// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/common/amba.c
 *
 *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
 */
#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 <linux/platform_device.h>
#include <linux/property.h>
#include <linux/reset.h>
#include <linux/of_irq.h>
#include <linux/of_device.h>
#include <linux/acpi.h>
#include <linux/iommu.h>
#include <linux/dma-map-ops.h>

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

/* called on periphid match and class 0x9 coresight device. */
static int
amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
{
        int ret = 0;
        struct amba_cs_uci_id *uci;

        uci = table->data;

        /* no table data or zero mask - return match on periphid */
        if (!uci || (uci->devarch_mask == 0))
                return 1;

        /* test against read devtype and masked devarch value */
        ret = (dev->uci.devtype == uci->devtype) &&
                ((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
        return ret;
}

static const struct amba_id *
amba_lookup(const struct amba_id *table, struct amba_device *dev)
{
        while (table->mask) {
                if (((dev->periphid & table->mask) == table->id) &&
                        ((dev->cid != CORESIGHT_CID) ||
                         (amba_cs_uci_id_match(table, dev))))
                        return table;
                table++;
        }
        return NULL;
}

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);
}


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

        device_lock(_dev);
        len = sprintf(buf, "%s\n", dev->driver_override);
        device_unlock(_dev);
        return len;
}

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);
        int ret;

        ret = driver_set_override(_dev, &dev->driver_override, buf, count);
        if (ret)
                return ret;

        return count;
}
static DEVICE_ATTR_RW(driver_override);

#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);                                  \
}                                                                       \
static DEVICE_ATTR_RO(name)

amba_attr_func(id, "%08x\n", dev->periphid);
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 attribute *amba_dev_attrs[] = {
        &dev_attr_id.attr,
        &dev_attr_resource.attr,
        &dev_attr_driver_override.attr,
        NULL,
};
ATTRIBUTE_GROUPS(amba_dev);

static int amba_read_periphid(struct amba_device *dev)
{
        struct reset_control *rstc;
        u32 size, pid, cid;
        void __iomem *tmp;
        int i, ret;

        ret = dev_pm_domain_attach(&dev->dev, PD_FLAG_ATTACH_POWER_ON);
        if (ret) {
                dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
                goto err_out;
        }

        ret = amba_get_enable_pclk(dev);
        if (ret) {
                dev_dbg(&dev->dev, "can't get pclk: %d\n", ret);
                goto err_pm;
        }

        /*
         * Find reset control(s) of the amba bus and de-assert them.
         */
        rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
        if (IS_ERR(rstc)) {
                ret = PTR_ERR(rstc);
                if (ret != -EPROBE_DEFER)
                        dev_err(&dev->dev, "can't get reset: %d\n", ret);
                goto err_clk;
        }
        reset_control_deassert(rstc);
        reset_control_put(rstc);

        size = resource_size(&dev->res);
        tmp = ioremap(dev->res.start, size);
        if (!tmp) {
                ret = -ENOMEM;
                goto err_clk;
        }

        /*
         * 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);

        if (cid == CORESIGHT_CID) {
                /* set the base to the start of the last 4k block */
                void __iomem *csbase = tmp + size - 4096;

                dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
                dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
        }

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

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

        iounmap(tmp);

err_clk:
        amba_put_disable_pclk(dev);
err_pm:
        dev_pm_domain_detach(&dev->dev, true);
err_out:
        return ret;
}

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

        mutex_lock(&pcdev->periphid_lock);
        if (!pcdev->periphid) {
                int ret = amba_read_periphid(pcdev);

                /*
                 * Returning any error other than -EPROBE_DEFER from bus match
                 * can cause driver registration failure. So, if there's a
                 * permanent failure in reading pid and cid, simply map it to
                 * -EPROBE_DEFER.
                 */
                if (ret) {
                        mutex_unlock(&pcdev->periphid_lock);
                        return -EPROBE_DEFER;
                }
                dev_set_uevent_suppress(dev, false);
                kobject_uevent(&dev->kobj, KOBJ_ADD);
        }
        mutex_unlock(&pcdev->periphid_lock);

        /* 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(const struct device *dev, struct kobj_uevent_env *env)
{
        const 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 int of_amba_device_decode_irq(struct amba_device *dev)
{
        struct device_node *node = dev->dev.of_node;
        int i, irq = 0;

        if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
                /* Decode the IRQs and address ranges */
                for (i = 0; i < AMBA_NR_IRQS; i++) {
                        irq = of_irq_get(node, i);
                        if (irq < 0) {
                                if (irq == -EPROBE_DEFER)
                                        return irq;
                                irq = 0;
                        }

