New driver crashes with "unable to handle paging request"

[Rolf Evers-Fischer]

Hi Sascha,

> Sascha Hauer <s.hauer at pengutronix.de> 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