[PATCH v6 5/6] smbios: add support for dynamic generation of Type 19 table

Raymond Mao
2026-02-13T22:54:00Z

This commit implements SMBIOS Type 19 (Memory Array Mapped Address)
generation with a hybrid approach supporting both:

1. Explicit definition via Device Tree 'smbios' node:
Child node under '/smbios/smbios/memory-array-mapped-address' will be
used to populate as individual Type 19 structure directly.
- Properties follow SMBIOS field names with lowercase letters and
hyphen-separated words (e.g., 'starting-address', 'ending-address',
'partition-width', etc.).
- This method supports precise platform-defined overrides and system
descriptions.

2. Fallback to automatic DT-based discovery:
If child node under '/smbios/smbios/memory-array-mapped-address' does
not exist, the implementation will:
- Scan all top-level 'memory@' nodes to populate Type 19 structure with
inferred size and location data.
- Scan nodes named or marked as 'memory-controller' and parse
associated 'dimm@' subnodes (if present) to extract DIMM sizes and
map them accordingly.

This dual-mode support enables flexible firmware SMBIOS reporting while
aligning with spec-compliant naming and runtime-detected memory topology.

Type 19 support is under GENERATE_SMBIOS_TABLE_VERBOSE to avoid
increasing rom size for those platforms which only require basic SMBIOS
support.

Signed-off-by: Raymond Mao <raymondmaoca@gmail.com>
---
Changes in v4:
- Initial patch.
Changes in v5:
- None.
Changes in v6:
- None.

arch/arm/dts/smbios_generic.dtsi | 3 +
cmd/smbios.c | 14 +++
include/smbios.h | 11 +++
include/smbios_def.h | 5 ++
lib/smbios.c | 150 +++++++++++++++++++++++++++++++
5 files changed, 183 insertions(+)

diff --git a/arch/arm/dts/smbios_generic.dtsi b/arch/arm/dts/smbios_generic.dtsi
index fd2df8d02e0..fe16037fc20 100644
--- a/arch/arm/dts/smbios_generic.dtsi
+++ b/arch/arm/dts/smbios_generic.dtsi
@@ -86,6 +86,9 @@

memory-device {
};
+
+ memory-array-mapped-address {
+ };
};
};
};
diff --git a/cmd/smbios.c b/cmd/smbios.c
index 39c9c44a28e..671c14e05b5 100644
--- a/cmd/smbios.c
+++ b/cmd/smbios.c
@@ -680,6 +680,17 @@ static void smbios_print_type17(struct smbios_type17 *table)
printf("\tRCD Revision Number: 0x%04x\n", table->rcd_rev_num);
}

+static void smbios_print_type19(struct smbios_type19 *table)
+{
+ printf("Memory Array Mapped Address:\n");
+ printf("\tStarting Address: 0x%08x\n", table->start_addr);
+ printf("\tEnding Address: 0x%08x\n", table->end_addr);
+ printf("\tMemory Array Handle: 0x%04x\n", table->mem_array_hdl);
+ printf("\tPartition Width: 0x%04x\n", table->partition_wid);
+ printf("\tExtended Starting Address: 0x%016llx\n", table->ext_start_addr);
+ printf("\tExtended Ending Address: 0x%016llx\n", table->ext_end_addr);
+}
+
static void smbios_print_type127(struct smbios_type127 *table)
{
printf("End Of Table\n");
@@ -768,6 +779,9 @@ static int do_smbios(struct cmd_tbl *cmdtp, int flag, int argc,
case SMBIOS_MEMORY_DEVICE:
smbios_print_type17((struct smbios_type17 *)pos);
break;
+ case SMBIOS_MEMORY_ARRAY_MAPPED_ADDRESS:
+ smbios_print_type19((struct smbios_type19 *)pos);
+ break;
case SMBIOS_END_OF_TABLE:
smbios_print_type127((struct smbios_type127 *)pos);
break;
diff --git a/include/smbios.h b/include/smbios.h
index 2deafea9aa1..e4b5ff314d9 100644
--- a/include/smbios.h
+++ b/include/smbios.h
@@ -372,6 +372,17 @@ struct __packed smbios_type17 {
char eos[SMBIOS_STRUCT_EOS_BYTES];
};

