/*
 *  linux/arch/arm/common/amba.c
 *
 *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/amba/bus.h>
#include <linux/sizes.h>
#include <linux/limits.h>
#include <linux/clk/clk-conf.h>

#include <asm/irq.h>

#define to_amba_driver(d)       container_of(d, struct amba_driver, drv)

static const struct amba_id *
amba_lookup(const struct amba_id *table, struct amba_device *dev)
{
        int ret = 0;

        while (table->mask) {
                ret = (dev->periphid & table->mask) == table->id;
                if (ret)
                        break;
                table++;
        }

        return ret ? table : NULL;
}

static int amba_match(struct device *dev, struct device_driver *drv)
{
        struct amba_device *pcdev = to_amba_device(dev);
        struct amba_driver *pcdrv = to_amba_driver(drv);

        /* When driver_override is set, only bind to the matching driver */
        if (pcdev->driver_override)
                return !strcmp(pcdev->driver_override, drv->name);

        return amba_lookup(pcdrv->id_table, pcdev) != NULL;
}

static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct amba_device *pcdev = to_amba_device(dev);
        int retval = 0;

        retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
        if (retval)
                return retval;

        retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
        return retval;
}

static ssize_t driver_override_show(struct device *_dev,
                                    struct device_attribute *attr, char *buf)
{
        struct amba_device *dev = to_amba_device(_dev);

        if (!dev->driver_override)
                return 0;

        return sprintf(buf, "%s\n", dev->driver_override);
}

static ssize_t driver_override_store(struct device *_dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        struct amba_device *dev = to_amba_device(_dev);
        char *driver_override, *old = dev->driver_override, *cp;

        if (count > PATH_MAX)
                return -EINVAL;

        driver_override = kstrndup(buf, count, GFP_KERNEL);
        if (!driver_override)
                return -ENOMEM;

        cp = strchr(driver_override, '\n');
        if (cp)
                *cp = '\0';

        if (strlen(driver_override)) {
                dev->driver_override = driver_override;
        } else {
               kfree(driver_override);
               dev->driver_override = NULL;
        }

        kfree(old);

        return count;
}

#define amba_attr_func(name,fmt,arg...)                                 \
static ssize_t name##_show(struct device *_dev,                         \
                           struct device_attribute *attr, char *buf)    \
{                                                                       \
        struct amba_device *dev = to_amba_device(_dev);                 \
        return sprintf(buf, fmt, arg);                                  \
}

#define amba_attr(name,fmt,arg...)      \
amba_attr_func(name,fmt,arg)            \
static DEVICE_ATTR(name, S_IRUGO, name##_show, NULL)

amba_attr_func(id, "%08x\n", dev->periphid);
amba_attr(irq0, "%u\n", dev->irq[0]);
amba_attr(irq1, "%u\n", dev->irq[1]);
amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
         (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
         dev->res.flags);

static struct device_attribute amba_dev_attrs[] = {
        __ATTR_RO(id),
        __ATTR_RO(resource),
        __ATTR_RW(driver_override),
        __ATTR_NULL,
};

#ifdef CONFIG_PM
/*
 * Hooks to provide runtime PM of the pclk (bus clock).  It is safe to
 * enable/disable the bus clock at runtime PM suspend/resume as this
 * does not result in loss of context.
 */
static int amba_pm_runtime_suspend(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);
        int ret = pm_generic_runtime_suspend(dev);

        if (ret == 0 && dev->driver) {
                if (pm_runtime_is_irq_safe(dev))
                        clk_disable(pcdev->pclk);
                else
                        clk_disable_unprepare(pcdev->pclk);
        }

        return ret;
}

static int amba_pm_runtime_resume(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);
        int ret;

        if (dev->driver) {
                if (pm_runtime_is_irq_safe(dev))
                        ret = clk_enable(pcdev->pclk);
                else
                        ret = clk_prepare_enable(pcdev->pclk);
                /* Failure is probably fatal to the system, but... */
                if (ret)
                        return ret;
        }

        return pm_generic_runtime_resume(dev);
}
#endif /* CONFIG_PM */

static const struct dev_pm_ops amba_pm = {
        .suspend        = pm_generic_suspend,
        .resume         = pm_generic_resume,
        .freeze         = pm_generic_freeze,
        .thaw           = pm_generic_thaw,
        .poweroff       = pm_generic_poweroff,
        .restore        = pm_generic_restore,
        SET_RUNTIME_PM_OPS(
                amba_pm_runtime_suspend,
                amba_pm_runtime_resume,
                NULL
        )
};

