diff options
| author | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-04-14 07:43:24 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-05-18 21:38:05 +0300 |
| commit | 2d2682512f0faf4d09a696184bf3c0bb6838baca (patch) | |
| tree | 31d238d63d671ff6b8ade87e521186d30afec7e7 /arch/riscv/include/asm/soc.h | |
| parent | b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce (diff) | |
| download | linux-2d2682512f0faf4d09a696184bf3c0bb6838baca.tar.xz | |
riscv: Allow device trees to be built into the kernel
Some systems don't provide a useful device tree to the kernel on boot.
Chasing around bootloaders for these systems is a headache, so instead
le't's just keep a device tree table in the kernel, keyed by the SOC's
unique identifier, that contains the relevant DTB.
This is only implemented for M mode right now. While we could implement
this via the SBI calls that allow access to these identifiers, we don't
have any systems that need this right now.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/include/asm/soc.h')
| -rw-r--r-- | arch/riscv/include/asm/soc.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/soc.h b/arch/riscv/include/asm/soc.h index 7cec1968c8b4..136a442ef876 100644 --- a/arch/riscv/include/asm/soc.h +++ b/arch/riscv/include/asm/soc.h @@ -1,6 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Copyright (C) 2020 Western Digital Corporation or its affiliates. + * Copyright (C) 2020 Google, Inc */ #ifndef _ASM_RISCV_SOC_H @@ -20,4 +21,42 @@ void soc_early_init(void); extern unsigned long __soc_early_init_table_start; extern unsigned long __soc_early_init_table_end; +/* + * Allows Linux to provide a device tree, which is necessary for SOCs that + * don't provide a useful one on their own. + */ +struct soc_builtin_dtb { + unsigned long vendor_id; + unsigned long arch_id; + unsigned long imp_id; + void *(*dtb_func)(void); +}; + +/* + * The argument name must specify a valid DTS file name without the dts + * extension. + */ +#define SOC_BUILTIN_DTB_DECLARE(name, vendor, arch, impl) \ + extern void *__dtb_##name##_begin; \ + \ + static __init __used \ + void *__soc_builtin_dtb_f__##name(void) \ + { \ + return (void *)&__dtb_##name##_begin; \ + } \ + \ + static const struct soc_builtin_dtb __soc_builtin_dtb__##name \ + __used __section(__soc_builtin_dtb_table) = \ + { \ + .vendor_id = vendor, \ + .arch_id = arch, \ + .imp_id = impl, \ + .dtb_func = __soc_builtin_dtb_f__##name, \ + } + +extern unsigned long __soc_builtin_dtb_table_start; +extern unsigned long __soc_builtin_dtb_table_end; + +void *soc_lookup_builtin_dtb(void); + #endif |