arm64: dmi: Add SMBIOS/DMI support

SMBIOS is important for server hardware vendors. It implements a spec for
providing descriptive information about the platform. Things like serial
numbers, physical layout of the ports, build configuration data, and the like.

Signed-off-by: Yi Li <yi.li@linaro.org>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

3 files changed, 55 insertions, 0 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9532f8d5857e..2c3c2ca6f8bc 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -401,6 +401,17 @@ config EFI
           allow the kernel to be booted as an EFI application. This
           is only useful on systems that have UEFI firmware.
 
+config DMI
+        bool "Enable support for SMBIOS (DMI) tables"
+        depends on EFI
+        default y
+        help
+          This enables SMBIOS/DMI feature for systems.
+
+          This option is only useful on systems that have UEFI firmware.
+          However, even with this option, the resultant kernel should
+          continue to boot on existing non-UEFI platforms.
+
 endmenu
 
 menu "Userspace binary formats"
diff --git a/arch/arm64/include/asm/dmi.h b/arch/arm64/include/asm/dmi.h
new file mode 100644
index 000000000000..69d37d87b159
--- /dev/null
+++ b/arch/arm64/include/asm/dmi.h
@@ -0,0 +1,31 @@
+/*
+ * arch/arm64/include/asm/dmi.h
+ *
+ * Copyright (C) 2013 Linaro Limited.
+ * Written by: Yi Li (yi.li@linaro.org)
+ *
+ * based on arch/ia64/include/asm/dmi.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#ifndef __ASM_DMI_H
+#define __ASM_DMI_H
+
+#include <linux/io.h>
+#include <linux/slab.h>
+
+/*
+ * According to section 2.3.6 of the UEFI spec, the firmware should not
+ * request a virtual mapping for configuration tables such as SMBIOS.
+ * This means we have to map them before use.
+ */
+#define dmi_early_remap(x, l)           ioremap_cache(x, l)
+#define dmi_early_unmap(x, l)           iounmap(x)
+#define dmi_remap(x, l)                 ioremap_cache(x, l)
+#define dmi_unmap(x)                    iounmap(x)
+#define dmi_alloc(l)                    kzalloc(l, GFP_KERNEL)
+
+#endif
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 558572ef1ea3..9ae5e7918b8f 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -11,6 +11,7 @@
  *
  */
 
+#include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
@@ -469,3 +470,15 @@ err_unmap:
         return -1;
 }
 early_initcall(arm64_enter_virtual_mode);
+
+static int __init arm64_dmi_init(void)
+{
+        /*
+         * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
+         * be called early because dmi_id_init(), which is an arch_initcall
+         * itself, depends on dmi_scan_machine() having been called already.
+         */
+        dmi_scan_machine();
+        return 0;
+}
+core_initcall(arm64_dmi_init);