OSCL-LXR linux-6.0.1/​drivers/​of/​fdt.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Functions for working with the Flattened Device Tree data format
  *
  * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
  * benh@kernel.crashing.org
  */
 
 #define pr_fmt(fmt) "OF: fdt: " fmt
 
 #include <linux/crash_dump.h>
 #include <linux/crc32.h>
 #include <linux/kernel.h>
 #include <linux/initrd.h>
 #include <linux/memblock.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/libfdt.h>
 #include <linux/debugfs.h>
 #include <linux/serial_core.h>
 #include <linux/sysfs.h>
 #include <linux/random.h>
 #include <linux/kmemleak.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
 
 #include "of_private.h"
 
 /*
  * of_fdt_limit_memory - limit the number of regions in the /memory node
  * @limit: maximum entries
  *
  * Adjust the flattened device tree to have at most 'limit' number of
  * memory entries in the /memory node. This function may be called
  * any time after initial_boot_param is set.
  */
 void __init of_fdt_limit_memory(int limit)
 {
     int memory;
     int len;
     const void *val;
     int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
     int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
     const __be32 *addr_prop;
     const __be32 *size_prop;
     int root_offset;
     int cell_size;
 
     root_offset = fdt_path_offset(initial_boot_params, "/");
     if (root_offset < 0)
         return;
 
     addr_prop = fdt_getprop(initial_boot_params, root_offset,
                 "#address-cells", NULL);
     if (addr_prop)
         nr_address_cells = fdt32_to_cpu(*addr_prop);
 
     size_prop = fdt_getprop(initial_boot_params, root_offset,
                 "#size-cells", NULL);
     if (size_prop)
         nr_size_cells = fdt32_to_cpu(*size_prop);
 
     cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
 
     memory = fdt_path_offset(initial_boot_params, "/memory");
     if (memory > 0) {
         val = fdt_getprop(initial_boot_params, memory, "reg", &len);
         if (len > limit*cell_size) {
             len = limit*cell_size;
             pr_debug("Limiting number of entries to %d\n", limit);
             fdt_setprop(initial_boot_params, memory, "reg", val,
                     len);
         }
     }
 }
 
 static bool of_fdt_device_is_available(const void *blob, unsigned long node)
 {
     const char *status = fdt_getprop(blob, node, "status", NULL);
 
     if (!status)
         return true;
 
     if (!strcmp(status, "ok") || !strcmp(status, "okay"))
         return true;
 
     return false;
 }
 
 static void *unflatten_dt_alloc(void **mem, unsigned long size,
                        unsigned long align)
 {
     void *res;
 
     *mem = PTR_ALIGN(*mem, align);
     res = *mem;
     *mem += size;
 
     return res;
 }
 
 static void populate_properties(const void *blob,
                 int offset,
                 void **mem,
                 struct device_node *np,
                 const char *nodename,
                 bool dryrun)
 {
     struct property *pp, **pprev = NULL;
     int cur;
     bool has_name = false;
 
     pprev = &np->properties;
     for (cur = fdt_first_property_offset(blob, offset);
          cur >= 0;
          cur = fdt_next_property_offset(blob, cur)) {
         const __be32 *val;
         const char *pname;
         u32 sz;
 
         val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
         if (!val) {
             pr_warn("Cannot locate property at 0x%x\n", cur);
             continue;
         }
 
         if (!pname) {
             pr_warn("Cannot find property name at 0x%x\n", cur);
             continue;
         }
 
         if (!strcmp(pname, "name"))
             has_name = true;
 
         pp = unflatten_dt_alloc(mem, sizeof(struct property),
                     __alignof__(struct property));
         if (dryrun)
             continue;
 
         /* We accept flattened tree phandles either in
          * ePAPR-style "phandle" properties, or the
          * legacy "linux,phandle" properties.  If both
          * appear and have different values, things
          * will get weird. Don't do that.
          */
         if (!strcmp(pname, "phandle") ||
             !strcmp(pname, "linux,phandle")) {
             if (!np->phandle)
                 np->phandle = be32_to_cpup(val);
         }
 
         /* And we process the "ibm,phandle" property
          * used in pSeries dynamic device tree
          * stuff
          */
         if (!strcmp(pname, "ibm,phandle"))
             np->phandle = be32_to_cpup(val);
 
         pp->name   = (char *)pname;
         pp->length = sz;
         pp->value  = (__be32 *)val;
         *pprev     = pp;
         pprev      = &pp->next;
     }
 
