hwrng: core - Don't use a stack buffer in add_early_randomness()

[linux/fpc-iii.git] / drivers / of / platform.c

/*
 *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
 *                       <benh@kernel.crashing.org>
 *    and                Arnd Bergmann, IBM Corp.
 *    Merged from powerpc/kernel/of_platform.c and
 *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
 *
 *  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.
 *
 */

#define pr_fmt(fmt)     "OF: " fmt

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/amba/bus.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

const struct of_device_id of_default_bus_match_table[] = {
        { .compatible = "simple-bus", },
        { .compatible = "simple-mfd", },
        { .compatible = "isa", },
#ifdef CONFIG_ARM_AMBA
        { .compatible = "arm,amba-bus", },
#endif /* CONFIG_ARM_AMBA */
        {} /* Empty terminated list */
};

static int of_dev_node_match(struct device *dev, void *data)
{
        return dev->of_node == data;
}

/**
 * of_find_device_by_node - Find the platform_device associated with a node
 * @np: Pointer to device tree node
 *
 * Returns platform_device pointer, or NULL if not found
 */
struct platform_device *of_find_device_by_node(struct device_node *np)
{
        struct device *dev;

        dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
        return dev ? to_platform_device(dev) : NULL;
}
EXPORT_SYMBOL(of_find_device_by_node);

#ifdef CONFIG_OF_ADDRESS
/*
 * The following routines scan a subtree and registers a device for
 * each applicable node.
 *
 * Note: sparc doesn't use these routines because it has a different
 * mechanism for creating devices from device tree nodes.
 */

/**
 * of_device_make_bus_id - Use the device node data to assign a unique name
 * @dev: pointer to device structure that is linked to a device tree node
 *
 * This routine will first try using the translated bus address to
 * derive a unique name. If it cannot, then it will prepend names from
 * parent nodes until a unique name can be derived.
 */
void of_device_make_bus_id(struct device *dev)
{
        struct device_node *node = dev->of_node;
        const __be32 *reg;
        u64 addr;

        /* Construct the name, using parent nodes if necessary to ensure uniqueness */
        while (node->parent) {
                /*
                 * If the address can be translated, then that is as much
                 * uniqueness as we need. Make it the first component and return
                 */
                reg = of_get_property(node, "reg", NULL);
                if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
                        dev_set_name(dev, dev_name(dev) ? "%llx.%s:%s" : "%llx.%s",
                                     (unsigned long long)addr, node->name,
                                     dev_name(dev));
                        return;
                }

                /* format arguments only used if dev_name() resolves to NULL */
                dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
                             strrchr(node->full_name, '/') + 1, dev_name(dev));
                node = node->parent;
        }
}

/**
 * of_device_alloc - Allocate and initialize an of_device
 * @np: device node to assign to device
 * @bus_id: Name to assign to the device.  May be null to use default name.
 * @parent: Parent device.
 */
struct platform_device *of_device_alloc(struct device_node *np,
                                  const char *bus_id,
                                  struct device *parent)
{
        struct platform_device *dev;
        int rc, i, num_reg = 0, num_irq;
        struct resource *res, temp_res;

        dev = platform_device_alloc("", -1);
        if (!dev)
                return NULL;

        /* count the io and irq resources */
        while (of_address_to_resource(np, num_reg, &temp_res) == 0)
                num_reg++;
        num_irq = of_irq_count(np);

        /* Populate the resource table */
        if (num_irq || num_reg) {
                res = kzalloc(sizeof(*res) * (num_irq + num_reg), GFP_KERNEL);
                if (!res) {
                        platform_device_put(dev);
                        return NULL;
                }

                dev->num_resources = num_reg + num_irq;
                dev->resource = res;
                for (i = 0; i < num_reg; i++, res++) {
                        rc = of_address_to_resource(np, i, res);
                        WARN_ON(rc);
                }
                if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
                        pr_debug("not all legacy IRQ resources mapped for %s\n",
                                 np->name);
        }

        dev->dev.of_node = of_node_get(np);
        dev->dev.fwnode = &np->fwnode;
        dev->dev.parent = parent ? : &platform_bus;

        if (bus_id)
                dev_set_name(&dev->dev, "%s", bus_id);
        else
                of_device_make_bus_id(&dev->dev);

        return dev;
}
EXPORT_SYMBOL(of_device_alloc);

static void of_dma_deconfigure(struct device *dev)
{
        arch_teardown_dma_ops(dev);
}

