[PATCH V3 1/1]MMC: add support of sdhci-pxa driver

[zhangfei gao]

On Sun, Oct 24, 2010 at 1:50 AM, Marek Vasut <marek.vasut at gmail.com> wrote:
> Dne So 23. října 2010 18:47:10 zhangfei gao napsal(a):
>> On Sat, Oct 23, 2010 at 10:24 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
>> >> +/**********************************************************************
>> >> *** ****\ + *
>> >>         * + * Device probing/removal
>> >>              * + *
>> >>                   *
>> >> +\**********************************************************************
>> >> ** *****/ +
>> >> +static int __devinit sdhci_pxa_probe(struct platform_device *pdev)
>> >> +{
>> >> +     struct sdhci_pxa_platdata *pdata = pdev->dev.platform_data;
>> >> +     struct device *dev = &pdev->dev;
>> >> +     struct sdhci_host *host = NULL;
>> >> +     struct resource *iomem = NULL;
>> >> +     struct sdhci_pxa *pxa = NULL;
>> >> +     int ret, irq;
>> >> +
>> >> +     irq = platform_get_irq(pdev, 0);
>> >> +     if (irq < 0) {
>> >> +             dev_err(dev, "no irq specified\n");
>> >> +             return irq;
>> >> +     }
>> >> +
>> >> +     iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> >> +     if (!iomem) {
>> >> +             dev_err(dev, "no memory specified\n");
>> >> +             return -ENOENT;
>> >> +     }
>> >> +
>> >> +     host = sdhci_alloc_host(&pdev->dev, sizeof(struct sdhci_pxa));
>> >> +     if (IS_ERR(host)) {
>> >> +             dev_err(dev, "failed to alloc host\n");
>> >> +             return PTR_ERR(host);
>> >> +     }
>> >> +
>> >> +     pxa = sdhci_priv(host);
>> >> +     pxa->host = host;
>> >> +     pxa->pdata = pdata;
>> >> +     pxa->clk_enable = 0;
>> >> +
>> >> +     pxa->clk = clk_get(dev, "PXA-SDHCLK");
>> >> +     if (IS_ERR(pxa->clk)) {
>> >> +             dev_err(dev, "failed to get io clock\n");
>> >> +             ret = PTR_ERR(pxa->clk);
>> >> +             goto out;
>> >> +     }
>> >> +
>> >> +     pxa->res = request_mem_region(iomem->start, resource_size(iomem),
>> >> +             mmc_hostname(host->mmc));
>> >> +     if (!pxa->res) {
>> >> +             dev_err(&pdev->dev, "cannot request region\n");
>> >> +             ret = -EBUSY;
>> >> +             goto out;
>> >> +     }
>> >> +
>> >> +     host->ioaddr = ioremap(iomem->start, resource_size(iomem));
>> >> +     if (!host->ioaddr) {
>> >> +             dev_err(&pdev->dev, "failed to remap registers\n");
>> >> +             ret = -ENOMEM;
>> >> +             goto out;
>> >> +     }
>> >> +
>> >> +     host->hw_name = "MMC";
>> >> +     host->ops = &sdhci_pxa_ops;
>> >> +     host->irq = irq;
>> >> +     host->quirks = SDHCI_QUIRK_BROKEN_ADMA |
>> >> SDHCI_QUIRK_BROKEN_TIMEOUT_VAL; +
>> >
>> > Maybe check if these aren't already set in pdata and warn user ?
>>
>> Here pdata->quirks only provide specific quirk like
>> SDHCI_QUIRK_BROKEN_CARD_DETECTION for on-chip device, the common quirk
>> is provided above.
>
> Right, but what if the user also provides such a quirk? It's unnecessary ... and
> in case the quirk was removed from here later, it'd have to be removed from
> user's code too ...

What do you mean 'in case the quirk was removed from here later'.
SDHCI_QUIRK_* is just move from drivers/mmc/host/sdhci.h to
include/linux/mmc/sdhci.h, so code in arch/arm could access them
directly.

We also consider use one flag here, like sdhci-s3c.c.
Code like this,
if (pdata->flags & PXA_FLAG_CARD_PERMENT)
     host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;

If SDHCI_QUIRK_* not permitted to access, it would be better to use this method.

>
>> In sdhci-s3c, host->quirks is modified here via pdata->cd_type, which
>> is also a good method.
>> Here we transfer SDHCI_QUIRK_BROKEN_CARD_DETECTION directly from pdata
>> since it already move to include folder.
>>
>> >> +     if (pdata->quirks)
>> >> +             host->quirks |= pdata->quirks;
>> >> +
>> >> +     ret = sdhci_add_host(host);
>> >> +     if (ret) {
>> >> +             dev_err(&pdev->dev, "failed to add host\n");
>> >> +             goto out;
>> >> +     }
>> >> +
>> >> +     if (pxa->pdata->max_speed)
>> >> +             host->mmc->f_max = pxa->pdata->max_speed;
>> >
>> > What happens otherwise ?
>>
>> Otherwise, host->mmc->f_max = host->max_clk set in sdhci_add_host,
>> host->max_clk is 50M in 2.0 controller, and 200M in 3.0 controller, if
>> controller does not need to provide get_max_clock.
>> it's better add defalut value in else condition.
>
> Thanks for clearing this
>>
>> Thanks Marek for review.
>>
>> >> +
>> >> +     platform_set_drvdata(pdev, host);
>> >> +
>> >> +     return 0;
>> >> +out:
>> >> +     if (host) {
>> >> +             clk_put(pxa->clk);
>> >> +             if (host->ioaddr)
>> >> +                     iounmap(host->ioaddr);
>> >> +             if (pxa->res)
>> >> +                     release_mem_region(pxa->res->start,
>> >> +                                     resource_size(pxa->res));
>> >> +             sdhci_free_host(host);
>> >> +     }
>> >> +
>> >> +     return ret;
>> >> +}
>> >> +
>> >
>> > Thanks!
>> >
>> > Cheers
>