     /* With version 0x10 we may not have the name property,
      * recreate it here from the unit name if absent
      */
     if (!has_name) {
         const char *p = nodename, *ps = p, *pa = NULL;
         int len;
 
         while (*p) {
             if ((*p) == '@')
                 pa = p;
             else if ((*p) == '/')
                 ps = p + 1;
             p++;
         }
 
         if (pa < ps)
             pa = p;
         len = (pa - ps) + 1;
         pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
                     __alignof__(struct property));
         if (!dryrun) {
             pp->name   = "name";
             pp->length = len;
             pp->value  = pp + 1;
             *pprev     = pp;
             memcpy(pp->value, ps, len - 1);
             ((char *)pp->value)[len - 1] = 0;
             pr_debug("fixed up name for %s -> %s\n",
                  nodename, (char *)pp->value);
         }
     }
 }
 
 static int populate_node(const void *blob,
               int offset,
               void **mem,
               struct device_node *dad,
               struct device_node **pnp,
               bool dryrun)
 {
     struct device_node *np;
     const char *pathp;
     int len;
 
     pathp = fdt_get_name(blob, offset, &len);
     if (!pathp) {
         *pnp = NULL;
         return len;
     }
 
     len++;
 
     np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
                 __alignof__(struct device_node));
     if (!dryrun) {
         char *fn;
         of_node_init(np);
         np->full_name = fn = ((char *)np) + sizeof(*np);
 
         memcpy(fn, pathp, len);
 
         if (dad != NULL) {
             np->parent = dad;
             np->sibling = dad->child;
             dad->child = np;
         }
     }
 
     populate_properties(blob, offset, mem, np, pathp, dryrun);
     if (!dryrun) {
         np->name = of_get_property(np, "name", NULL);
         if (!np->name)
             np->name = "<NULL>";
     }
 
     *pnp = np;
     return 0;
 }
 
 static void reverse_nodes(struct device_node *parent)
 {
     struct device_node *child, *next;
 
     /* In-depth first */
     child = parent->child;
     while (child) {
         reverse_nodes(child);
 
         child = child->sibling;
     }
 
     /* Reverse the nodes in the child list */
     child = parent->child;
     parent->child = NULL;
     while (child) {
         next = child->sibling;
 
         child->sibling = parent->child;
         parent->child = child;
         child = next;
     }
 }
 
 /**
  * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
  * @blob: The parent device tree blob
  * @mem: Memory chunk to use for allocating device nodes and properties
  * @dad: Parent struct device_node
  * @nodepp: The device_node tree created by the call
  *
  * Return: The size of unflattened device tree or error code
  */
 static int unflatten_dt_nodes(const void *blob,
                   void *mem,
                   struct device_node *dad,
                   struct device_node **nodepp)
 {
     struct device_node *root;
     int offset = 0, depth = 0, initial_depth = 0;
 #define FDT_MAX_DEPTH   64
     struct device_node *nps[FDT_MAX_DEPTH];
     void *base = mem;
     bool dryrun = !base;
     int ret;
 
     if (nodepp)
         *nodepp = NULL;
 
     /*
      * We're unflattening device sub-tree if @dad is valid. There are
      * possibly multiple nodes in the first level of depth. We need
      * set @depth to 1 to make fdt_next_node() happy as it bails
      * immediately when negative @depth is found. Otherwise, the device
      * nodes except the first one won't be unflattened successfully.
      */
     if (dad)
         depth = initial_depth = 1;
 
     root = dad;
     nps[depth] = dad;
 
     for (offset = 0;
          offset >= 0 && depth >= initial_depth;
          offset = fdt_next_node(blob, offset, &depth)) {
         if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
             continue;
 
         if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
             !of_fdt_device_is_available(blob, offset))
             continue;
 
         ret = populate_node(blob, offset, &mem, nps[depth],
                    &nps[depth+1], dryrun);
         if (ret < 0)
             return ret;
 
         if (!dryrun && nodepp && !*nodepp)
             *nodepp = nps[depth+1];
         if (!dryrun && !root)
             root = nps[depth+1];
     }
 
     if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
         pr_err("Error %d processing FDT\n", offset);
         return -EINVAL;
     }
 
