OMAPDSS: VENC: fix NULL pointer dereference in DSS2 VENC sysfs debug attr on OMAP4

[zen-stable.git] / drivers / amba / bus.c

/*
 *  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 <asm/irq.h>
#include <asm/sizes.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.  However, disabling vcore power
 * would do, so we leave that to the driver.
 */
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);
}

static int amba_get_enable_vcore(struct amba_device *pcdev)
{
        struct regulator *vcore = regulator_get(&pcdev->dev, "vcore");
        int ret;

        pcdev->vcore = vcore;

        if (IS_ERR(vcore)) {
                /* It is OK not to supply a vcore regulator */
                if (PTR_ERR(vcore) == -ENODEV)
                        return 0;
                return PTR_ERR(vcore);
        }

        ret = regulator_enable(vcore);
        if (ret) {
                regulator_put(vcore);
                pcdev->vcore = ERR_PTR(-ENODEV);
        }

        return ret;
}

static void amba_put_disable_vcore(struct amba_device *pcdev)
{
        struct regulator *vcore = pcdev->vcore;

        if (!IS_ERR(vcore)) {
                regulator_disable(vcore);
                regulator_put(vcore);
        }
}

/*
 * 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_vcore(pcdev);
                if (ret)
                        break;

                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);
                amba_put_disable_vcore(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);
        amba_put_disable_vcore(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));
}

/**
 *      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);
}

/**
 *      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)
{
        u32 size;
        void __iomem *tmp;
        int i, ret;

        device_initialize(&dev->dev);

        /*
         * Copy from device_add
         */
        if (dev->dev.init_name) {
                dev_set_name(&dev->dev, "%s", dev->dev.init_name);
                dev->dev.init_name = NULL;
        }

        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);

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

        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] != NO_IRQ)
                ret = device_create_file(&dev->dev, &dev_attr_irq0);
        if (ret == 0 && dev->irq[1] != NO_IRQ)
                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;
}

/**
 *      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);