Re: [PATCH] soc: kunpeng_hccs: fix some sparse warnings about incorrect type

From: "lihuisong (C)" <lihuisong@huawei.com>
To: Arnd Bergmann <arnd@arndb.de>, Arnd Bergmann <arnd@kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <soc@kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <liuyonglong@huawei.com>,
	<xuwei5@hisilicon.com>, <lihuisong@huawei.com>
Subject: Re: [PATCH] soc: kunpeng_hccs: fix some sparse warnings about incorrect type
Date: Fri, 18 Aug 2023 09:38:36 +0800	[thread overview]
Message-ID: <584734f7-3eb7-961f-10a2-3707cf03819c@huawei.com> (raw)
In-Reply-To: <4f72b1d7-00b4-4318-b3c3-50d11e4a233c@app.fastmail.com>


在 2023/8/17 19:54, Arnd Bergmann 写道:
> On Thu, Aug 17, 2023, at 03:37, lihuisong (C) wrote:
>> 在 2023/8/16 21:17, Arnd Bergmann 写道:
>>> On Tue, Aug 15, 2023, at 14:52, Huisong Li wrote:
>>>> @@ -199,8 +200,8 @@ static int hccs_pcc_cmd_send(struct hccs_dev *hdev, u8 cmd,
>>>>    			     struct hccs_desc *desc)
>>>>    {
>>>>    	struct hccs_mbox_client_info *cl_info = &hdev->cl_info;
>>>> -	struct acpi_pcct_shared_memory *comm_base = cl_info->pcc_comm_addr;
>>>> -	void *comm_space = (void *)(comm_base + 1);
>>>> +	void __iomem *comm_space = (u8 *)cl_info->pcc_comm_addr +
>>>> +					sizeof(struct acpi_pcct_shared_memory);
>>>>    	struct hccs_fw_inner_head *fw_inner_head;
>>>>    	struct acpi_pcct_shared_memory tmp = {0};
>>>>    	u16 comm_space_size;
>>> The cast still looks wrong, while both comm_space and ->pcc_comm_addr
>>> are __iomem pointers, casting to a non-__iomem u8 pointer should
>>> still produce that warning. I'd suggest casting to (u8 __iomem *)
>>> or (void __iomem *), I assume you still need a cast here to get
>>> the correct address.
>> Thanks Arnd.
>>
>> You are right. So I modify it by dropping (u8 *) here in patch v2.
>> Please take a look at this again.
> Right, if pcc_comm_addr is already a u8 __iomem* or void*, that
> works, I though the cast was needed since it points to a larger
> object, which would throw off the calculation.
This pcc_comm_addr is already defined "void __iomem *" type in patch v2.
So that works well, right?

/Huisong
>
>> If it is ok for you, can you apply this patch to soc/soc.git?
> Yes, of course.
>
>         Arnd
> .