/*
 * ocp.c
 *
 *      (c) Benjamin Herrenschmidt (benh@kernel.crashing.org)
 *          Mipsys - France
 *
 *          Derived from work (c) Armin Kuster akuster@pacbell.net
 *
 *          Additional support and port to 2.6 LDM/sysfs by
 *          Matt Porter <mporter@kernel.crashing.org>
 *          Copyright 2004 MontaVista Software, Inc.
 *
 *  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;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  OCP (On Chip Peripheral) is a software emulated "bus" with a
 *  pseudo discovery method for dumb peripherals. Usually these type
 *  of peripherals are found on embedded SoC (System On a Chip)
 *  processors or highly integrated system controllers that have
 *  a host bridge and many peripherals.  Common examples where
 *  this is already used include the PPC4xx, PPC85xx, MPC52xx,
 *  and MV64xxx parts.
 *
 *  This subsystem creates a standard OCP bus type within the
 *  device model.  The devices on the OCP bus are seeded by an
 *  an initial OCP device array created by the arch-specific
 *  Device entries can be added/removed/modified through OCP
 *  helper functions to accommodate system and  board-specific
 *  parameters commonly found in embedded systems. OCP also
 *  provides a standard method for devices to describe extended
 *  attributes about themselves to the system.  A standard access
 *  method allows OCP drivers to obtain the information, both
 *  SoC-specific and system/board-specific, needed for operation.
 */

#include <linux/module.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/bootmem.h>
#include <linux/device.h>
#include <linux/rwsem.h>

#include <asm/io.h>
#include <asm/ocp.h>
#include <asm/errno.h>
#include <asm/semaphore.h>

//#define DBG(x)        printk x
#define DBG(x)

extern int mem_init_done;

extern struct ocp_def core_ocp[];       /* Static list of devices, provided by
                                           CPU core */

LIST_HEAD(ocp_devices);                 /* List of all OCP devices */
DECLARE_RWSEM(ocp_devices_sem);         /* Global semaphores for those lists */

static int ocp_inited;

/* Sysfs support */
#define OCP_DEF_ATTR(field, format_string)                              \
static ssize_t                                                          \
show_##field(struct device *dev, struct device_attribute *attr, char *buf)                              \
{                                                                       \
        struct ocp_device *odev = to_ocp_dev(dev);                      \
                                                                        \
        return sprintf(buf, format_string, odev->def->field);           \
}                                                                       \
static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);

OCP_DEF_ATTR(vendor, "0x%04x\n");
OCP_DEF_ATTR(function, "0x%04x\n");
OCP_DEF_ATTR(index, "0x%04x\n");
#ifdef CONFIG_PTE_64BIT
OCP_DEF_ATTR(paddr, "0x%016Lx\n");
#else
OCP_DEF_ATTR(paddr, "0x%08lx\n");
#endif
OCP_DEF_ATTR(irq, "%d\n");
OCP_DEF_ATTR(pm, "%lu\n");

void ocp_create_sysfs_dev_files(struct ocp_device *odev)
{
        struct device *dev = &odev->dev;

        /* Current OCP device def attributes */
        device_create_file(dev, &dev_attr_vendor);
        device_create_file(dev, &dev_attr_function);
        device_create_file(dev, &dev_attr_index);
        device_create_file(dev, &dev_attr_paddr);
        device_create_file(dev, &dev_attr_irq);
        device_create_file(dev, &dev_attr_pm);
        /* Current OCP device additions attributes */
        if (odev->def->additions && odev->def->show)
                odev->def->show(dev);
}

/**
 *      ocp_device_match        -       Match one driver to one device
 *      @drv: driver to match
 *      @dev: device to match
 *
 *      This function returns 0 if the driver and device don't match
 */
static int
ocp_device_match(struct device *dev, struct device_driver *drv)
{
        struct ocp_device *ocp_dev = to_ocp_dev(dev);
        struct ocp_driver *ocp_drv = to_ocp_drv(drv);
        const struct ocp_device_id *ids = ocp_drv->id_table;

        if (!ids)
                return 0;

        while (ids->vendor || ids->function) {
                if ((ids->vendor == OCP_ANY_ID
                     || ids->vendor == ocp_dev->def->vendor)
                    && (ids->function == OCP_ANY_ID
                        || ids->function == ocp_dev->def->function))
                        return 1;
                ids++;
        }
        return 0;
}

static int
ocp_device_probe(struct device *dev)
{
        int error = 0;
        struct ocp_driver *drv;
        struct ocp_device *ocp_dev;

        drv = to_ocp_drv(dev->driver);
        ocp_dev = to_ocp_dev(dev);

        if (drv->probe) {
                error = drv->probe(ocp_dev);
                if (error >= 0) {
                        ocp_dev->driver = drv;
                        error = 0;
                }
        }
        return error;
}

static int
ocp_device_remove(struct device *dev)
{
        struct ocp_device *ocp_dev = to_ocp_dev(dev);

        if (ocp_dev->driver) {
                if (ocp_dev->driver->remove)
                        ocp_dev->driver->remove(ocp_dev);
                ocp_dev->driver = NULL;
        }
        return 0;
}

