DMI: Parse memory device (type 17) in SMBIOS

This patch adds a new interface to decode memory device (type 17)
to help error reporting on DIMMs.

Original-author: Tony Luck <[e-mail]>
Signed-off-by: Chen, Gong <[e-mail]>
Acked-by: Naveen N. Rao <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Reviewed-by: Mauro Carvalho Chehab <[e-mail]>
Signed-off-by: Tony Luck <[e-mail]>

arch/ia64/kernel/setup.c

···
 static int __init run_dmi_scan(void)
 {
 	dmi_scan_machine();
+	dmi_memdev_walk();
 	dmi_set_dump_stack_arch_desc();
 	return 0;
 }

arch/x86/kernel/setup.c

···
 		efi_init();
 
 	dmi_scan_machine();
+	dmi_memdev_walk();
 	dmi_set_dump_stack_arch_desc();
 
 	/*

drivers/firmware/dmi_scan.c

···
 /* DMI system identification string used during boot */
 static char dmi_ids_string[128] __initdata;
 
+static struct dmi_memdev_info {
+	const char *device;
+	const char *bank;
+	u16 handle;
+} *dmi_memdev;
+static int dmi_memdev_nr;
+
 static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
 {
 	const u8 *bp = ((u8 *) dm) + dm->length;
···
 	dmi_save_dev_onboard(*(d+1), *(u16 *)(d+2), *(d+4), *(d+5),
 			     dmi_string_nosave(dm, *(d-1)));
 	dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
+}
+
+static void __init count_mem_devices(const struct dmi_header *dm, void *v)
+{
+	if (dm->type != DMI_ENTRY_MEM_DEVICE)
+		return;
+	dmi_memdev_nr++;
+}
+
+static void __init save_mem_devices(const struct dmi_header *dm, void *v)
+{
+	const char *d = (const char *)dm;
+	static int nr;
+
+	if (dm->type != DMI_ENTRY_MEM_DEVICE)
+		return;
+	if (nr >= dmi_memdev_nr) {
+		pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");
+		return;
+	}
+	dmi_memdev[nr].handle = dm->handle;
+	dmi_memdev[nr].device = dmi_string(dm, d[0x10]);
+	dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
+	nr++;
+}
+
+void __init dmi_memdev_walk(void)
+{
+	if (!dmi_available)
+		return;
+
+	if (dmi_walk_early(count_mem_devices) == 0 && dmi_memdev_nr) {
+		dmi_memdev = dmi_alloc(sizeof(*dmi_memdev) * dmi_memdev_nr);
+		if (dmi_memdev)
+			dmi_walk_early(save_mem_devices);
+	}
 }
 
 /*
···
 	return !strcmp(info, str);
 }
 EXPORT_SYMBOL_GPL(dmi_match);
+
+void dmi_memdev_name(u16 handle, const char **bank, const char **device)
+{
+	int n;
+
+	if (dmi_memdev == NULL)
+		return;
+
+	for (n = 0; n < dmi_memdev_nr; n++) {
+		if (handle == dmi_memdev[n].handle) {
+			*bank = dmi_memdev[n].bank;
+			*device = dmi_memdev[n].device;
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(dmi_memdev_name);

include/linux/dmi.h

···
 extern const struct dmi_device * dmi_find_device(int type, const char *name,
 	const struct dmi_device *from);
 extern void dmi_scan_machine(void);
+extern void dmi_memdev_walk(void);
 extern void dmi_set_dump_stack_arch_desc(void);
 extern bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp);
 extern int dmi_name_in_vendors(const char *str);
···
 extern int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 	void *private_data);
 extern bool dmi_match(enum dmi_field f, const char *str);
+extern void dmi_memdev_name(u16 handle, const char **bank, const char **device);
 
 #else
 
···
 static inline const struct dmi_device * dmi_find_device(int type, const char *name,
 	const struct dmi_device *from) { return NULL; }
 static inline void dmi_scan_machine(void) { return; }
+static inline void dmi_memdev_walk(void) { }
 static inline void dmi_set_dump_stack_arch_desc(void) { }
 static inline bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
 {
···
 	void *private_data) { return -1; }
 static inline bool dmi_match(enum dmi_field f, const char *str)
 	{ return false; }
+static inline void dmi_memdev_name(u16 handle, const char **bank,
+		const char **device) { }
 static inline const struct dmi_system_id *
 	dmi_first_match(const struct dmi_system_id *list) { return NULL; }