On 21/02/18 17:00, Manish Narani wrote: > Hi Adrian, > >> -----Original Message----- >> From: Manish Narani >> Sent: Wednesday, February 21, 2018 11:39 AM >> To: Adrian Hunter <adrian.hunter@xxxxxxxxx>; michal.simek@xxxxxxxxxx; >> ulf.hansson@xxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- >> mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >> devicetree@xxxxxxxxxxxxxxx; mark.rutland@xxxxxxx; robh+dt@xxxxxxxxxx >> Cc: Anirudha Sarangi <anirudh@xxxxxxxxxx>; Srinivas Goud >> <sgoud@xxxxxxxxxx> >> Subject: RE: [RFC PATCH] mmc: sdhci-of-arasan: Add auto tuning support for >> ZynqMP Platform >> >> Hi Adrian, >> >> >>> -----Original Message----- >>> From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] >>> Sent: Friday, February 16, 2018 7:37 PM >>> To: Manish Narani <MNARANI@xxxxxxxxxx>; michal.simek@xxxxxxxxxx; >>> ulf.hansson@xxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- >>> mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >>> devicetree@xxxxxxxxxxxxxxx; mark.rutland@xxxxxxx; robh+dt@xxxxxxxxxx >>> Cc: Anirudha Sarangi <anirudh@xxxxxxxxxx>; Srinivas Goud >>> <sgoud@xxxxxxxxxx>; Manish Narani <MNARANI@xxxxxxxxxx> >>> Subject: Re: [RFC PATCH] mmc: sdhci-of-arasan: Add auto tuning support >>> for ZynqMP Platform >>> >>> On 30/01/18 20:14, Manish Narani wrote: >>>> This patch adds support of SD auto tuning for ZynqMP platform. Auto >>>> tuning sequence sends tuning block to card when operating in UHS-1 >>>> modes. This resets the DLL and sends CMD19/CMD21 as a part of the >>>> auto tuning process. Once the auto tuning process gets completed, >>>> reset the DLL to load the newly obtained SDHC tuned tap value. >>> >>> How is this different from: >>> 1. reset the dll >>> 2. call sdhci_execute_tuning >>> 3. reset the dll >>> > Below is my take on your above comments: > - 'Reset the dll' is a platform specific call inside 'arasan_zynqmp_execute_tuning' which is implemented in sdhci-of-arasan.c > - 'arasan_zynqmp_execute_tuning' is called from 'sdhci_execute_tuning' as a platform_execute_tuning routine > - So to keep 'DLL reset' routine called from sdhci-of-arasan.c, I have implemented the execute_tuning in sdhci-of-arasan.c I meant something like: if (of_device_is_compatible(pdev->dev.of_node, "xlnx,zynqmp-8.9a")) host->mmc_host_ops.execute_tuning = arasan_zynqmp_execute_tuning; static int arasan_zynqmp_execute_tuning(struct mmc_host *mmc, u32 opcode) { struct sdhci_host *host = mmc_priv(mmc); struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host); int err; arasan_zynqmp_dll_reset(host, sdhci_arasan->device_id); err = sdhci_execute_tuning(mmc, opcode); if (err) return err; arasan_zynqmp_dll_reset(host, sdhci_arasan->device_id); return 0; } > > Alternative way (Please review): > - Define a host->quirk2 bit (SDHCI_QUIRK2_DLL_RESET_NEEDED) in sdhci-of-arasan.c indicating DLL reset needed while tuning operation > - Call 'dll reset' routine before and after __sdhci_execute_tuning() in sdhci.c when a host->quirk2 bit (SDHCI_QUIRK2_DLL_RESET_NEEDED) is set We should try to avoid quirks. -- 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