static int
ocp_device_suspend(struct device *dev, pm_message_t state)
{
        struct ocp_device *ocp_dev = to_ocp_dev(dev);
        struct ocp_driver *ocp_drv = to_ocp_drv(dev->driver);

        if (dev->driver && ocp_drv->suspend)
                return ocp_drv->suspend(ocp_dev, state);
        return 0;
}

static int
ocp_device_resume(struct device *dev)
{
        struct ocp_device *ocp_dev = to_ocp_dev(dev);
        struct ocp_driver *ocp_drv = to_ocp_drv(dev->driver);

        if (dev->driver && ocp_drv->resume)
                return ocp_drv->resume(ocp_dev);
        return 0;
}

struct bus_type ocp_bus_type = {
        .name = "ocp",
        .match = ocp_device_match,
        .probe = ocp_device_probe,
        .remove = ocp_device_remove,
        .suspend = ocp_device_suspend,
        .resume = ocp_device_resume,
};

/**
 *      ocp_register_driver     -       Register an OCP driver
 *      @drv: pointer to statically defined ocp_driver structure
 *
 *      The driver's probe() callback is called either recursively
 *      by this function or upon later call of ocp_driver_init
 *
 *      NOTE: Detection of devices is a 2 pass step on this implementation,
 *      hotswap isn't supported. First, all OCP devices are put in the device
 *      list, _then_ all drivers are probed on each match.
 */
int
ocp_register_driver(struct ocp_driver *drv)
{
        /* initialize common driver fields */
        drv->driver.name = drv->name;
        drv->driver.bus = &ocp_bus_type;

        /* register with core */
        return driver_register(&drv->driver);
}

/**
 *      ocp_unregister_driver   -       Unregister an OCP driver
 *      @drv: pointer to statically defined ocp_driver structure
 *
 *      The driver's remove() callback is called recursively
 *      by this function for any device already registered
 */
void
ocp_unregister_driver(struct ocp_driver *drv)
{
        DBG(("ocp: ocp_unregister_driver(%s)...\n", drv->name));

        driver_unregister(&drv->driver);

        DBG(("ocp: ocp_unregister_driver(%s)... done.\n", drv->name));
}

/* Core of ocp_find_device(). Caller must hold ocp_devices_sem */
static struct ocp_device *
__ocp_find_device(unsigned int vendor, unsigned int function, int index)
{
        struct list_head        *entry;
        struct ocp_device       *dev, *found = NULL;

        DBG(("ocp: __ocp_find_device(vendor: %x, function: %x, index: %d)...\n", vendor, function, index));

        list_for_each(entry, &ocp_devices) {
                dev = list_entry(entry, struct ocp_device, link);
                if (vendor != OCP_ANY_ID && vendor != dev->def->vendor)
                        continue;
                if (function != OCP_ANY_ID && function != dev->def->function)
                        continue;
                if (index != OCP_ANY_INDEX && index != dev->def->index)
                        continue;
                found = dev;
                break;
        }

        DBG(("ocp: __ocp_find_device(vendor: %x, function: %x, index: %d)... done\n", vendor, function, index));

        return found;
}

/**
 *      ocp_find_device -       Find a device by function & index
 *      @vendor: vendor ID of the device (or OCP_ANY_ID)
 *      @function: function code of the device (or OCP_ANY_ID)
 *      @idx: index of the device (or OCP_ANY_INDEX)
 *
 *      This function allows a lookup of a given function by it's
 *      index, it's typically used to find the MAL or ZMII associated
 *      with an EMAC or similar horrors.
 *      You can pass vendor, though you usually want OCP_ANY_ID there...
 */
struct ocp_device *
ocp_find_device(unsigned int vendor, unsigned int function, int index)
{
        struct ocp_device       *dev;

        down_read(&ocp_devices_sem);
        dev = __ocp_find_device(vendor, function, index);
        up_read(&ocp_devices_sem);

        return dev;
}

/**
 *      ocp_get_one_device -    Find a def by function & index
 *      @vendor: vendor ID of the device (or OCP_ANY_ID)
 *      @function: function code of the device (or OCP_ANY_ID)
 *      @idx: index of the device (or OCP_ANY_INDEX)
 *
 *      This function allows a lookup of a given ocp_def by it's
 *      vendor, function, and index.  The main purpose for is to
 *      allow modification of the def before binding to the driver
 */
struct ocp_def *
ocp_get_one_device(unsigned int vendor, unsigned int function, int index)
{
        struct ocp_device       *dev;
        struct ocp_def          *found = NULL;

        DBG(("ocp: ocp_get_one_device(vendor: %x, function: %x, index: %d)...\n",
                vendor, function, index));

        dev = ocp_find_device(vendor, function, index);

        if (dev)
                found = dev->def;

