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Segmentation Fault

Enrique Contreras1
Prodigy 140 points
Other Parts Discussed in Thread: AM1707

Hi,

I have adapted y used the source code of "sw_am17x" (See the Post in http://e2e.ti.com/support/embedded/starterware/f/790/p/151682/569258.aspx#569258)  to control the HCUSB 1.1 Interrupts. I can compile my aplication with no errors, but when I run it, a "Segmentation Fault" message is printed  in the console. I have debugged it using gdb, and this fault occurs in the next call to HWREG macro:

HWREG(SOC_AINTC_0_REGS + AINTC_ECR(cnt)) = AINTC_ECR_DISABLE;

The application runs over a Linux 3.3 embedded in a OMAP L 137, which ARM core is identical to the AM1707 and the register addesses are the same.

My questions are, can not I use that macro from user space? Must I use a module for accessing to registers?

How could I solve this problem? Any idea?

  • 0
    TI__Guru** 116100 points

    Hi,

    If you want to access the register then you have to use kernel module driver for that task.

    We have to do "ioremap" to that MMR register before access.

    Ex:

    unsigned int *usb_reg;

    usb_reg = ioremap(AINTC_BASE+OFFSET,size);

  • 0
    Guru 26430 points

    Not sure if I can help. I am curious why you don't use the OHCI driver in linux. Porting bare metal StarterWare code to linux seems like a lot of needless work.

  • 0 in reply to Norman Wong
    Prodigy 140 points

    I already use the OHCI driver in Linux. The problem is this driver doesn't manage the USB Interrupts, I mean, it seems only manages data transfers. In the "menuconfig", you only can enable/disable the OHCI driver, but there isn't any option to enable/disable the Interrupts management.

    On the other hand, the OHCI driver neither provides any API to manage the USB Interrupts from user space. So it seems necessary to implement a module (.ko) which accesses to the necessary registers and some API which allows us configuring, enabling and managing the USB Host interrupts from user space  

  • 0 in reply to Enrique Contreras1
    TI__Guru** 116100 points

    Hi Enrique,

    I'm curious about your USB interrupt programming in user space and one more thing that it was worked earlier kernel right ?

    If you enabled OHCI support for USB1.1 then that driver would take care of everything including interrupt stuff.

    I have adapted y used the source code of "sw_am17x" (See the Post in http://e2e.ti.com/support/embedded/starterware/f/790/p/151682/569258.aspx#569258)

    Actually the attached code in that project is, bare-metal code ie it is non-OS code which is called as Starterware.

    What is your intention from user space, doing USB stuff ?

  • 0 in reply to Enrique Contreras1
    Guru 26430 points

    Please clarify what you mean by interrupt management. Please give an example usage.