     /*
      * Reverse the child list. Some drivers assumes node order matches .dts
      * node order
      */
     if (!dryrun)
         reverse_nodes(root);
 
     return mem - base;
 }
 
 /**
  * __unflatten_device_tree - create tree of device_nodes from flat blob
  * @blob: The blob to expand
  * @dad: Parent device node
  * @mynodes: The device_node tree created by the call
  * @dt_alloc: An allocator that provides a virtual address to memory
  * for the resulting tree
  * @detached: if true set OF_DETACHED on @mynodes
  *
  * unflattens a device-tree, creating the tree of struct device_node. It also
  * fills the "name" and "type" pointers of the nodes so the normal device-tree
  * walking functions can be used.
  *
  * Return: NULL on failure or the memory chunk containing the unflattened
  * device tree on success.
  */
 void *__unflatten_device_tree(const void *blob,
                   struct device_node *dad,
                   struct device_node **mynodes,
                   void *(*dt_alloc)(u64 size, u64 align),
                   bool detached)
 {
     int size;
     void *mem;
     int ret;
 
     if (mynodes)
         *mynodes = NULL;
 
     pr_debug(" -> unflatten_device_tree()\n");
 
     if (!blob) {
         pr_debug("No device tree pointer\n");
         return NULL;
     }
 
     pr_debug("Unflattening device tree:\n");
     pr_debug("magic: %08x\n", fdt_magic(blob));
     pr_debug("size: %08x\n", fdt_totalsize(blob));
     pr_debug("version: %08x\n", fdt_version(blob));
 
     if (fdt_check_header(blob)) {
         pr_err("Invalid device tree blob header\n");
         return NULL;
     }
 
     /* First pass, scan for size */
     size = unflatten_dt_nodes(blob, NULL, dad, NULL);
     if (size <= 0)
         return NULL;
 
     size = ALIGN(size, 4);
     pr_debug("  size is %d, allocating...\n", size);
 
     /* Allocate memory for the expanded device tree */
     mem = dt_alloc(size + 4, __alignof__(struct device_node));
     if (!mem)
         return NULL;
 
     memset(mem, 0, size);
 
     *(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
 
     pr_debug("  unflattening %p...\n", mem);
 
     /* Second pass, do actual unflattening */
     ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
 
     if (be32_to_cpup(mem + size) != 0xdeadbeef)
         pr_warn("End of tree marker overwritten: %08x\n",
             be32_to_cpup(mem + size));
 
     if (ret <= 0)
         return NULL;
 
     if (detached && mynodes && *mynodes) {
         of_node_set_flag(*mynodes, OF_DETACHED);
         pr_debug("unflattened tree is detached\n");
     }
 
     pr_debug(" <- unflatten_device_tree()\n");
     return mem;
 }
 
 static void *kernel_tree_alloc(u64 size, u64 align)
 {
     return kzalloc(size, GFP_KERNEL);
 }
 
 static DEFINE_MUTEX(of_fdt_unflatten_mutex);
 
 /**
  * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
  * @blob: Flat device tree blob
  * @dad: Parent device node
  * @mynodes: The device tree created by the call
  *
  * unflattens the device-tree passed by the firmware, creating the
  * tree of struct device_node. It also fills the "name" and "type"
  * pointers of the nodes so the normal device-tree walking functions
  * can be used.
  *
  * Return: NULL on failure or the memory chunk containing the unflattened
  * device tree on success.
  */
 void *of_fdt_unflatten_tree(const unsigned long *blob,
                 struct device_node *dad,
                 struct device_node **mynodes)
 {
     void *mem;
 
     mutex_lock(&of_fdt_unflatten_mutex);
     mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
                       true);
     mutex_unlock(&of_fdt_unflatten_mutex);
 
     return mem;
 }
 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 
 /* Everything below here references initial_boot_params directly. */
 int __initdata dt_root_addr_cells;
 int __initdata dt_root_size_cells;
 
 void *initial_boot_params __ro_after_init;
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
 
 static u32 of_fdt_crc32;
 
 static int __init early_init_dt_reserve_memory(phys_addr_t base,
                            phys_addr_t size, bool nomap)
 {
     if (nomap) {
         /*
          * If the memory is already reserved (by another region), we
          * should not allow it to be marked nomap, but don't worry
          * if the region isn't memory as it won't be mapped.
          */
         if (memblock_overlaps_region(&memblock.memory, base, size) &&
             memblock_is_region_reserved(base, size))
             return -EBUSY;
 
         return memblock_mark_nomap(base, size);
     }
     return memblock_reserve(base, size);
 }
 
