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[212.182.62.129]) by smtp.gmail.com with ESMTPSA id d27-20020a19385b000000b0050a026d3a26sm1705739lfj.227.2023.11.15.08.42.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Nov 2023 08:42:01 -0800 (PST) Message-ID: Date: Wed, 15 Nov 2023 17:42:00 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/3] iommu/arm-smmu: add ACTLR data and support for SM8550 Content-Language: en-US To: Bibek Kumar Patro , Dmitry Baryshkov Cc: will@kernel.org, robin.murphy@arm.com, joro@8bytes.org, a39.skl@gmail.com, quic_pkondeti@quicinc.com, quic_molvera@quicinc.com, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, qipl.kernel.upstream@quicinc.com References: <20231114135654.30475-1-quic_bibekkum@quicinc.com> <20231114135654.30475-3-quic_bibekkum@quicinc.com> <7edad996-f148-42d5-8e72-0334d3b9101f@quicinc.com> From: Konrad Dybcio In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/15/23 13:49, Bibek Kumar Patro wrote: > > > On 11/15/2023 4:15 PM, Dmitry Baryshkov wrote: >> On Wed, 15 Nov 2023 at 11:51, Bibek Kumar Patro >> wrote: >>> >>> >>> >>> On 11/15/2023 3:08 PM, Dmitry Baryshkov wrote: >>>> On Wed, 15 Nov 2023 at 11:22, Bibek Kumar Patro >>>> wrote: >>>>> >>>>> >>>>> >>>>> On 11/14/2023 7:42 PM, Dmitry Baryshkov wrote: >>>>>> On Tue, 14 Nov 2023 at 15:57, Bibek Kumar Patro >>>>>> wrote: >>>>>>> >>>>>>> Add ACTLR data table for SM8550 along with support for >>>>>>> same including SM8550 specific implementation operations. >>>>>>> >>>>>>> Signed-off-by: Bibek Kumar Patro >>>>>>> --- >>>>>>>     drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 92 +++++++++++++++++++++- >>>>>>>     1 file changed, 88 insertions(+), 4 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>>>>> index 578c662c7c30..0eaf6f2a2e49 100644 >>>>>>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>>>>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>>>>> @@ -25,6 +25,70 @@ struct actlr_data { >>>>>>>            u32 actlr; >>>>>>>     }; >>>>>>> >>>>>>> +#define PRE_FETCH_1    0 >>>>>>> +#define PRE_FETCH_2    BIT(8) >>>>>>> +#define PRE_FETCH_3    (BIT(9) | BIT(8)) >>>>>> >>>>>> What is the difference between PRE_FETCH_3 and PRE_FETCH_2? And >>>>>> PRE_FETCH_1? Are these real numbers that refer to some amount / count >>>>>> or just dummy names? >>>>>> >>>>> >>>>> No,these are not real numbers, but prefetch settings for a particular >>>>> perfect configuration. >>>> >>>> Then I'd ask for some better names or descriptions. >>>> >>> >>> Noted, PREFETCH_SETTING_n / PREFETCH_OPTION_n sounds like a better name >>> in the following case. Would it be okay to use this name instead? >> >> Not really. >> > > Any suggestion you have in mind, if not this nomenclature? Dmitry's concern seems to be that you provide: PRE_FETCH_1 /* prefetcher with settings preset no. 1 */ PRE_FETCH_2 /* prefetcher with settings preset no. 2 */ PRE_FETCH_3 /* prefetcher with settings preset no. 3 */ whereas it would be both useful and interesting to see what these settings mean, i.e. what differences there are between all of these presets. Konrad