linux-kernel - Re: [PATCH v2 3/4] usb: ehci: Add new EHCI driver for Broadcom STB SoC's

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Message-ID: <CAOGqxeVkgPttD7kqANAtp1uD=aFuSqV_2sWT4ybG3m0c_2SSjA@mail.gmail.com>
Date:   Mon, 6 Apr 2020 14:46:26 -0400
From:   Alan Cooper <alcooperx@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     ": Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        BCM Kernel Feedback <bcm-kernel-feedback-list@...adcom.com>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        DTML <devicetree@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jonathan Neuschäfer <j.neuschaefer@....net>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        USB list <linux-usb@...r.kernel.org>,
        Mark Rutland <mark.rutland@....com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH v2 3/4] usb: ehci: Add new EHCI driver for Broadcom STB SoC's

On Sat, Mar 28, 2020 at 4:18 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Fri, Mar 27, 2020 at 04:47:10PM -0400, Al Cooper wrote:
> > Add a new EHCI driver for Broadcom STB SoC's. A new EHCI driver
> > was created instead of adding support to the existing ehci platform
> > driver because of the code required to workaround bugs in the EHCI
> > controller.
>
> I'm not sure this has been tested. See below.
>
> ...
>
> > +#include <linux/acpi.h>
> > +#include <linux/of.h>
>
> I didn;t find evidence these are needed.

I removed them.

>
> ...
>
>
> > +     res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,
> > +                                      (val != frame_idx), 1, 130);
>
> Too many parentheses.
>

Fixed

> > +     if (res)
> > +             dev_err(ehci_to_hcd(ehci)->self.controller,
> > +                     "Error waiting for SOF\n");
>
> ...
>
> > +static int ehci_brcm_probe(struct platform_device *pdev)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct resource *res_mem;
> > +     struct brcm_priv *priv;
> > +     struct usb_hcd *hcd;
> > +     int irq;
> > +     int err;
> > +
> > +     if (usb_disabled())
> > +             return -ENODEV;
> > +
> > +     err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> > +     if (err)
> > +             return err;
> > +
>
> > +     irq = platform_get_irq(pdev, 0);
> > +             return irq;
>
> I'm not sure it was an intention to leave a lot of dead code below.
>

Fixed.

> > +     /* Hook the hub control routine to work around a bug */
>
> > +     if (org_hub_control == NULL)
>
>         if (!org_hub_control) ?
>

Changed.

> > +             org_hub_control = ehci_brcm_hc_driver.hub_control;
> > +     ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;
>
> > +     device_wakeup_enable(hcd->self.controller);
> > +     device_enable_async_suspend(hcd->self.controller);
> > +     platform_set_drvdata(pdev, hcd);
> > +
>
> > +     return err;
>
>         return 0; ?
>
Changed.


> > +err_clk:
> > +     clk_disable_unprepare(priv->clk);
> > +err_hcd:
> > +     usb_put_hcd(hcd);
> > +
> > +     return err;
> > +}
>
> ...
>
> > +#ifdef CONFIG_PM_SLEEP
>
> You also can use __maybe_unused annotations.
>

Changed.

> > +static int ehci_brcm_suspend(struct device *dev)
> > +{
> > +     int ret;
> > +     struct usb_hcd *hcd = dev_get_drvdata(dev);
> > +     struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
> > +     bool do_wakeup = device_may_wakeup(dev);
> > +
>
> > +     ret = ehci_suspend(hcd, do_wakeup);
> > +     clk_disable_unprepare(priv->clk);
> > +     return ret;
>
> So, if you fail to suspend the device, clocks will become unusable, how to recover from such case?
>

Changed to handle the failure.

> > +}
>
> > +#endif /* CONFIG_PM_SLEEP */
>
> ...
>
> > +MODULE_DESCRIPTION(BRCM_DRIVER_DESC);
>
> Better to have it explicit.
>

Changed.

> --
> With Best Regards,
> Andy Shevchenko
>
>

v3 coming.
Thanks again for the review
Al