Hi, John Youn <[email protected]> writes: >> John Youn <[email protected]> writes: >>> On 4/28/2016 1:01 AM, Felipe Balbi wrote: >>>> NumP field of DCFG register is used on NumP field of >>>> ACK TP header and it tells the host how many packets >>>> an endpoint can receive before waiting for >>>> synchronization. >>>> >>>> Documentation says it should be set to anything >>>> <=bMaxBurst. Interestingly, however, this setting is >>>> not per-endpoint how it should be (different >>>> endpoints could have different burst sizes), but >>>> things seem to work okay right now. >>>> >>>> Signed-off-by: Felipe Balbi <[email protected]> >>>> --- >>>> drivers/usb/dwc3/core.h | 3 +++ >>>> drivers/usb/dwc3/gadget.c | 14 ++++++++++++-- >>>> 2 files changed, 15 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h >>>> index 87df6dd20d23..c5f576aa1903 100644 >>>> --- a/drivers/usb/dwc3/core.h >>>> +++ b/drivers/usb/dwc3/core.h >>>> @@ -271,6 +271,9 @@ >>>> #define DWC3_DCFG_LOWSPEED (2 << 0) >>>> #define DWC3_DCFG_FULLSPEED1 (3 << 0) >>>> >>>> +#define DWC3_DCFG_NUMP_SHIFT 17 >>>> +#define DWC3_DCFG_NUMP(n) (((n) & 0x1f) >> DWC3_DCFG_NUMP_SHIFT) >>>> +#define DWC3_DCFG_NUMP_MASK (0x1f << DWC3_DCFG_NUMP_SHIFT) >>>> #define DWC3_DCFG_LPM_CAP (1 << 22) >>>> >>>> /* Device Control Register */ >>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c >>>> index 43efb627d1cf..4b681b0d420f 100644 >>>> --- a/drivers/usb/dwc3/gadget.c >>>> +++ b/drivers/usb/dwc3/gadget.c >>>> @@ -464,9 +464,19 @@ static int dwc3_gadget_set_ep_config(struct dwc3 >>>> *dwc, struct dwc3_ep *dep, >>>> >>>> /* Burst size is only needed in SuperSpeed mode */ >>>> if (dwc->gadget.speed >= USB_SPEED_SUPER) { >>>> - u32 burst = dep->endpoint.maxburst - 1; >>>> + u32 burst = dep->endpoint.maxburst; >>>> + u32 nump; >>>> + u32 reg; >>>> >>>> - params.param0 |= DWC3_DEPCFG_BURST_SIZE(burst); >>>> + /* update NumP */ >>>> + reg = dwc3_readl(dwc->regs, DWC3_DCFG); >>>> + nump = DWC3_DCFG_NUMP(reg); >>>> + nump = max(nump, burst); >>>> + reg &= ~DWC3_DCFG_NUMP_MASK; >>>> + reg |= nump << DWC3_DCFG_NUMP_SHIFT; >>>> + dwc3_writel(dwc->regs, DWC3_DCFG, reg); >>>> + >>>> + params.param0 |= DWC3_DEPCFG_BURST_SIZE(burst - 1); >>> >>> Hi Felipe, >>> >>> The controller already takes care not to send a NUMP greater than the >>> configured maxburst for the endpoint. So there is no need to do >>> this. You can just set it globally in core init. >> >> iow, we just set this to the maximum value and forget about it ? That > > You can do that and it will always work, but it might not be optimal > for every system. You may want to tweak this value in that case, or > set it to calculate based on the rx fifo space.
How about setting it to rx_fifo_size / wMaxPacketSize ? and I guess rx_fifo_size can be computed with num_words * mdwidth, right? -- balbi
signature.asc
Description: PGP signature
