Hi Adrian, > -----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. 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. ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
