I have resolved the problem by enabling the USB clocks: Write "2" to register "CM_PER_USB0_CLKCTRL" (address 0x44e0001c). Kind regards, Rolf > Rolf Evers-Fischer <embedded24@xxxxxxxxxxxxxxxx> hat am 24. April 2014 um > 10:52 geschrieben: > > > > Hi Sascha, > > > Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> hat am 24. April 2014 um 08:58 > > geschrieben: > > > > > > Hi Rolf, > > > > On Wed, Apr 23, 2014 at 06:09:40PM +0200, Rolf Evers-Fischer wrote: > > > I'm just trying to port the USB driver "musb" (for the AM335x platform) > > > from > > > linux kernel to barebox. > > > But whenever I want to read any address in the range > > > 0x47401400-0x474017ff, > > > the > > > barebox crashes with "unable to handle paging request". > > > I have already tried to invoke a "map_io_sections(0x0, 0x47400000, > > > 0x2000)", > > > but > > > it didn't help. > > > > barebox creates a flat 1:1 mapping when the MMU is enabled. You won't > > need any calls to map_io_sections or some ioremap correspondent > > function. > > > > Thank you. That's good to know. > > > It may be that you have to enable some bus clocks in order to access the > > musb. > > > > Maybe. I found this in TI's "Technical Reference Manual": > "Prior to configuring the USB Module Registers, the USB SubSystem and PHY are > required to be released > from reset, enable interconnects and controllers clocks as well as configure > the > USB PHY with appropriate > setting." > > Quite a lot of work, but I'll definitely have to check it. > > > To make sure you don't have MMU trouble could you post the output of > > 'mmuinfo 0x47400000'? > > > > PAR result for 0x47400000: > privileged read: 0x47400290 > Physical Address [31:12]: 0x47400000 > Reserved [11]: 0x0 > Not Outer Shareable [10]: 0x0 > Non-Secure [9]: 0x1 > Impl. def. [8]: 0x0 > Shareable [7]: 0x1 > Inner mem. attr. [6:4]: 0x1 (0b001 Strongly-ordered) > Outer mem. attr. [3:2]: 0x0 (0b00 Non-cacheable) > SuperSection [1]: 0x0 > Failure [0]: 0x0 > privileged write: 0x47400290 > Physical Address [31:12]: 0x47400000 > Reserved [11]: 0x0 > Not Outer Shareable [10]: 0x0 > Non-Secure [9]: 0x1 > Impl. def. [8]: 0x0 > Shareable [7]: 0x1 > Inner mem. attr. [6:4]: 0x1 (0b001 Strongly-ordered) > Outer mem. attr. [3:2]: 0x0 (0b00 Non-cacheable) > SuperSection [1]: 0x0 > Failure [0]: 0x0 > > > Best regards, > Rolf _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
