[PATCH 1/4] usb: dwc2: Fix AHB burst type for bcm2835

[Stefan Wahren]

Hi John,

> John Youn <johnyoun at synopsys.com> 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