/*
* Will relocate the DTB to the tags addr if the device tree is found and return
* its address
*
* Arguments: kernel - Start address of the kernel loaded in RAM
* tags - Start address of the tags loaded in RAM
* kernel_size - Size of the kernel in bytes
*
* Return Value: DTB address : If appended device tree is found
* 'NULL' : Otherwise
*/
void *dev_tree_appended(void *kernel, void *tags, uint32_t kernel_size)
{
uint32_t app_dtb_offset = 0;
uint32_t size;
memcpy((void*) &app_dtb_offset, (void*) (kernel + DTB_OFFSET), sizeof(uint32_t));
/*
* Check if we have valid offset for the DTB, if not return error.
* If the kernel image does not have appeneded device tree, DTB offset
* might contain some random address which is not accessible & cause
* data abort. If kernel start + dtb offset address exceed the total
* size of the kernel, then we dont have an appeneded DTB.
*/
if (app_dtb_offset < kernel_size)
{
if (!fdt_check_header((void*) (kernel + app_dtb_offset)))
{
void *dtb;
int rc;
debugf( "Found Appeneded Flattened Device tree\n");
dtb = kernel + app_dtb_offset;
size = fdt_totalsize(dtb);
if (check_aboot_addr_range_overlap(tags, size))
{
debugf("Appended dtb aboot overlap check failed.\n");
return NULL;
}
rc = fdt_open_into(dtb, tags, size);
if (rc == 0)
{
/* clear out the old DTB magic so kernel doesn't find it */
*((uint32_t *)dtb) = 0;
return tags;
}
}
}
else
debugf( "DTB offset is incorrect, kernel image does not have appended DTB\n");
return NULL;
}
/*
* Will relocate the DTB to the tags addr if the device tree is found and return
* its address
*
* Arguments: kernel - Start address of the kernel loaded in RAM
* tags - Start address of the tags loaded in RAM
* kernel_size - Size of the kernel in bytes
*
* Return Value: DTB address : If appended device tree is found
* 'NULL' : Otherwise
*/
void *dev_tree_appended(void *kernel, uint32_t kernel_size, void *tags)
{
void *kernel_end = kernel + kernel_size;
uint32_t app_dtb_offset = 0;
void *dtb;
void *bestmatch_tag = NULL;
uint32_t bestmatch_tag_size;
uint32_t bestmatch_soc_rev_id = INVALID_SOC_REV_ID;
memcpy((void*) &app_dtb_offset, (void*) (kernel + DTB_OFFSET), sizeof(uint32_t));
dtb = kernel + app_dtb_offset;
while (dtb + sizeof(struct fdt_header) < kernel_end) {
uint32_t dtb_soc_rev_id;
struct fdt_header dtb_hdr;
uint32_t dtb_size;
/* the DTB could be unaligned, so extract the header,
* and operate on it separately */
memcpy(&dtb_hdr, dtb, sizeof(struct fdt_header));
if (fdt_check_header((const void *)&dtb_hdr) != 0 ||
(dtb + fdt_totalsize((const void *)&dtb_hdr) > kernel_end))
break;
dtb_size = fdt_totalsize(&dtb_hdr);
if (check_aboot_addr_range_overlap(tags, dtb_size)) {
dprintf(CRITICAL, "Tags addresses overlap with aboot addresses.\n");
return NULL;
}
/* now that we know we have a valid DTB, we need to copy
* it somewhere aligned, like tags */
memcpy(tags, dtb, dtb_size);
dtb_soc_rev_id = dev_tree_compatible(tags);
if (dtb_soc_rev_id == board_soc_version()) {
/* clear out the old DTB magic so kernel doesn't find it */
*((uint32_t *)(kernel + app_dtb_offset)) = 0;
return tags;
} else if ((dtb_soc_rev_id != INVALID_SOC_REV_ID) &&
(dtb_soc_rev_id < board_soc_version())) {
/* if current bestmatch is less than new dtb_soc_rev_id then update
bestmatch_tag */
if((bestmatch_soc_rev_id == INVALID_SOC_REV_ID) ||
(bestmatch_soc_rev_id < dtb_soc_rev_id)) {
bestmatch_tag = dtb;
bestmatch_tag_size = dtb_size;
bestmatch_soc_rev_id = dtb_soc_rev_id;
}
}
/* goto the next device tree if any */
dtb += dtb_size;
}
if(bestmatch_tag) {
dprintf(INFO,"DTB found with bestmatch soc rev id 0x%x.Board soc rev id 0x%x\n",
bestmatch_soc_rev_id, board_soc_version());
memcpy(tags, bestmatch_tag, bestmatch_tag_size);
/* clear out the old DTB magic so kernel doesn't find it */
*((uint32_t *)(kernel + app_dtb_offset)) = 0;
return tags;
}
dprintf(CRITICAL, "DTB offset is incorrect, kernel image does not have appended DTB\n");
return NULL;
}