Commit 60e43e98 authored by Eric Auger's avatar Eric Auger Committed by Alex Williamson
Browse files

device_tree: introduce load_device_tree_from_sysfs 



This function returns the host device tree blob from sysfs
(/proc/device-tree). It uses a recursive function inspired
from dtc read_fstree.

Signed-off-by: default avatarEric Auger <eric.auger@linaro.org>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 62d95512

device_tree.c

+100 −0
Original line number Diff line number Diff line
@@ -13,6 +13,10 @@ 


#include "qemu/osdep.h"



#ifdef CONFIG_LINUX

#include <dirent.h>

#endif



#include "qemu-common.h"

#include "qemu/error-report.h"

#include "sysemu/device_tree.h"
@@ -112,6 +116,102 @@ fail: 
    return NULL;

}



#ifdef CONFIG_LINUX



#define SYSFS_DT_BASEDIR "/proc/device-tree"



/**

 * read_fstree: this function is inspired from dtc read_fstree

 * @fdt: preallocated fdt blob buffer, to be populated

 * @dirname: directory to scan under SYSFS_DT_BASEDIR

 * the search is recursive and the tree is searched down to the

 * leaves (property files).

 *

 * the function asserts in case of error

 */

static void read_fstree(void *fdt, const char *dirname)

{

    DIR *d;

    struct dirent *de;

    struct stat st;

    const char *root_dir = SYSFS_DT_BASEDIR;

    const char *parent_node;



    if (strstr(dirname, root_dir) != dirname) {

        error_setg(&error_fatal, "%s: %s must be searched within %s",

                   __func__, dirname, root_dir);

    }

    parent_node = &dirname[strlen(SYSFS_DT_BASEDIR)];



    d = opendir(dirname);

    if (!d) {

        error_setg(&error_fatal, "%s cannot open %s", __func__, dirname);

    }



    while ((de = readdir(d)) != NULL) {

        char *tmpnam;



        if (!g_strcmp0(de->d_name, ".")

            || !g_strcmp0(de->d_name, "..")) {

            continue;

        }



        tmpnam = g_strdup_printf("%s/%s", dirname, de->d_name);



        if (lstat(tmpnam, &st) < 0) {

            error_setg(&error_fatal, "%s cannot lstat %s", __func__, tmpnam);

        }



        if (S_ISREG(st.st_mode)) {

            gchar *val;

            gsize len;



            if (!g_file_get_contents(tmpnam, &val, &len, NULL)) {

                error_setg(&error_fatal, "%s not able to extract info from %s",

                           __func__, tmpnam);

            }



            if (strlen(parent_node) > 0) {

                qemu_fdt_setprop(fdt, parent_node,

                                 de->d_name, val, len);

            } else {

                qemu_fdt_setprop(fdt, "/", de->d_name, val, len);

            }

            g_free(val);

        } else if (S_ISDIR(st.st_mode)) {

            char *node_name;



            node_name = g_strdup_printf("%s/%s",

                                        parent_node, de->d_name);

            qemu_fdt_add_subnode(fdt, node_name);

            g_free(node_name);

            read_fstree(fdt, tmpnam);

        }



        g_free(tmpnam);

    }



    closedir(d);

}



/* load_device_tree_from_sysfs: extract the dt blob from host sysfs */

void *load_device_tree_from_sysfs(void)

{

    void *host_fdt;

    int host_fdt_size;



    host_fdt = create_device_tree(&host_fdt_size);

    read_fstree(host_fdt, SYSFS_DT_BASEDIR);

    if (fdt_check_header(host_fdt)) {

        error_setg(&error_fatal,

                   "%s host device tree extracted into memory is invalid",

                   __func__);

    }

    return host_fdt;

}



#endif /* CONFIG_LINUX */



static int findnode_nofail(void *fdt, const char *node_path)

{

    int offset;

include/sysemu/device_tree.h

+8 −0
Original line number Diff line number Diff line
@@ -16,6 +16,14 @@ 


void *create_device_tree(int *sizep);

void *load_device_tree(const char *filename_path, int *sizep);

#ifdef CONFIG_LINUX

/**

 * load_device_tree_from_sysfs: reads the device tree information in the

 * /proc/device-tree directory and return the corresponding binary blob

 * buffer pointer. Asserts in case of error.

 */

void *load_device_tree_from_sysfs(void);

#endif



int qemu_fdt_setprop(void *fdt, const char *node_path,

                     const char *property, const void *val, int size);