bus.c

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/*
 *  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/amba/bus.h>
#include <linux/sizes.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);

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

#ifdef CONFIG_HOTPLUG
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;
}
#else
#define amba_uevent NULL
#endif

#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_NULL,
};

#ifdef CONFIG_PM_SLEEP

static int amba_legacy_suspend(struct device *dev, pm_message_t mesg)
{
    struct amba_driver *adrv = to_amba_driver(dev->driver);
    struct amba_device *adev = to_amba_device(dev);
    int ret = 0;

    if (dev->driver && adrv->suspend)
        ret = adrv->suspend(adev, mesg);

    return ret;
}

static int amba_legacy_resume(struct device *dev)
{
    struct amba_driver *adrv = to_amba_driver(dev->driver);
    struct amba_device *adev = to_amba_device(dev);
    int ret = 0;

    if (dev->driver && adrv->resume)
        ret = adrv->resume(adev);

    return ret;
}

#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_SUSPEND

static int amba_pm_suspend(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->suspend)
            ret = drv->pm->suspend(dev);
    } else {
        ret = amba_legacy_suspend(dev, PMSG_SUSPEND);
    }

    return ret;
}

static int amba_pm_resume(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->resume)
            ret = drv->pm->resume(dev);
    } else {
        ret = amba_legacy_resume(dev);
    }

    return ret;
}

#else /* !CONFIG_SUSPEND */

#define amba_pm_suspend     NULL
#define amba_pm_resume      NULL

#endif /* !CONFIG_SUSPEND */

#ifdef CONFIG_HIBERNATE_CALLBACKS

static int amba_pm_freeze(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->freeze)
            ret = drv->pm->freeze(dev);
    } else {
        ret = amba_legacy_suspend(dev, PMSG_FREEZE);
    }

    return ret;
}

static int amba_pm_thaw(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->thaw)
            ret = drv->pm->thaw(dev);
    } else {
        ret = amba_legacy_resume(dev);
    }

    return ret;
}

static int amba_pm_poweroff(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->poweroff)
            ret = drv->pm->poweroff(dev);
    } else {
        ret = amba_legacy_suspend(dev, PMSG_HIBERNATE);
    }

    return ret;
}

static int amba_pm_restore(struct device *dev)
{
    struct device_driver *drv = dev->driver;
    int ret = 0;

    if (!drv)
        return 0;

    if (drv->pm) {
        if (drv->pm->restore)
            ret = drv->pm->restore(dev);
    } else {
        ret = amba_legacy_resume(dev);
    }

    return ret;
}

#else /* !CONFIG_HIBERNATE_CALLBACKS */

#define amba_pm_freeze      NULL
#define amba_pm_thaw        NULL
#define amba_pm_poweroff        NULL
#define amba_pm_restore     NULL

#endif /* !CONFIG_HIBERNATE_CALLBACKS */

#ifdef CONFIG_PM_RUNTIME
/*
 * 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)
        clk_disable(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) {
        ret = clk_enable(pcdev->pclk);
        /* Failure is probably fatal to the system, but... */
        if (ret)
            return ret;
    }

    return pm_generic_runtime_resume(dev);
}
#endif

#ifdef CONFIG_PM

static const struct dev_pm_ops amba_pm = {
    .suspend    = amba_pm_suspend,
    .resume     = amba_pm_resume,
    .freeze     = amba_pm_freeze,
    .thaw       = amba_pm_thaw,
    .poweroff   = amba_pm_poweroff,
    .restore    = amba_pm_restore,
    SET_RUNTIME_PM_OPS(
        amba_pm_runtime_suspend,
        amba_pm_runtime_resume,
        pm_generic_runtime_idle
    )
};

#define AMBA_PM (&amba_pm)

#else /* !CONFIG_PM */

#define AMBA_PM NULL

#endif /* !CONFIG_PM */

/*
 * 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)
{
    struct clk *pclk = clk_get(&pcdev->dev, "apb_pclk");
    int ret;

    pcdev->pclk = pclk;

    if (IS_ERR(pclk))
        return PTR_ERR(pclk);

    ret = clk_prepare(pclk);
    if (ret) {
        clk_put(pclk);
        return ret;
    }

    ret = clk_enable(pclk);
    if (ret) {
        clk_unprepare(pclk);
        clk_put(pclk);
    }

    return ret;
}

static void amba_put_disable_pclk(struct amba_device *pcdev)
{
    struct clk *pclk = pcdev->pclk;

    clk_disable(pclk);
    clk_unprepare(pclk);
    clk_put(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 = amba_get_enable_pclk(pcdev);
        if (ret)
            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);
    } 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);

    return ret;
}

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

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);
}

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);
}

int amba_device_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 = 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)
            dev->periphid = pid;

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

    iounmap(tmp);

    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;
}
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 amba_device *dev;
    int ret;

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

    dev->dma_mask = dma_mask;
    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, &iomem_resource);
    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);
}
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);
}
EXPORT_SYMBOL_GPL(amba_ahb_device_add);

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->dma_mask;
    dev->res.name = dev_name(&dev->dev);
}

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);

int amba_device_register(struct amba_device *dev, struct resource *parent)
{
    amba_device_initialize(dev, dev->dev.init_name);
    dev->dev.init_name = NULL;

    if (!dev->dev.coherent_dma_mask && dev->dma_mask)
        dev_warn(&dev->dev, "coherent dma mask is unset\n");

    return amba_device_add(dev, parent);
}

void amba_device_put(struct amba_device *dev)
{
    put_device(&dev->dev);
}
EXPORT_SYMBOL_GPL(amba_device_put);

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;
}

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;
}

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;
}

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);