Merge tag 'mmc-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc

[mirror_ubuntu-hirsute-kernel.git] / drivers / of / address.c

// SPDX-License-Identifier: GPL-2.0
#define pr_fmt(fmt)     "OF: " fmt

#include <linux/device.h>
#include <linux/fwnode.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/logic_pio.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/string.h>

/* Max address size we deal with */
#define OF_MAX_ADDR_CELLS       4
#define OF_CHECK_ADDR_COUNT(na) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)
#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) > 0)

static struct of_bus *of_match_bus(struct device_node *np);
static int __of_address_to_resource(struct device_node *dev,
                const __be32 *addrp, u64 size, unsigned int flags,
                const char *name, struct resource *r);

/* Debug utility */
#ifdef DEBUG
static void of_dump_addr(const char *s, const __be32 *addr, int na)
{
        pr_debug("%s", s);
        while (na--)
                pr_cont(" %08x", be32_to_cpu(*(addr++)));
        pr_cont("\n");
}
#else
static void of_dump_addr(const char *s, const __be32 *addr, int na) { }
#endif

/* Callbacks for bus specific translators */
struct of_bus {
        const char      *name;
        const char      *addresses;
        int             (*match)(struct device_node *parent);
        void            (*count_cells)(struct device_node *child,
                                       int *addrc, int *sizec);
        u64             (*map)(__be32 *addr, const __be32 *range,
                                int na, int ns, int pna);
        int             (*translate)(__be32 *addr, u64 offset, int na);
        unsigned int    (*get_flags)(const __be32 *addr);
};

/*
 * Default translator (generic bus)
 */

static void of_bus_default_count_cells(struct device_node *dev,
                                       int *addrc, int *sizec)
{
        if (addrc)
                *addrc = of_n_addr_cells(dev);
        if (sizec)
                *sizec = of_n_size_cells(dev);
}

static u64 of_bus_default_map(__be32 *addr, const __be32 *range,
                int na, int ns, int pna)
{
        u64 cp, s, da;

        cp = of_read_number(range, na);
        s  = of_read_number(range + na + pna, ns);
        da = of_read_number(addr, na);

        pr_debug("default map, cp=%llx, s=%llx, da=%llx\n",
                 (unsigned long long)cp, (unsigned long long)s,
                 (unsigned long long)da);

        if (da < cp || da >= (cp + s))
                return OF_BAD_ADDR;
        return da - cp;
}

static int of_bus_default_translate(__be32 *addr, u64 offset, int na)
{
        u64 a = of_read_number(addr, na);
        memset(addr, 0, na * 4);
        a += offset;
        if (na > 1)
                addr[na - 2] = cpu_to_be32(a >> 32);
        addr[na - 1] = cpu_to_be32(a & 0xffffffffu);

        return 0;
}

static unsigned int of_bus_default_get_flags(const __be32 *addr)
{
        return IORESOURCE_MEM;
}

#ifdef CONFIG_PCI
/*
 * PCI bus specific translator
 */

static int of_bus_pci_match(struct device_node *np)
{
        /*
         * "pciex" is PCI Express
         * "vci" is for the /chaos bridge on 1st-gen PCI powermacs
         * "ht" is hypertransport
         */
        return of_node_is_type(np, "pci") || of_node_is_type(np, "pciex") ||
                of_node_is_type(np, "vci") || of_node_is_type(np, "ht");
}

static void of_bus_pci_count_cells(struct device_node *np,
                                   int *addrc, int *sizec)
{
        if (addrc)
                *addrc = 3;
        if (sizec)
                *sizec = 2;
}

static unsigned int of_bus_pci_get_flags(const __be32 *addr)
{
        unsigned int flags = 0;
        u32 w = be32_to_cpup(addr);

        switch((w >> 24) & 0x03) {
        case 0x01:
                flags |= IORESOURCE_IO;
                break;
        case 0x02: /* 32 bits */
        case 0x03: /* 64 bits */
                flags |= IORESOURCE_MEM;
                break;
        }
        if (w & 0x40000000)
                flags |= IORESOURCE_PREFETCH;
        return flags;
}

static u64 of_bus_pci_map(__be32 *addr, const __be32 *range, int na, int ns,
                int pna)
{
        u64 cp, s, da;
        unsigned int af, rf;

        af = of_bus_pci_get_flags(addr);
        rf = of_bus_pci_get_flags(range);