/*
 * Primecells are part of the Advanced Microcontroller Bus Architecture,
 * so we call the bus "amba".
 */
struct bus_type amba_bustype = {
        .name           = "amba",
        .dev_attrs      = amba_dev_attrs,
        .match          = amba_match,
        .uevent         = amba_uevent,
        .pm             = &amba_pm,
};

static int __init amba_init(void)
{
        return bus_register(&amba_bustype);
}

postcore_initcall(amba_init);

static int amba_get_enable_pclk(struct amba_device *pcdev)
{
        int ret;

        pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
        if (IS_ERR(pcdev->pclk))
                return PTR_ERR(pcdev->pclk);

        ret = clk_prepare_enable(pcdev->pclk);
        if (ret)
                clk_put(pcdev->pclk);

        return ret;
}

static void amba_put_disable_pclk(struct amba_device *pcdev)
{
        clk_disable_unprepare(pcdev->pclk);
        clk_put(pcdev->pclk);
}

/*
 * These are the device model conversion veneers; they convert the
 * device model structures to our more specific structures.
 */
static int amba_probe(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);
        struct amba_driver *pcdrv = to_amba_driver(dev->driver);
        const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
        int ret;

        do {
                ret = of_clk_set_defaults(dev->of_node, false);
                if (ret < 0)
                        break;

                ret = dev_pm_domain_attach(dev, true);
                if (ret == -EPROBE_DEFER)
                        break;

                ret = amba_get_enable_pclk(pcdev);
                if (ret) {
                        dev_pm_domain_detach(dev, true);
                        break;
                }

                pm_runtime_get_noresume(dev);
                pm_runtime_set_active(dev);
                pm_runtime_enable(dev);

                ret = pcdrv->probe(pcdev, id);
                if (ret == 0)
                        break;

                pm_runtime_disable(dev);
                pm_runtime_set_suspended(dev);
                pm_runtime_put_noidle(dev);

                amba_put_disable_pclk(pcdev);
                dev_pm_domain_detach(dev, true);
        } while (0);

        return ret;
}

static int amba_remove(struct device *dev)
{
        struct amba_device *pcdev = to_amba_device(dev);
        struct amba_driver *drv = to_amba_driver(dev->driver);
        int ret;

        pm_runtime_get_sync(dev);
        ret = drv->remove(pcdev);
        pm_runtime_put_noidle(dev);

        /* Undo the runtime PM settings in amba_probe() */
        pm_runtime_disable(dev);
        pm_runtime_set_suspended(dev);
        pm_runtime_put_noidle(dev);

        amba_put_disable_pclk(pcdev);
        dev_pm_domain_detach(dev, true);

        return ret;
}

static void amba_shutdown(struct device *dev)
{
        struct amba_driver *drv = to_amba_driver(dev->driver);
        drv->shutdown(to_amba_device(dev));
}

/**
 *      amba_driver_register - register an AMBA device driver
 *      @drv: amba device driver structure
 *
 *      Register an AMBA device driver with the Linux device model
 *      core.  If devices pre-exist, the drivers probe function will
 *      be called.
 */
int amba_driver_register(struct amba_driver *drv)
{
        drv->drv.bus = &amba_bustype;

