From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ludovic BARRE Subject: Re: [PATCH 0/2] mmc: mmci: add quirk property to add stm32 transfer mode Date: Mon, 25 Feb 2019 11:48:56 +0100 Message-ID: <9c88d76c-2080-71b1-c9c6-c24d0f0aeb91@st.com> References: <1550743851-13588-1-git-send-email-ludovic.Barre@st.com> <20190221102739.cc37au6elqu6gvfe@shell.armlinux.org.uk> <20190221103049.tspc5igoe6wmt3jd@shell.armlinux.org.uk> <20190221140300.y3tunrvsh3gyig5f@shell.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190221140300.y3tunrvsh3gyig5f@shell.armlinux.org.uk> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Russell King - ARM Linux admin Cc: devicetree@vger.kernel.org, Ulf Hansson , Alexandre Torgue , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , srinivas.kandagatla@linaro.org, Maxime Coquelin , linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org hi Russell & Ulf On 2/21/19 3:03 PM, Russell King - ARM Linux admin wrote: > On Thu, Feb 21, 2019 at 02:38:36PM +0100, Ludovic BARRE wrote: >> hi Russell & Ulf >> >> On 2/21/19 11:30 AM, Russell King - ARM Linux admin wrote: >>> On Thu, Feb 21, 2019 at 10:27:39AM +0000, Russell King - ARM Linux admin wrote: >>>> On Thu, Feb 21, 2019 at 11:10:49AM +0100, Ludovic Barre wrote: >>>>> From: Ludovic Barre >>>>> >>>>> This patch series introduces a bitmap of hardware quirks that require >>>>> some special action. This should reduce the number of boolean >>>>> into variant structure. >>>>> And adds quirk bit to define sdmmc specific transfer modes. >>>> >>>> Please find some other way to deal with these differences. As far as >>>> I'm concerned, introducing a quirk bitmask such as what was done in >>>> sdhci is a complete disaster and leads to long-term maintanability >>>> problems. >>>> >>>> We already have a way to deal with variants in mmci. >>> >>> ... to finish what I was saying ... >>> >>> and I think that: >>> >>> if (variant->blksz_datactrl16) >>> datactrl = variant->datactrl_dpsm_enable | (data->blksz << 16); >>> else if (variant->blksz_datactrl4) >>> datactrl = variant->datactrl_dpsm_enable | (data->blksz << 4); >>> else >>> datactrl = variant->datactrl_dpsm_enable | blksz_bits << 4; >>> >>> ought to become a variant function call which returns the appropriate >>> datactrl value. This would shrink the amount of variant testing in this >>> path, and also means that going forward we aren't facing an endlessly >>> increasing number of tests here. >> >> For blksz_datactrl case: >> We could create an inline function for datactrl16 and blksz_datactrl4 >> which returns the appropriate datactrl value (specific for ux500v2 and >> qcom). This function could be register in mmci_host_ops structure. > > Yes, this is what I'm proposing (except for the "inline" bit which > seems meaningless if it's called via the mmci_host_ops structure.) > I'm also proposing that it shouldn't just be the blksz that's > returned but anything that the variant needs to take account of, > including the stm transfer mode. Ulf, are you alright with this callback approach (just to be sure that every body is align, before send a patch)? This mmci_host_ops callback could return datactrl config to start data (defined by variant). > >> in mmci_start_data function we could call a common function which call a >> hook if defined. >> >> int mmci_dblksz(struct mmci_host *host) > > As this is returning a register value, "u32" would be more appropriate > than "int". > >> { >> if (host->ops && host->ops->dblksz) >> return host->ops->dblk(host); >> >> /* default data block size definition */ >> blksz_bits = ffs(data->blksz) - 1; >> return blksz_bits << 4; >> } >> >> what do you think about it? > > I don't see any reason not to make the call unconditional and have every > variant supply an appropriate function pointer. IMHO that keeps stuff > cleaner. > >> After, I'm afraid to multiply callback function in mmci_host_ops. >> >> For stm32 transfer mode: >> ditto, a callback function or I keep a boolean? >> >> BR >> Ludo >> >>> >>>> >>>>> >>>>> Ludovic Barre (2): >>>>> mmc: mmci: introduce a quirks property into variant struct >>>>> mmc: mmci: add quirk property to add stm32 transfer mode >>>>> >>>>> drivers/mmc/host/mmci.c | 11 +++++++++++ >>>>> drivers/mmc/host/mmci.h | 9 +++++++++ >>>>> 2 files changed, 20 insertions(+) >>>>> >>>>> -- >>>>> 2.7.4 >>>>> >>>>> >>>>> _______________________________________________ >>>>> linux-arm-kernel mailing list >>>>> linux-arm-kernel@lists.infradead.org >>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>>>> >>>> >>>> -- >>>> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ >>>> FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up >>>> According to speedtest.net: 11.9Mbps down 500kbps up >>>> >>>> _______________________________________________ >>>> linux-arm-kernel mailing list >>>> linux-arm-kernel@lists.infradead.org >>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>>> >>> >> >