uboot下init_sequence_f函数之reserve_fdt

最新推荐文章于 2024-07-21 14:45:26 发布

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本文介绍U-Boot环境下为设备树(FDT)预留内存的过程。针对不同配置，代码会检查设备树是否需要重新定位，并据此调整内存布局。特别地，如果设备树位于镜像上方，则需要为其预留足够的空间。

reserve_fdt:

static int reserve_fdt(void)
{
#ifndef CONFIG_OF_EMBED
 /*
  * If the device tree is sitting immediately above our image then we
  * must relocate it. If it is embedded in the data section, then it
  * will be relocated with other data.
  */
 if (gd->fdt_blob) {
  gd->fdt_size = ALIGN(fdt_totalsize(gd->fdt_blob) + 0x1000, 32);
  gd->start_addr_sp -= gd->fdt_size;
  gd->new_fdt = map_sysmem(gd->start_addr_sp, gd->fdt_size);
  debug("Reserving %lu Bytes for FDT at: %08lx\n",
        gd->fdt_size, gd->start_addr_sp);
 }
#endif
 return 0;
}