        /* Check address type match */
        if ((af ^ rf) & (IORESOURCE_MEM | IORESOURCE_IO))
                return OF_BAD_ADDR;

        /* Read address values, skipping high cell */
        cp = of_read_number(range + 1, na - 1);
        s  = of_read_number(range + na + pna, ns);
        da = of_read_number(addr + 1, na - 1);

        pr_debug("PCI map, cp=%llx, s=%llx, da=%llx\n",
                 (unsigned long long)cp, (unsigned long long)s,
                 (unsigned long long)da);

        if (da < cp || da >= (cp + s))
                return OF_BAD_ADDR;
        return da - cp;
}

static int of_bus_pci_translate(__be32 *addr, u64 offset, int na)
{
        return of_bus_default_translate(addr + 1, offset, na - 1);
}

const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
                        unsigned int *flags)
{
        const __be32 *prop;
        unsigned int psize;
        struct device_node *parent;
        struct of_bus *bus;
        int onesize, i, na, ns;

        /* Get parent & match bus type */
        parent = of_get_parent(dev);
        if (parent == NULL)
                return NULL;
        bus = of_match_bus(parent);
        if (strcmp(bus->name, "pci")) {
                of_node_put(parent);
                return NULL;
        }
        bus->count_cells(dev, &na, &ns);
        of_node_put(parent);
        if (!OF_CHECK_ADDR_COUNT(na))
                return NULL;

        /* Get "reg" or "assigned-addresses" property */
        prop = of_get_property(dev, bus->addresses, &psize);
        if (prop == NULL)
                return NULL;
        psize /= 4;

        onesize = na + ns;
        for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++) {
                u32 val = be32_to_cpu(prop[0]);
                if ((val & 0xff) == ((bar_no * 4) + PCI_BASE_ADDRESS_0)) {
                        if (size)
                                *size = of_read_number(prop + na, ns);
                        if (flags)
                                *flags = bus->get_flags(prop);
                        return prop;
                }
        }
        return NULL;
}
EXPORT_SYMBOL(of_get_pci_address);

int of_pci_address_to_resource(struct device_node *dev, int bar,
                               struct resource *r)
{
        const __be32    *addrp;
        u64             size;
        unsigned int    flags;

        addrp = of_get_pci_address(dev, bar, &size, &flags);
        if (addrp == NULL)
                return -EINVAL;
        return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
}
EXPORT_SYMBOL_GPL(of_pci_address_to_resource);

static int parser_init(struct of_pci_range_parser *parser,
                        struct device_node *node, const char *name)
{
        const int na = 3, ns = 2;
        int rlen;

        parser->node = node;
        parser->pna = of_n_addr_cells(node);
        parser->np = parser->pna + na + ns;

        parser->range = of_get_property(node, name, &rlen);
        if (parser->range == NULL)
                return -ENOENT;

        parser->end = parser->range + rlen / sizeof(__be32);

        return 0;
}

int of_pci_range_parser_init(struct of_pci_range_parser *parser,
                                struct device_node *node)
{
        return parser_init(parser, node, "ranges");
}
EXPORT_SYMBOL_GPL(of_pci_range_parser_init);

int of_pci_dma_range_parser_init(struct of_pci_range_parser *parser,
                                struct device_node *node)
{
        return parser_init(parser, node, "dma-ranges");
}
EXPORT_SYMBOL_GPL(of_pci_dma_range_parser_init);

struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
                                                struct of_pci_range *range)
{
        const int na = 3, ns = 2;

        if (!range)
                return NULL;

        if (!parser->range || parser->range + parser->np > parser->end)
                return NULL;

        range->pci_space = be32_to_cpup(parser->range);
        range->flags = of_bus_pci_get_flags(parser->range);
        range->pci_addr = of_read_number(parser->range + 1, ns);
        range->cpu_addr = of_translate_address(parser->node,
                                parser->range + na);
        range->size = of_read_number(parser->range + parser->pna + na, ns);

        parser->range += parser->np;

