Re: [PATCH v2,RESEND] MIPS: Scan the DMI system information

From: Tiezhu Yang
Date: Mon Feb 03 2020 - 03:32:23 EST


On 1/16/20 9:26 PM, Tiezhu Yang wrote:
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.

This patch works fine on the Loongson 3A3000 platform which belongs to
MIPS architecture and has no influence on the other architectures such
as x86 and ARM.

Co-developed-by: Yinglu Yang <yangyinglu@xxxxxxxxxxx>
Signed-off-by: Yinglu Yang <yangyinglu@xxxxxxxxxxx>
[jiaxun.yang@xxxxxxxxxxx: Refine definitions and Kconfig]
Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Reviewed-by: Huacai Chen <chenhc@xxxxxxxxxx>
---

v2:
- add SMBIOS_ENTRY_POINT_SCAN_START suggested by Jean
- refine definitions and Kconfig by Jiaxun

arch/mips/Kconfig | 10 ++++++++++
arch/mips/include/asm/dmi.h | 20 ++++++++++++++++++++
arch/mips/kernel/setup.c | 2 ++
drivers/firmware/dmi_scan.c | 6 +++++-
4 files changed, 37 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/include/asm/dmi.h


Hi Paul and Jean,

How do you think this patch?

Should I split it into the following two patches?
[PATCH v3 1/2] firmware: dmi: Add macro SMBIOS_ENTRY_POINT_SCAN_START
[PATCH v3 2/2] MIPS: Add support for Desktop Management Interface (DMI)

The first patch is only related with the common dmi code
drivers/firmware/dmi_scan.c, the other patch is only related
with the mips code under arch/mips.

If you have any questions or suggestions, please let me know.
I am looking forward to your early reply.

Thanks,

Tiezhu Yang



diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 4b83507..c097f78 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2773,6 +2773,16 @@ 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. Required by PNP
+ BIOS code.
+
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 0000000..27415a2
--- /dev/null
+++ b/arch/mips/include/asm/dmi.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_DMI_H
+#define _ASM_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_DMI_H */
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 701f4bc..d9bd841 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>
@@ -800,6 +801,7 @@ 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 2045566..f59163c 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);
@@ -663,7 +667,7 @@ 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;