Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: Re: [PATCH v2] LoongArch: Remove LOONGARCH_CPUCFG48 and some CSR
 definitions
To:     Tiezhu Yang <yangtiezhu@loongson.cn>,
        Huacai Chen <chenhuacai@kernel.org>
Cc:     WANG Xuerui <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        loongarch@lists.linux.dev, linux-kernel@vger.kernel.org
References: <1658305979-2073-1-git-send-email-yangtiezhu@loongson.cn>
 <fc5a891d-e5a9-c02d-08e0-318213cde8f4@loongson.cn>
From:   Jianmin Lv <lvjianmin@loongson.cn>
Message-ID: <6ccd15ed-bbed-18fd-ec97-510d2150c27c@loongson.cn>
Date:   Fri, 22 Jul 2022 15:16:25 +0800
User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101
 Thunderbird/68.7.0
MIME-Version: 1.0
In-Reply-To: <fc5a891d-e5a9-c02d-08e0-318213cde8f4@loongson.cn>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk


On 2022/7/22 下午2:58, Tiezhu Yang wrote:
> 
> 
> On 07/20/2022 04:32 PM, Tiezhu Yang wrote:
>> According to the configuration information accessible by the CPUCFG
>> instruction [1] and the Overview of Control and Status Registers [2],
>> we can not see the descriptions about LOONGARCH_CPUCFG48 (0x30),
>> LOONGARCH_CSR_PRID (0xc0), LOONGARCH_CSR_MCSR* (0xc0 ~ 0xff) and
>> LOONGARCH_CSR_UCAWIN* (0x100 ~ 0x109), they are not used in the
>> current kernel code.
>>
>> LOONGARCH_CPUCFG48 may be used only in the firmware layer, it should
>> not be used in the future for kernel developers, remove the related
>> LOONGARCH_CPUCFG48 definitions.
>>
>> LOONGARCH_CSR_MCSR* is shadow of LOONGARCH_CPUCFG*, no need to access
>> LOONGARCH_CSR_MCSR* and LOONGARCH_CSR_PRID through CSR instruction,
>> use CPUCFG instruction to access LOONGARCH_CPUCFG* is enough, so also
>> remove LOONGARCH_CSR_MCSR* and LOONGARCH_CSR_PRID definitions.
>>
>> LOONGARCH_CSR_UCAWIN* may be not implemented in hardware, use CSR
>> instruction to access them is meaningless, so also remove the related
>> LOONGARCH_CSR_UCAWIN* definitions.
>>
>> The intention of this patch is to keep consistent between the code and
>> the manual.
>>

Agree, they are should be cleaned up for consistency.

Acked-by: Jianmin Lv <lvjianmin@loongson.cn>