(1)
#define AVS_MBOX_PARAM3         AVS_MBOX_PARAM(2)
#define AVS_MBOX_PARAM4         AVS_MBOX_PARAM(3)

/*
 * This table stores the name, access permissions and offset for each hardware
 * register and is used to generate debugfs entries.
 */
static struct debugfs_entry debugfs_entries[] = {
        DEBUGFS_ENTRY(COMMAND, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(STATUS, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(VOLTAGE0, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(TEMP0, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(PV0, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(MV0, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(PARAM1, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(PARAM2, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(PARAM3, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(PARAM4, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(REVISION, 0, DEBUGFS_REV),
        DEBUGFS_ENTRY(PSTATE, 0, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(HEARTBEAT, 0, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(MAGIC, S_IWUSR, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(SIGMA_HVT, 0, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(SIGMA_SVT, 0, DEBUGFS_NORMAL),
        DEBUGFS_ENTRY(VOLTAGE1, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(TEMP1, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(PV1, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(MV1, 0, DEBUGFS_FLOAT),
        DEBUGFS_ENTRY(FREQUENCY, 0, DEBUGFS_NORMAL),
};

static int brcm_avs_target_index(struct cpufreq_policy *, unsigned int);

static char *__strtolower(char *s)
{
        char *p;

        for (p = s; *p; p++)
                *p = tolower(*p);

        return s;
}

#endif /* CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG */

static void __iomem *__map_region(const char *name)
{
        struct device_node *np;
        void __iomem *ptr;

        np = of_find_compatible_node(NULL, NULL, name);
        if (!np)
                return NULL;

        ptr = of_iomap(np, 0);
        of_node_put(np);

        return ptr;
}

static int __issue_avs_command(struct private_data *priv, int cmd, bool is_send,
                               u32 args[])
{
        unsigned long time_left = msecs_to_jiffies(AVS_TIMEOUT);
        void __iomem *base = priv->base;
        unsigned int i;
        int ret;
        u32 val;

        ret = down_interruptible(&priv->sem);
        if (ret)
                return ret;

        /*
         * Make sure no other command is currently running: cmd is 0 if AVS
         * co-processor is idle. Due to the guard above, we should almost never
         * have to wait here.
         */
        for (i = 0, val = 1; val != 0 && i < AVS_LOOP_LIMIT; i++)
                val = readl(base + AVS_MBOX_COMMAND);

        /* Give the caller a chance to retry if AVS is busy. */
        if (i == AVS_LOOP_LIMIT) {
                ret = -EAGAIN;
                goto out;
        }

        /* Clear status before we begin. */
        writel(AVS_STATUS_CLEAR, base + AVS_MBOX_STATUS);

        /* We need to send arguments for this command. */
        if (args && is_send) {
                for (i = 0; i < AVS_MAX_CMD_ARGS; i++)
                        writel(args[i], base + AVS_MBOX_PARAM(i));
        }

        /* Protect from spurious interrupts. */
        reinit_completion(&priv->done);

        /* Now issue the command & tell firmware to wake up to process it. */
        writel(cmd, base + AVS_MBOX_COMMAND);
        writel(AVS_CPU_L2_INT_MASK, priv->avs_intr_base + AVS_CPU_L2_SET0);

        /* Wait for AVS co-processor to finish processing the command. */
        time_left = wait_for_completion_timeout(&priv->done, time_left);

        /*
         * If the AVS status is not in the expected range, it means AVS didn't
         * complete our command in time, and we return an error. Also, if there
         * is no "time left", we timed out waiting for the interrupt.
         */
        val = readl(base + AVS_MBOX_STATUS);
        if (time_left == 0 || val == 0 || val > AVS_STATUS_MAX) {
                dev_err(priv->dev, "AVS command %#x didn't complete in time\n",
                        cmd);
                dev_err(priv->dev, "    Time left: %u ms, AVS status: %#x\n",
                        jiffies_to_msecs(time_left), val);
                ret = -ETIMEDOUT;
                goto out;
        }

