by Felipe Balbi

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Subject: Re: [RFC 2/2] usb: dwc3: Add Qualcomm DWC3 glue layer driver

Hi,

On Tue, Aug 06, 2013 at 02:53:11PM +0300, Ivan T. Ivanov wrote:
> diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
> new file mode 100644
> index 0000000..e509abc
> --- /dev/null
> +++ b/drivers/usb/dwc3/dwc3-msm.c
> @@ -0,0 +1,175 @@
> +#undef CONFIG_REGULATOR

why ??????

> +static int dwc3_msm_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct dwc3_msm *mdwc;
> + struct resource *res;
> + void __iomem *tcsr;
> + int ret = 0;
> +
> + dev_info(&pdev->dev, "MSM DWC3\n");

please don't. This is hardly necessary.

> + mdwc = devm_kzalloc(&pdev->dev, sizeof(*mdwc), GFP_KERNEL);
> + if (!mdwc) {
> + dev_err(&pdev->dev, "not enough memory\n");

this message isn't needed either

> + /*
> + * DWC3 Core requires its CORE CLK (aka master / bus clk) to
> + * run at 125Mhz in SSUSB mode and >60MHZ for HSUSB mode.
> + */
> + clk_set_rate(mdwc->core_clk, 125000000);

if this is dwc3's core clock, why don't we teach dwc3.ko about this
requirement ? Just make sure to have it optional, since x86 and OMAP
wouldn't need direct fiddling with the clocks.

> + clk_prepare_enable(mdwc->core_clk);
> + clk_prepare_enable(mdwc->iface_clk);
> + clk_prepare_enable(mdwc->sleep_clk);
> + clk_prepare_enable(mdwc->utmi_clk);

do you really need to enable your clocks here ? Why don't you enable
them on runtime_resume and disable on runtime_suspend ?

> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + tcsr = devm_ioremap_resource(&pdev->dev, res);
> + if (!tcsr) {
> + dev_dbg(&pdev->dev, "tcsr ioremap failed\n");

no need to ioremap, also you're likely leaking clocks and regulators
enabled here.

Make sure to have something like:

if (!tcsr)
goto err_disable_clocks;

/* TODO This has to be revised */\

[...]

> + } else {
> + /* TODO: This has to be revised */
> +
> + /* Enable USB3 on the primary USB port. */
> + writel_relaxed(0x1, tcsr);
> + /*
> + * Ensure that TCSR write is completed before
> + * USB registers initialization.
> + */
> + mb();

why don't you use writel() instead. It will add the memory barrier for
you.

--
balbi

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2013-08-09 13:25:22

On Fri, Aug 09, 2013 at 07:09:18PM +0300, Ivan T. Ivanov wrote:
> Hi,
>
> On Fri, 2013-08-09 at 16:23 +0300, Felipe Balbi wrote:
> > Hi,
> >
> > On Tue, Aug 06, 2013 at 02:53:11PM +0300, Ivan T. Ivanov wrote:
> > > diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
> > > new file mode 100644
> > > index 0000000..e509abc
> > > --- /dev/null
> > > +++ b/drivers/usb/dwc3/dwc3-msm.c
> > > @@ -0,0 +1,175 @@
> > > +#undef CONFIG_REGULATOR
> >
> > why ??????
> >
>
> 1. This shows that driver is still not fully tested
> Regulators support is still missing in the MSM
> 2. Helps me to load driver successfully.

Then remove all the regulator-related code from this.

> > > + clk_prepare_enable(mdwc->core_clk);
> > > + clk_prepare_enable(mdwc->iface_clk);
> > > + clk_prepare_enable(mdwc->sleep_clk);
> > > + clk_prepare_enable(mdwc->utmi_clk);
> >
> > do you really need to enable your clocks here ? Why don't you enable
> > them on runtime_resume and disable on runtime_suspend ?
>
> I will like to make it working first and then will improve
> power management.

alright, makes sense.

> > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > + tcsr = devm_ioremap_resource(&pdev->dev, res);
> > > + if (!tcsr) {
> > > + dev_dbg(&pdev->dev, "tcsr ioremap failed\n");
> >
> > no need to ioremap, also you're likely leaking clocks and regulators
> > enabled here.
> >
> > Make sure to have something like:
> >
> > if (!tcsr)
> > goto err_disable_clocks;
> >
> > /* TODO This has to be revised */\
> >
> > [...]
> >
>
> Sure.

just to make it clear, I meant to say that you don't need to print the
error message :-)

--
balbi

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2013-08-14 09:29:40

by Ivan T. Ivanov

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Subject: Re: [RFC 2/2] usb: dwc3: Add Qualcomm DWC3 glue layer driver

