Hi,
John Youn <John.Youn@xxxxxxxxxxxx> writes:
>> @@ -1589,6 +1578,46 @@ static void dwc3_gadget_disable_irq(struct dwc3 *dwc)
>> static irqreturn_t dwc3_interrupt(int irq, void *_dwc);
>> static irqreturn_t dwc3_thread_interrupt(int irq, void *_dwc);
>>
>> +/**
>> + * dwc3_gadget_setup_nump - Calculate and initialize NUMP field of DCFG
>> + * dwc: pointer to our context structure
>> + *
>> + * The following looks like complex but it's actually very simple. In order to
>> + * calculate the number of packets we can burst at once on OUT transfers, we're
>> + * gonna use RxFIFO size.
>> + *
>> + * To calculate RxFIFO size we need two numbers:
>> + * MDWIDTH = size, in bits, of the internal memory bus
>> + * RAM2_DEPTH = depth, in MDWIDTH, of internal RAM2 (where RxFIFO sits)
>> + *
>> + * Given these two numbers, the formula is simple:
>> + *
>> + * RxFIFO Size = (RAM2_DEPTH * MDWIDTH / 8) - 24 - 16;
>> + *
>> + * 24 bytes is for 3x SETUP packets
>> + * 16 bytes is a clock domain crossing tolerance
>> + *
>> + * Given RxFIFO Size, NUMP = RxFIFOSize / 1024;
>> + */
>> +static void dwc3_gadget_setup_nump(struct dwc3 *dwc)
>> +{
>> + u32 ram2_depth;
>> + u32 mdwidth;
>> + u32 nump;
>> + u32 reg;
>> +
>> + ram2_depth = DWC3_GHWPARAMS7_RAM2_DEPTH(dwc->hwparams.hwparams7);
>> + mdwidth = DWC3_GHWPARAMS0_MDWIDTH(dwc->hwparams.hwparams0);
>> +
>> + nump = ((ram2_depth * mdwidth / 8) - 24 - 16) / 1024;
>
> This value should be capped to 16.
I'll add a min() here.
--
balbi
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