        /* This command returned arguments, so we read them back. */
        if (args && !is_send) {
                for (i = 0; i < AVS_MAX_CMD_ARGS; i++)
                        args[i] = readl(base + AVS_MBOX_PARAM(i));
        }

        /* Clear status to tell AVS co-processor we are done. */
        writel(AVS_STATUS_CLEAR, base + AVS_MBOX_STATUS);

        /* Convert firmware errors to errno's as much as possible. */
        switch (val) {
        case AVS_STATUS_INVALID:
                ret = -EINVAL;
                break;
        case AVS_STATUS_NO_SUPP:
                ret = -ENOTSUPP;
                break;
        case AVS_STATUS_NO_MAP:
                ret = -ENOENT;
                break;
        case AVS_STATUS_MAP_SET:
                ret = -EEXIST;
                break;
        case AVS_STATUS_FAILURE:
                ret = -EIO;
                break;
        }

out:
        up(&priv->sem);

        return ret;
}

static irqreturn_t irq_handler(int irq, void *data)
{
        struct private_data *priv = data;

        /* AVS command completed execution. Wake up __issue_avs_command(). */
        complete(&priv->done);

        return IRQ_HANDLED;
}

static char *brcm_avs_mode_to_string(unsigned int mode)
{
        switch (mode) {
        case AVS_MODE_AVS:
                return "AVS";
        case AVS_MODE_DFS:
                return "DFS";
        case AVS_MODE_DVS:
                return "DVS";
        case AVS_MODE_DVFS:
                return "DVFS";
        }
        return NULL;
}

static void brcm_avs_parse_p1(u32 p1, unsigned int *mdiv_p0, unsigned int *pdiv,
                              unsigned int *ndiv)
{
        *mdiv_p0 = (p1 >> MDIV_P0_SHIFT) & MDIV_P0_MASK;
        *pdiv = (p1 >> PDIV_SHIFT) & PDIV_MASK;
        *ndiv = (p1 >> NDIV_INT_SHIFT) & NDIV_INT_MASK;
}

static void brcm_avs_parse_p2(u32 p2, unsigned int *mdiv_p1,
                              unsigned int *mdiv_p2, unsigned int *mdiv_p3,
                              unsigned int *mdiv_p4)
{
        *mdiv_p4 = (p2 >> MDIV_P4_SHIFT) & MDIV_P4_MASK;
        *mdiv_p3 = (p2 >> MDIV_P3_SHIFT) & MDIV_P3_MASK;
        *mdiv_p2 = (p2 >> MDIV_P2_SHIFT) & MDIV_P2_MASK;
        *mdiv_p1 = (p2 >> MDIV_P1_SHIFT) & MDIV_P1_MASK;
}

static int brcm_avs_get_pmap(struct private_data *priv, struct pmap *pmap)
{
        u32 args[AVS_MAX_CMD_ARGS];
        int ret;

        ret = __issue_avs_command(priv, AVS_CMD_GET_PMAP, false, args);
        if (ret || !pmap)
                return ret;

        pmap->mode = args[0];
        pmap->p1 = args[1];
        pmap->p2 = args[2];
        pmap->state = args[3];

        return 0;
}

static int brcm_avs_set_pmap(struct private_data *priv, struct pmap *pmap)
{
        u32 args[AVS_MAX_CMD_ARGS];

        args[0] = pmap->mode;
        args[1] = pmap->p1;
        args[2] = pmap->p2;
        args[3] = pmap->state;

        return __issue_avs_command(priv, AVS_CMD_SET_PMAP, true, args);
}

static int brcm_avs_get_pstate(struct private_data *priv, unsigned int *pstate)
{
        u32 args[AVS_MAX_CMD_ARGS];
        int ret;

        ret = __issue_avs_command(priv, AVS_CMD_GET_PSTATE, false, args);
        if (ret)
                return ret;
        *pstate = args[0];

