Re: [PATCH] MIPS: Scan the DMI system information
From: Tiezhu Yang
Date: Thu Nov 07 2019 - 06:08:04 EST
On 11/07/2019 06:42 PM, Jean Delvare wrote:
On Thu, 7 Nov 2019 17:26:58 +0800, Tiezhu Yang wrote:
Sorry to resend this email because the mail list server was denied
due to it is not plain text.
On 11/07/2019 11:42 AM, Jiaxun Yang wrote:
ä 2019å11æ7æ GMT+08:00 äå10:42:23, Tiezhu Yang<yangtiezhu@xxxxxxxxxxx> åå:
On 11/07/2019 08:35 AM, Jiaxun Yang wrote:
ä 2019å11æ7æ GMT+08:00 äå12:05:41, Tiezhu Yang
<yangtiezhu@xxxxxxxxxxx> åå:
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@xxxxxxxxxxx>
Signed-off-by: Yinglu Yang<yangyinglu@xxxxxxxxxxx>
Signed-off-by: Tiezhu Yang<yangtiezhu@xxxxxxxxxxx>
---
arch/mips/Kconfig | 12 ++++++++++++
arch/mips/include/asm/dmi.h | 43
+++++++++++++++++++++++++++++++++++++++++++
arch/mips/kernel/setup.c | 2 ++
3 files changed, 57 insertions(+)
create mode 100644 arch/mips/include/asm/dmi.h
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 7cb8947..0a67b18 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2757,6 +2757,18 @@ config HW_PERF_EVENTS
Enable hardware performance counter support for perf events. If
disabled, perf events will use software events only.
+# Mark as expert because too many people got it wrong.
+# The code disables itself when not needed.
+config DMI
+ default y
+ select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
+ bool "Enable DMI scanning" if EXPERT
+ 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..1f3da37
--- /dev/null
+++ b/arch/mips/include/asm/dmi.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_MIPS_DMI_H
+#define _ASM_MIPS_DMI_H
+
+#define dmi_early_remap mips_early_memremap
+#define dmi_early_unmap mips_early_memunmap
+#define dmi_remap(_x, _l) mips_memremap(_x, _l, MEMREMAP_WB)
+#define dmi_unmap(_x) mips_memunmap(_x)
+
+#define dmi_alloc(l) memblock_alloc_low(l, PAGE_SIZE)
+
+void __init *mips_early_memremap(resource_size_t phys_addr,
unsigned
long size)
+{
+#if defined(CONFIG_MACH_LOONGSON64)
+ if (phys_addr == 0xF0000)
+ phys_addr = 0xFFFE000;
+
+ return (void *)TO_CAC(phys_addr);
+#else
+ return NULL;
+#endif
+}
Hi Tiezhu,
It is really tricky to hijack dmi address here during remap.
I think we should set the dmi table address at dmi_scan.c by a marco
or something else rather than hijack it during remap.
Hi Jiaxun,
Thanks for your review. I agree with you, let me think about it and try
to
find a proper way, and then I will send a v2 patch.
Hi Jiaxun,
It seems that there is no absolutely better way to handle this case.
1. use conditional compilation in drivers/firmware/dmi_scan.c:
#if defined(CONFIG_MACH_LOONGSON64)
p = dmi_early_remap(0xFFFE000, 0x10000);
#else
p = dmi_early_remap(0xF0000, 0x10000);
#endif
This will influence the common code.
2. use callback function in arch/mips/include/asm/dmi.h:
I see no reason to go that route if the decision can be made at build
time. Callback functions are good when the decision is made at run time.
struct plat_dmi_ops {
void (*early_memremap)(void);
void (*memremap)(void);
};
extern struct plat_dmi_ops *dmi_ops;
void __init *mips_early_memremap(resource_size_t phys_addr, unsigned long size)
{
dmi_ops->early_memremap();
}
void *mips_memremap(resource_size_t offset, size_t size, unsigned long flags)
{
dmi_ops->memremap();
}
we can implement the callback function in various of MIPS platforms,
like this:
struct plat_dmi_ops loongson3_dmi_ops = {
.early_memremap = loongson3_early_memremap,
.memremap = loongson3_memremap,
};
register_dmi_ops(&loongson3_dmi_ops);
#ifdef CONFIG_DMI
void __init *loongson3_early_memremap(resource_size_t phys_addr, unsigned long size)
{
if (phys_addr == 0xF0000)
phys_addr = 0xfffe000;
return (void *)TO_CAC(phys_addr);
}
void *loongson3_memremap(resource_size_t offset, size_t size, unsigned long flags)
{
return (void *)TO_CAC(phys_addr);
}
#else
void __init __iomem *loongson3_early_memremap(u64 phys_addr, unsigned long size)
{
return NULL;
}
void __init __iomem *loongson3_memremap(u64 phys_addr, unsigned long size)
{
return NULL;
}
#endif
This will not influence the common code.
What do you think?
Hi Jean,
Could you give some suggestions?
What about:
#if defined(CONFIG_MACH_LOONGSON64)
#define SMBIOS_ENTRY_POINT_SCAN_START 0xFFFE000
#else
#define SMBIOS_ENTRY_POINT_SCAN_START 0xF0000
#endif
And then just use SMBIOS_ENTRY_POINT_SCAN_START instead of the raw
address everywhere it is needed?
OK, good idea, thank you very much!
I will send a v2 patch as soon as possible.
Thanks,
Tiezhu Yang