From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ludovic BARRE Subject: Re: [PATCH V2 0/5] mmc: mmci: add busy detect for stm32 sdmmc variant Date: Tue, 21 May 2019 11:17:48 +0200 Message-ID: <7e15c8ec-f851-b0d3-a3ce-dfad2a398e78@st.com> References: <1556264798-18540-1-git-send-email-ludovic.Barre@st.com> <74b91eb4-e5a3-38b2-f732-29cdd058eb6a@st.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Ulf Hansson Cc: Rob Herring , Srinivas Kandagatla , Maxime Coquelin , Alexandre Torgue , Linux ARM , Linux Kernel Mailing List , DTML , "linux-mmc@vger.kernel.org" , linux-stm32@st-md-mailman.stormreply.com List-Id: devicetree@vger.kernel.org On 5/21/19 9:56 AM, Ulf Hansson wrote: > On Tue, 21 May 2019 at 09:38, Ludovic BARRE wrote: >> >> hi Ulf >> >> Just a "gentleman ping" about the rest of series. >> "mmc: mmci: add busy detect for stm32 sdmmc variant" > > Thanks! > > It's been a busy period and I am currently traveling. My plan is to > look at in detail beginning of next week when get back home. I hope > that's okay. yes, I understand, it's just to not forget me :-) > > Kind regards > Uffe > >> >> Regards >> Ludo >> >> On 5/3/19 3:29 PM, Ulf Hansson wrote: >>> On Tue, 30 Apr 2019 at 14:06, Ludovic BARRE wrote: >>>> >>>> >>>> >>>> On 4/30/19 1:13 PM, Ulf Hansson wrote: >>>>> On Fri, 26 Apr 2019 at 09:46, Ludovic Barre wrote: >>>>>> >>>>>> From: Ludovic Barre >>>>>> >>>>>> This patch series adds busy detect for stm32 sdmmc variant. >>>>>> Some adaptations are required: >>>>>> -Avoid to check and poll busy status when is not expected. >>>>>> -Clear busy status bit if busy_detect_flag and busy_detect_mask are >>>>>> different. >>>>>> -Add hardware busy timeout with MMCIDATATIMER register. >>>>>> >>>>>> V2: >>>>>> -mmci_cmd_irq cleanup in separate patch. >>>>>> -simplify the busy_detect_flag exclude >>>>>> -replace sdmmc specific comment in >>>>>> "mmc: mmci: avoid fake busy polling in mmci_irq" >>>>>> to focus on common behavior >>>>>> >>>>>> Ludovic Barre (5): >>>>>> mmc: mmci: cleanup mmci_cmd_irq for busy detect feature >>>>>> mmc: mmci: avoid fake busy polling in mmci_irq >>>>>> mmc: mmci: fix clear of busy detect status >>>>>> mmc: mmci: add hardware busy timeout feature >>>>>> mmc: mmci: add busy detect for stm32 sdmmc variant >>>>>> >>>>>> drivers/mmc/host/mmci.c | 61 ++++++++++++++++++++++++++++++++++++++----------- >>>>>> drivers/mmc/host/mmci.h | 3 +++ >>>>>> 2 files changed, 51 insertions(+), 13 deletions(-) >>>>>> >>>>>> -- >>>>>> 2.7.4 >>>>>> >>>>> >>>>> Ludovic, just wanted to let you know that I am reviewing and testing >>>>> this series. >>>>> >>>>> However, while running some tests on Ux500 for validating the busy >>>>> detection code, even without your series applied, I encounter some odd >>>>> behaviors. I am looking into the problem to understand better and will >>>>> let you know as soon as I have some more data to share. >>>> >>>> Oops, don't hesitate to share your status, if I could help. >>> >>> Thanks! Good and bad news here, then. >>> >>> I now understand what is going on - and there is certainly room for >>> improvements here, but more importantly the actual mmci busy detection >>> works as expected. >>> >>> When it comes to improvements, the main issue I have found is how we >>> treat DATA WRITES. In many cases we simply don't use the HW busy >>> detection at all, but instead rely on the mmc core to send CMD13 in a >>> loop to poll. Well, then if the polling would have consisted of a >>> couple of CMD13s that wouldn't be an issue, but my observations is >>> rather that the numbers of CMD13 sent to poll is in the range or >>> hundreds/thousands - per each WRITE request! >>> >>> I am going to send a patch (or two) that improves the behavior. It >>> might even involve changing parts in core layer, not sure how the end >>> result will look like yet. >>> >>> In any case, I have applied patch 1 and patch2 for next, as the tests >>> turned out well at my side. I also took the liberty of updating some >>> of the comments/changelogs, please have look and tell if there is >>> something you want to change. >>> >>> I will continue with the rest of series next week. >>> >>> Kind regards >>> Uffe >>>