[PATCH resend v2] arm64: dmi: Add SMBIOS/DMI support

[Ard Biesheuvel]

From: Yi Li <yi.li at linaro.org>

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.

This has been tested by dmidecode and lshw tools.

Signed-off-by: Yi Li <yi.li at linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
Changes since previous version:
- changed double inclusion guard to arm64 flavour
- use kzalloc(GFP_KERNEL) as GFP_ATOMIC is not needed
- do a sanity check on the size of the requested mapping

 arch/arm64/Kconfig           | 10 ++++++++++
 arch/arm64/include/asm/dmi.h | 41 +++++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/setup.c    |  2 ++
 3 files changed, 53 insertions(+)
 create mode 100644 arch/arm64/include/asm/dmi.h

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a474de346be6..560996c4a172 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -307,6 +307,16 @@ 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..b0882a8620e1
--- /dev/null
+++ b/arch/arm64/include/asm/dmi.h
@@ -0,0 +1,41 @@
+/*
+ * arch/arm64/include/asm/dmi.h
+ *
+ * Copyright (C) 2013 Linaro Limited.
+ * Written by: Yi Li (yi.li at 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/slab.h>
+#include <linux/efi.h>
+
+static inline void __iomem *dmi_remap(u64 phys, u64 size)
+{
+	void __iomem *p = efi_lookup_mapped_addr(phys);
+
+	/*
+	 * If the mapping spans multiple pages, do a minimal check to ensure
+	 * that the mapping returned by efi_lookup_mapped_addr() covers the
+	 * whole requested range (but ignore potential holes)
+	 */
+	if ((phys & ~PAGE_MASK) + size > PAGE_SIZE
+	    && (p + size - 1) != efi_lookup_mapped_addr(phys + size - 1))
+		return NULL;
+	return p;
+}
+
+/* Reuse existing UEFI mappings for DMI */
+#define dmi_alloc(l)			kzalloc(l, GFP_KERNEL)
+#define dmi_early_remap(x, l)		dmi_remap(x, l)
+#define dmi_early_unmap(x, l)
+#define dmi_unmap(x)
+
+#endif
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 46d1125571f6..4075e46282b1 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -43,6 +43,7 @@
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 #include <linux/efi.h>
+#include <linux/dmi.h>
 
 #include <asm/fixmap.h>
 #include <asm/cputype.h>
@@ -413,6 +414,7 @@ void __init setup_arch(char **cmdline_p)
 static int __init arm64_device_init(void)
 {
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+	dmi_scan_machine();
 	return 0;
 }
 arch_initcall_sync(arm64_device_init);
-- 
1.8.3.2