On Thu, Aug 13, 2015 at 08:37:36AM +0000, John Youn wrote: > On 8/12/2015 12:33 PM, Felipe Balbi wrote: > > On Wed, Aug 12, 2015 at 07:06:09PM +0800, Yunzhi Li wrote: > >> Hi , > >> 在 2015/8/11 22:12, Felipe Balbi 写道: > >>> 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 ? > > > > even on platform only, how do you know all users provide a ahb_reset > > reset controller ? > > > > Also where do you provide the ahb_reset? I don't see it as a > property for dwc2. > > With regards to PCI, I'm also not sure how you'd accomplish > something like this. But the platform I use at least doesn't need > this. Is the reset controller optional ? That _optional should always return a valid pointer, right ? Even if that valid pointer is NULL :-) -- balbi
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