/**
 * of_platform_device_create_pdata - Alloc, initialize and register an of_device
 * @np: pointer to node to create device for
 * @bus_id: name to assign device
 * @platform_data: pointer to populate platform_data pointer with
 * @parent: Linux device model parent device.
 *
 * Returns pointer to created platform device, or NULL if a device was not
 * registered.  Unavailable devices will not get registered.
 */
static struct platform_device *of_platform_device_create_pdata(
                                        struct device_node *np,
                                        const char *bus_id,
                                        void *platform_data,
                                        struct device *parent)
{
        struct platform_device *dev;

        if (!of_device_is_available(np) ||
            of_node_test_and_set_flag(np, OF_POPULATED))
                return NULL;

        dev = of_device_alloc(np, bus_id, parent);
        if (!dev)
                goto err_clear_flag;

        dev->dev.bus = &platform_bus_type;
        dev->dev.platform_data = platform_data;
        of_dma_configure(&dev->dev, dev->dev.of_node);
        of_msi_configure(&dev->dev, dev->dev.of_node);

        if (of_device_add(dev) != 0) {
                of_dma_deconfigure(&dev->dev);
                platform_device_put(dev);
                goto err_clear_flag;
        }

        return dev;

err_clear_flag:
        of_node_clear_flag(np, OF_POPULATED);
        return NULL;
}

/**
 * of_platform_device_create - Alloc, initialize and register an of_device
 * @np: pointer to node to create device for
 * @bus_id: name to assign device
 * @parent: Linux device model parent device.
 *
 * Returns pointer to created platform device, or NULL if a device was not
 * registered.  Unavailable devices will not get registered.
 */
struct platform_device *of_platform_device_create(struct device_node *np,
                                            const char *bus_id,
                                            struct device *parent)
{
        return of_platform_device_create_pdata(np, bus_id, NULL, parent);
}
EXPORT_SYMBOL(of_platform_device_create);

#ifdef CONFIG_ARM_AMBA
static struct amba_device *of_amba_device_create(struct device_node *node,
                                                 const char *bus_id,
                                                 void *platform_data,
                                                 struct device *parent)
{
        struct amba_device *dev;
        const void *prop;
        int i, ret;

        pr_debug("Creating amba device %s\n", node->full_name);

        if (!of_device_is_available(node) ||
            of_node_test_and_set_flag(node, OF_POPULATED))
                return NULL;

        dev = amba_device_alloc(NULL, 0, 0);
        if (!dev)
                goto err_clear_flag;

        /* setup generic device info */
        dev->dev.of_node = of_node_get(node);
        dev->dev.fwnode = &node->fwnode;
        dev->dev.parent = parent ? : &platform_bus;
        dev->dev.platform_data = platform_data;
        if (bus_id)
                dev_set_name(&dev->dev, "%s", bus_id);
        else
                of_device_make_bus_id(&dev->dev);
        of_dma_configure(&dev->dev, dev->dev.of_node);

        /* Allow the HW Peripheral ID to be overridden */
        prop = of_get_property(node, "arm,primecell-periphid", NULL);
        if (prop)
                dev->periphid = of_read_ulong(prop, 1);

        /* Decode the IRQs and address ranges */
        for (i = 0; i < AMBA_NR_IRQS; i++)
                dev->irq[i] = irq_of_parse_and_map(node, i);

        ret = of_address_to_resource(node, 0, &dev->res);
        if (ret) {
                pr_err("amba: of_address_to_resource() failed (%d) for %s\n",
                       ret, node->full_name);
                goto err_free;
        }

        ret = amba_device_add(dev, &iomem_resource);
        if (ret) {
                pr_err("amba_device_add() failed (%d) for %s\n",
                       ret, node->full_name);
                goto err_free;
        }

        return dev;

err_free:
        amba_device_put(dev);
err_clear_flag:
        of_node_clear_flag(node, OF_POPULATED);
        return NULL;
}
#else /* CONFIG_ARM_AMBA */
static struct amba_device *of_amba_device_create(struct device_node *node,
                                                 const char *bus_id,
                                                 void *platform_data,
                                                 struct device *parent)
{
        return NULL;
}
#endif /* CONFIG_ARM_AMBA */

/**
 * of_devname_lookup() - Given a device node, lookup the preferred Linux name
 */
static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
                                 struct device_node *np)
{
        const struct of_dev_auxdata *auxdata;
        struct resource res;
        int compatible = 0;

        if (!lookup)
                return NULL;

        auxdata = lookup;
        for (; auxdata->compatible; auxdata++) {
                if (!of_device_is_compatible(np, auxdata->compatible))
                        continue;
                compatible++;
                if (!of_address_to_resource(np, 0, &res))
                        if (res.start != auxdata->phys_addr)
                                continue;
                pr_debug("%s: devname=%s\n", np->full_name, auxdata->name);
                return auxdata;
        }

        if (!compatible)
                return NULL;