 /*
  * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
  */
 static int __init __reserved_mem_reserve_reg(unsigned long node,
                          const char *uname)
 {
     int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
     phys_addr_t base, size;
     int len;
     const __be32 *prop;
     int first = 1;
     bool nomap;
 
     prop = of_get_flat_dt_prop(node, "reg", &len);
     if (!prop)
         return -ENOENT;
 
     if (len && len % t_len != 0) {
         pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
                uname);
         return -EINVAL;
     }
 
     nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 
     while (len >= t_len) {
         base = dt_mem_next_cell(dt_root_addr_cells, &prop);
         size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
         if (size &&
             early_init_dt_reserve_memory(base, size, nomap) == 0) {
             pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
                 uname, &base, (unsigned long)(size / SZ_1M));
             if (!nomap)
                 kmemleak_alloc_phys(base, size, 0);
         }
         else
             pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
                    uname, &base, (unsigned long)(size / SZ_1M));
 
         len -= t_len;
         if (first) {
             fdt_reserved_mem_save_node(node, uname, base, size);
             first = 0;
         }
     }
     return 0;
 }
 
 /*
  * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
  * in /reserved-memory matches the values supported by the current implementation,
  * also check if ranges property has been provided
  */
 static int __init __reserved_mem_check_root(unsigned long node)
 {
     const __be32 *prop;
 
     prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
     if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
         return -EINVAL;
 
     prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
     if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
         return -EINVAL;
 
     prop = of_get_flat_dt_prop(node, "ranges", NULL);
     if (!prop)
         return -EINVAL;
     return 0;
 }
 
 /*
  * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
  */
 static int __init fdt_scan_reserved_mem(void)
 {
     int node, child;
     const void *fdt = initial_boot_params;
 
     node = fdt_path_offset(fdt, "/reserved-memory");
     if (node < 0)
         return -ENODEV;
 
     if (__reserved_mem_check_root(node) != 0) {
         pr_err("Reserved memory: unsupported node format, ignoring\n");
         return -EINVAL;
     }
 
     fdt_for_each_subnode(child, fdt, node) {
         const char *uname;
         int err;
 
         if (!of_fdt_device_is_available(fdt, child))
             continue;
 
         uname = fdt_get_name(fdt, child, NULL);
 
         err = __reserved_mem_reserve_reg(child, uname);
         if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
             fdt_reserved_mem_save_node(child, uname, 0, 0);
     }
     return 0;
 }
 
 /*
  * fdt_reserve_elfcorehdr() - reserves memory for elf core header
  *
  * This function reserves the memory occupied by an elf core header
  * described in the device tree. This region contains all the
  * information about primary kernel's core image and is used by a dump
  * capture kernel to access the system memory on primary kernel.
  */
 static void __init fdt_reserve_elfcorehdr(void)
 {
     if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
         return;
 
     if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
         pr_warn("elfcorehdr is overlapped\n");
         return;
     }
 
     memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
 
     pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
         elfcorehdr_size >> 10, elfcorehdr_addr);
 }
 
 /**
  * early_init_fdt_scan_reserved_mem() - create reserved memory regions
  *
  * This function grabs memory from early allocator for device exclusive use
  * defined in device tree structures. It should be called by arch specific code
  * once the early allocator (i.e. memblock) has been fully activated.
  */
 void __init early_init_fdt_scan_reserved_mem(void)
 {
     int n;
     u64 base, size;
 
     if (!initial_boot_params)
         return;
 
     /* Process header /memreserve/ fields */
     for (n = 0; ; n++) {
         fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
         if (!size)
             break;
         memblock_reserve(base, size);
     }
 
     fdt_scan_reserved_mem();
     fdt_reserve_elfcorehdr();
     fdt_init_reserved_mem();
 }
 
 /**
  * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
  */
 void __init early_init_fdt_reserve_self(void)
 {
     if (!initial_boot_params)
         return;
 
     /* Reserve the dtb region */
     memblock_reserve(__pa(initial_boot_params),
              fdt_totalsize(initial_boot_params));
 }
 
 /**
  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
  * @it: callback function
  * @data: context data pointer
  *
  * This function is used to scan the flattened device-tree, it is
  * used to extract the memory information at boot before we can
  * unflatten the tree
  */
 int __init of_scan_flat_dt(int (*it)(unsigned long node,
                      const char *uname, int depth,
                      void *data),
                void *data)
 {
     const void *blob = initial_boot_params;
     const char *pathp;
     int offset, rc = 0, depth = -1;
 
     if (!blob)
         return 0;
 
     for (offset = fdt_next_node(blob, -1, &depth);
          offset >= 0 && depth >= 0 && !rc;
          offset = fdt_next_node(blob, offset, &depth)) {
 
         pathp = fdt_get_name(blob, offset, NULL);
         rc = it(offset, pathp, depth, data);
     }
     return rc;
 }
 
