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    SubjectRe: [RFC PATCH V3 12/21] mmc: sdhci: UHS-II support, add hooks for additional operations
    On Thu, Sep 17, 2020 at 07:52:03AM +0300, Adrian Hunter wrote:
    > On 17/09/20 5:31 am, AKASHI Takahiro wrote:
    > > Adrian,
    > >
    > > On Wed, Sep 16, 2020 at 01:00:35PM +0300, Adrian Hunter wrote:
    > >> On 16/09/20 11:05 am, AKASHI Takahiro wrote:
    > >>> Adrian,
    > >>>
    > >>> Your comments are scattered over various functions, and so
    > >>> I would like to address them in separate replies.
    > >>>
    > >>> First, I'd like to discuss sdhci_[add|remove]_host().
    > >>>
    > >>> On Fri, Aug 21, 2020 at 05:08:32PM +0300, Adrian Hunter wrote:
    > >>>> On 10/07/20 2:10 pm, Ben Chuang wrote:
    > >>>>> From: Ben Chuang <ben.chuang@genesyslogic.com.tw>
    > >>>>>
    > >>>>> In this commit, UHS-II related operations will be called via a function
    > >>>>> pointer array, sdhci_uhs2_ops, in order to make UHS-II support as
    > >>>>> a kernel module.
    > >>>>> This array will be initialized only if CONFIG_MMC_SDHCI_UHS2 is enabled
    > >>>>> and when the UHS-II module is loaded. Otherwise, all the functions
    > >>>>> stay void.
    > >>>>>
    > >>>>> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
    > >>>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
    > >>>>> ---
    > >>>
    > >>> (snip)
    > >>>
    > >>>>> if (intmask & (SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE)) {
    > >>>>> u32 present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
    > >>>>> SDHCI_CARD_PRESENT;
    > >>>>> @@ -4717,6 +4812,14 @@ int sdhci_setup_host(struct sdhci_host *host)
    > >>>>> /* This may alter mmc->*_blk_* parameters */
    > >>>>> sdhci_allocate_bounce_buffer(host);
    > >>>>>
    > >>>>> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
    > >>>>> + host->version >= SDHCI_SPEC_400 &&
    > >>>>> + sdhci_uhs2_ops.add_host) {
    > >>>>> + ret = sdhci_uhs2_ops.add_host(host, host->caps1);
    > >>>>> + if (ret)
    > >>>>> + goto unreg;
    > >>>>> + }
    > >>>>> +
    > >>>>
    > >>>> I think you should look at creating uhs2_add_host() instead
    > >>>>
    > >>>>> return 0;
    > >>>>>
    > >>>>> unreg:
    > >>>>> @@ -4738,6 +4841,8 @@ void sdhci_cleanup_host(struct sdhci_host *host)
    > >>>>> {
    > >>>>> struct mmc_host *mmc = host->mmc;
    > >>>>>
    > >>>>> + /* FIXME: Do we have to do some cleanup for UHS2 here? */
    > >>>>> +
    > >>>>> if (!IS_ERR(mmc->supply.vqmmc))
    > >>>>> regulator_disable(mmc->supply.vqmmc);
    > >>>>>
    > >>>>> @@ -4766,6 +4871,14 @@ int __sdhci_add_host(struct sdhci_host *host)
    > >>>>> mmc->cqe_ops = NULL;
    > >>>>> }
    > >>>>>
    > >>>>> + if ((mmc->caps & MMC_CAP_UHS2) && !host->v4_mode) {
    > >>>>> + /* host doesn't want to enable UHS2 support */
    > >>>>> + mmc->caps &= ~MMC_CAP_UHS2;
    > >>>>> + mmc->flags &= ~MMC_UHS2_SUPPORT;
    > >>>>> +
    > >>>>> + /* FIXME: Do we have to do some cleanup here? */
    > >>>>> + }
    > >>>>> +
    > >>>>> host->complete_wq = alloc_workqueue("sdhci", flags, 0);
    > >>>>> if (!host->complete_wq)
    > >>>>> return -ENOMEM;
    > >>>>> @@ -4812,6 +4925,9 @@ int __sdhci_add_host(struct sdhci_host *host)
    > >>>>> unled:
    > >>>>> sdhci_led_unregister(host);
    > >>>>> unirq:
    > >>>>> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
    > >>>>> + sdhci_uhs2_ops.remove_host)
    > >>>>> + sdhci_uhs2_ops.remove_host(host, 0);
    > >>>>> sdhci_do_reset(host, SDHCI_RESET_ALL);
    > >>>>> sdhci_writel(host, 0, SDHCI_INT_ENABLE);
    > >>>>> sdhci_writel(host, 0, SDHCI_SIGNAL_ENABLE);
    > >>>>> @@ -4869,6 +4985,10 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
    > >>>>>
    > >>>>> sdhci_led_unregister(host);
    > >>>>>
    > >>>>> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
    > >>>>> + sdhci_uhs2_ops.remove_host)
    > >>>>> + sdhci_uhs2_ops.remove_host(host, dead);
    > >>>>> +
    > >>>>
    > >>>> I think you should look at creating uhs2_remove_host() instead
    > >>>
    > >>> You suggest that we will have separate sdhci_uhs2_[add|remove]_host(),
    > >>> but I don't think it's always convenient.
    > >>>
    > >>> UHS-II capable host will be set to call sdhci_uhs2_add_host() explicitly,
    > >>> but we can't do that in case of pci and pltfm based drivers as they utilize
    > >>> common helper functions, sdhci_pci_probe() and sdhci_pltfm_register(),
    > >>> respectively.
    > >>
    > >> sdhci-pci has an add_host op
    > >>
    > >> sdhci_pltfm_init can be used instead of sdhci_pltfm_register
    > >>
    > >>
    > >>> Therefore, we inevitably have to call sdhci_uhs2_add_host() there.
    > >>>
    > >>> If so, why should we distinguish sdhci_uhs2_add_host from sdhci_uhs_add_host?
    > >>> I don't see any good reason.
    > >>> Moreover, as a result, there exists a mixed usage of sdhci_ interfaces
    > >>> and sdhci_uhs2_ interfaces in sdhci-pci-core.c and sdhci-pltfm.c.
    > >>>
    > >>> It sounds odd to me.
    > >>
    > >> It is already done that way for cqhci.
    > >
    > > Okay, if it is your policy, I will follow that.
    > > Then, I'm going to add
    > > - remove_host field to struct sdhci_pci_fixes
    > > - a controller specific helper function to each driver (only pci-gli for now)
    > > even though it looks quite generic.
    >
    > If they seem generic then consider naming them
    > sdhci_pci_uhs2_[add|remove]_host and putting them in sdhci-pci-core.c

    So you don't mind that UHS-I and UHS-II code are mixed in sdhci-pci-core.c,
    do you?

    -Takahiro Akashi

    > >
    > > sdhci_gli_[add|remove]_host(struct sdhci_pci_slot *slot)
    > > {
    > > return sdhci_uhs2_[add|remove]_host(slot->host);
    > > }
    > >
    > > # Or do you want to create a file like sdhci-uhs2-pci.c for those functions?
    >
    > No
    >
    > >
    > > -Takahiro Akashi
    > >
    > >>>
    > >>> -Takahiro Akashi
    > >>>
    > >>>
    > >>>>
    > >>>>> if (!dead)
    > >>>>> sdhci_do_reset(host, SDHCI_RESET_ALL);
    > >>>>>
    > >>>>>
    > >>>>
    > >>
    >

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