Add an 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 --- include/smbios.h | 37 ++++++++++ lib/Kconfig | 6 ++ lib/Makefile | 1 + lib/smbios-parser.c | 162 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 206 insertions(+) create mode 100644 lib/smbios-parser.c
diff --git a/include/smbios.h b/include/smbios.h index 97b9ddce23..ad44e54245 100644 --- a/include/smbios.h +++ b/include/smbios.h @@ -237,4 +237,41 @@ typedef int (*smbios_write_type)(ulong *addr, int handle); */ ulong write_smbios_table(ulong addr);
+ +struct smbios_parser; + +/** + * smbios_parser_create() - Create smbios parser + * + * @addr: start address to search for SMBIOS structure + * @len: size of search area + * @return: NULL or valid pointer to a struct smbios_parser + */ +struct smbios_parser *smbios_parser_create(unsigned int addr, unsigned int len); + +/** + * smbios_parser_destroy() - Destroy smbios parser + * + * @p: pointer to a struct smbios_parser + */ +void smbios_parser_destroy(struct smbios_parser *p); + +/** + * smbios_header() - Search for SMBIOS header type + * + * @p: pointer to a struct smbios_parser + * @type: SMBIOS type + * @return: NULL or a valid pointer to a struct smbios_header + */ +struct smbios_header *smbios_header(const struct smbios_parser *p, 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 2120216593..59aafc63a7 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -432,6 +432,12 @@ config SMBIOS_PRODUCT_NAME
endmenu
+config SMBIOS_PARSER + bool "SMBIOS parser" + default n + 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 47829bfed5..f095bd420a 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -34,6 +34,7 @@ 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_MD5) += md5.o diff --git a/lib/smbios-parser.c b/lib/smbios-parser.c new file mode 100644 index 0000000000..b24fd7210c --- /dev/null +++ b/lib/smbios-parser.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019, Bachmann electronic GmbH + */ + +#include <common.h> +#include <malloc.h> +#include <mapmem.h> +#include <smbios.h> + +struct smbios_parser { + void *search_area; + unsigned int search_area_len; + struct smbios_entry *entry; + void *data; +}; + +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; +} + +static struct smbios_entry *find_smbios_entry(const struct smbios_parser *p) +{ + static const char sm_sig[] = "_SM_"; + u8 *buf = (u8 *)p->search_area; + const u8 *end = (u8 *)p->search_area + p->search_area_len; + struct smbios_entry *entry = NULL; + + /* look for smbios entry */ + while (buf < end) { + if (memcmp(sm_sig, buf, 4) == 0) { + entry = (struct smbios_entry *)buf; + + if (verify_checksum(entry)) { + entry = NULL; + buf++; + continue; + } + + break; + } + + buf++; + } + + return entry; +} + +void smbios_parser_destroy(struct smbios_parser *p) +{ + if (!p) + return; + + unmap_sysmem(p->data); + unmap_sysmem(p->search_area); + + free(p); +} + +struct smbios_parser *smbios_parser_create(unsigned int addr, unsigned int len) +{ + struct smbios_parser *p = malloc(sizeof(struct smbios_parser)); + + if (!p) + return NULL; + + p->search_area_len = len; + p->search_area = map_sysmem(addr, len); + + if (!p->search_area) + goto fail; + + /* find main entry smbios table */ + p->entry = find_smbios_entry(p); + + if (!p->entry) + goto fail; + + /* map smbios data area */ + p->data = map_sysmem(p->entry->struct_table_address, + p->entry->struct_table_length); + + if (!p->data) + goto fail; + + return p; + +fail: + smbios_parser_destroy(p); + + return NULL; +} + +static 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; +} + +struct smbios_header *smbios_header(const struct smbios_parser *p, int type) +{ + const struct smbios_entry *entry = p->entry; + const unsigned int num_header = entry->struct_count; + struct smbios_header *header = (struct smbios_header *)p->data; + + 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); +}