#define SETFN(fn)       if (drv->fn) drv->drv.fn = amba_##fn
        SETFN(probe);
        SETFN(remove);
        SETFN(shutdown);

        return driver_register(&drv->drv);
}

/**
 *      amba_driver_unregister - remove an AMBA device driver
 *      @drv: AMBA device driver structure to remove
 *
 *      Unregister an AMBA device driver from the Linux device
 *      model.  The device model will call the drivers remove function
 *      for each device the device driver is currently handling.
 */
void amba_driver_unregister(struct amba_driver *drv)
{
        driver_unregister(&drv->drv);
}


static void amba_device_release(struct device *dev)
{
        struct amba_device *d = to_amba_device(dev);

        if (d->res.parent)
                release_resource(&d->res);
        kfree(d);
}

static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
{
        u32 size;
        void __iomem *tmp;
        int i, ret;

        WARN_ON(dev->irq[0] == (unsigned int)-1);
        WARN_ON(dev->irq[1] == (unsigned int)-1);

        ret = request_resource(parent, &dev->res);
        if (ret)
                goto err_out;

        /* Hard-coded primecell ID instead of plug-n-play */
        if (dev->periphid != 0)
                goto skip_probe;

        /*
         * Dynamically calculate the size of the resource
         * and use this for iomap
         */
        size = resource_size(&dev->res);
        tmp = ioremap(dev->res.start, size);
        if (!tmp) {
                ret = -ENOMEM;
                goto err_release;
        }

        ret = dev_pm_domain_attach(&dev->dev, true);
        if (ret == -EPROBE_DEFER) {
                iounmap(tmp);
                goto err_release;
        }

        ret = amba_get_enable_pclk(dev);
        if (ret == 0) {
                u32 pid, cid;

                /*
                 * Read pid and cid based on size of resource
                 * they are located at end of region
                 */
                for (pid = 0, i = 0; i < 4; i++)
                        pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
                                (i * 8);
                for (cid = 0, i = 0; i < 4; i++)
                        cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
                                (i * 8);

                amba_put_disable_pclk(dev);

                if (cid == AMBA_CID || cid == CORESIGHT_CID)
                        dev->periphid = pid;

                if (!dev->periphid)
                        ret = -ENODEV;
        }

        iounmap(tmp);
        dev_pm_domain_detach(&dev->dev, true);

        if (ret)
                goto err_release;

 skip_probe:
        ret = device_add(&dev->dev);
        if (ret)
                goto err_release;

        if (dev->irq[0])
                ret = device_create_file(&dev->dev, &dev_attr_irq0);
        if (ret == 0 && dev->irq[1])
                ret = device_create_file(&dev->dev, &dev_attr_irq1);
        if (ret == 0)
                return ret;

        device_unregister(&dev->dev);

 err_release:
        release_resource(&dev->res);
 err_out:
        return ret;
}

/*
 * Registration of AMBA device require reading its pid and cid registers.
 * To do this, the device must be turned on (if it is a part of power domain)
 * and have clocks enabled. However in some cases those resources might not be
 * yet available. Returning EPROBE_DEFER is not a solution in such case,
 * because callers don't handle this special error code. Instead such devices
 * are added to the special list and their registration is retried from
 * periodic worker, until all resources are available and registration succeeds.
 */
struct deferred_device {
        struct amba_device *dev;
        struct resource *parent;
        struct list_head node;
};

static LIST_HEAD(deferred_devices);
static DEFINE_MUTEX(deferred_devices_lock);

static void amba_deferred_retry_func(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);

#define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))

static void amba_deferred_retry_func(struct work_struct *dummy)
{
        struct deferred_device *ddev, *tmp;

        mutex_lock(&deferred_devices_lock);

        list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
                int ret = amba_device_try_add(ddev->dev, ddev->parent);

                if (ret == -EPROBE_DEFER)
                        continue;

                list_del_init(&ddev->node);
                kfree(ddev);
        }

        if (!list_empty(&deferred_devices))
                schedule_delayed_work(&deferred_retry_work,
                                      DEFERRED_DEVICE_TIMEOUT);

        mutex_unlock(&deferred_devices_lock);
}

/**
 *      amba_device_add - add a previously allocated AMBA device structure
 *      @dev: AMBA device allocated by amba_device_alloc
 *      @parent: resource parent for this devices resources
 *
 *      Claim the resource, and read the device cell ID if not already
 *      initialized.  Register the AMBA device with the Linux device
 *      manager.
 */
int amba_device_add(struct amba_device *dev, struct resource *parent)
{
        int ret = amba_device_try_add(dev, parent);

        if (ret == -EPROBE_DEFER) {
                struct deferred_device *ddev;

                ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
                if (!ddev)
                        return -ENOMEM;

                ddev->dev = dev;
                ddev->parent = parent;
                ret = 0;

                mutex_lock(&deferred_devices_lock);

                if (list_empty(&deferred_devices))
                        schedule_delayed_work(&deferred_retry_work,
                                              DEFERRED_DEVICE_TIMEOUT);
                list_add_tail(&ddev->node, &deferred_devices);

                mutex_unlock(&deferred_devices_lock);
        }
        return ret;
}
EXPORT_SYMBOL_GPL(amba_device_add);

static struct amba_device *
amba_aphb_device_add(struct device *parent, const char *name,
                     resource_size_t base, size_t size, int irq1, int irq2,
                     void *pdata, unsigned int periphid, u64 dma_mask,
                     struct resource *resbase)
{
        struct amba_device *dev;
        int ret;

        dev = amba_device_alloc(name, base, size);
        if (!dev)
                return ERR_PTR(-ENOMEM);

        dev->dev.coherent_dma_mask = dma_mask;
        dev->irq[0] = irq1;
        dev->irq[1] = irq2;
        dev->periphid = periphid;
        dev->dev.platform_data = pdata;
        dev->dev.parent = parent;

        ret = amba_device_add(dev, resbase);
        if (ret) {
                amba_device_put(dev);
                return ERR_PTR(ret);
        }

        return dev;
}

struct amba_device *
amba_apb_device_add(struct device *parent, const char *name,
                    resource_size_t base, size_t size, int irq1, int irq2,
                    void *pdata, unsigned int periphid)
{
        return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
                                    periphid, 0, &iomem_resource);
}
EXPORT_SYMBOL_GPL(amba_apb_device_add);

struct amba_device *
amba_ahb_device_add(struct device *parent, const char *name,
                    resource_size_t base, size_t size, int irq1, int irq2,
                    void *pdata, unsigned int periphid)
{
        return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
                                    periphid, ~0ULL, &iomem_resource);
}
EXPORT_SYMBOL_GPL(amba_ahb_device_add);

struct amba_device *
amba_apb_device_add_res(struct device *parent, const char *name,
                        resource_size_t base, size_t size, int irq1,
                        int irq2, void *pdata, unsigned int periphid,
                        struct resource *resbase)
{
        return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
                                    periphid, 0, resbase);
}
EXPORT_SYMBOL_GPL(amba_apb_device_add_res);

struct amba_device *
amba_ahb_device_add_res(struct device *parent, const char *name,
                        resource_size_t base, size_t size, int irq1,
                        int irq2, void *pdata, unsigned int periphid,
                        struct resource *resbase)
{
        return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
                                    periphid, ~0ULL, resbase);
}
EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);


static void amba_device_initialize(struct amba_device *dev, const char *name)
{
        device_initialize(&dev->dev);
        if (name)
                dev_set_name(&dev->dev, "%s", name);
        dev->dev.release = amba_device_release;
        dev->dev.bus = &amba_bustype;
        dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
        dev->res.name = dev_name(&dev->dev);
}

/**
 *      amba_device_alloc - allocate an AMBA device
 *      @name: sysfs name of the AMBA device
 *      @base: base of AMBA device
 *      @size: size of AMBA device
 *
 *      Allocate and initialize an AMBA device structure.  Returns %NULL
 *      on failure.
 */
struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
        size_t size)
{
        struct amba_device *dev;

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (dev) {
                amba_device_initialize(dev, name);
                dev->res.start = base;
                dev->res.end = base + size - 1;
                dev->res.flags = IORESOURCE_MEM;
        }

        return dev;
}
EXPORT_SYMBOL_GPL(amba_device_alloc);

