On 23/02/18 09:29, Manish Narani wrote: > > >> -----Original Message----- >> From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] >> Sent: Thursday, February 22, 2018 1:50 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> >> Subject: Re: [RFC PATCH] mmc: sdhci-of-arasan: Add auto tuning support for >> ZynqMP Platform >> >> 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; >> > This will need the removal of 'const' from 'static const struct mmc_host_ops sdhci_ops = {}' in sdhci.c file. Please confirm. No, it is not const. You are not looking at the right place. i.e. $ grep mmc_host_ops drivers/mmc/host/sdhci.h struct mmc_host_ops mmc_host_ops; /* MMC host ops */ > > Thanks, > Manish >> >> 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 devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
