From 9e0afe3910ff7e5493c5d8ebe3b499994b5e0272 Mon Sep 17 00:00:00 2001
From: Jean Delvare <jdelvare@suse.de>
Date: Tue, 3 Dec 2019 11:20:37 +0100
Subject: [PATCH] firmware: dmi: Remember the memory type

Store the memory type while walking the memory slots, and provide a
way to retrieve it later.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
---
 drivers/firmware/dmi_scan.c | 25 ++++++++++++++++++++++++-
 include/linux/dmi.h         |  2 ++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 1e21fc3e9851..6f28e515fdc0 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -35,6 +35,7 @@ static struct dmi_memdev_info {
 	const char *bank;
 	u64 size;		/* bytes */
 	u16 handle;
+	u8 type;		/* DDR2, DDR3, DDR4 etc */
 } *dmi_memdev;
 static int dmi_memdev_nr;
 
@@ -391,7 +392,7 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
 	u64 bytes;
 	u16 size;
 
-	if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x12)
+	if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x13)
 		return;
 	if (nr >= dmi_memdev_nr) {
 		pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");
@@ -400,6 +401,7 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
 	dmi_memdev[nr].handle = get_unaligned(&dm->handle);
 	dmi_memdev[nr].device = dmi_string(dm, d[0x10]);
 	dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
+	dmi_memdev[nr].type = d[0x12];
 
 	size = get_unaligned((u16 *)&d[0xC]);
 	if (size == 0)
@@ -1128,3 +1130,24 @@ u64 dmi_memdev_size(u16 handle)
 	return ~0ull;
 }
 EXPORT_SYMBOL_GPL(dmi_memdev_size);
+
+/**
+ * dmi_memdev_type - get the memory type
+ * @handle: DMI structure handle
+ *
+ * Return the DMI memory type of the module in the slot associated with the
+ * given DMI handle, or 0x0 if no such DMI handle exists.
+ */
+u8 dmi_memdev_type(u16 handle)
+{
+	int n;
+
+	if (dmi_memdev) {
+		for (n = 0; n < dmi_memdev_nr; n++) {
+			if (handle == dmi_memdev[n].handle)
+				return dmi_memdev[n].type;
+		}
+	}
+	return 0x0;	/* Not a valid value */
+}
+EXPORT_SYMBOL_GPL(dmi_memdev_type);
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index 8de8c4f15163..13a48b167e2d 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -113,6 +113,7 @@ extern int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 extern bool dmi_match(enum dmi_field f, const char *str);
 extern void dmi_memdev_name(u16 handle, const char **bank, const char **device);
 extern u64 dmi_memdev_size(u16 handle);
+extern u8 dmi_memdev_type(u16 handle);
 
 #else
 
@@ -142,6 +143,7 @@ static inline bool dmi_match(enum dmi_field f, const char *str)
 static inline void dmi_memdev_name(u16 handle, const char **bank,
 		const char **device) { }
 static inline u64 dmi_memdev_size(u16 handle) { return ~0ul; }
+static inline u8 dmi_memdev_type(u16 handle) { return 0x0; }
 static inline const struct dmi_system_id *
 	dmi_first_match(const struct dmi_system_id *list) { return NULL; }