Add a very simple API to be able to access SMBIOS strings like vendor, model and bios version.

Signed-off-by: Christian Gmeiner christian.gmeiner@gmail.com Reviewed-by: Bin Meng bmeng.cn@gmail.com --- include/smbios.h | 27 +++++++++++++ lib/Kconfig | 5 +++ lib/Makefile | 1 + lib/smbios-parser.c | 96 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 129 insertions(+) create mode 100644 lib/smbios-parser.c

diff --git a/include/smbios.h b/include/smbios.h index 97b9ddce23..44f49e9556 100644 --- a/include/smbios.h +++ b/include/smbios.h @@ -237,4 +237,31 @@ typedef int (*smbios_write_type)(ulong *addr, int handle); */ ulong write_smbios_table(ulong addr);

+/** + * smbios_entry() - Get a valid struct smbios_entry pointer + * + * @address: address where smbios tables is located + * @size: size of smbios table + * @return: NULL or a valid pointer to a struct smbios_entry + */ +const struct smbios_entry *smbios_entry(u64 address, u32 size); + +/** + * smbios_header() - Search for SMBIOS header type + * + * @entry: pointer to a struct smbios_entry + * @type: SMBIOS type + * @return: NULL or a valid pointer to a struct smbios_header + */ +const struct smbios_header *smbios_header(const struct smbios_entry *entry, int type); + +/** + * smbios_string() - Return string from SMBIOS + * + * @header: pointer to struct smbios_header + * @index: string index + * @return: NULL or a valid const char pointer + */ +const char *smbios_string(const struct smbios_header *header, int index); + #endif /* _SMBIOS_H_ */ diff --git a/lib/Kconfig b/lib/Kconfig index 79651eaad1..5f1b95d7d7 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -680,6 +680,11 @@ config OID_REGISTRY help Enable fast lookup object identifier registry.

+config SMBIOS_PARSER + bool "SMBIOS parser" + help + A simple parser for SMBIOS data. + source lib/efi/Kconfig source lib/efi_loader/Kconfig source lib/optee/Kconfig diff --git a/lib/Makefile b/lib/Makefile index 7c7fb9aae7..851a80ef3b 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_FIT) += fdtdec_common.o obj-$(CONFIG_TEST_FDTDEC) += fdtdec_test.o obj-$(CONFIG_GZIP_COMPRESSED) += gzip.o obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += smbios.o +obj-$(CONFIG_SMBIOS_PARSER) += smbios-parser.o obj-$(CONFIG_IMAGE_SPARSE) += image-sparse.o obj-y += ldiv.o obj-$(CONFIG_XXHASH) += xxhash.o diff --git a/lib/smbios-parser.c b/lib/smbios-parser.c new file mode 100644 index 0000000000..b89f988ef9 --- /dev/null +++ b/lib/smbios-parser.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2020, Bachmann electronic GmbH + */ + +#include <common.h> +#include <smbios.h> + +static inline int verify_checksum(const struct smbios_entry *e) +{ + /* + * Checksums for SMBIOS tables are calculated to have a value, so that + * the sum over all bytes yields zero (using unsigned 8 bit arithmetic). + */ + u8 *byte = (u8 *)e; + u8 sum = 0; + + for (int i = 0; i < e->length; i++) + sum += byte[i]; + + return sum; +} + +const struct smbios_entry *smbios_entry(u64 address, u32 size) +{ + const struct smbios_entry *entry = (struct smbios_entry *)(uintptr_t)address; + + if (!address | !size) + return NULL; + + if (memcmp(entry->anchor, "_SM_", 4)) + return NULL; + + if (verify_checksum(entry)) + return NULL; + + return entry; +} + +static const struct smbios_header *next_header(const struct smbios_header *curr) +{ + u8 *pos = ((u8 *)curr) + curr->length; + + /* search for _double_ NULL bytes */ + while (!((*pos == 0) && (*(pos + 1) == 0))) + pos++; + + /* step behind the double NULL bytes */ + pos += 2; + + return (struct smbios_header *)pos; +} + +const struct smbios_header *smbios_header(const struct smbios_entry *entry, int type) +{ + const unsigned int num_header = entry->struct_count; + const struct smbios_header *header = (struct smbios_header *)entry->struct_table_address; + + for (unsigned int i = 0; i < num_header; i++) { + if (header->type == type) + return header; + + header = next_header(header); + } + + return NULL; +} + +static const char *string_from_smbios_table(const struct smbios_header *header, + int idx) +{ + unsigned int i = 1; + u8 *pos; + + if (!header) + return NULL; + + pos = ((u8 *)header) + header->length; + + while (i < idx) { + if (*pos == 0x0) + i++; + + pos++; + } + + return (const char *)pos; +} + +const char *smbios_string(const struct smbios_header *header, int index) +{ + if (!header) + return NULL; + + return string_from_smbios_table(header, index); +}