        /* Now consume following elements while they are contiguous */
        while (parser->range + parser->np <= parser->end) {
                u32 flags;
                u64 pci_addr, cpu_addr, size;

                flags = of_bus_pci_get_flags(parser->range);
                pci_addr = of_read_number(parser->range + 1, ns);
                cpu_addr = of_translate_address(parser->node,
                                parser->range + na);
                size = of_read_number(parser->range + parser->pna + na, ns);

                if (flags != range->flags)
                        break;
                if (pci_addr != range->pci_addr + range->size ||
                    cpu_addr != range->cpu_addr + range->size)
                        break;

                range->size += size;
                parser->range += parser->np;
        }

        return range;
}
EXPORT_SYMBOL_GPL(of_pci_range_parser_one);

/*
 * of_pci_range_to_resource - Create a resource from an of_pci_range
 * @range:      the PCI range that describes the resource
 * @np:         device node where the range belongs to
 * @res:        pointer to a valid resource that will be updated to
 *              reflect the values contained in the range.
 *
 * Returns EINVAL if the range cannot be converted to resource.
 *
 * Note that if the range is an IO range, the resource will be converted
 * using pci_address_to_pio() which can fail if it is called too early or
 * if the range cannot be matched to any host bridge IO space (our case here).
 * To guard against that we try to register the IO range first.
 * If that fails we know that pci_address_to_pio() will do too.
 */
int of_pci_range_to_resource(struct of_pci_range *range,
                             struct device_node *np, struct resource *res)
{
        int err;
        res->flags = range->flags;
        res->parent = res->child = res->sibling = NULL;
        res->name = np->full_name;

        if (res->flags & IORESOURCE_IO) {
                unsigned long port;
                err = pci_register_io_range(&np->fwnode, range->cpu_addr,
                                range->size);
                if (err)
                        goto invalid_range;
                port = pci_address_to_pio(range->cpu_addr);
                if (port == (unsigned long)-1) {
                        err = -EINVAL;
                        goto invalid_range;
                }
                res->start = port;
        } else {
                if ((sizeof(resource_size_t) < 8) &&
                    upper_32_bits(range->cpu_addr)) {
                        err = -EINVAL;
                        goto invalid_range;
                }

                res->start = range->cpu_addr;
        }
        res->end = res->start + range->size - 1;
        return 0;

invalid_range:
        res->start = (resource_size_t)OF_BAD_ADDR;
        res->end = (resource_size_t)OF_BAD_ADDR;
        return err;
}
EXPORT_SYMBOL(of_pci_range_to_resource);
#endif /* CONFIG_PCI */

/*
 * ISA bus specific translator
 */

static int of_bus_isa_match(struct device_node *np)
{
        return of_node_name_eq(np, "isa");
}

static void of_bus_isa_count_cells(struct device_node *child,
                                   int *addrc, int *sizec)
{
        if (addrc)
                *addrc = 2;
        if (sizec)
                *sizec = 1;
}

static u64 of_bus_isa_map(__be32 *addr, const __be32 *range, int na, int ns,
                int pna)
{
        u64 cp, s, da;

        /* Check address type match */
        if ((addr[0] ^ range[0]) & cpu_to_be32(1))
                return OF_BAD_ADDR;

        /* Read address values, skipping high cell */
        cp = of_read_number(range + 1, na - 1);
        s  = of_read_number(range + na + pna, ns);
        da = of_read_number(addr + 1, na - 1);

        pr_debug("ISA map, cp=%llx, s=%llx, da=%llx\n",
                 (unsigned long long)cp, (unsigned long long)s,
                 (unsigned long long)da);

        if (da < cp || da >= (cp + s))
                return OF_BAD_ADDR;
        return da - cp;
}

static int of_bus_isa_translate(__be32 *addr, u64 offset, int na)
{
        return of_bus_default_translate(addr + 1, offset, na - 1);
}

static unsigned int of_bus_isa_get_flags(const __be32 *addr)
{
        unsigned int flags = 0;
        u32 w = be32_to_cpup(addr);

        if (w & 1)
                flags |= IORESOURCE_IO;
        else
                flags |= IORESOURCE_MEM;
        return flags;
}