        /* Try compatible match if no phys_addr and name are specified */
        auxdata = lookup;
        for (; auxdata->compatible; auxdata++) {
                if (!of_device_is_compatible(np, auxdata->compatible))
                        continue;
                if (!auxdata->phys_addr && !auxdata->name) {
                        pr_debug("%s: compatible match\n", np->full_name);
                        return auxdata;
                }
        }

        return NULL;
}

/**
 * of_platform_bus_create() - Create a device for a node and its children.
 * @bus: device node of the bus to instantiate
 * @matches: match table for bus nodes
 * @lookup: auxdata table for matching id and platform_data with device nodes
 * @parent: parent for new device, or NULL for top level.
 * @strict: require compatible property
 *
 * Creates a platform_device for the provided device_node, and optionally
 * recursively create devices for all the child nodes.
 */
static int of_platform_bus_create(struct device_node *bus,
                                  const struct of_device_id *matches,
                                  const struct of_dev_auxdata *lookup,
                                  struct device *parent, bool strict)
{
        const struct of_dev_auxdata *auxdata;
        struct device_node *child;
        struct platform_device *dev;
        const char *bus_id = NULL;
        void *platform_data = NULL;
        int rc = 0;

        /* Make sure it has a compatible property */
        if (strict && (!of_get_property(bus, "compatible", NULL))) {
                pr_debug("%s() - skipping %s, no compatible prop\n",
                         __func__, bus->full_name);
                return 0;
        }

        if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
                pr_debug("%s() - skipping %s, already populated\n",
                        __func__, bus->full_name);
                return 0;
        }

        auxdata = of_dev_lookup(lookup, bus);
        if (auxdata) {
                bus_id = auxdata->name;
                platform_data = auxdata->platform_data;
        }

        if (of_device_is_compatible(bus, "arm,primecell")) {
                /*
                 * Don't return an error here to keep compatibility with older
                 * device tree files.
                 */
                of_amba_device_create(bus, bus_id, platform_data, parent);
                return 0;
        }

        dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
        if (!dev || !of_match_node(matches, bus))
                return 0;

        for_each_child_of_node(bus, child) {
                pr_debug("   create child: %s\n", child->full_name);
                rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
                if (rc) {
                        of_node_put(child);
                        break;
                }
        }
        of_node_set_flag(bus, OF_POPULATED_BUS);
        return rc;
}

/**
 * of_platform_bus_probe() - Probe the device-tree for platform buses
 * @root: parent of the first level to probe or NULL for the root of the tree
 * @matches: match table for bus nodes
 * @parent: parent to hook devices from, NULL for toplevel
 *
 * Note that children of the provided root are not instantiated as devices
 * unless the specified root itself matches the bus list and is not NULL.
 */
int of_platform_bus_probe(struct device_node *root,
                          const struct of_device_id *matches,
                          struct device *parent)
{
        struct device_node *child;
        int rc = 0;

        root = root ? of_node_get(root) : of_find_node_by_path("/");
        if (!root)
                return -EINVAL;

        pr_debug("%s()\n", __func__);
        pr_debug(" starting at: %s\n", root->full_name);

        /* Do a self check of bus type, if there's a match, create children */
        if (of_match_node(matches, root)) {
                rc = of_platform_bus_create(root, matches, NULL, parent, false);
        } else for_each_child_of_node(root, child) {
                if (!of_match_node(matches, child))
                        continue;
                rc = of_platform_bus_create(child, matches, NULL, parent, false);
                if (rc) {
                        of_node_put(child);
                        break;
                }
        }

        of_node_put(root);
        return rc;
}
EXPORT_SYMBOL(of_platform_bus_probe);

/**
 * of_platform_populate() - Populate platform_devices from device tree data
 * @root: parent of the first level to probe or NULL for the root of the tree
 * @matches: match table, NULL to use the default
 * @lookup: auxdata table for matching id and platform_data with device nodes
 * @parent: parent to hook devices from, NULL for toplevel
 *
 * Similar to of_platform_bus_probe(), this function walks the device tree
 * and creates devices from nodes.  It differs in that it follows the modern
 * convention of requiring all device nodes to have a 'compatible' property,
 * and it is suitable for creating devices which are children of the root
 * node (of_platform_bus_probe will only create children of the root which
 * are selected by the @matches argument).
 *
 * New board support should be using this function instead of
 * of_platform_bus_probe().
 *
 * Returns 0 on success, < 0 on failure.
 */
int of_platform_populate(struct device_node *root,
                        const struct of_device_id *matches,
                        const struct of_dev_auxdata *lookup,
                        struct device *parent)
{
        struct device_node *child;
        int rc = 0;

        root = root ? of_node_get(root) : of_find_node_by_path("/");
        if (!root)
                return -EINVAL;

        pr_debug("%s()\n", __func__);
        pr_debug(" starting at: %s\n", root->full_name);

        for_each_child_of_node(root, child) {
                rc = of_platform_bus_create(child, matches, lookup, parent, true);
                if (rc) {
                        of_node_put(child);
                        break;
                }
        }
        of_node_set_flag(root, OF_POPULATED_BUS);

        of_node_put(root);
        return rc;
}
EXPORT_SYMBOL_GPL(of_platform_populate);

int of_platform_default_populate(struct device_node *root,
                                 const struct of_dev_auxdata *lookup,
                                 struct device *parent)
{
        return of_platform_populate(root, of_default_bus_match_table, lookup,
                                    parent);
}
EXPORT_SYMBOL_GPL(of_platform_default_populate);

