// SPDX-License-Identifier: GPL-2.0
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_reserved_mem.h>
#include <linux/dma-direct.h> /* for bus_dma_region */
#include <linux/dma-map-ops.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include <asm/errno.h>
#include "of_private.h"

/**
 * of_match_device - Tell if a struct device matches an of_device_id list
 * @matches: array of of device match structures to search in
 * @dev: the of device structure to match against
 *
 * Used by a driver to check whether an platform_device present in the
 * system is in its list of supported devices.
 */
const struct of_device_id *of_match_device(const struct of_device_id *matches,
                                           const struct device *dev)
{
        if (!matches || !dev->of_node || dev->of_node_reused)
                return NULL;
        return of_match_node(matches, dev->of_node);
}
EXPORT_SYMBOL(of_match_device);

int of_device_add(struct platform_device *ofdev)
{
        BUG_ON(ofdev->dev.of_node == NULL);

        /* name and id have to be set so that the platform bus doesn't get
         * confused on matching */
        ofdev->name = dev_name(&ofdev->dev);
        ofdev->id = PLATFORM_DEVID_NONE;

        /*
         * If this device has not binding numa node in devicetree, that is
         * of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
         * device is on the same node as the parent.
         */
        set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));

        return device_add(&ofdev->dev);
}

static void
of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
{
        struct device_node *node, *of_node = dev->of_node;
        int count, i;

        if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
                return;

        count = of_property_count_elems_of_size(of_node, "memory-region",
                                                sizeof(u32));
        /*
         * If dev->of_node doesn't exist or doesn't contain memory-region, try
         * the OF node having DMA configuration.
         */
        if (count <= 0) {
                of_node = np;
                count = of_property_count_elems_of_size(
                        of_node, "memory-region", sizeof(u32));
        }

        for (i = 0; i < count; i++) {
                node = of_parse_phandle(of_node, "memory-region", i);
                /*
                 * There might be multiple memory regions, but only one
                 * restricted-dma-pool region is allowed.
                 */
                if (of_device_is_compatible(node, "restricted-dma-pool") &&
                    of_device_is_available(node))
                        break;
        }

        /*
         * Attempt to initialize a restricted-dma-pool region if one was found.
         * Note that count can hold a negative error code.
         */
        if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
                dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
}

/**
 * of_dma_configure_id - Setup DMA configuration
 * @dev:        Device to apply DMA configuration
 * @np:         Pointer to OF node having DMA configuration
 * @force_dma:  Whether device is to be set up by of_dma_configure() even if
 *              DMA capability is not explicitly described by firmware.
 * @id:         Optional const pointer value input id
 *
 * Try to get devices's DMA configuration from DT and update it
 * accordingly.
 *
 * If platform code needs to use its own special DMA configuration, it
 * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
 * to fix up DMA configuration.
 */
int of_dma_configure_id(struct device *dev, struct device_node *np,
                        bool force_dma, const u32 *id)
{
        const struct iommu_ops *iommu;
        const struct bus_dma_region *map = NULL;
        u64 dma_start = 0;
        u64 mask, end, size = 0;
        bool coherent;
        int ret;

        ret = of_dma_get_range(np, &map);
        if (ret < 0) {
                /*
                 * For legacy reasons, we have to assume some devices need
                 * DMA configuration regardless of whether "dma-ranges" is
                 * correctly specified or not.
                 */
                if (!force_dma)
                        return ret == -ENODEV ? 0 : ret;
        } else {
                const struct bus_dma_region *r = map;
                u64 dma_end = 0;

                /* Determine the overall bounds of all DMA regions */
                for (dma_start = ~0; r->size; r++) {
                        /* Take lower and upper limits */
                        if (r->dma_start < dma_start)
                                dma_start = r->dma_start;
                        if (r->dma_start + r->size > dma_end)
                                dma_end = r->dma_start + r->size;
                }
                size = dma_end - dma_start;

                /*
                 * Add a work around to treat the size as mask + 1 in case
                 * it is defined in DT as a mask.
                 */
                if (size & 1) {
                        dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
                                 size);
                        size = size + 1;
                }

                if (!size) {
                        dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
                        kfree(map);
                        return -EINVAL;
                }
        }

        /*
         * If @dev is expected to be DMA-capable then the bus code that created
         * it should have initialised its dma_mask pointer by this point. For
         * now, we'll continue the legacy behaviour of coercing it to the
         * coherent mask if not, but we'll no longer do so quietly.
         */
        if (!dev->dma_mask) {
                dev_warn(dev, "DMA mask not set\n");
                dev->dma_mask = &dev->coherent_dma_mask;
        }

        if (!size && dev->coherent_dma_mask)
                size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
        else if (!size)
                size = 1ULL << 32;