+struct __packed smbios_type19 {
+ struct smbios_header hdr;
+ u32 start_addr;
+ u32 end_addr;
+ u16 mem_array_hdl;
+ u8 partition_wid;
+ u64 ext_start_addr;
+ u64 ext_end_addr;
+ char eos[SMBIOS_STRUCT_EOS_BYTES];
+};
+
struct __packed smbios_type32 {
u8 type;
u8 length;
diff --git a/include/smbios_def.h b/include/smbios_def.h
index ce913f2f32a..ae50e1a808e 100644
--- a/include/smbios_def.h
+++ b/include/smbios_def.h
@@ -436,4 +436,9 @@
#define SMBIOS_MD_ERRINFO_NONE 0xFFFE
#define SMBIOS_MD_ERRINFO_NOERR 0xFFFF

+/* Memory Array Mapped Address */
+
+/* Partition Width */
+#define SMBIOS_MAMA_PW_DEF 1 /* not partitioned */
+
#endif /* _SMBIOS_DEF_H_ */
diff --git a/lib/smbios.c b/lib/smbios.c
index 7c6ad63b1c7..d5f18c8bd69 100644
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -1807,6 +1807,155 @@ static int smbios_write_type17(ulong *current, int *handle,
smbios_write_type17_from_memctrl_node);
}

