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Date: Thu, 7 Nov 2019 17:26:58 +0800
From: Tiezhu Yang <yangtiezhu@...ngson.cn>
To: Jiaxun Yang <jiaxun.yang@...goat.com>,
Paul Burton <paulburton@...nel.org>,
Ralf Baechle <ralf@...ux-mips.org>,
James Hogan <jhogan@...nel.org>,
Jean Delvare <jdelvare@...e.com>,
Huacai Chen <chenhc@...ote.com>
Cc: linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
Yinglu Yang <yangyinglu@...ngson.cn>,
Xuefeng Li <lixuefeng@...ngson.cn>
Subject: Re: [PATCH] MIPS: Scan the DMI system information
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:
> 于 2019年11月7日 GMT+08:00 上午10:42:23, Tiezhu Yang<yangtiezhu@...ngson.cn> 写到:
>> On 11/07/2019 08:35 AM, Jiaxun Yang wrote:
>>> 于 2019年11月7日 GMT+08:00 上午12:05:41, Tiezhu Yang
>> <yangtiezhu@...ngson.cn> 写到:
>>>> 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>
>>>> ---
>>>> 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:
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?
>>> Btw: Probably we should set DMI default y when MACH_LOONGSON64 is
>> set?
>>
>> CONFIG_DMI is set to y by default, I think there is no need to select
>> DMI when
>> set CONFIG_MACH_LOONGSON64.
> Sorry, I meant only default to y when MACH_LOONGSON64 is set or even depends on MACH_LOONGSON64. As Loongson is the only known MIPS platform that supports DMI. Default y unconditionally may lead to regression on other MIPS platforms.
OK, I prefer to select DMI when set MACH_LOONGSON64 instead of
DMI depends on MACH_LOONGSON64, I will modify the Kconfig file.
Thanks,
Tiezhu Yang
>> Thanks,
>>
>> Tiezhu Yang
>>
>>> Thanks.
>>>
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