/**
 *      amba_device_register - register an AMBA device
 *      @dev: AMBA device to register
 *      @parent: parent memory resource
 *
 *      Setup the AMBA device, reading the cell ID if present.
 *      Claim the resource, and register the AMBA device with
 *      the Linux device manager.
 */
int amba_device_register(struct amba_device *dev, struct resource *parent)
{
        amba_device_initialize(dev, dev->dev.init_name);
        dev->dev.init_name = NULL;

        return amba_device_add(dev, parent);
}

/**
 *      amba_device_put - put an AMBA device
 *      @dev: AMBA device to put
 */
void amba_device_put(struct amba_device *dev)
{
        put_device(&dev->dev);
}
EXPORT_SYMBOL_GPL(amba_device_put);

/**
 *      amba_device_unregister - unregister an AMBA device
 *      @dev: AMBA device to remove
 *
 *      Remove the specified AMBA device from the Linux device
 *      manager.  All files associated with this object will be
 *      destroyed, and device drivers notified that the device has
 *      been removed.  The AMBA device's resources including
 *      the amba_device structure will be freed once all
 *      references to it have been dropped.
 */
void amba_device_unregister(struct amba_device *dev)
{
        device_unregister(&dev->dev);
}


struct find_data {
        struct amba_device *dev;
        struct device *parent;
        const char *busid;
        unsigned int id;
        unsigned int mask;
};

static int amba_find_match(struct device *dev, void *data)
{
        struct find_data *d = data;
        struct amba_device *pcdev = to_amba_device(dev);
        int r;

        r = (pcdev->periphid & d->mask) == d->id;
        if (d->parent)
                r &= d->parent == dev->parent;
        if (d->busid)
                r &= strcmp(dev_name(dev), d->busid) == 0;

        if (r) {
                get_device(dev);
                d->dev = pcdev;
        }

        return r;
}

/**
 *      amba_find_device - locate an AMBA device given a bus id
 *      @busid: bus id for device (or NULL)
 *      @parent: parent device (or NULL)
 *      @id: peripheral ID (or 0)
 *      @mask: peripheral ID mask (or 0)
 *
 *      Return the AMBA device corresponding to the supplied parameters.
 *      If no device matches, returns NULL.
 *
 *      NOTE: When a valid device is found, its refcount is
 *      incremented, and must be decremented before the returned
 *      reference.
 */
struct amba_device *
amba_find_device(const char *busid, struct device *parent, unsigned int id,
                 unsigned int mask)
{
        struct find_data data;

        data.dev = NULL;
        data.parent = parent;
        data.busid = busid;
        data.id = id;
        data.mask = mask;

        bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);

        return data.dev;
}

/**
 *      amba_request_regions - request all mem regions associated with device
 *      @dev: amba_device structure for device
 *      @name: name, or NULL to use driver name
 */
int amba_request_regions(struct amba_device *dev, const char *name)
{
        int ret = 0;
        u32 size;

        if (!name)
                name = dev->dev.driver->name;

        size = resource_size(&dev->res);

        if (!request_mem_region(dev->res.start, size, name))
                ret = -EBUSY;

        return ret;
}

/**
 *      amba_release_regions - release mem regions associated with device
 *      @dev: amba_device structure for device
 *
 *      Release regions claimed by a successful call to amba_request_regions.
 */
void amba_release_regions(struct amba_device *dev)
{
        u32 size;

        size = resource_size(&dev->res);
        release_mem_region(dev->res.start, size);
}

EXPORT_SYMBOL(amba_driver_register);
EXPORT_SYMBOL(amba_driver_unregister);
EXPORT_SYMBOL(amba_device_register);
EXPORT_SYMBOL(amba_device_unregister);
EXPORT_SYMBOL(amba_find_device);
EXPORT_SYMBOL(amba_request_regions);
EXPORT_SYMBOL(amba_release_regions);