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

[Marek Vasut <marek.vasut@gmail.com>]

Dne Ne 24. října 2010 05:26:38 zhangfei gao napsal(a):
> On Sun, Oct 24, 2010 at 1:50 AM, Marek Vasut <marek.vasut@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@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'.

I mean ... if setting the quirk was removed from the driver source, it'd have to 
be removed from user code that uses the driver as well -- in case user also set 
such a quirk in pdata->quirks. So it might be a good idea to warn user that he's 
setting something that's getting set elsewhere (in the driver) anyway.

> 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