/*
 * Array of bus specific translators
 */

static struct of_bus of_busses[] = {
#ifdef CONFIG_PCI
        /* PCI */
        {
                .name = "pci",
                .addresses = "assigned-addresses",
                .match = of_bus_pci_match,
                .count_cells = of_bus_pci_count_cells,
                .map = of_bus_pci_map,
                .translate = of_bus_pci_translate,
                .get_flags = of_bus_pci_get_flags,
        },
#endif /* CONFIG_PCI */
        /* ISA */
        {
                .name = "isa",
                .addresses = "reg",
                .match = of_bus_isa_match,
                .count_cells = of_bus_isa_count_cells,
                .map = of_bus_isa_map,
                .translate = of_bus_isa_translate,
                .get_flags = of_bus_isa_get_flags,
        },
        /* Default */
        {
                .name = "default",
                .addresses = "reg",
                .match = NULL,
                .count_cells = of_bus_default_count_cells,
                .map = of_bus_default_map,
                .translate = of_bus_default_translate,
                .get_flags = of_bus_default_get_flags,
        },
};

static struct of_bus *of_match_bus(struct device_node *np)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(of_busses); i++)
                if (!of_busses[i].match || of_busses[i].match(np))
                        return &of_busses[i];
        BUG();
        return NULL;
}

static int of_empty_ranges_quirk(struct device_node *np)
{
        if (IS_ENABLED(CONFIG_PPC)) {
                /* To save cycles, we cache the result for global "Mac" setting */
                static int quirk_state = -1;

                /* PA-SEMI sdc DT bug */
                if (of_device_is_compatible(np, "1682m-sdc"))
                        return true;

                /* Make quirk cached */
                if (quirk_state < 0)
                        quirk_state =
                                of_machine_is_compatible("Power Macintosh") ||
                                of_machine_is_compatible("MacRISC");
                return quirk_state;
        }
        return false;
}

static int of_translate_one(struct device_node *parent, struct of_bus *bus,
                            struct of_bus *pbus, __be32 *addr,
                            int na, int ns, int pna, const char *rprop)
{
        const __be32 *ranges;
        unsigned int rlen;
        int rone;
        u64 offset = OF_BAD_ADDR;

        /*
         * Normally, an absence of a "ranges" property means we are
         * crossing a non-translatable boundary, and thus the addresses
         * below the current cannot be converted to CPU physical ones.
         * Unfortunately, while this is very clear in the spec, it's not
         * what Apple understood, and they do have things like /uni-n or
         * /ht nodes with no "ranges" property and a lot of perfectly
         * useable mapped devices below them. Thus we treat the absence of
         * "ranges" as equivalent to an empty "ranges" property which means
         * a 1:1 translation at that level. It's up to the caller not to try
         * to translate addresses that aren't supposed to be translated in
         * the first place. --BenH.
         *
         * As far as we know, this damage only exists on Apple machines, so
         * This code is only enabled on powerpc. --gcl
         */
        ranges = of_get_property(parent, rprop, &rlen);
        if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
                pr_debug("no ranges; cannot translate\n");
                return 1;
        }
        if (ranges == NULL || rlen == 0) {
                offset = of_read_number(addr, na);
                memset(addr, 0, pna * 4);
                pr_debug("empty ranges; 1:1 translation\n");
                goto finish;
        }

        pr_debug("walking ranges...\n");

        /* Now walk through the ranges */
        rlen /= 4;
        rone = na + pna + ns;
        for (; rlen >= rone; rlen -= rone, ranges += rone) {
                offset = bus->map(addr, ranges, na, ns, pna);
                if (offset != OF_BAD_ADDR)
                        break;
        }
        if (offset == OF_BAD_ADDR) {
                pr_debug("not found !\n");
                return 1;
        }
        memcpy(addr, ranges + na, 4 * pna);

 finish:
        of_dump_addr("parent translation for:", addr, pna);
        pr_debug("with offset: %llx\n", (unsigned long long)offset);

        /* Translate it into parent bus space */
        return pbus->translate(addr, offset, pna);
}