 /**
  * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
  * @parent: parent node
  * @it: callback function
  * @data: context data pointer
  *
  * This function is used to scan sub-nodes of a node.
  */
 int __init of_scan_flat_dt_subnodes(unsigned long parent,
                     int (*it)(unsigned long node,
                           const char *uname,
                           void *data),
                     void *data)
 {
     const void *blob = initial_boot_params;
     int node;
 
     fdt_for_each_subnode(node, blob, parent) {
         const char *pathp;
         int rc;
 
         pathp = fdt_get_name(blob, node, NULL);
         rc = it(node, pathp, data);
         if (rc)
             return rc;
     }
     return 0;
 }
 
 /**
  * of_get_flat_dt_subnode_by_name - get the subnode by given name
  *
  * @node: the parent node
  * @uname: the name of subnode
  * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
  */
 
 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
 {
     return fdt_subnode_offset(initial_boot_params, node, uname);
 }
 
 /*
  * of_get_flat_dt_root - find the root node in the flat blob
  */
 unsigned long __init of_get_flat_dt_root(void)
 {
     return 0;
 }
 
 /*
  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
  *
  * This function can be used within scan_flattened_dt callback to get
  * access to properties
  */
 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
                        int *size)
 {
     return fdt_getprop(initial_boot_params, node, name, size);
 }
 
 /**
  * of_fdt_is_compatible - Return true if given node from the given blob has
  * compat in its compatible list
  * @blob: A device tree blob
  * @node: node to test
  * @compat: compatible string to compare with compatible list.
  *
  * Return: a non-zero value on match with smaller values returned for more
  * specific compatible values.
  */
 static int of_fdt_is_compatible(const void *blob,
               unsigned long node, const char *compat)
 {
     const char *cp;
     int cplen;
     unsigned long l, score = 0;
 
     cp = fdt_getprop(blob, node, "compatible", &cplen);
     if (cp == NULL)
         return 0;
     while (cplen > 0) {
         score++;
         if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
             return score;
         l = strlen(cp) + 1;
         cp += l;
         cplen -= l;
     }
 
     return 0;
 }
 
 /**
  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
  * @node: node to test
  * @compat: compatible string to compare with compatible list.
  */
 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 {
     return of_fdt_is_compatible(initial_boot_params, node, compat);
 }
 
 /*
  * of_flat_dt_match - Return true if node matches a list of compatible values
  */
 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
 {
     unsigned int tmp, score = 0;
 
     if (!compat)
         return 0;
 
     while (*compat) {
         tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
         if (tmp && (score == 0 || (tmp < score)))
             score = tmp;
         compat++;
     }
 
     return score;
 }
 
 /*
  * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
  */
 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
 {
     return fdt_get_phandle(initial_boot_params, node);
 }
 
 struct fdt_scan_status {
     const char *name;
     int namelen;
     int depth;
     int found;
     int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
     void *data;
 };
 
 const char * __init of_flat_dt_get_machine_name(void)
 {
     const char *name;
     unsigned long dt_root = of_get_flat_dt_root();
 
     name = of_get_flat_dt_prop(dt_root, "model", NULL);
     if (!name)
         name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
     return name;
 }
 
 /**
  * of_flat_dt_match_machine - Iterate match tables to find matching machine.
  *
  * @default_match: A machine specific ptr to return in case of no match.
  * @get_next_compat: callback function to return next compatible match table.
  *
  * Iterate through machine match tables to find the best match for the machine
  * compatible string in the FDT.
  */
 const void * __init of_flat_dt_match_machine(const void *default_match,
         const void * (*get_next_compat)(const char * const**))
 {
     const void *data = NULL;
     const void *best_data = default_match;
     const char *const *compat;
     unsigned long dt_root;
     unsigned int best_score = ~1, score = 0;
 
     dt_root = of_get_flat_dt_root();
     while ((data = get_next_compat(&compat))) {
         score = of_flat_dt_match(dt_root, compat);
         if (score > 0 && score < best_score) {
             best_data = data;
             best_score = score;
         }
     }
     if (!best_data) {
         const char *prop;
         int size;
 
