On Wed, Jul 22, 2015 at 5:29 PM, Felipe Balbi <balbi@xxxxxx> wrote: > On Wed, Jul 22, 2015 at 04:26:57PM -0500, Felipe Balbi wrote: >> On Wed, Jul 22, 2015 at 04:58:07PM -0400, Al Cooper wrote: >> > V2 - Fix a compiler bug that happend when the config options >> > CONFIG_USB_GADGET_DEBUG and CONFIG_USB_GADGET_VERBOSE >> > were enabled. >> > >> > ep_dequeue() in bdc_ep.c was capturing the hw dequeue pointer >> > incorrectly by reading the wrong register for the upper 32 bits. >> > The header file defining the registers was incorrect. >> >> btw, the header file was really "incorrect" as long as you passed 0 to >> the argument :-p > > in fact, the minimal fix for this bug would be the one below: > > diff --git a/drivers/usb/gadget/udc/bdc/bdc_ep.c b/drivers/usb/gadget/udc/bdc/bdc_ep.c > index b04980cf6dc4..1efa61265d8d 100644 > --- a/drivers/usb/gadget/udc/bdc/bdc_ep.c > +++ b/drivers/usb/gadget/udc/bdc/bdc_ep.c > @@ -779,7 +779,7 @@ static int ep_dequeue(struct bdc_ep *ep, struct bdc_req *req) > /* The current hw dequeue pointer */ > tmp_32 = bdc_readl(bdc->regs, BDC_EPSTS0(0)); > deq_ptr_64 = tmp_32; > - tmp_32 = bdc_readl(bdc->regs, BDC_EPSTS0(1)); > + tmp_32 = bdc_readl(bdc->regs, BDC_EPSTS1(0)); > deq_ptr_64 |= ((u64)tmp_32 << 32); > > /* we have the dma addr of next bd that will be fetched by hardware */ > > And $subject becomes a cleanup patch for v4.3. Can you make these > changes, please ? Yes, I can make these changes, but first let me explain why I did it this way. The 8 End Point Status registers are 32 bit consecutive registers, so defining them as: #define BDC_EPSTS0(n) (0x60 + (n * 0x10)) #define BDC_EPSTS1(n) (0x64 + (n * 0x10)) #define BDC_EPSTS2(n) (0x68 + (n * 0x10)) #define BDC_EPSTS3(n) (0x6c + (n * 0x10)) #define BDC_EPSTS4(n) (0x70 + (n * 0x10)) #define BDC_EPSTS5(n) (0x74 + (n * 0x10)) #define BDC_EPSTS6(n) (0x78 + (n * 0x10)) #define BDC_EPSTS7(n) (0x7c + (n * 0x10)) seems misleading, does not reflect the hardware and using anything other than (0) would get you to some other unexpected register and should be considered a coding error. I think the original hardware spec had each End Point Status as a block of registers but the first silicon had them as single registers and they are expected to stay that way. Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
