linux-kernel - Re: [PATCH 2/2] mfd: intel-m10-bmc: add access table configuration to the regmap

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Message-ID: <0f17f8a7-d2f5-e88e-b3dc-0a75ea7f5ada@redhat.com>
Date:   Wed, 20 Jan 2021 07:32:53 -0800
From:   Tom Rix <trix@...hat.com>
To:     Xu Yilun <yilun.xu@...el.com>, lee.jones@...aro.org,
        linux-kernel@...r.kernel.org
Cc:     matthew.gerlach@...ux.intel.com, russell.h.weight@...el.com,
        lgoncalv@...hat.com, hao.wu@...el.com
Subject: Re: [PATCH 2/2] mfd: intel-m10-bmc: add access table configuration to
 the regmap


On 1/19/21 6:34 PM, Xu Yilun wrote:
> From: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>
> This patch adds access tables to the MAX 10 BMC regmap. This prevents
> the host from accessing the unwanted I/O space. It also filters out the
> invalid outputs when reading the regmap debugfs interface.
>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
> ---
>  drivers/mfd/intel-m10-bmc.c       | 14 ++++++++++++++
>  include/linux/mfd/intel-m10-bmc.h |  5 ++++-
>  2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mfd/intel-m10-bmc.c b/drivers/mfd/intel-m10-bmc.c
> index b84579b..0ae3053 100644
> --- a/drivers/mfd/intel-m10-bmc.c
> +++ b/drivers/mfd/intel-m10-bmc.c
> @@ -23,10 +23,24 @@ static struct mfd_cell m10bmc_pacn3000_subdevs[] = {
>  	{ .name = "n3000bmc-secure" },
>  };
>  
> +static const struct regmap_range m10bmc_regmap_range[] = {
> +	regmap_reg_range(M10BMC_LEGACY_SYS_BASE + M10BMC_BUILD_VER,
> +			 M10BMC_LEGACY_SYS_BASE + M10BMC_BUILD_VER),

If this is the only value in the legacy map to be accessed, could it have its own #define ?

Something like

#define M10BMC_LEGACY_BUILD_VER ?

> +	regmap_reg_range(M10BMC_SYS_BASE, M10BMC_SYS_END),
> +	regmap_reg_range(M10BMC_FLASH_BASE, M10BMC_FLASH_END),
> +};
> +
> +static const struct regmap_access_table m10bmc_access_table = {
> +	.yes_ranges	= m10bmc_regmap_range,
> +	.n_yes_ranges	= ARRAY_SIZE(m10bmc_regmap_range),
> +};
> +
>  static struct regmap_config intel_m10bmc_regmap_config = {
>  	.reg_bits = 32,
>  	.val_bits = 32,
>  	.reg_stride = 4,
> +	.wr_table = &m10bmc_access_table,
> +	.rd_table = &m10bmc_access_table,

The legacy build ver should only be read, so shouldn't these tables be different ?

Tom

>  	.max_register = M10BMC_MEM_END,
>  };
>  
> diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
> index 06da62c..4ba88ed 100644
> --- a/include/linux/mfd/intel-m10-bmc.h
> +++ b/include/linux/mfd/intel-m10-bmc.h
> @@ -11,7 +11,10 @@
>  
>  #define M10BMC_LEGACY_SYS_BASE		0x300400
>  #define M10BMC_SYS_BASE			0x300800
> -#define M10BMC_MEM_END			0x1fffffff
> +#define M10BMC_SYS_END			0x300fff
> +#define M10BMC_FLASH_BASE		0x10000000
> +#define M10BMC_FLASH_END		0x1fffffff
> +#define M10BMC_MEM_END			M10BMC_FLASH_END
>  
>  /* Register offset of system registers */
>  #define NIOS2_FW_VERSION		0x0