Re: [PATCH v1] usb: dwc2: reset AHB hclk domain before init

[Yunzhi Li]

Hi ,
å 2015/8/11 22:12, Felipe Balbi åé:
> Hi,
>
> On Tue, Aug 11, 2015 at 10:27:42AM +0800, Yunzhi Li wrote:
> > We initiate dwc2 usb controller in BIOS, when kernel driver
> > start-up we should reset AHB hclk domain to reset all AHB
> > interface registers to default. Without this the FIFO value
> > setting might be incorrect because calculating FIFO size need the
> > power-on value of GRXFSIZ/GNPTXFSIZ/HPTXFSIZ registers.
> >
> > This patch could avoid warnning massage like in rk3288 platform:
> > [    2.074764] dwc2 ff580000.usb: 256 invalid for
> > host_perio_tx_fifo_size. Check HW configuration.
> >
> > Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>
> >
> > ---
> >
> >   drivers/usb/dwc2/platform.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> > index 9093530..3da21ab 100644
> > --- a/drivers/usb/dwc2/platform.c
> > +++ b/drivers/usb/dwc2/platform.c
> > @@ -42,6 +42,7 @@
> >   #include <linux/of_device.h>
> >   #include <linux/mutex.h>
> >   #include <linux/platform_device.h>
> > +#include <linux/reset.h>
> >   
> >   #include <linux/usb/of.h>
> >   
> > @@ -165,6 +166,7 @@ static int dwc2_driver_probe(struct platform_device *dev)
> >   	struct resource *res;
> >   	struct phy *phy;
> >   	struct usb_phy *uphy;
> > +	struct reset_control *rst;
> >   	int retval;
> >   	int irq;
> >   
> > @@ -189,6 +191,16 @@ static int dwc2_driver_probe(struct platform_device *dev)
> >   
> >   	hsotg->dev = &dev->dev;
> >   
> > +	/* AHB hclk domain reset, set all AHB interface registers to default */
> > +	rst = devm_reset_control_get_optional(&dev->dev, "ahb_reset");
> why isn't this done in core so PCI systems can also make use of it ?
I have no ides about how to reset a PCI interface dwc2 controller, John 
could you please give some infomation about it ?
Is it also needed for PCI interface dwc2 IP ?

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