         pr_err("\n unrecognized device tree list:\n[ ");
 
         prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
         if (prop) {
             while (size > 0) {
                 printk("'%s' ", prop);
                 size -= strlen(prop) + 1;
                 prop += strlen(prop) + 1;
             }
         }
         printk("]\n\n");
         return NULL;
     }
 
     pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
 
     return best_data;
 }
 
 static void __early_init_dt_declare_initrd(unsigned long start,
                        unsigned long end)
 {
     /* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
      * enabled since __va() is called too early. ARM64 does make use
      * of phys_initrd_start/phys_initrd_size so we can skip this
      * conversion.
      */
     if (!IS_ENABLED(CONFIG_ARM64)) {
         initrd_start = (unsigned long)__va(start);
         initrd_end = (unsigned long)__va(end);
         initrd_below_start_ok = 1;
     }
 }
 
 /**
  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
  * @node: reference to node containing initrd location ('chosen')
  */
 static void __init early_init_dt_check_for_initrd(unsigned long node)
 {
     u64 start, end;
     int len;
     const __be32 *prop;
 
     if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
         return;
 
     pr_debug("Looking for initrd properties... ");
 
     prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
     if (!prop)
         return;
     start = of_read_number(prop, len/4);
 
     prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
     if (!prop)
         return;
     end = of_read_number(prop, len/4);
 
     __early_init_dt_declare_initrd(start, end);
     phys_initrd_start = start;
     phys_initrd_size = end - start;
 
     pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n", start, end);
 }
 
 /**
  * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
  * tree
  * @node: reference to node containing elfcorehdr location ('chosen')
  */
 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
 {
     const __be32 *prop;
     int len;
 
     if (!IS_ENABLED(CONFIG_CRASH_DUMP))
         return;
 
     pr_debug("Looking for elfcorehdr property... ");
 
     prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
     if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
         return;
 
     elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
     elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
     pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
          elfcorehdr_addr, elfcorehdr_size);
 }
 
 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
 
 /*
  * The main usage of linux,usable-memory-range is for crash dump kernel.
  * Originally, the number of usable-memory regions is one. Now there may
  * be two regions, low region and high region.
  * To make compatibility with existing user-space and older kdump, the low
  * region is always the last range of linux,usable-memory-range if exist.
  */
 #define MAX_USABLE_RANGES       2
 
 /**
  * early_init_dt_check_for_usable_mem_range - Decode usable memory range
  * location from flat tree
  */
 void __init early_init_dt_check_for_usable_mem_range(void)
 {
     struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
     const __be32 *prop, *endp;
     int len, i;
     unsigned long node = chosen_node_offset;
 
     if ((long)node < 0)
         return;
 
     pr_debug("Looking for usable-memory-range property... ");
 
     prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
     if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
         return;
 
     endp = prop + (len / sizeof(__be32));
     for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
         rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
         rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
         pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
              i, &rgn[i].base, &rgn[i].size);
     }
 
     memblock_cap_memory_range(rgn[0].base, rgn[0].size);
     for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
         memblock_add(rgn[i].base, rgn[i].size);
 }
 
 #ifdef CONFIG_SERIAL_EARLYCON
 
 int __init early_init_dt_scan_chosen_stdout(void)
 {
     int offset;
     const char *p, *q, *options = NULL;
     int l;
     const struct earlycon_id *match;
     const void *fdt = initial_boot_params;
     int ret;
 
     offset = fdt_path_offset(fdt, "/chosen");
     if (offset < 0)
         offset = fdt_path_offset(fdt, "/chosen@0");
     if (offset < 0)
         return -ENOENT;
 
     p = fdt_getprop(fdt, offset, "stdout-path", &l);
     if (!p)
         p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
     if (!p || !l)
         return -ENOENT;
 
     q = strchrnul(p, ':');
     if (*q != '\0')
         options = q + 1;
     l = q - p;
 
     /* Get the node specified by stdout-path */
     offset = fdt_path_offset_namelen(fdt, p, l);
     if (offset < 0) {
         pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
         return 0;
     }
 
     for (match = __earlycon_table; match < __earlycon_table_end; match++) {
         if (!match->compatible[0])
             continue;
 
         if (fdt_node_check_compatible(fdt, offset, match->compatible))
             continue;
 
         ret = of_setup_earlycon(match, offset, options);
         if (!ret || ret == -EALREADY)
             return 0;
     }
     return -ENODEV;
 }
 #endif
 
