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/* Copyright 2013-2015 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <dirent.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <libflash/file.h>
#include "arch_flash.h"
#define FDT_FLASH_PATH "/proc/device-tree/chosen/ibm,system-flash"
#define SYSFS_MTD_PATH "/sys/class/mtd"
static inline void hint_root(void)
{
fprintf(stderr, "Do you have permission? Are you root?\n");
}
static int get_dev_attr(const char *dev, const char *attr_file, uint32_t *attr)
{
char *dev_path = NULL;
int fd, rc;
/*
* Needs to be large enough to hold at most uint32_t represented as a
* string in hex with leading 0x
*/
char attr_buf[10];
rc = asprintf(&dev_path, "%s/%s/%s", SYSFS_MTD_PATH, dev, attr_file);
if (rc < 0) {
dev_path = NULL;
goto out;
}
fd = open(dev_path, O_RDONLY);
if (fd == -1)
goto out;
rc = read(fd, attr_buf, sizeof(attr_buf));
close(fd);
if (rc == -1)
goto out;
if (attr)
*attr = strtol(attr_buf, NULL, 0);
free(dev_path);
return 0;
out:
free(dev_path);
fprintf(stderr, "Couldn't get MTD attribute '%s' from '%s'\n", dev, attr_file);
return -1;
}
static int get_dev_mtd(const char *fdt_flash_path, char **mtd_path)
{
struct dirent **namelist;
char fdt_node_path[PATH_MAX];
int count, i, rc, fd;
bool done;
if (!fdt_flash_path)
return -1;
fd = open(fdt_flash_path, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Couldn't open '%s' FDT attribute to determine which flash device to use\n",
fdt_flash_path);
fprintf(stderr, "Is your skiboot new enough to expose the flash through the device tree?\n");
hint_root();
return -1;
}
rc = read(fd, fdt_node_path, sizeof(fdt_node_path));
close(fd);
if (rc == -1) {
fprintf(stderr, "Couldn't read flash FDT node from '%s'\n", fdt_flash_path);
hint_root();
return -1;
}
count = scandir(SYSFS_MTD_PATH, &namelist, NULL, alphasort);
if (count == -1) {
fprintf(stderr, "Couldn't scan '%s' for MTD\n", SYSFS_MTD_PATH);
hint_root();
return -1;
}
rc = 0;
done = false;
for (i = 0; i < count; i++) {
struct dirent *dirent;
char *dev_path;
char fdt_node_path_tmp[PATH_MAX];
dirent = namelist[i];
/*
* The call to asprintf must happen last as when it succeeds it
* will allocate dev_path
*/
if (dirent->d_name[0] == '.' || rc || done ||
asprintf(&dev_path, "%s/%s/device/of_node", SYSFS_MTD_PATH, dirent->d_name) < 0) {
free(namelist[i]);
continue;
}
rc = readlink(dev_path, fdt_node_path_tmp, sizeof(fdt_node_path_tmp) - 1);
free(dev_path);
if (rc == -1) {
/*
* This might fail because it could not exist if the system has flash
* devices that present as mtd but don't have corresponding FDT
* nodes, just continue silently.
*/
free(namelist[i]);
/* Should still try the next dir so reset rc */
rc = 0;
continue;
}
fdt_node_path_tmp[rc] = '\0';
if (strstr(fdt_node_path_tmp, fdt_node_path)) {
uint32_t flags, size;
/*
* size and flags could perhaps have be gotten another way but this
* method is super unlikely to fail so it will do.
*/
/* Check to see if device is writeable */
rc = get_dev_attr(dirent->d_name, "flags", &flags);
if (rc) {
free(namelist[i]);
continue;
}
/* Get the size of the mtd device while we're at it */
rc = get_dev_attr(dirent->d_name, "size", &size);
if (rc) {
free(namelist[i]);
continue;
}
rc = asprintf(&dev_path, "/dev/%s", dirent->d_name);
if (rc < 0) {
free(namelist[i]);
continue;
}
rc = 0;
*mtd_path = dev_path;
done = true;
}
free(namelist[i]);
}
free(namelist);
if (!done) {
fprintf(stderr, "Couldn't find '%s' corresponding MTD\n", fdt_flash_path);
fprintf(stderr, "Is your kernel new enough to expose MTD?\n");
}
/* explicit negative value so as to not return a libflash code */
return done ? rc : -1;
}
static struct blocklevel_device *arch_init_blocklevel(const char *file, bool keep_alive)
{
int rc;
struct blocklevel_device *new_bl = NULL;
char *real_file = NULL;
if (!file) {
rc = get_dev_mtd(FDT_FLASH_PATH, &real_file);
if (rc)
return NULL;
}
file_init_path(file ? file : real_file, NULL, keep_alive, &new_bl);
free(real_file);
return new_bl;
}
/* Skiboot will worry about this for us */
int arch_flash_set_wrprotect(struct blocklevel_device *bl, int set)
{
return 0;
}
int arch_flash_init(struct blocklevel_device **r_bl, const char *file, bool keep_alive)
{
struct blocklevel_device *new_bl;
new_bl = arch_init_blocklevel(file, keep_alive);
if (!new_bl)
return -1;
*r_bl = new_bl;
return 0;
}
void arch_flash_close(struct blocklevel_device *bl, const char *file)
{
file_exit_close(bl);
}
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