linux-kernel - [PATCH] LoongArch: Fix wrong "ROM Size" of boardinfo

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Date:   Thu, 21 Jul 2022 17:53:01 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     WANG Xuerui <kernel@...0n.name>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH] LoongArch: Fix wrong "ROM Size" of boardinfo

We can see the "ROM Size" is different in the following outputs:

[root@...ux loongson]# cat /sys/firmware/loongson/boardinfo
BIOS Information
Vendor                  : Loongson
Version                 : vUDK2018-LoongArch-V2.0.pre-beta8
ROM Size                : 63 KB
Release Date            : 06/15/2022

Board Information
Manufacturer            : Loongson
Board Name              : Loongson-LS3A5000-7A1000-1w-A2101
Family                  : LOONGSON64

[root@...ux loongson]# dmidecode | head -11
...
Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
	Vendor: Loongson
	Version: vUDK2018-LoongArch-V2.0.pre-beta8
	Release Date: 06/15/2022
	ROM Size: 4 MB

According to "BIOS Information (Type 0) structure" in the SMBIOS
Reference Specification [1], it shows 64K * (n+1) is the size of
the physical device containing the BIOS if the size is less than
16M.

Additionally, we can see the related code in dmidecode [2]:

  u64 s = { .l = (code1 + 1) << 6 };

So the output of dmidecode is correct, the output of boardinfo
is wrong, fix it.

By the way, at present no need to consider the size is 16M or
greater on LoongArch, because it is usually 4M or 8M which is
enough to use.

[1] https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
[2] https://git.savannah.nongnu.org/cgit/dmidecode.git/tree/dmidecode.c#n347

Fixes: 628c3bb40e9a ("LoongArch: Add boot and setup routines")
Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 arch/loongarch/kernel/setup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index c74860b..8f5c2f9 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -126,7 +126,7 @@ static void __init parse_bios_table(const struct dmi_header *dm)
 	char *dmi_data = (char *)dm;
 
 	bios_extern = *(dmi_data + SMBIOS_BIOSEXTERN_OFFSET);
-	b_info.bios_size = *(dmi_data + SMBIOS_BIOSSIZE_OFFSET);
+	b_info.bios_size = (*(dmi_data + SMBIOS_BIOSSIZE_OFFSET) + 1) << 6;
 
 	if (bios_extern & LOONGSON_EFI_ENABLE)
 		set_bit(EFI_BOOT, &efi.flags);
-- 
2.1.0