/*
 * Translate an address from the device-tree into a CPU physical address,
 * this walks up the tree and applies the various bus mappings on the
 * way.
 *
 * Note: We consider that crossing any level with #size-cells == 0 to mean
 * that translation is impossible (that is we are not dealing with a value
 * that can be mapped to a cpu physical address). This is not really specified
 * that way, but this is traditionally the way IBM at least do things
 *
 * Whenever the translation fails, the *host pointer will be set to the
 * device that had registered logical PIO mapping, and the return code is
 * relative to that node.
 */
static u64 __of_translate_address(struct device_node *dev,
                                  struct device_node *(*get_parent)(const struct device_node *),
                                  const __be32 *in_addr, const char *rprop,
                                  struct device_node **host)
{
        struct device_node *parent = NULL;
        struct of_bus *bus, *pbus;
        __be32 addr[OF_MAX_ADDR_CELLS];
        int na, ns, pna, pns;
        u64 result = OF_BAD_ADDR;

        pr_debug("** translation for device %pOF **\n", dev);

        /* Increase refcount at current level */
        of_node_get(dev);

        *host = NULL;
        /* Get parent & match bus type */
        parent = get_parent(dev);
        if (parent == NULL)
                goto bail;
        bus = of_match_bus(parent);

        /* Count address cells & copy address locally */
        bus->count_cells(dev, &na, &ns);
        if (!OF_CHECK_COUNTS(na, ns)) {
                pr_debug("Bad cell count for %pOF\n", dev);
                goto bail;
        }
        memcpy(addr, in_addr, na * 4);

        pr_debug("bus is %s (na=%d, ns=%d) on %pOF\n",
            bus->name, na, ns, parent);
        of_dump_addr("translating address:", addr, na);

        /* Translate */
        for (;;) {
                struct logic_pio_hwaddr *iorange;

                /* Switch to parent bus */
                of_node_put(dev);
                dev = parent;
                parent = get_parent(dev);

                /* If root, we have finished */
                if (parent == NULL) {
                        pr_debug("reached root node\n");
                        result = of_read_number(addr, na);
                        break;
                }

                /*
                 * For indirectIO device which has no ranges property, get
                 * the address from reg directly.
                 */
                iorange = find_io_range_by_fwnode(&dev->fwnode);
                if (iorange && (iorange->flags != LOGIC_PIO_CPU_MMIO)) {
                        result = of_read_number(addr + 1, na - 1);
                        pr_debug("indirectIO matched(%pOF) 0x%llx\n",
                                 dev, result);
                        *host = of_node_get(dev);
                        break;
                }

                /* Get new parent bus and counts */
                pbus = of_match_bus(parent);
                pbus->count_cells(dev, &pna, &pns);
                if (!OF_CHECK_COUNTS(pna, pns)) {
                        pr_err("Bad cell count for %pOF\n", dev);
                        break;
                }

                pr_debug("parent bus is %s (na=%d, ns=%d) on %pOF\n",
                    pbus->name, pna, pns, parent);

                /* Apply bus translation */
                if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
                        break;

                /* Complete the move up one level */
                na = pna;
                ns = pns;
                bus = pbus;

                of_dump_addr("one level translation:", addr, na);
        }
 bail:
        of_node_put(parent);
        of_node_put(dev);

        return result;
}

u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
{
        struct device_node *host;
        u64 ret;

        ret = __of_translate_address(dev, of_get_parent,
                                     in_addr, "ranges", &host);
        if (host) {
                of_node_put(host);
                return OF_BAD_ADDR;
        }

        return ret;
}
EXPORT_SYMBOL(of_translate_address);

static struct device_node *__of_get_dma_parent(const struct device_node *np)
{
        struct of_phandle_args args;
        int ret, index;

        index = of_property_match_string(np, "interconnect-names", "dma-mem");
        if (index < 0)
                return of_get_parent(np);

        ret = of_parse_phandle_with_args(np, "interconnects",
                                         "#interconnect-cells",
                                         index, &args);
        if (ret < 0)
                return of_get_parent(np);

        return of_node_get(args.np);
}

u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
{
        struct device_node *host;
        u64 ret;

        ret = __of_translate_address(dev, __of_get_dma_parent,
                                     in_addr, "dma-ranges", &host);

        if (host) {
                of_node_put(host);
                return OF_BAD_ADDR;
        }

        return ret;
}
EXPORT_SYMBOL(of_translate_dma_address);

const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
                    unsigned int *flags)
{
        const __be32 *prop;
        unsigned int psize;
        struct device_node *parent;
        struct of_bus *bus;
        int onesize, i, na, ns;

