riscv: Add SOC early init support

Browse source

Add a mechanism for early SoC initialization for platforms that need
additional hardware initialization not possible through the regular
device tree and drivers mechanism. With this, a SoC specific
initialization function can be called very early, before DTB parsing
is done by parse_dtb() in Linux RISC-V kernel setup code.

This can be very useful for early hardware initialization for No-MMU
kernels booted directly in M-mode because it is quite likely that no
other booting stage exist prior to the No-MMU kernel.

Example use of a SoC early initialization is as follows:

static void vendor_abc_early_init(const void *fdt)
{
	/*
	 * some early init code here that can use simple matches
	 * against the flat device tree file.
	 */
}
SOC_EARLY_INIT_DECLARE("vendor,abc", abc_early_init);

This early initialization function is executed only if the flat device
tree for the board has a 'compatible = "vendor,abc"' entry;

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

...

This commit is contained in:

Damien Le Moal 2020-03-16 09:47:38 +09:00 • committed by Palmer Dabbelt

parent 956d705dd2

commit 335b139057

No known key found for this signature in database

GPG key ID: 2E1319F35FBB1889

5 changed files with 59 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

23

arch/riscv/include/asm/soc.h

View file

1

arch/riscv/kernel/Makefile

View file

1

arch/riscv/kernel/head.S

View file

28

arch/riscv/kernel/soc.c

View file

6

arch/riscv/kernel/vmlinux.lds.S

View file