diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/Kbuild | 1 | ||||
| -rw-r--r-- | arch/riscv/Kconfig | 5 | ||||
| -rw-r--r-- | arch/riscv/include/asm/soc.h | 39 | ||||
| -rw-r--r-- | arch/riscv/kernel/setup.c | 4 | ||||
| -rw-r--r-- | arch/riscv/kernel/soc.c | 27 | ||||
| -rw-r--r-- | arch/riscv/kernel/vmlinux.lds.S | 5 | ||||
| -rw-r--r-- | arch/riscv/mm/init.c | 9 |
7 files changed, 90 insertions, 0 deletions
diff --git a/arch/riscv/Kbuild b/arch/riscv/Kbuild index d1d0aa70fdf1..4614c01ba5b3 100644 --- a/arch/riscv/Kbuild +++ b/arch/riscv/Kbuild @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y += kernel/ mm/ net/ +obj-$(CONFIG_BUILTIN_DTB) += boot/dts/ diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index a31e1a41913a..539cd444df06 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -381,6 +381,11 @@ endchoice endmenu +config BUILTIN_DTB + def_bool n + depends on RISCV_M_MODE + depends on OF + menu "Power management options" source "kernel/power/Kconfig" 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 diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 145128a7e560..3e528312f615 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -75,7 +75,11 @@ void __init setup_arch(char **cmdline_p) setup_bootmem(); paging_init(); +#if IS_ENABLED(CONFIG_BUILTIN_DTB) + unflatten_and_copy_device_tree(); +#else unflatten_device_tree(); +#endif clint_init_boot_cpu(); #ifdef CONFIG_SWIOTLB diff --git a/arch/riscv/kernel/soc.c b/arch/riscv/kernel/soc.c index 0b3b3dc9ad0f..1fc87621c728 100644 --- a/arch/riscv/kernel/soc.c +++ b/arch/riscv/kernel/soc.c @@ -26,3 +26,30 @@ void __init soc_early_init(void) } } } + +static bool soc_builtin_dtb_match(unsigned long vendor_id, + unsigned long arch_id, unsigned long imp_id, + const struct soc_builtin_dtb *entry) +{ + return entry->vendor_id == vendor_id && + entry->arch_id == arch_id && + entry->imp_id == imp_id; +} + +void * __init soc_lookup_builtin_dtb(void) +{ + unsigned long vendor_id, arch_id, imp_id; + const struct soc_builtin_dtb *s; + + __asm__ ("csrr %0, mvendorid" : "=r"(vendor_id)); + __asm__ ("csrr %0, marchid" : "=r"(arch_id)); + __asm__ ("csrr %0, mimpid" : "=r"(imp_id)); + + for (s = (void *)&__soc_builtin_dtb_table_start; + (void *)s < (void *)&__soc_builtin_dtb_table_end; s++) { + if (soc_builtin_dtb_match(vendor_id, arch_id, imp_id, s)) + return s->dtb_func(); + } + + return NULL; +} diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 0339b6bbe11a..e6f8016b366a 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -34,6 +34,11 @@ SECTIONS KEEP(*(__soc_early_init_table)) __soc_early_init_table_end = .; } + __soc_builtin_dtb_table : { + __soc_builtin_dtb_table_start = .; + KEEP(*(__soc_builtin_dtb_table)) + __soc_builtin_dtb_table_end = .; + } /* we have to discard exit text and such at runtime, not link time */ .exit.text : { diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 27a334106708..c18b3db4c507 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -17,6 +17,7 @@ #include <asm/fixmap.h> #include <asm/tlbflush.h> #include <asm/sections.h> +#include <asm/soc.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -493,7 +494,15 @@ void free_initmem(void) #else asmlinkage void __init setup_vm(uintptr_t dtb_pa) { +#ifdef CONFIG_BUILTIN_DTB + dtb_early_va = soc_lookup_builtin_dtb(); + if (!dtb_early_va) { + /* Fallback to first available DTS */ + dtb_early_va = (void *) __dtb_start; + } +#else dtb_early_va = (void *)dtb_pa; +#endif } static inline void setup_vm_final(void) |