linux-kernel - [PATCH REPLY] MIPS: Scan the DMI system information

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Date:   Thu,  7 Nov 2019 19:28:01 +0800
From:   Jiaxun Yang <jiaxun.yang@...goat.com>
To:     yangtiezhu@...ngson.cn
Cc:     linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        yangyinglu@...ngson.cn, jdelvare@...e.de,
        Jiaxun Yang <jiaxun.yang@...goat.com>
Subject: [PATCH REPLY] MIPS: Scan the DMI system information

Hi Tiezhu and Jean,

What about do like this?
We shouldn't follow x86's Kconfig as most of MIPS devices
don't support DMI.

And, we can reuse map/unmap from io.h to reduce
maintinance overhead.

Thanks

Jiaxun

>8------------------------------------------------------8<

Enable DMI scanning on the MIPS architecture, this setups DMI identifiers
(dmi_system_id) for printing it out on task dumps and prepares DIMM entry
information (dmi_memdev_info) from the SMBIOS table. With this patch, the
driver can easily match various of mainboards.

In the SMBIOS reference specification, the table anchor string "_SM_" is
present in the address range 0xF0000 to 0xFFFFF on a 16-byte boundary,
but there exists a special case for loongson platform, when call function
dmi_early_remap, it should specify the start address to 0xFFFE000 due to
it is reserved for SMBIOS and can be normally access in the BIOS.

Co-developed-by: Yinglu Yang <yangyinglu@...ngson.cn>
Signed-off-by: Yinglu Yang <yangyinglu@...ngson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
[jiaxun.yang@...goat.com: Refine definitions and Kconfig]
Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
---
 arch/mips/Kconfig           |  9 +++++++++
 arch/mips/include/asm/dmi.h | 20 ++++++++++++++++++++
 arch/mips/kernel/setup.c    |  2 ++
 drivers/firmware/dmi_scan.c |  6 +++++-
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 arch/mips/include/asm/dmi.h

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c3a022ca3345..414f3a0ea397 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2759,6 +2759,15 @@ config HW_PERF_EVENTS
 	  Enable hardware performance counter support for perf events. If
 	  disabled, perf events will use software events only.
 
+config DMI
+	default y if MACH_LOONGSON64
+	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
+	bool "Enable DMI scanning"
+	help
+	  Enabled scanning of DMI to identify machine quirks. Say Y
+	  here unless you have verified that your setup is not
+	  affected by entries in the DMI blacklist.
+
 config SMP
 	bool "Multi-Processing support"
 	depends on SYS_SUPPORTS_SMP
diff --git a/arch/mips/include/asm/dmi.h b/arch/mips/include/asm/dmi.h
new file mode 100644
index 000000000000..5153ef6fe8a2
--- /dev/null
+++ b/arch/mips/include/asm/dmi.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_MIPS_DMI_H
+#define _ASM_MIPS_DMI_H
+
+#include <linux/io.h>
+#include <linux/memblock.h>
+
+#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)
+
+/* MIPS initialize DMI scan before SLAB is ready, so we use memblock here */
+#define dmi_alloc(l)			memblock_alloc_low(l, PAGE_SIZE)
+
+#if defined(CONFIG_MACH_LOONGSON64)
+#define SMBIOS_ENTRY_POINT_SCAN_START	0xfffe000
+#endif
+
+#endif /* _ASM_MIPS_DMI_H */
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index c3d4212b5f1d..da7d312e20eb 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -28,6 +28,7 @@
 #include <linux/decompress/generic.h>
 #include <linux/of_fdt.h>
 #include <linux/of_reserved_mem.h>
+#include <linux/dmi.h>
 
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
@@ -802,6 +803,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 	arch_mem_init(cmdline_p);
+	dmi_setup();
 
 	resource_init();
 	plat_smp_setup();
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 35ed56b9c34f..ee2dbebf2063 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -11,6 +11,10 @@
 #include <asm/dmi.h>
 #include <asm/unaligned.h>
 
+#ifndef SMBIOS_ENTRY_POINT_SCAN_START
+#define SMBIOS_ENTRY_POINT_SCAN_START 0xf0000
+#endif
+
 struct kobject *dmi_kobj;
 EXPORT_SYMBOL_GPL(dmi_kobj);
 
@@ -661,7 +665,7 @@ static void __init dmi_scan_machine(void)
 			return;
 		}
 	} else if (IS_ENABLED(CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK)) {
-		p = dmi_early_remap(0xF0000, 0x10000);
+		p = dmi_early_remap(SMBIOS_ENTRY_POINT_SCAN_START, 0x10000);
 		if (p == NULL)
 			goto error;
 
-- 
2.24.0.rc1