On 03/02/2016 16:33, Mason wrote: > On 03/02/2016 16:21, Sören Brinkmann wrote: >> On Wed, 2016-02-03 at 10:58:24 +0100, Michal Simek wrote: >>> On 3.2.2016 09:31, Mason wrote: >>>> On 03/02/2016 08:20, Michal Simek wrote: >>>> >>>>> On 3.2.2016 03:33, Shawn Lin wrote: >>>>>> + Michal, Sören Brinkmann >>>>>> >>>>>> On 2016/2/2 17:49, Mason wrote: >>>>>>> Hello everyone, >>>>>>> >>>>>>> Documentation/devicetree/bindings/mmc/arasan,sdhci.txt states: >>>>>>> >>>>>>> Required Properties: >>>>>>> - compatible: Compatibility string. Must be 'arasan,sdhci-8.9a' or >>>>>>> 'arasan,sdhci-4.9a' or 'arasan,sdhci-5.1' >>>>>>> >>>>>>> What do 8.9a, 4.9a, and 5.1 refer to? >>>>>>> >>>>>> >>>>>> Good question. >>>>>> >>>>>> Michal told me that 8.9a and 4.9a came from Xilinx >>>>>> databook which define their available arasan controller to be version >>>>>> 4.9a and 8.9a. >>>>> >>>>> Our version is coming from here. >>>>> http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf >>>>> page 28 >>>>> >>>>> Datasheets from 2012 and 2010 doesn't look too recent and I expect that >>>>> Arasan did a lot of work from that time that's why I am not surprised >>>>> that you are not able to see that versions. >>>> >>>> Hello Michal, >>>> >>>> I'm even more confused. >>>> >>>> Arasan's 2010-02-19 data sheet is titled >>>> SD3.0 / SDIO3.0 / eMMC4.4 AHB Host Controller >>>> >>>> Page 28 of the Xilinx data sheet mentions >>>> SD2.0 / SDIO2.0 / MMC3.31 AHB Host Controller >>>> Version 8.9A_apr02nd_2010 >>>> >>>> It does not make sense that Arasan would support SD3.0 in February, >>>> then go back to SD 2.0 in April. >>>> >>>> I do note eMMC4.4 vs MMC3.31 => perhaps these are two *different* >>>> IP blocks? >>>> >>>> Do your data sheets come with revision history? >>> >>> I don't have datasheet for this IP in my hand that's why I can't check it. >>> But I can't see any problem with it. Our zynq SoC supports SD2.0 and it >>> was requirement at that time. Bugs can happen. Arasan fixed it and >>> create new version. >>> At the same time can have 3.0 versions but vendor is just decide not to >>> use it for whatever reason. >>> >>> That's why timing of features and versions can upgrade any time and >>> unfortunately bugs happen. >> >> We have several Arasan data sheets here. The document names are: >> "SD2.0 / SDIO2.0 / MMC3.31 AHB Userguide" and the revisions are 9.2a, >> 4.4a and 5.4a. I have the feeling that the document revisions have >> been mistaken as the IP revision. I cannot find any other indicator >> for the IP revision though. Does the IP have a way to discover its >> revision? > > To summarize, it looks to me like > 4.9a and 8.9a are documentation revision numbers for this IP: > "SD2.0 / SDIO2.0 / MMC3.31 AHB Host Controller" > > and 5.1 seems to be the eMMC standard, so one of these IP: > http://arasan.com/products/emmc51/sd3-emmc-5-1-host/ > http://arasan.com/products/emmc51/emmc-5-1-sd-4-1-host/ > > Whereas my board is using still another IP: > "SD3.0 / SDIO3.0 / eMMC4.4 AHB Host Controller" > > > If that is correct, then I should be able to use the 8.9a > compatible string, and perhaps my hardware will work in > slightly degraded performance mode, from not using the > newest protocol gizmos available. Resurrecting this thread after a chat with Michal on IRC. The driver now supports a few more compatible strings. Tracing the history... Soren/Xilinx defined "arasan,sdhci-8.9a" in e3ec3a3d11ad They have the "SD2.0/SDIO2.0/MMC3.31 AHB Host Controller" version (8.9a might be a document revision number, dated 2010-04-02) Suman/APM added "arasan,sdhci-4.9a" in 308f3f8d8112 @Suman, @Rameshwar: what specific IP block does your SoC embed? What does 4.9a refer to? The documentation revision number? Shawn/Rockchip added "arasan,sdhci-5.1" in da795ec26e25 This seems to be for an *actual* eMMC 5.1 version (instead of a documentation version) as mentioned in the commit message. Douglas added "rockchip,rk3399-sdhci-5.1" and made several other improvements. I have reached out to Arasan support. Hopefully they can also help clear up the confusion, assuming they care about the Linux driver. Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