 /*
  * early_init_dt_scan_root - fetch the top level address and size cells
  */
 int __init early_init_dt_scan_root(void)
 {
     const __be32 *prop;
     const void *fdt = initial_boot_params;
     int node = fdt_path_offset(fdt, "/");
 
     if (node < 0)
         return -ENODEV;
 
     dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
     dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 
     prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
     if (prop)
         dt_root_size_cells = be32_to_cpup(prop);
     pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
 
     prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
     if (prop)
         dt_root_addr_cells = be32_to_cpup(prop);
     pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
 
     return 0;
 }
 
 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
 {
     const __be32 *p = *cellp;
 
     *cellp = p + s;
     return of_read_number(p, s);
 }
 
 /*
  * early_init_dt_scan_memory - Look for and parse memory nodes
  */
 int __init early_init_dt_scan_memory(void)
 {
     int node;
     const void *fdt = initial_boot_params;
 
     fdt_for_each_subnode(node, fdt, 0) {
         const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
         const __be32 *reg, *endp;
         int l;
         bool hotpluggable;
 
         /* We are scanning "memory" nodes only */
         if (type == NULL || strcmp(type, "memory") != 0)
             continue;
 
         if (!of_fdt_device_is_available(fdt, node))
             continue;
 
         reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
         if (reg == NULL)
             reg = of_get_flat_dt_prop(node, "reg", &l);
         if (reg == NULL)
             continue;
 
         endp = reg + (l / sizeof(__be32));
         hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
 
         pr_debug("memory scan node %s, reg size %d,\n",
              fdt_get_name(fdt, node, NULL), l);
 
         while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
             u64 base, size;
 
             base = dt_mem_next_cell(dt_root_addr_cells, &reg);
             size = dt_mem_next_cell(dt_root_size_cells, &reg);
 
             if (size == 0)
                 continue;
             pr_debug(" - %llx, %llx\n", base, size);
 
             early_init_dt_add_memory_arch(base, size);
 
             if (!hotpluggable)
                 continue;
 
             if (memblock_mark_hotplug(base, size))
                 pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
                     base, base + size);
         }
     }
     return 0;
 }
 
 int __init early_init_dt_scan_chosen(char *cmdline)
 {
     int l, node;
     const char *p;
     const void *rng_seed;
     const void *fdt = initial_boot_params;
 
     node = fdt_path_offset(fdt, "/chosen");
     if (node < 0)
         node = fdt_path_offset(fdt, "/chosen@0");
     if (node < 0)
         return -ENOENT;
 
     chosen_node_offset = node;
 
     early_init_dt_check_for_initrd(node);
     early_init_dt_check_for_elfcorehdr(node);
 
     /* Retrieve command line */
     p = of_get_flat_dt_prop(node, "bootargs", &l);
     if (p != NULL && l > 0)
         strlcpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
 
     /*
      * CONFIG_CMDLINE is meant to be a default in case nothing else
      * managed to set the command line, unless CONFIG_CMDLINE_FORCE
      * is set in which case we override whatever was found earlier.
      */
 #ifdef CONFIG_CMDLINE
 #if defined(CONFIG_CMDLINE_EXTEND)
     strlcat(cmdline, " ", COMMAND_LINE_SIZE);
     strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #elif defined(CONFIG_CMDLINE_FORCE)
     strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #else
     /* No arguments from boot loader, use kernel's  cmdl*/
     if (!((char *)cmdline)[0])
         strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #endif
 #endif /* CONFIG_CMDLINE */
 
     pr_debug("Command line is: %s\n", (char *)cmdline);
 
     rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
     if (rng_seed && l > 0) {
         add_bootloader_randomness(rng_seed, l);
 
         /* try to clear seed so it won't be found. */
         fdt_nop_property(initial_boot_params, node, "rng-seed");
 
         /* update CRC check value */
         of_fdt_crc32 = crc32_be(~0, initial_boot_params,
                 fdt_totalsize(initial_boot_params));
     }
 
     return 0;
 }
 
 #ifndef MIN_MEMBLOCK_ADDR
 #define MIN_MEMBLOCK_ADDR   __pa(PAGE_OFFSET)
 #endif
 #ifndef MAX_MEMBLOCK_ADDR
 #define MAX_MEMBLOCK_ADDR   ((phys_addr_t)~0)
 #endif
 