        DBG(("ocp: ocp_get_one_device(vendor: %x, function: %x, index: %d)... done.\n",
                vendor, function, index));

        return found;
}

/**
 *      ocp_add_one_device      -       Add a device
 *      @def: static device definition structure
 *
 *      This function adds a device definition to the
 *      device list. It may only be called before
 *      ocp_driver_init() and will return an error
 *      otherwise.
 */
int
ocp_add_one_device(struct ocp_def *def)
{
        struct  ocp_device      *dev;

        DBG(("ocp: ocp_add_one_device()...\n"));

        /* Can't be called after ocp driver init */
        if (ocp_inited)
                return 1;

        if (mem_init_done)
                dev = kmalloc(sizeof(*dev), GFP_KERNEL);
        else
                dev = alloc_bootmem(sizeof(*dev));

        if (dev == NULL)
                return 1;
        memset(dev, 0, sizeof(*dev));
        dev->def = def;
        dev->current_state = 4;
        sprintf(dev->name, "OCP device %04x:%04x:%04x",
                dev->def->vendor, dev->def->function, dev->def->index);
        down_write(&ocp_devices_sem);
        list_add_tail(&dev->link, &ocp_devices);
        up_write(&ocp_devices_sem);

        DBG(("ocp: ocp_add_one_device()...done\n"));

        return 0;
}

/**
 *      ocp_remove_one_device - Remove a device by function & index
 *      @vendor: vendor ID of the device (or OCP_ANY_ID)
 *      @function: function code of the device (or OCP_ANY_ID)
 *      @idx: index of the device (or OCP_ANY_INDEX)
 *
 *      This function allows removal of a given function by its
 *      index. It may only be called before ocp_driver_init()
 *      and will return an error otherwise.
 */
int
ocp_remove_one_device(unsigned int vendor, unsigned int function, int index)
{
        struct ocp_device *dev;

        DBG(("ocp: ocp_remove_one_device(vendor: %x, function: %x, index: %d)...\n", vendor, function, index));

        /* Can't be called after ocp driver init */
        if (ocp_inited)
                return 1;

        down_write(&ocp_devices_sem);
        dev = __ocp_find_device(vendor, function, index);
        list_del((struct list_head *)dev);
        up_write(&ocp_devices_sem);

        DBG(("ocp: ocp_remove_one_device(vendor: %x, function: %x, index: %d)... done.\n", vendor, function, index));

        return 0;
}

/**
 *      ocp_for_each_device     -       Iterate over OCP devices
 *      @callback: routine to execute for each ocp device.
 *      @arg: user data to be passed to callback routine.
 *
 *      This routine holds the ocp_device semaphore, so the
 *      callback routine cannot modify the ocp_device list.
 */
void
ocp_for_each_device(void(*callback)(struct ocp_device *, void *arg), void *arg)
{
        struct list_head *entry;

        if (callback) {
                down_read(&ocp_devices_sem);
                list_for_each(entry, &ocp_devices)
                        callback(list_entry(entry, struct ocp_device, link),
                                arg);
                up_read(&ocp_devices_sem);
        }
}

/**
 *      ocp_early_init  -       Init OCP device management
 *
 *      This function builds the list of devices before setup_arch.
 *      This allows platform code to modify the device lists before
 *      they are bound to drivers (changes to paddr, removing devices
 *      etc)
 */
int __init
ocp_early_init(void)
{
        struct ocp_def  *def;

        DBG(("ocp: ocp_early_init()...\n"));

        /* Fill the devices list */
        for (def = core_ocp; def->vendor != OCP_VENDOR_INVALID; def++)
                ocp_add_one_device(def);

        DBG(("ocp: ocp_early_init()... done.\n"));

        return 0;
}

/**
 *      ocp_driver_init -       Init OCP device management
 *
 *      This function is meant to be called via OCP bus registration.
 */
static int __init
ocp_driver_init(void)
{
        int ret = 0, index = 0;
        struct device *ocp_bus;
        struct list_head *entry;
        struct ocp_device *dev;

        if (ocp_inited)
                return ret;
        ocp_inited = 1;

        DBG(("ocp: ocp_driver_init()...\n"));

        /* Allocate/register primary OCP bus */
        ocp_bus = kzalloc(sizeof(struct device), GFP_KERNEL);
        if (ocp_bus == NULL)
                return 1;
        strcpy(ocp_bus->bus_id, "ocp");

        bus_register(&ocp_bus_type);

        device_register(ocp_bus);

        /* Put each OCP device into global device list */
        list_for_each(entry, &ocp_devices) {
                dev = list_entry(entry, struct ocp_device, link);
                sprintf(dev->dev.bus_id, "%2.2x", index);
                dev->dev.parent = ocp_bus;
                dev->dev.bus = &ocp_bus_type;
                device_register(&dev->dev);
                ocp_create_sysfs_dev_files(dev);
                index++;
        }

        DBG(("ocp: ocp_driver_init()... done.\n"));

        return 0;
}

postcore_initcall(ocp_driver_init);

EXPORT_SYMBOL(ocp_bus_type);
EXPORT_SYMBOL(ocp_find_device);
EXPORT_SYMBOL(ocp_register_driver);
EXPORT_SYMBOL(ocp_unregister_driver);