        return 0;
}

static int brcm_avs_set_pstate(struct private_data *priv, unsigned int pstate)
{
        u32 args[AVS_MAX_CMD_ARGS];

        args[0] = pstate;

        return __issue_avs_command(priv, AVS_CMD_SET_PSTATE, true, args);
}

static unsigned long brcm_avs_get_voltage(void __iomem *base)
{
        return readl(base + AVS_MBOX_VOLTAGE1);
}

static unsigned long brcm_avs_get_frequency(void __iomem *base)
{
        return readl(base + AVS_MBOX_FREQUENCY) * 1000; /* in kHz */
}

/*
 * We determine which frequencies are supported by cycling through all P-states
 * and reading back what frequency we are running at for each P-state.
 */
static struct cpufreq_frequency_table *
brcm_avs_get_freq_table(struct device *dev, struct private_data *priv)
{
        struct cpufreq_frequency_table *table;
        unsigned int pstate;
        int i, ret;

        /* Remember P-state for later */
        ret = brcm_avs_get_pstate(priv, &pstate);
        if (ret)
                return ERR_PTR(ret);

        table = devm_kzalloc(dev, (AVS_PSTATE_MAX + 1) * sizeof(*table),
                             GFP_KERNEL);
        if (!table)
                return ERR_PTR(-ENOMEM);

        for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
                ret = brcm_avs_set_pstate(priv, i);
                if (ret)
                        return ERR_PTR(ret);
                table[i].frequency = brcm_avs_get_frequency(priv->base);
                table[i].driver_data = i;
        }
        table[i].frequency = CPUFREQ_TABLE_END;

        /* Restore P-state */
        ret = brcm_avs_set_pstate(priv, pstate);
        if (ret)
                return ERR_PTR(ret);

        return table;
}

#ifdef CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG

#define MANT(x) (unsigned int)(abs((x)) / 1000)
#define FRAC(x) (unsigned int)(abs((x)) - abs((x)) / 1000 * 1000)

static int brcm_avs_debug_show(struct seq_file *s, void *data)
{
        struct debugfs_data *dbgfs = s->private;
        void __iomem *base;
        u32 val, offset;

        if (!dbgfs) {
                seq_puts(s, "No device pointer\n");
                return 0;
        }

        base = dbgfs->priv->base;
        offset = dbgfs->entry->offset;
        val = readl(base + offset);
        switch (dbgfs->entry->format) {
        case DEBUGFS_NORMAL:
                seq_printf(s, "%u\n", val);
                break;
        case DEBUGFS_FLOAT:
                seq_printf(s, "%d.%03d\n", MANT(val), FRAC(val));
                break;
        case DEBUGFS_REV:
                seq_printf(s, "%c.%c.%c.%c\n", (val >> 24 & 0xff),
                           (val >> 16 & 0xff), (val >> 8 & 0xff),
                           val & 0xff);
                break;
        }
        seq_printf(s, "0x%08x\n", val);

        return 0;
}

#undef MANT
#undef FRAC

static ssize_t brcm_avs_seq_write(struct file *file, const char __user *buf,
                                  size_t size, loff_t *ppos)
{
        struct seq_file *s = file->private_data;
        struct debugfs_data *dbgfs = s->private;
        struct private_data *priv = dbgfs->priv;
        void __iomem *base, *avs_intr_base;
        bool use_issue_command = false;
        unsigned long val, offset;
        char str[128];
        int ret;
        char *str_ptr = str;

        if (size >= sizeof(str))
                return -E2BIG;

        memset(str, 0, sizeof(str));
        ret = copy_from_user(str, buf, size);
        if (ret)
                return ret;

        base = priv->base;
        avs_intr_base = priv->avs_intr_base;
        offset = dbgfs->entry->offset;
        /*
         * Special case writing to "command" entry only: if the string starts
         * with a 'c', we use the driver's __issue_avs_command() function.
         * Otherwise, we perform a raw write. This should allow testing of raw
         * access as well as using the higher level function. (Raw access
         * doesn't clear the firmware return status after issuing the command.)
         */
        if (str_ptr[0] == 'c' && offset == AVS_MBOX_COMMAND) {
                use_issue_command = true;
                str_ptr++;
        }
        if (kstrtoul(str_ptr, 0, &val) != 0)
                return -EINVAL;

