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From: Ard Biesheuvel <ardb@kernel.org>
Date: Tue, 19 Mar 2024 18:14:23 +0100
Message-ID: <CAMj1kXFgohP_dOCxbmem_5ZWiFs5KmYFOPkj3uAZWhumBfOWFQ@mail.gmail.com>
Subject: Re: [PATCH v2] riscv: dmi: Add SMBIOS/DMI support
To: Haibo Xu <haibo1.xu@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, 
	linux-efi@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, 
	aou@eecs.berkeley.edu, sunilvl@ventanamicro.com, xiaobo55x@gmail.com
Content-Type: text/plain; charset="UTF-8"

On Mon, 18 Mar 2024 at 02:55, Haibo Xu <haibo1.xu@intel.com> wrote:
>
> Enable the dmi driver for riscv which would allow access the
> SMBIOS info through some userspace file(/sys/firmware/dmi/*).
>
> The change was based on that of arm64 and has been verified
> by dmidecode tool.
>
> Signed-off-by: Haibo Xu <haibo1.xu@intel.com>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>


> ---
> Changes since v1
>   - Change to use memremap/memunmap for dmi_(early)_remap/unmap
>     definition(suggested by Ard)
>   - Minor clean up for comments (Ard)
> ---
>  arch/riscv/Kconfig                   | 11 +++++++++++
>  arch/riscv/include/asm/dmi.h         | 24 ++++++++++++++++++++++++
>  drivers/firmware/efi/riscv-runtime.c | 13 +++++++++++++
>  3 files changed, 48 insertions(+)
>  create mode 100644 arch/riscv/include/asm/dmi.h
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 8ebafe337eac..3639151cb4ef 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -952,6 +952,17 @@ config EFI
>           allow the kernel to be booted as an EFI application. This
>           is only useful on systems that have UEFI firmware.
>
> +config DMI
> +       bool "Enable support for SMBIOS (DMI) tables"
> +       depends on EFI
> +       default y
> +       help
> +         This enables SMBIOS/DMI feature for systems.
> +
> +         This option is only useful on systems that have UEFI firmware.
> +         However, even with this option, the resultant kernel should
> +         continue to boot on existing non-UEFI platforms.
> +
>  config CC_HAVE_STACKPROTECTOR_TLS
>         def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)
>
> diff --git a/arch/riscv/include/asm/dmi.h b/arch/riscv/include/asm/dmi.h
> new file mode 100644
> index 000000000000..ca7cce557ef7
> --- /dev/null
> +++ b/arch/riscv/include/asm/dmi.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2024 Intel Corporation
> + *
> + * based on arch/arm64/include/asm/dmi.h
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + */
> +
> +#ifndef __ASM_DMI_H
> +#define __ASM_DMI_H
> +
> +#include <linux/io.h>
> +#include <linux/slab.h>
> +
> +#define dmi_early_remap(x, l)          memremap(x, l, MEMREMAP_WB)
> +#define dmi_early_unmap(x, l)          memunmap(x)
> +#define dmi_remap(x, l)                        memremap(x, l, MEMREMAP_WB)
> +#define dmi_unmap(x)                   memunmap(x)
> +#define dmi_alloc(l)                   kzalloc(l, GFP_KERNEL)
> +
> +#endif
> diff --git a/drivers/firmware/efi/riscv-runtime.c b/drivers/firmware/efi/riscv-runtime.c
> index 09525fb5c240..c3bfb9e77e02 100644
> --- a/drivers/firmware/efi/riscv-runtime.c
> +++ b/drivers/firmware/efi/riscv-runtime.c
> @@ -152,3 +152,16 @@ void arch_efi_call_virt_teardown(void)
>  {
>         efi_virtmap_unload();
>  }
> +
> +static int __init riscv_dmi_init(void)
> +{
> +       /*
> +        * On riscv, DMI depends on UEFI, and dmi_setup() needs to
> +        * be called early because dmi_id_init(), which is an arch_initcall
> +        * itself, depends on dmi_scan_machine() having been called already.
> +        */
> +       dmi_setup();
> +
> +       return 0;
> +}
> +core_initcall(riscv_dmi_init);
> --
> 2.34.1
>