 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 {
     const u64 phys_offset = MIN_MEMBLOCK_ADDR;
 
     if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
         pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
             base, base + size);
         return;
     }
 
     if (!PAGE_ALIGNED(base)) {
         size -= PAGE_SIZE - (base & ~PAGE_MASK);
         base = PAGE_ALIGN(base);
     }
     size &= PAGE_MASK;
 
     if (base > MAX_MEMBLOCK_ADDR) {
         pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
             base, base + size);
         return;
     }
 
     if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
         pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
             ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
         size = MAX_MEMBLOCK_ADDR - base + 1;
     }
 
     if (base + size < phys_offset) {
         pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
             base, base + size);
         return;
     }
     if (base < phys_offset) {
         pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
             base, phys_offset);
         size -= phys_offset - base;
         base = phys_offset;
     }
     memblock_add(base, size);
 }
 
 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
 {
     void *ptr = memblock_alloc(size, align);
 
     if (!ptr)
         panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
               __func__, size, align);
 
     return ptr;
 }
 
 bool __init early_init_dt_verify(void *params)
 {
     if (!params)
         return false;
 
     /* check device tree validity */
     if (fdt_check_header(params))
         return false;
 
     /* Setup flat device-tree pointer */
     initial_boot_params = params;
     of_fdt_crc32 = crc32_be(~0, initial_boot_params,
                 fdt_totalsize(initial_boot_params));
     return true;
 }
 
 
 void __init early_init_dt_scan_nodes(void)
 {
     int rc;
 
     /* Initialize {size,address}-cells info */
     early_init_dt_scan_root();
 
     /* Retrieve various information from the /chosen node */
     rc = early_init_dt_scan_chosen(boot_command_line);
     if (rc)
         pr_warn("No chosen node found, continuing without\n");
 
     /* Setup memory, calling early_init_dt_add_memory_arch */
     early_init_dt_scan_memory();
 
     /* Handle linux,usable-memory-range property */
     early_init_dt_check_for_usable_mem_range();
 }
 
 bool __init early_init_dt_scan(void *params)
 {
     bool status;
 
     status = early_init_dt_verify(params);
     if (!status)
         return false;
 
     early_init_dt_scan_nodes();
     return true;
 }
 
 /**
  * unflatten_device_tree - create tree of device_nodes from flat blob
  *
  * unflattens the device-tree passed by the firmware, creating the
  * tree of struct device_node. It also fills the "name" and "type"
  * pointers of the nodes so the normal device-tree walking functions
  * can be used.
  */
 void __init unflatten_device_tree(void)
 {
     __unflatten_device_tree(initial_boot_params, NULL, &of_root,
                 early_init_dt_alloc_memory_arch, false);
 
     /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
     of_alias_scan(early_init_dt_alloc_memory_arch);
 
     unittest_unflatten_overlay_base();
 }
 
 /**
  * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
  *
  * Copies and unflattens the device-tree passed by the firmware, creating the
  * tree of struct device_node. It also fills the "name" and "type"
  * pointers of the nodes so the normal device-tree walking functions
  * can be used. This should only be used when the FDT memory has not been
  * reserved such is the case when the FDT is built-in to the kernel init
  * section. If the FDT memory is reserved already then unflatten_device_tree
  * should be used instead.
  */
 void __init unflatten_and_copy_device_tree(void)
 {
     int size;
     void *dt;
 
     if (!initial_boot_params) {
         pr_warn("No valid device tree found, continuing without\n");
         return;
     }
 
     size = fdt_totalsize(initial_boot_params);
     dt = early_init_dt_alloc_memory_arch(size,
                          roundup_pow_of_two(FDT_V17_SIZE));
 
     if (dt) {
         memcpy(dt, initial_boot_params, size);
         initial_boot_params = dt;
     }
     unflatten_device_tree();
 }
 
 #ifdef CONFIG_SYSFS
 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
                    struct bin_attribute *bin_attr,
                    char *buf, loff_t off, size_t count)
 {
     memcpy(buf, initial_boot_params + off, count);
     return count;
 }
 
 static int __init of_fdt_raw_init(void)
 {
     static struct bin_attribute of_fdt_raw_attr =
         __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
 
     if (!initial_boot_params)
         return 0;
 
     if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
                      fdt_totalsize(initial_boot_params))) {
         pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
         return 0;
     }
     of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
     return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
 }
 late_initcall(of_fdt_raw_init);
 #endif
 
 #endif /* CONFIG_OF_EARLY_FLATTREE */

This page was automatically generated by the 2.1.0 LXR engine. The LXR team