        /*
         * Setting the P-state is a special case. We need to update the CPU
         * frequency we report.
         */
        if (val == AVS_CMD_SET_PSTATE) {
                struct cpufreq_policy *policy;
                unsigned int pstate;

                policy = cpufreq_cpu_get(smp_processor_id());
                /* Read back the P-state we are about to set */
                pstate = readl(base + AVS_MBOX_PARAM(0));
                if (use_issue_command) {
                        ret = brcm_avs_target_index(policy, pstate);
                        return ret ? ret : size;
                }
                policy->cur = policy->freq_table[pstate].frequency;
        }

        if (use_issue_command) {
                ret = __issue_avs_command(priv, val, false, NULL);
        } else {
                /* Locking here is not perfect, but is only for debug. */
                ret = down_interruptible(&priv->sem);
                if (ret)
                        return ret;

                writel(val, base + offset);
                /* We have to wake up the firmware to process a command. */
                if (offset == AVS_MBOX_COMMAND)
                        writel(AVS_CPU_L2_INT_MASK,
                               avs_intr_base + AVS_CPU_L2_SET0);
                up(&priv->sem);
        }

        return ret ? ret : size;
}

static struct debugfs_entry *__find_debugfs_entry(const char *name)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(debugfs_entries); i++)
                if (strcasecmp(debugfs_entries[i].name, name) == 0)
                        return &debugfs_entries[i];

        return NULL;
}

static int brcm_avs_debug_open(struct inode *inode, struct file *file)
{
        struct debugfs_data *data;
        fmode_t fmode;
        int ret;

        /*
         * seq_open(), which is called by single_open(), clears "write" access.
         * We need write access to some files, so we preserve our access mode
         * and restore it.
         */
        fmode = file->f_mode;
        /*
         * Check access permissions even for root. We don't want to be writing
         * to read-only registers. Access for regular users has already been
         * checked by the VFS layer.
         */
        if ((fmode & FMODE_WRITER) && !(inode->i_mode & S_IWUSR))
                return -EACCES;

        data = kmalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;
        /*
         * We use the same file system operations for all our debug files. To
         * produce specific output, we look up the file name upon opening a
         * debugfs entry and map it to a memory offset. This offset is then used
         * in the generic "show" function to read a specific register.
         */
        data->entry = __find_debugfs_entry(file->f_path.dentry->d_iname);
        data->priv = inode->i_private;

        ret = single_open(file, brcm_avs_debug_show, data);
        if (ret)
                kfree(data);
        file->f_mode = fmode;

        return ret;
}

static int brcm_avs_debug_release(struct inode *inode, struct file *file)
{
        struct seq_file *seq_priv = file->private_data;
        struct debugfs_data *data = seq_priv->private;

        kfree(data);
        return single_release(inode, file);
}

static const struct file_operations brcm_avs_debug_ops = {
        .open           = brcm_avs_debug_open,
        .read           = seq_read,
        .write          = brcm_avs_seq_write,
        .llseek         = seq_lseek,
        .release        = brcm_avs_debug_release,
};

static void brcm_avs_cpufreq_debug_init(struct platform_device *pdev)
{
        struct private_data *priv = platform_get_drvdata(pdev);
        struct dentry *dir;
        int i;

        if (!priv)
                return;

        dir = debugfs_create_dir(BRCM_AVS_CPUFREQ_NAME, NULL);
        if (IS_ERR_OR_NULL(dir))
                return;
        priv->debugfs = dir;