        /* Get parent & match bus type */
        parent = of_get_parent(dev);
        if (parent == NULL)
                return NULL;
        bus = of_match_bus(parent);
        bus->count_cells(dev, &na, &ns);
        of_node_put(parent);
        if (!OF_CHECK_ADDR_COUNT(na))
                return NULL;

        /* Get "reg" or "assigned-addresses" property */
        prop = of_get_property(dev, bus->addresses, &psize);
        if (prop == NULL)
                return NULL;
        psize /= 4;

        onesize = na + ns;
        for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++)
                if (i == index) {
                        if (size)
                                *size = of_read_number(prop + na, ns);
                        if (flags)
                                *flags = bus->get_flags(prop);
                        return prop;
                }
        return NULL;
}
EXPORT_SYMBOL(of_get_address);

static u64 of_translate_ioport(struct device_node *dev, const __be32 *in_addr,
                        u64 size)
{
        u64 taddr;
        unsigned long port;
        struct device_node *host;

        taddr = __of_translate_address(dev, of_get_parent,
                                       in_addr, "ranges", &host);
        if (host) {
                /* host-specific port access */
                port = logic_pio_trans_hwaddr(&host->fwnode, taddr, size);
                of_node_put(host);
        } else {
                /* memory-mapped I/O range */
                port = pci_address_to_pio(taddr);
        }

        if (port == (unsigned long)-1)
                return OF_BAD_ADDR;

        return port;
}

static int __of_address_to_resource(struct device_node *dev,
                const __be32 *addrp, u64 size, unsigned int flags,
                const char *name, struct resource *r)
{
        u64 taddr;

        if (flags & IORESOURCE_MEM)
                taddr = of_translate_address(dev, addrp);
        else if (flags & IORESOURCE_IO)
                taddr = of_translate_ioport(dev, addrp, size);
        else
                return -EINVAL;

        if (taddr == OF_BAD_ADDR)
                return -EINVAL;
        memset(r, 0, sizeof(struct resource));

        r->start = taddr;
        r->end = taddr + size - 1;
        r->flags = flags;
        r->name = name ? name : dev->full_name;

        return 0;
}

/**
 * of_address_to_resource - Translate device tree address and return as resource
 *
 * Note that if your address is a PIO address, the conversion will fail if
 * the physical address can't be internally converted to an IO token with
 * pci_address_to_pio(), that is because it's either called too early or it
 * can't be matched to any host bridge IO space
 */
int of_address_to_resource(struct device_node *dev, int index,
                           struct resource *r)
{
        const __be32    *addrp;
        u64             size;
        unsigned int    flags;
        const char      *name = NULL;

        addrp = of_get_address(dev, index, &size, &flags);
        if (addrp == NULL)
                return -EINVAL;

        /* Get optional "reg-names" property to add a name to a resource */
        of_property_read_string_index(dev, "reg-names", index, &name);

        return __of_address_to_resource(dev, addrp, size, flags, name, r);
}
EXPORT_SYMBOL_GPL(of_address_to_resource);

struct device_node *of_find_matching_node_by_address(struct device_node *from,
                                        const struct of_device_id *matches,
                                        u64 base_address)
{
        struct device_node *dn = of_find_matching_node(from, matches);
        struct resource res;

        while (dn) {
                if (!of_address_to_resource(dn, 0, &res) &&
                    res.start == base_address)
                        return dn;

                dn = of_find_matching_node(dn, matches);
        }

        return NULL;
}


/**
 * of_iomap - Maps the memory mapped IO for a given device_node
 * @device:     the device whose io range will be mapped
 * @index:      index of the io range
 *
 * Returns a pointer to the mapped memory
 */
void __iomem *of_iomap(struct device_node *np, int index)
{
        struct resource res;

        if (of_address_to_resource(np, index, &res))
                return NULL;

        return ioremap(res.start, resource_size(&res));
}
EXPORT_SYMBOL(of_iomap);

