Add an very simple API to be able to access SMBIOS strings
like vendor, model and bios version.
Signed-off-by: Christian Gmeiner <christian.gmei...@gmail.com>
---
include/smbios.h | 27 +++++++++++++
lib/Kconfig | 6 +++
lib/Makefile | 1 +
lib/smbios-parser.c | 96 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 130 insertions(+)
create mode 100644 lib/smbios-parser.c
diff --git a/include/smbios.h b/include/smbios.h
index 97b9ddce23..ed60c00fae 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 vaild 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 8efb154f73..c92131b7bc 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -667,6 +667,12 @@ config OID_REGISTRY
help
Enable fast lookup object identifier registry.
+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 0cd7bea282..0383fddf2c 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);
+}
--
2.28.0