        /*
         * Limit coherent and dma mask based on size and default mask
         * set by the driver.
         */
        end = dma_start + size - 1;
        mask = DMA_BIT_MASK(ilog2(end) + 1);
        dev->coherent_dma_mask &= mask;
        *dev->dma_mask &= mask;
        /* ...but only set bus limit and range map if we found valid dma-ranges earlier */
        if (!ret) {
                dev->bus_dma_limit = end;
                dev->dma_range_map = map;
        }

        coherent = of_dma_is_coherent(np);
        dev_dbg(dev, "device is%sdma coherent\n",
                coherent ? " " : " not ");

        iommu = of_iommu_configure(dev, np, id);
        if (PTR_ERR(iommu) == -EPROBE_DEFER) {
                /* Don't touch range map if it wasn't set from a valid dma-ranges */
                if (!ret)
                        dev->dma_range_map = NULL;
                kfree(map);
                return -EPROBE_DEFER;
        }

        dev_dbg(dev, "device is%sbehind an iommu\n",
                iommu ? " " : " not ");

        arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);

        if (!iommu)
                of_dma_set_restricted_buffer(dev, np);

        return 0;
}
EXPORT_SYMBOL_GPL(of_dma_configure_id);

int of_device_register(struct platform_device *pdev)
{
        device_initialize(&pdev->dev);
        return of_device_add(pdev);
}
EXPORT_SYMBOL(of_device_register);

void of_device_unregister(struct platform_device *ofdev)
{
        device_unregister(&ofdev->dev);
}
EXPORT_SYMBOL(of_device_unregister);

const void *of_device_get_match_data(const struct device *dev)
{
        const struct of_device_id *match;

        match = of_match_device(dev->driver->of_match_table, dev);
        if (!match)
                return NULL;

        return match->data;
}
EXPORT_SYMBOL(of_device_get_match_data);

static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
{
        const char *compat;
        char *c;
        struct property *p;
        ssize_t csize;
        ssize_t tsize;

        if ((!dev) || (!dev->of_node))
                return -ENODEV;

        /* Name & Type */
        /* %p eats all alphanum characters, so %c must be used here */
        csize = snprintf(str, len, "of:N%pOFn%c%s", dev->of_node, 'T',
                         of_node_get_device_type(dev->of_node));
        tsize = csize;
        len -= csize;
        if (str)
                str += csize;

        of_property_for_each_string(dev->of_node, "compatible", p, compat) {
                csize = strlen(compat) + 1;
                tsize += csize;
                if (csize > len)
                        continue;

                csize = snprintf(str, len, "C%s", compat);
                for (c = str; c; ) {
                        c = strchr(c, ' ');
                        if (c)
                                *c++ = '_';
                }
                len -= csize;
                str += csize;
        }

        return tsize;
}

int of_device_request_module(struct device *dev)
{
        char *str;
        ssize_t size;
        int ret;

        size = of_device_get_modalias(dev, NULL, 0);
        if (size < 0)
                return size;

        str = kmalloc(size + 1, GFP_KERNEL);
        if (!str)
                return -ENOMEM;

        of_device_get_modalias(dev, str, size);
        str[size] = '\0';
        ret = request_module(str);
        kfree(str);

        return ret;
}
EXPORT_SYMBOL_GPL(of_device_request_module);

/**
 * of_device_modalias - Fill buffer with newline terminated modalias string
 * @dev:        Calling device
 * @str:        Modalias string
 * @len:        Size of @str
 */
ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
{
        ssize_t sl = of_device_get_modalias(dev, str, len - 2);
        if (sl < 0)
                return sl;
        if (sl > len - 2)
                return -ENOMEM;

        str[sl++] = '\n';
        str[sl] = 0;
        return sl;
}
EXPORT_SYMBOL_GPL(of_device_modalias);

/**
 * of_device_uevent - Display OF related uevent information
 * @dev:        Device to apply DMA configuration
 * @env:        Kernel object's userspace event reference
 */
void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        const char *compat, *type;
        struct alias_prop *app;
        struct property *p;
        int seen = 0;

        if ((!dev) || (!dev->of_node))
                return;

        add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
        add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
        type = of_node_get_device_type(dev->of_node);
        if (type)
                add_uevent_var(env, "OF_TYPE=%s", type);

        /* Since the compatible field can contain pretty much anything
         * it's not really legal to split it out with commas. We split it
         * up using a number of environment variables instead. */
        of_property_for_each_string(dev->of_node, "compatible", p, compat) {
                add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
                seen++;
        }
        add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);

        seen = 0;
        mutex_lock(&of_mutex);
        list_for_each_entry(app, &aliases_lookup, link) {
                if (dev->of_node == app->np) {
                        add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
                                       app->alias);
                        seen++;
                }
        }
        mutex_unlock(&of_mutex);
}

int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
{
        int sl;

        if ((!dev) || (!dev->of_node))
                return -ENODEV;

        /* Devicetree modalias is tricky, we add it in 2 steps */
        if (add_uevent_var(env, "MODALIAS="))
                return -ENOMEM;

        sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
                                    sizeof(env->buf) - env->buflen);
        if (sl >= (sizeof(env->buf) - env->buflen))
                return -ENOMEM;
        env->buflen += sl;

        return 0;
}
EXPORT_SYMBOL_GPL(of_device_uevent_modalias);