+static void smbios_pop_type19_general_si(struct smbios_ctx *ctx,
+ struct smbios_type19 *t)
+{
+ t->partition_wid =
+ smbios_get_val_si(ctx, "partition-width ",
+ SYSID_NONE, SMBIOS_MAMA_PW_DEF);
+}
+
+static void smbios_pop_type19_addr_si(struct smbios_ctx *ctx,
+ struct smbios_type19 *t)
+{
+ t->start_addr = smbios_get_val_si(ctx, "starting-address", SYSID_NONE,
+ 0);
+ t->end_addr = smbios_get_val_si(ctx, "ending-address", SYSID_NONE, 0);
+ t->ext_start_addr = smbios_get_u64_si(ctx, "extended-starting-address",
+ SYSID_NONE, 0);
+ t->ext_end_addr = smbios_get_u64_si(ctx, "extended-ending-address",
+ SYSID_NONE, 0);
+}
+
+static void
+smbios_pop_type19_addr_from_memory_node(ofnode node, struct smbios_type19 *t)
+{
+ const fdt32_t *reg;
+ int len;
+ u64 sz;
+ u64 addr;
+
+ /* Read property 'reg' from the node */
+ reg = ofnode_read_prop(node, "reg", &len);
+ if (!reg || len < sizeof(fdt32_t) * 4 || len % sizeof(fdt32_t))
+ return;
+
+ /* Combine hi/lo for size and address (typically 64-bit) */
+ sz = ((u64)fdt32_to_cpu(reg[2]) << 32) | fdt32_to_cpu(reg[3]);
+ addr = ((u64)fdt32_to_cpu(reg[0]) << 32) | fdt32_to_cpu(reg[1]);
+
+ t->ext_start_addr = cpu_to_le64(addr);
+ t->ext_end_addr = cpu_to_le64(addr + sz - 1);
+
+ /* If address range fits in 32-bit, populate legacy fields */
+ if ((addr + sz - 1) <= 0xFFFFFFFFULL) {
+ t->start_addr = cpu_to_le32((u32)addr);
+ t->end_addr = cpu_to_le32((u32)(addr + sz - 1));
+ } else {
+ t->start_addr = cpu_to_le32(0xFFFFFFFF);
+ t->end_addr = cpu_to_le32(0xFFFFFFFF);
+ }
+}
+
+static int
+smbios_write_type19_from_memctrl_node(ulong *current, int handle,
+ struct smbios_ctx *ctx, int idx,
+ u64 base, u64 sz)
+{
+ struct smbios_type19 *t;
+ int len;
+ u8 *eos_addr;
+ void *hdl;
+ size_t hdl_size;
+
+ len = sizeof(*t);
+ t = map_sysmem(*current, len);
+ memset(t, 0, len);
+
+ fill_smbios_header(t, SMBIOS_MEMORY_ARRAY_MAPPED_ADDRESS, len, handle);
+
+ /* eos is at the end of the structure */
+ eos_addr = (u8 *)t + len - sizeof(t->eos);
+ smbios_set_eos(ctx, eos_addr);
+
+ /* Read the memory array handles */
+ if (!sysinfo_get_data(ctx->dev, SYSID_SM_MEMARRAY_HANDLE, &hdl,
+ &hdl_size) &&
+ hdl_size == SYSINFO_MEM_HANDLE_MAX * sizeof(u16))
+ t->mem_array_hdl = *((u16 *)hdl + idx);
+
+ t->ext_start_addr = cpu_to_le64(base);
+ t->ext_end_addr = cpu_to_le64(base + sz - 1);
+
+ if ((base + sz - 1) <= 0xFFFFFFFFULL) {
+ t->start_addr = cpu_to_le32((u32)base);
+ t->end_addr = cpu_to_le32((u32)(base + sz - 1));
+ } else {
+ t->start_addr = cpu_to_le32(0xFFFFFFFF);
+ t->end_addr = cpu_to_le32(0xFFFFFFFF);
+ }
+
+ /* Write other general fields */
+ smbios_pop_type19_general_si(ctx, t);
+
+ len = t->hdr.length + smbios_string_table_len(ctx);
+ *current += len;
+ unmap_sysmem(t);
+
+ return len;
+}
+
+static int smbios_write_type19_mem(ulong *current, int handle,
+ struct smbios_ctx *ctx, int idx,
+ int type)
+{
+ struct smbios_type19 *t;
+ int len;
+ u8 *eos_addr;
+ void *hdl;
+ size_t hdl_size;
+
+ len = sizeof(*t);
+ t = map_sysmem(*current, len);
+ memset(t, 0, len);
+
+ fill_smbios_header(t, SMBIOS_MEMORY_ARRAY_MAPPED_ADDRESS, len, handle);
+
+ /* eos is at the end of the structure */
+ eos_addr = (u8 *)t + len - sizeof(t->eos);
+ smbios_set_eos(ctx, eos_addr);
+
+ if (type == SMBIOS_MEM_CUSTOM) {
+ smbios_pop_type19_addr_si(ctx, t);
+ t->mem_array_hdl = smbios_get_val_si(ctx, "memory-array-handle",
+ SYSID_NONE, 0);
+ } else if (type == SMBIOS_MEM_FDT_MEM_NODE) {
+ smbios_pop_type19_addr_from_memory_node(ctx->node, t);
+ /* Read the memory array handles */
+ if (!sysinfo_get_data(ctx->dev, SYSID_SM_MEMARRAY_HANDLE, &hdl,
+ &hdl_size) &&
+ hdl_size == SYSINFO_MEM_HANDLE_MAX * sizeof(u16))
+ t->mem_array_hdl = *((u16 *)hdl + idx);
+ }
+
+ /* Write other general fields */
+ smbios_pop_type19_general_si(ctx, t);
+
+ len = t->hdr.length + smbios_string_table_len(ctx);
+ *current += len;
+ unmap_sysmem(t);
+
+ return len;
+}
+
+static int smbios_write_type19(ulong *current, int *handle,
+ struct smbios_ctx *ctx)
+{
+ return smbios_write_type1719(current, handle, ctx,
+ smbios_write_type19_mem,
+ smbios_write_type19_from_memctrl_node);
+}
+
#endif /* #if IS_ENABLED(CONFIG_GENERATE_SMBIOS_TABLE_VERBOSE) */

static int smbios_write_type32(ulong *current, int *handle,
@@ -1857,6 +2006,7 @@ static struct smbios_write_method smbios_write_funcs[] = {
{ smbios_write_type9, "system-slot"},
{ smbios_write_type16, "memory-array"},
{ smbios_write_type17, "memory-device"},
+ { smbios_write_type19, "memory-array-mapped-address"},
#endif
{ smbios_write_type32, },
{ smbios_write_type127 },
--
2.25.1