Re: [PATCH v1 3/6] bus: mhi: Add MMIO region length to controller structure

From: Bhaumik Bhatt <bbhatt@codeaurora.org>
To: Jeffrey Hugo <quic_jhugo@quicinc.com>
Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org,
	hemantk@codeaurora.org, linux-kernel@vger.kernel.org,
	loic.poulain@linaro.org, linux-wireless@vger.kernel.org,
	kvalo@codeaurora.org, ath11k@lists.infradead.org
Subject: Re: [PATCH v1 3/6] bus: mhi: Add MMIO region length to controller structure
Date: Tue, 04 May 2021 16:04:12 -0700	[thread overview]
Message-ID: <928a29dca0d2b141d4e21b7878c1c42e@codeaurora.org> (raw)
In-Reply-To: <83589a09-e1a0-4611-a844-0ea52ca036b9@quicinc.com>

Hi Jeff,

On 2021-05-04 10:28 AM, Jeffrey Hugo wrote:
> On 4/16/2021 12:47 PM, Bhaumik Bhatt wrote:
>> Make controller driver specify the MMIO register region length
>> for range checking of BHI or BHIe space. This can help validate
>> that offsets are in acceptable memory region or not and avoid any
>> boot-up issues due to BHI or BHIe memory accesses.
>> 
>> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
>> ---
>>   include/linux/mhi.h | 2 ++
>>   1 file changed, 2 insertions(+)
>> 
>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
>> index 944aa3a..ad53b24 100644
>> --- a/include/linux/mhi.h
>> +++ b/include/linux/mhi.h
>> @@ -293,6 +293,7 @@ struct mhi_controller_config {
>>    * @mhi_dev: MHI device instance for the controller
>>    * @debugfs_dentry: MHI controller debugfs directory
>>    * @regs: Base address of MHI MMIO register space (required)
>> + * @reg_len: Length of the MHI MMIO region (required)
>>    * @bhi: Points to base of MHI BHI register space
>>    * @bhie: Points to base of MHI BHIe register space
>>    * @wake_db: MHI WAKE doorbell register address
>> @@ -375,6 +376,7 @@ struct mhi_controller {
>>   	struct mhi_device *mhi_dev;
>>   	struct dentry *debugfs_dentry;
>>   	void __iomem *regs;
>> +	size_t reg_len;
> 
> Didn't Mani make sure this struct was packed using pahole when things
> were first upstreamed?  Feels like sticking this in the middle of a
> bunch of void * entries will add some padding.  Am I wrong?
> 
OK. I missed out on this detail. I can move this size_t entry in v2.
>>   	void __iomem *bhi;
>>   	void __iomem *bhie;
>>   	void __iomem *wake_db;
>> 

Thanks,
Bhaumik
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