Unverified Commit f105aa94 authored by Vitaly Wool's avatar Vitaly Wool Committed by Palmer Dabbelt
Browse files

riscv: add BUILTIN_DTB support for MMU-enabled targets 



Sometimes, especially in a production system we may not want to
use a "smart bootloader" like u-boot to load kernel, ramdisk and
device tree from a filesystem on eMMC, but rather load the kernel
from a NAND partition and just run it as soon as we can, and in
this case it is convenient to have device tree compiled into the
kernel binary. Since this case is not limited to MMU-less systems,
let's support it for these which have MMU enabled too.

While at it, provide __dtb_start as a parameter to setup_vm() in
BUILTIN_DTB case, so we don't have to duplicate BUILTIN_DTB specific
processing in MMU-enabled and MMU-disabled versions of setup_vm().

Signed-off-by: default avatarVitaly Wool <vitaly.wool@konsulko.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent f766f77a

arch/riscv/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -460,7 +460,6 @@ endmenu 


config BUILTIN_DTB

	def_bool n

	depends on RISCV_M_MODE

	depends on OF



menu "Power management options"

arch/riscv/kernel/head.S

+4 −0
Original line number Diff line number Diff line
@@ -260,7 +260,11 @@ clear_bss_done: 


	/* Initialize page tables and relocate to virtual addresses */

	la sp, init_thread_union + THREAD_SIZE

#ifdef CONFIG_BUILTIN_DTB

	la a0, __dtb_start

#else

	mv a0, s1

#endif /* CONFIG_BUILTIN_DTB */

	call setup_vm

#ifdef CONFIG_MMU

	la a0, early_pg_dir

arch/riscv/mm/init.c

+13 −6
Original line number Diff line number Diff line
@@ -192,9 +192,12 @@ void __init setup_bootmem(void) 
#endif /* CONFIG_BLK_DEV_INITRD */



	/*

	 * Avoid using early_init_fdt_reserve_self() since __pa() does

	 * If DTB is built in, no need to reserve its memblock.

	 * Otherwise, do reserve it but avoid using

	 * early_init_fdt_reserve_self() since __pa() does

	 * not work for DTB pointers that are fixmap addresses

	 */

	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))

		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));



	early_init_fdt_scan_reserved_mem();
@@ -499,6 +502,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) 
	/* Setup early PMD for DTB */

	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,

			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);

#ifndef CONFIG_BUILTIN_DTB

	/* Create two consecutive PMD mappings for FDT early scan */

	pa = dtb_pa & ~(PMD_SIZE - 1);

	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
@@ -506,7 +510,11 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) 
	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,

			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);

	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));

#else /* CONFIG_BUILTIN_DTB */

	dtb_early_va = __va(dtb_pa);

#endif /* CONFIG_BUILTIN_DTB */

#else

#ifndef CONFIG_BUILTIN_DTB

	/* Create two consecutive PGD mappings for FDT early scan */

	pa = dtb_pa & ~(PGDIR_SIZE - 1);

	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
@@ -514,6 +522,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) 
	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,

			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);

	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));

#else /* CONFIG_BUILTIN_DTB */

	dtb_early_va = __va(dtb_pa);

#endif /* CONFIG_BUILTIN_DTB */

#endif

	dtb_early_pa = dtb_pa;
@@ -604,11 +615,7 @@ static void __init setup_vm_final(void) 
#else

asmlinkage void __init setup_vm(uintptr_t dtb_pa)

{

#ifdef CONFIG_BUILTIN_DTB

	dtb_early_va = (void *) __dtb_start;

#else

	dtb_early_va = (void *)dtb_pa;

#endif

	dtb_early_pa = dtb_pa;

}