        for (i = 0; i < ARRAY_SIZE(debugfs_entries); i++) {
                /*
                 * The DEBUGFS_ENTRY macro generates uppercase strings. We
                 * convert them to lowercase before creating the debugfs
                 * entries.
                 */
                char *entry = __strtolower(debugfs_entries[i].name);
                fmode_t mode = debugfs_entries[i].mode;

                if (!debugfs_create_file(entry, S_IFREG | S_IRUGO | mode,
                                         dir, priv, &brcm_avs_debug_ops)) {
                        priv->debugfs = NULL;
                        debugfs_remove_recursive(dir);
                        break;
                }
        }
}

static void brcm_avs_cpufreq_debug_exit(struct platform_device *pdev)
{
        struct private_data *priv = platform_get_drvdata(pdev);

        if (priv && priv->debugfs) {
                debugfs_remove_recursive(priv->debugfs);
                priv->debugfs = NULL;
        }
}

#else

static void brcm_avs_cpufreq_debug_init(struct platform_device *pdev) {}
static void brcm_avs_cpufreq_debug_exit(struct platform_device *pdev) {}

#endif /* CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG */

/*
 * To ensure the right firmware is running we need to
 *    - check the MAGIC matches what we expect
 *    - brcm_avs_get_pmap() doesn't return -ENOTSUPP or -EINVAL
 * We need to set up our interrupt handling before calling brcm_avs_get_pmap()!
 */
static bool brcm_avs_is_firmware_loaded(struct private_data *priv)
{
        u32 magic;
        int rc;

        rc = brcm_avs_get_pmap(priv, NULL);
        magic = readl(priv->base + AVS_MBOX_MAGIC);

        return (magic == AVS_FIRMWARE_MAGIC) && (rc != -ENOTSUPP) &&
                (rc != -EINVAL);
}

static unsigned int brcm_avs_cpufreq_get(unsigned int cpu)
{
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
        struct private_data *priv = policy->driver_data;

        return brcm_avs_get_frequency(priv->base);
}

static int brcm_avs_target_index(struct cpufreq_policy *policy,
                                 unsigned int index)
{
        return brcm_avs_set_pstate(policy->driver_data,
                                  policy->freq_table[index].driver_data);
}

static int brcm_avs_suspend(struct cpufreq_policy *policy)
{
        struct private_data *priv = policy->driver_data;
        int ret;

        ret = brcm_avs_get_pmap(priv, &priv->pmap);
        if (ret)
                return ret;

        /*
         * We can't use the P-state returned by brcm_avs_get_pmap(), since
         * that's the initial P-state from when the P-map was downloaded to the
         * AVS co-processor, not necessarily the P-state we are running at now.
         * So, we get the current P-state explicitly.
         */
        return brcm_avs_get_pstate(priv, &priv->pmap.state);
}

static int brcm_avs_resume(struct cpufreq_policy *policy)
{
        struct private_data *priv = policy->driver_data;
        int ret;

        ret = brcm_avs_set_pmap(priv, &priv->pmap);
        if (ret == -EEXIST) {
                struct platform_device *pdev  = cpufreq_get_driver_data();
                struct device *dev = &pdev->dev;

                dev_warn(dev, "PMAP was already set\n");
                ret = 0;
        }

        return ret;
}

/*
 * All initialization code that we only want to execute once goes here. Setup
 * code that can be re-tried on every core (if it failed before) can go into
 * brcm_avs_cpufreq_init().
 */
static int brcm_avs_prepare_init(struct platform_device *pdev)
{
        struct private_data *priv;
        struct device *dev;
        int host_irq, ret;

        dev = &pdev->dev;
        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->dev = dev;
        sema_init(&priv->sem, 1);
        init_completion(&priv->done);
        platform_set_drvdata(pdev, priv);

        priv->base = __map_region(BRCM_AVS_CPU_DATA);
        if (!priv->base) {
                dev_err(dev, "Couldn't find property %s in device tree.\n",
                        BRCM_AVS_CPU_DATA);
                return -ENOENT;
        }