Hi,

On Mon, 2013-08-12 at 13:24 -0500, Felipe Balbi wrote:
> On Fri, Aug 09, 2013 at 07:09:18PM +0300, Ivan T. Ivanov wrote:
> > Hi,
> >
> > On Fri, 2013-08-09 at 16:23 +0300, Felipe Balbi wrote:
> > > Hi,
> > >
> > > On Tue, Aug 06, 2013 at 02:53:11PM +0300, Ivan T. Ivanov wrote:
> > > > diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
> > > > new file mode 100644
> > > > index 0000000..e509abc
> > > > --- /dev/null
> > > > +++ b/drivers/usb/dwc3/dwc3-msm.c
> > > > @@ -0,0 +1,175 @@
> > > > +#undef CONFIG_REGULATOR
> > >
> > > why ??????
> > >
> >
> > 1. This shows that driver is still not fully tested
> > Regulators support is still missing in the MSM
> > 2. Helps me to load driver successfully.
>
> Then remove all the regulator-related code from this.

I would like to keep them. I will just remove #undef line.
Code will continue to build fine. And once regulators drivers
are upstreamed this driver 'will not' require further
modifications.

>
> > > > + clk_prepare_enable(mdwc->core_clk);
> > > > + clk_prepare_enable(mdwc->iface_clk);
> > > > + clk_prepare_enable(mdwc->sleep_clk);
> > > > + clk_prepare_enable(mdwc->utmi_clk);
> > >
> > > do you really need to enable your clocks here ? Why don't you enable
> > > them on runtime_resume and disable on runtime_suspend ?
> >
> > I will like to make it working first and then will improve
> > power management.
>
> alright, makes sense.
>
> > > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > > + tcsr = devm_ioremap_resource(&pdev->dev, res);
> > > > + if (!tcsr) {
> > > > + dev_dbg(&pdev->dev, "tcsr ioremap failed\n");
> > >
> > > no need to ioremap, also you're likely leaking clocks and regulators
> > > enabled here.
> > >
> > > Make sure to have something like:
> > >
> > > if (!tcsr)
> > > goto err_disable_clocks;
> > >
> > > /* TODO This has to be revised */\
> > >
> > > [...]
> > >
> >
> > Sure.
>
> just to make it clear, I meant to say that you don't need to print the
> error message :-)

Yes. I got it.

Regards,
Ivan

2013-08-14 09:44:45

by Ivan T. Ivanov

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Subject: Re: [RFC 2/2] usb: dwc3: Add Qualcomm DWC3 glue layer driver

Hi,

On Fri, 2013-08-09 at 16:23 +0300, Felipe Balbi wrote:

<snip>

>
> > + /*
> > + * DWC3 Core requires its CORE CLK (aka master / bus clk) to
> > + * run at 125Mhz in SSUSB mode and >60MHZ for HSUSB mode.
> > + */
> > + clk_set_rate(mdwc->core_clk, 125000000);
>
> if this is dwc3's core clock, why don't we teach dwc3.ko about this
> requirement ? Just make sure to have it optional, since x86 and OMAP
> wouldn't need direct fiddling with the clocks.

I believe this is Qualcomm specific requirement. Something is modified
inside DWC in respect of the clocks. I will like to keep this here, in
the glue layer driver.

Regards,
Ivan

2013-08-27 18:47:42

by Felipe Balbi

[permalink] [raw]

Subject: Re: [RFC 2/2] usb: dwc3: Add Qualcomm DWC3 glue layer driver

On Wed, Aug 14, 2013 at 12:28:17PM +0300, Ivan T. Ivanov wrote:
>
> Hi,
>
> On Mon, 2013-08-12 at 13:24 -0500, Felipe Balbi wrote:
> > On Fri, Aug 09, 2013 at 07:09:18PM +0300, Ivan T. Ivanov wrote:
> > > Hi,
> > >
> > > On Fri, 2013-08-09 at 16:23 +0300, Felipe Balbi wrote:
> > > > Hi,
> > > >
> > > > On Tue, Aug 06, 2013 at 02:53:11PM +0300, Ivan T. Ivanov wrote:
> > > > > diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
> > > > > new file mode 100644
> > > > > index 0000000..e509abc
> > > > > --- /dev/null
> > > > > +++ b/drivers/usb/dwc3/dwc3-msm.c
> > > > > @@ -0,0 +1,175 @@
> > > > > +#undef CONFIG_REGULATOR
> > > >
> > > > why ??????
> > > >
> > >
> > > 1. This shows that driver is still not fully tested
> > > Regulators support is still missing in the MSM
> > > 2. Helps me to load driver successfully.
> >
> > Then remove all the regulator-related code from this.
>
> I would like to keep them. I will just remove #undef line.
> Code will continue to build fine. And once regulators drivers
> are upstreamed this driver 'will not' require further
> modifications.

fair enough.

--
balbi

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