#ifndef CONFIG_PPC
static int __init of_platform_default_populate_init(void)
{
        struct device_node *node;

        if (!of_have_populated_dt())
                return -ENODEV;

        /*
         * Handle ramoops explicitly, since it is inside /reserved-memory,
         * which lacks a "compatible" property.
         */
        node = of_find_node_by_path("/reserved-memory");
        if (node) {
                node = of_find_compatible_node(node, NULL, "ramoops");
                if (node)
                        of_platform_device_create(node, NULL, NULL);
        }

        /* Populate everything else. */
        of_platform_default_populate(NULL, NULL, NULL);

        return 0;
}
arch_initcall_sync(of_platform_default_populate_init);
#endif

static int of_platform_device_destroy(struct device *dev, void *data)
{
        /* Do not touch devices not populated from the device tree */
        if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
                return 0;

        /* Recurse for any nodes that were treated as busses */
        if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
                device_for_each_child(dev, NULL, of_platform_device_destroy);

        if (dev->bus == &platform_bus_type)
                platform_device_unregister(to_platform_device(dev));
#ifdef CONFIG_ARM_AMBA
        else if (dev->bus == &amba_bustype)
                amba_device_unregister(to_amba_device(dev));
#endif

        of_dma_deconfigure(dev);
        of_node_clear_flag(dev->of_node, OF_POPULATED);
        of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
        return 0;
}

/**
 * of_platform_depopulate() - Remove devices populated from device tree
 * @parent: device which children will be removed
 *
 * Complementary to of_platform_populate(), this function removes children
 * of the given device (and, recurrently, their children) that have been
 * created from their respective device tree nodes (and only those,
 * leaving others - eg. manually created - unharmed).
 *
 * Returns 0 when all children devices have been removed or
 * -EBUSY when some children remained.
 */
void of_platform_depopulate(struct device *parent)
{
        if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
                device_for_each_child(parent, NULL, of_platform_device_destroy);
                of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
        }
}
EXPORT_SYMBOL_GPL(of_platform_depopulate);

#ifdef CONFIG_OF_DYNAMIC
static int of_platform_notify(struct notifier_block *nb,
                                unsigned long action, void *arg)
{
        struct of_reconfig_data *rd = arg;
        struct platform_device *pdev_parent, *pdev;
        bool children_left;

        switch (of_reconfig_get_state_change(action, rd)) {
        case OF_RECONFIG_CHANGE_ADD:
                /* verify that the parent is a bus */
                if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
                        return NOTIFY_OK;       /* not for us */

                /* already populated? (driver using of_populate manually) */
                if (of_node_check_flag(rd->dn, OF_POPULATED))
                        return NOTIFY_OK;

                /* pdev_parent may be NULL when no bus platform device */
                pdev_parent = of_find_device_by_node(rd->dn->parent);
                pdev = of_platform_device_create(rd->dn, NULL,
                                pdev_parent ? &pdev_parent->dev : NULL);
                of_dev_put(pdev_parent);

                if (pdev == NULL) {
                        pr_err("%s: failed to create for '%s'\n",
                                        __func__, rd->dn->full_name);
                        /* of_platform_device_create tosses the error code */
                        return notifier_from_errno(-EINVAL);
                }
                break;

        case OF_RECONFIG_CHANGE_REMOVE:

                /* already depopulated? */
                if (!of_node_check_flag(rd->dn, OF_POPULATED))
                        return NOTIFY_OK;

                /* find our device by node */
                pdev = of_find_device_by_node(rd->dn);
                if (pdev == NULL)
                        return NOTIFY_OK;       /* no? not meant for us */

                /* unregister takes one ref away */
                of_platform_device_destroy(&pdev->dev, &children_left);

                /* and put the reference of the find */
                of_dev_put(pdev);
                break;
        }

        return NOTIFY_OK;
}

static struct notifier_block platform_of_notifier = {
        .notifier_call = of_platform_notify,
};

void of_platform_register_reconfig_notifier(void)
{
        WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
}
#endif /* CONFIG_OF_DYNAMIC */

#endif /* CONFIG_OF_ADDRESS */