        priv->avs_intr_base = __map_region(BRCM_AVS_CPU_INTR);
        if (!priv->avs_intr_base) {
                dev_err(dev, "Couldn't find property %s in device tree.\n",
                        BRCM_AVS_CPU_INTR);
                ret = -ENOENT;
                goto unmap_base;
        }

        host_irq = platform_get_irq_byname(pdev, BRCM_AVS_HOST_INTR);
        if (host_irq < 0) {
                dev_err(dev, "Couldn't find interrupt %s -- %d\n",
                        BRCM_AVS_HOST_INTR, host_irq);
                ret = host_irq;
                goto unmap_intr_base;
        }

        ret = devm_request_irq(dev, host_irq, irq_handler, IRQF_TRIGGER_RISING,
                               BRCM_AVS_HOST_INTR, priv);
        if (ret) {
                dev_err(dev, "IRQ request failed: %s (%d) -- %d\n",
                        BRCM_AVS_HOST_INTR, host_irq, ret);
                goto unmap_intr_base;
        }

        if (brcm_avs_is_firmware_loaded(priv))
                return 0;

        dev_err(dev, "AVS firmware is not loaded or doesn't support DVFS\n");
        ret = -ENODEV;

unmap_intr_base:
        iounmap(priv->avs_intr_base);
unmap_base:
        iounmap(priv->base);

        return ret;
}

static int brcm_avs_cpufreq_init(struct cpufreq_policy *policy)
{
        struct cpufreq_frequency_table *freq_table;
        struct platform_device *pdev;
        struct private_data *priv;
        struct device *dev;
        int ret;

        pdev = cpufreq_get_driver_data();
        priv = platform_get_drvdata(pdev);
        policy->driver_data = priv;
        dev = &pdev->dev;

        freq_table = brcm_avs_get_freq_table(dev, priv);
        if (IS_ERR(freq_table)) {
                ret = PTR_ERR(freq_table);
                dev_err(dev, "Couldn't determine frequency table (%d).\n", ret);
                return ret;
        }

        ret = cpufreq_table_validate_and_show(policy, freq_table);
        if (ret) {
                dev_err(dev, "invalid frequency table: %d\n", ret);
                return ret;
        }

        /* All cores share the same clock and thus the same policy. */
        cpumask_setall(policy->cpus);

        ret = __issue_avs_command(priv, AVS_CMD_ENABLE, false, NULL);
        if (!ret) {
                unsigned int pstate;

                ret = brcm_avs_get_pstate(priv, &pstate);
                if (!ret) {
                        policy->cur = freq_table[pstate].frequency;
                        dev_info(dev, "registered\n");
                        return 0;
                }
        }

        dev_err(dev, "couldn't initialize driver (%d)\n", ret);

        return ret;
}

static ssize_t show_brcm_avs_pstate(struct cpufreq_policy *policy, char *buf)
{
        struct private_data *priv = policy->driver_data;
        unsigned int pstate;

        if (brcm_avs_get_pstate(priv, &pstate))
                return sprintf(buf, "<unknown>\n");

        return sprintf(buf, "%u\n", pstate);
}

static ssize_t show_brcm_avs_mode(struct cpufreq_policy *policy, char *buf)
{
        struct private_data *priv = policy->driver_data;
        struct pmap pmap;

        if (brcm_avs_get_pmap(priv, &pmap))
                return sprintf(buf, "<unknown>\n");

        return sprintf(buf, "%s %u\n", brcm_avs_mode_to_string(pmap.mode),
                pmap.mode);
}

static ssize_t show_brcm_avs_pmap(struct cpufreq_policy *policy, char *buf)
{
        unsigned int mdiv_p0, mdiv_p1, mdiv_p2, mdiv_p3, mdiv_p4;
        struct private_data *priv = policy->driver_data;
        unsigned int ndiv, pdiv;
        struct pmap pmap;

        if (brcm_avs_get_pmap(priv, &pmap))
                return sprintf(buf, "<unknown>\n");

