On 11/16/2016 1:25 AM, Stefan Wahren wrote: > Hi John, > >> John Youn <johnyoun@xxxxxxxxxxxx> hat am 16. November 2016 um 01:36 >> geschrieben: >> >> >> The ahbcfg param for bcm2835 is specifying a HBSTLEN of 0x8 (0x10 >> 1) >> which is not a valid value for that field. Remove the param and default >> to using INCR4. > > i don't have any Synopsys documentation about this IP core. But according to p. > 204 of the BCM2835 datasheet [1] the register USB_GAHBCFG is different than the > other implementations: > > Address 0x 7E98 0008 > The USB_GAHBCFG register has been adapted. Bits [4:1] which are marked in the > Synopsys documentation as "Burst Length/Type (HBstLen)" have been used > differently. > > [4] 1 = Wait for all outstanding AXI writes to complete before signalling > (internally) that > DMA is done. > 0 = don't wait. > [3] Not used > [2:1] Sets the maximum AXI burst length, but the bits are inverted, > 00 = maximum AXI burst length of 4, > 01 = maximum AXI burst length of 3, > 10 = maximum AXI burst length of 2 > 11 = maximum AXI burst length of 1 > > Did you already take care of that? > > [1] - > https://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > Ok, so that explains it. Thanks for reviewing. Since there is no checking on that value it should be fine to leave it. I'll revert this change and add a comment. If we ever get around to removing the ahbcfg parameter, we can add a special case for it. Regards, John -- 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
