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

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Date:   Mon, 3 Feb 2020 16:32:03 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Paul Burton <paulburton@...nel.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Jean Delvare <jdelvare@...e.com>,
        Jean Delvare <jdelvare@...e.de>
Cc:     Huacai Chen <chenhc@...ote.com>,
        Xuefeng Li <lixuefeng@...ngson.cn>, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org, Yinglu Yang <yangyinglu@...ngson.cn>,
        Jiaxun Yang <jiaxun.yang@...goat.com>
Subject: Re: [PATCH v2,RESEND] MIPS: Scan the DMI system information

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@...ngson.cn>
> Signed-off-by: Yinglu Yang <yangyinglu@...ngson.cn>
> [jiaxun.yang@...goat.com: Refine definitions and Kconfig]
> Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> Reviewed-by: Huacai Chen <chenhc@...ote.com>
> ---
>
> 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;
>