Hi Chrisさん > From: Chris Brandt, Sent: Thursday, May 9, 2019 3:08 AM > > Hi Shimodaさん > > > From: Yoshihiro Shimoda > > Sent: Tuesday, May 07, 2019 5:17 AM > > > For the most part, the RZ/A2 has the same USB 2.0 host and device > > > HW as the R-Car Gen3, so we can reuse a lot of the code. > > > > > > However, there are a couple extra register bits, and the CFIFO > > > register 8-bit access works a little different (weird, no idea why). > > > > This is just my gut feeling, but if we set the BIGEND bit in the CFIFOSEL > > of RZ/A2M (R-Car Gen3 doesn't have such a bit though), could the original > > code work correctly? > > I just tried to set CFIFOSEL.BIGEND = 1 Thank you for trying it! > * Set CFIFOSEL.BIGEND = 1 > * Write 8-bit values to CFIFO (same method as R-Car) > * Set CFIFOSEL.BIGEND = 0 > > The result is bad. I got it... > But, then I tried this: > * Set CFIFOSEL.MBW = 0 (CFIFO port access = 8-bit) > * Write 8-bit values to CFIFO > * Set CFIFOSEL.MBW = 2 (CFIFO port access = 32-bit) > > Code: > u16 cfifosel = usbhs_read(priv, fifo->sel); > > usbhs_write(priv, fifo->sel, cfifosel & 0xF3FF); // MBW = 8-bit > > for (i = 0; i < len; i++) > iowrite8(buf[i], addr); //same address each time > > usbhs_write(priv, fifo->sel, cfifosel); // MBW = 32-bit > > > This method works good. I got it. > (I assume this method would work with R-Car also) Unfortunately, R-Car cannot work with this method... But, "iowrite8(buf[i], addr + 3);" or "iowrite32(buf[i], addr);" works on the R-Car. And then, I realized that R-Car CFIFO register allows 32-bit access only... # So, I'm asking HW guy whether the 8-bit access can be allowed or not now... > But...then we have extra register reads and writes. > Register accesses are slower, so performance is lower. > > So, I prefer my original method: > if (usbhsc_flags_has(priv, USBHSF_CFIFO_BYTE_ADDR)) > for (i = 0; i < len; i++) > iowrite8(buf[i], addr + (i & 0x03)); > else > for (i = 0; i < len; i++) > iowrite8(buf[i], addr + (0x03 - (i & 0x03))); > > > Do you agree? I agree. However, I have some comments about the patch. So, I'll reply on the patch later. Best regards, Yoshihiro Shimoda > Chris
