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SubjectRe: [RFC PATCH V3 12/21] mmc: sdhci: UHS-II support, add hooks for additional operations
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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.

>
> -Takahiro Akashi
>
>
>>
>>> if (!dead)
>>> sdhci_do_reset(host, SDHCI_RESET_ALL);
>>>
>>>
>>

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