/*
 * of_io_request_and_map - Requests a resource and maps the memory mapped IO
 *                         for a given device_node
 * @device:     the device whose io range will be mapped
 * @index:      index of the io range
 * @name:       name "override" for the memory region request or NULL
 *
 * Returns a pointer to the requested and mapped memory or an ERR_PTR() encoded
 * error code on failure. Usage example:
 *
 *      base = of_io_request_and_map(node, 0, "foo");
 *      if (IS_ERR(base))
 *              return PTR_ERR(base);
 */
void __iomem *of_io_request_and_map(struct device_node *np, int index,
                                    const char *name)
{
        struct resource res;
        void __iomem *mem;

        if (of_address_to_resource(np, index, &res))
                return IOMEM_ERR_PTR(-EINVAL);

        if (!name)
                name = res.name;
        if (!request_mem_region(res.start, resource_size(&res), name))
                return IOMEM_ERR_PTR(-EBUSY);

        mem = ioremap(res.start, resource_size(&res));
        if (!mem) {
                release_mem_region(res.start, resource_size(&res));
                return IOMEM_ERR_PTR(-ENOMEM);
        }

        return mem;
}
EXPORT_SYMBOL(of_io_request_and_map);

/**
 * of_dma_get_range - Get DMA range info
 * @np:         device node to get DMA range info
 * @dma_addr:   pointer to store initial DMA address of DMA range
 * @paddr:      pointer to store initial CPU address of DMA range
 * @size:       pointer to store size of DMA range
 *
 * Look in bottom up direction for the first "dma-ranges" property
 * and parse it.
 *  dma-ranges format:
 *      DMA addr (dma_addr)     : naddr cells
 *      CPU addr (phys_addr_t)  : pna cells
 *      size                    : nsize cells
 *
 * It returns -ENODEV if "dma-ranges" property was not found
 * for this device in DT.
 */
int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *size)
{
        struct device_node *node = of_node_get(np);
        const __be32 *ranges = NULL;
        int len, naddr, nsize, pna;
        int ret = 0;
        u64 dmaaddr;

        if (!node)
                return -EINVAL;

        while (1) {
                struct device_node *parent;

                naddr = of_n_addr_cells(node);
                nsize = of_n_size_cells(node);

                parent = __of_get_dma_parent(node);
                of_node_put(node);

                node = parent;
                if (!node)
                        break;

                ranges = of_get_property(node, "dma-ranges", &len);

                /* Ignore empty ranges, they imply no translation required */
                if (ranges && len > 0)
                        break;

                /*
                 * At least empty ranges has to be defined for parent node if
                 * DMA is supported
                 */
                if (!ranges)
                        break;
        }

        if (!ranges) {
                pr_debug("no dma-ranges found for node(%pOF)\n", np);
                ret = -ENODEV;
                goto out;
        }

        len /= sizeof(u32);

        pna = of_n_addr_cells(node);

        /* dma-ranges format:
         * DMA addr     : naddr cells
         * CPU addr     : pna cells
         * size         : nsize cells
         */
        dmaaddr = of_read_number(ranges, naddr);
        *paddr = of_translate_dma_address(np, ranges);
        if (*paddr == OF_BAD_ADDR) {
                pr_err("translation of DMA address(%pad) to CPU address failed node(%pOF)\n",
                       dma_addr, np);
                ret = -EINVAL;
                goto out;
        }
        *dma_addr = dmaaddr;

        *size = of_read_number(ranges + naddr + pna, nsize);

        pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
                 *dma_addr, *paddr, *size);

out:
        of_node_put(node);

        return ret;
}
EXPORT_SYMBOL_GPL(of_dma_get_range);

/**
 * of_dma_is_coherent - Check if device is coherent
 * @np: device node
 *
 * It returns true if "dma-coherent" property was found
 * for this device in DT.
 */
bool of_dma_is_coherent(struct device_node *np)
{
        struct device_node *node = of_node_get(np);

        while (node) {
                if (of_property_read_bool(node, "dma-coherent")) {
                        of_node_put(node);
                        return true;
                }
                node = of_get_next_parent(node);
        }
        of_node_put(node);
        return false;
}
EXPORT_SYMBOL_GPL(of_dma_is_coherent);