        brcm_avs_parse_p1(pmap.p1, &mdiv_p0, &pdiv, &ndiv);
        brcm_avs_parse_p2(pmap.p2, &mdiv_p1, &mdiv_p2, &mdiv_p3, &mdiv_p4);

        return sprintf(buf, "0x%08x 0x%08x %u %u %u %u %u %u %u %u %u\n",
                pmap.p1, pmap.p2, ndiv, pdiv, mdiv_p0, mdiv_p1, mdiv_p2,
                mdiv_p3, mdiv_p4, pmap.mode, pmap.state);
}

static ssize_t show_brcm_avs_voltage(struct cpufreq_policy *policy, char *buf)
{
        struct private_data *priv = policy->driver_data;

        return sprintf(buf, "0x%08lx\n", brcm_avs_get_voltage(priv->base));
}

static ssize_t show_brcm_avs_frequency(struct cpufreq_policy *policy, char *buf)
{
        struct private_data *priv = policy->driver_data;

        return sprintf(buf, "0x%08lx\n", brcm_avs_get_frequency(priv->base));
}

cpufreq_freq_attr_ro(brcm_avs_pstate);
cpufreq_freq_attr_ro(brcm_avs_mode);
cpufreq_freq_attr_ro(brcm_avs_pmap);
cpufreq_freq_attr_ro(brcm_avs_voltage);
cpufreq_freq_attr_ro(brcm_avs_frequency);

static struct freq_attr *brcm_avs_cpufreq_attr[] = {
        &cpufreq_freq_attr_scaling_available_freqs,
        &brcm_avs_pstate,
        &brcm_avs_mode,
        &brcm_avs_pmap,
        &brcm_avs_voltage,
        &brcm_avs_frequency,
        NULL
};

static struct cpufreq_driver brcm_avs_driver = {
        .flags          = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
        .verify         = cpufreq_generic_frequency_table_verify,
        .target_index   = brcm_avs_target_index,
        .get            = brcm_avs_cpufreq_get,
        .suspend        = brcm_avs_suspend,
        .resume         = brcm_avs_resume,
        .init           = brcm_avs_cpufreq_init,
        .attr           = brcm_avs_cpufreq_attr,
        .name           = BRCM_AVS_CPUFREQ_PREFIX,
};

static int brcm_avs_cpufreq_probe(struct platform_device *pdev)
{
        int ret;

        ret = brcm_avs_prepare_init(pdev);
        if (ret)
                return ret;

        brcm_avs_driver.driver_data = pdev;
        ret = cpufreq_register_driver(&brcm_avs_driver);
        if (!ret)
                brcm_avs_cpufreq_debug_init(pdev);

        return ret;
}

static int brcm_avs_cpufreq_remove(struct platform_device *pdev)
{
        struct private_data *priv;
        int ret;

        ret = cpufreq_unregister_driver(&brcm_avs_driver);
        if (ret)
                return ret;

        brcm_avs_cpufreq_debug_exit(pdev);

        priv = platform_get_drvdata(pdev);
        iounmap(priv->base);
        iounmap(priv->avs_intr_base);

        return 0;
}

static const struct of_device_id brcm_avs_cpufreq_match[] = {
        { .compatible = BRCM_AVS_CPU_DATA },
        { }
};
MODULE_DEVICE_TABLE(of, brcm_avs_cpufreq_match);

static struct platform_driver brcm_avs_cpufreq_platdrv = {
        .driver = {
                .name   = BRCM_AVS_CPUFREQ_NAME,
                .of_match_table = brcm_avs_cpufreq_match,
        },
        .probe          = brcm_avs_cpufreq_probe,
        .remove         = brcm_avs_cpufreq_remove,
};
module_platform_driver(brcm_avs_cpufreq_platdrv);

MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
MODULE_DESCRIPTION("CPUfreq driver for Broadcom STB AVS");
MODULE_LICENSE("GPL");