                        dev->irq[i] = irq;
                }
        }

        return 0;
}

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

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

                ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON |
                                                PD_FLAG_DETACH_POWER_OFF);
                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);
        } while (0);

        return ret;
}

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

        pm_runtime_get_sync(dev);
        if (drv->remove)
                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);
}

static void amba_shutdown(struct device *dev)
{
        struct amba_driver *drv;

        if (!dev->driver)
                return;

        drv = to_amba_driver(dev->driver);
        if (drv->shutdown)
                drv->shutdown(to_amba_device(dev));
}

static int amba_dma_configure(struct device *dev)
{
        struct amba_driver *drv = to_amba_driver(dev->driver);
        enum dev_dma_attr attr;
        int ret = 0;

        if (dev->of_node) {
                ret = of_dma_configure(dev, dev->of_node, true);
        } else if (has_acpi_companion(dev)) {
                attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
                ret = acpi_dma_configure(dev, attr);
        }

        /* @drv may not be valid when we're called from the IOMMU layer */
        if (!ret && dev->driver && !drv->driver_managed_dma) {
                ret = iommu_device_use_default_domain(dev);
                if (ret)
                        arch_teardown_dma_ops(dev);
        }

        return ret;
}

static void amba_dma_cleanup(struct device *dev)
{
        struct amba_driver *drv = to_amba_driver(dev->driver);

        if (!drv->driver_managed_dma)
                iommu_device_unuse_default_domain(dev);
}

#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 = {
        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".
 * DMA configuration for platform and AMBA bus is same. So here we reuse
 * platform's DMA config routine.
 */
const struct bus_type amba_bustype = {
        .name           = "amba",
        .dev_groups     = amba_dev_groups,
        .match          = amba_match,
        .uevent         = amba_uevent,
        .probe          = amba_probe,
        .remove         = amba_remove,
        .shutdown       = amba_shutdown,
        .dma_configure  = amba_dma_configure,
        .dma_cleanup    = amba_dma_cleanup,
        .pm             = &amba_pm,
};
EXPORT_SYMBOL_GPL(amba_bustype);

bool dev_is_amba(const struct device *dev)
{
        return dev->bus == &amba_bustype;
}
EXPORT_SYMBOL_GPL(dev_is_amba);

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

postcore_initcall(amba_init);

static int amba_proxy_probe(struct amba_device *adev,
                            const struct amba_id *id)
{
        WARN(1, "Stub driver should never match any device.\n");
        return -ENODEV;
}

static const struct amba_id amba_stub_drv_ids[] = {
        { 0, 0 },
};

static struct amba_driver amba_proxy_drv = {
        .drv = {
                .name = "amba-proxy",
        },
        .probe = amba_proxy_probe,
        .id_table = amba_stub_drv_ids,
};

static int __init amba_stub_drv_init(void)
{
        if (!IS_ENABLED(CONFIG_MODULES))
                return 0;

        /*
         * The amba_match() function will get called only if there is at least
         * one amba driver registered. If all amba drivers are modules and are
         * only loaded based on uevents, then we'll hit a chicken-and-egg
         * situation where amba_match() is waiting on drivers and drivers are
         * waiting on amba_match(). So, register a stub driver to make sure
         * amba_match() is called even if no amba driver has been registered.
         */
        return __amba_driver_register(&amba_proxy_drv, NULL);
}
late_initcall_sync(amba_stub_drv_init);

/**
 *      __amba_driver_register - register an AMBA device driver
 *      @drv: amba device driver structure
 *      @owner: owning module/driver
 *
 *      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,
                           struct module *owner)
{
        if (!drv->probe)
                return -EINVAL;

        drv->drv.owner = owner;
        drv->drv.bus = &amba_bustype;

        return driver_register(&drv->drv);
}
EXPORT_SYMBOL(__amba_driver_register);

/**
 *      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);
}
EXPORT_SYMBOL(amba_driver_unregister);

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

        fwnode_handle_put(dev_fwnode(&d->dev));
        if (d->res.parent)
                release_resource(&d->res);
        mutex_destroy(&d->periphid_lock);
        kfree(d);
}

/**
 *      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;

        fwnode_handle_get(dev_fwnode(&dev->dev));

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

        /* If primecell ID isn't hard-coded, figure it out */
        if (!dev->periphid) {
                /*
                 * AMBA device uevents require reading its pid and cid
                 * registers.  To do this, the device must be on, clocked and
                 * out of reset.  However in some cases those resources might
                 * not yet be available.  If that's the case, we suppress the
                 * generation of uevents until we can read the pid and cid
                 * registers.  See also amba_match().
                 */
                if (amba_read_periphid(dev))
                        dev_set_uevent_suppress(&dev->dev, true);
        }

        ret = device_add(&dev->dev);
        if (ret)
                release_resource(&dev->res);

        return ret;
}
EXPORT_SYMBOL_GPL(amba_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->dev.coherent_dma_mask;
        dev->dev.dma_parms = &dev->dma_parms;
        dev->res.name = dev_name(&dev->dev);
        mutex_init(&dev->periphid_lock);
}

/**
 *      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_obj(*dev);
        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);
}
EXPORT_SYMBOL(amba_device_register);

/**
 *      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);
}
EXPORT_SYMBOL(amba_device_unregister);

/**
 *      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;
}
EXPORT_SYMBOL(amba_request_regions);

/**
 *      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_release_regions);