[U-Boot] [PATCH 1/2] smbios: add parsing API
Christian Gmeiner
christian.gmeiner at gmail.com
Thu Apr 25 06:27:47 UTC 2019
Am Di., 16. Apr. 2019 um 13:38 Uhr schrieb Christian Gmeiner
<christian.gmeiner at gmail.com>:
>
> Add an very simple API to be able to access SMBIOS strings
> like vendor, model and bios version.
>
ping
> Signed-off-by: Christian Gmeiner <christian.gmeiner at 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);
> +}
> --
> 2.20.1
>
--
greets
--
Christian Gmeiner, MSc
https://christian-gmeiner.info
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