CODEWITHSUNDEEP
linuxdebianbeagleboneblack
RobertAalto
RobertAalto

Reputation: 1305

Beaglebone black - Debian 4.1 - PRU - prussdrv_open() failed with -1

I am running the example as root http://mythopoeic.org/BBB-PRU/pru-helloworld/example.c and I receive the Error: 

"prussdrv_open() failed with -1" during the execution

BBB has Debian 4.1

These are the commands used:

sudo cp EBB-PRU-Example‐00A0.dtbo /lib/firmware
echo EBB-PRU-Example > /sys/devices/platform/bone_capemgr/slots
cat /sys/devices/platform/bone_capemgr/slots
 0: PF----  -1
 1: PF----  -1
 2: PF----  -1
 3: PF----  -1
 4: P-O-L-   0 Override Board Name,00A0,Override Manuf,EBB-PRU-Example
modprobe uio_pruss
dmesg
[  195.985512] bone_capemgr bone_capemgr: part_number 'EBB-PRU-Example', version 'N/A'
[  195.994182] bone_capemgr bone_capemgr: slot #4: override
[  195.999703] bone_capemgr bone_capemgr: Using override eeprom data at slot 4
[  196.006752] bone_capemgr bone_capemgr: slot #4: 'Override Board Name,00A0,Override Manuf,EBB-PRU-Example'
[  196.039095] pruss_uio 4a300000.pruss: No children
[  196.057144] gpio-of-helper ocp:gpio_helper: ready
[  196.070956] bone_capemgr bone_capemgr: slot #4: dtbo 'EBB-PRU-Example-00A0.dtbo' loaded; overlay id #0

and /boot/uEnv.txt has disabled the HDMI

EBB-PRU-Example.dts

/* Device Tree Overlay for enabling the pins that are used in Chapter 13
* This overlay is based on the BB-PRU-01 overlay
* Written by Derek Molloy for the book "Exploring BeagleBone: Tools and 
* Techniques for Building with Embedded Linux" by John Wiley & Sons, 2014
* ISBN 9781118935125. Please see the file README.md in the repository root 
* directory for copyright and GNU GPLv3 license information.
*/
/dts-v1/;
/plugin/;

/ {
   compatible = "ti,beaglebone", "ti,beaglebone-black";

   part-number = "EBB-PRU-Example";
   version = "00A0";

   /* This overlay uses the following resources */
   exclusive-use =
         "P9.11", "P9.13", "P9.27", "P9.28", "pru0";

   fragment@0 {
      target = <&am33xx_pinmux>;
      __overlay__ {

         gpio_pins: pinmux_gpio_pins {         // The GPIO pins
            pinctrl-single,pins = <
               0x070 0x07  // P9_11 MODE7 | OUTPUT | GPIO pull-down
               0x074 0x27  // P9_13 MODE7 | INPUT | GPIO pull-down
            >;
         };

         pru_pru_pins: pinmux_pru_pru_pins {   // The PRU pin modes
            pinctrl-single,pins = <
               0x1a4 0x05  // P9_27 pr1_pru0_pru_r30_5, MODE5 | OUTPUT | PRU
               0x19c 0x26  // P9_28 pr1_pru0_pru_r31_3, MODE6 | INPUT | PRU
            >;
         };
      };
   };

   fragment@1 {         // Enable the PRUSS
      target = <&pruss>;
      __overlay__ {
         status = "okay";
         pinctrl-names = "default";
         pinctrl-0 = <&pru_pru_pins>;
      };
   };

   fragment@2 {         // Enable the GPIOs
      target = <&ocp>;
      __overlay__ {
         gpio_helper {
            compatible = "gpio-of-helper";
            status = "okay";
            pinctrl-names = "default";
            pinctrl-0 = <&gpio_pins>;
         };
      };
   };
};

Upvotes: 1

Views: 2636

Answers (3)

Rafael Vega
Rafael Vega

Reputation: 4645

There are two pre compiled versions of the 4.1 kernel for the BBB in the repos: The "TI" version and the "Bone" version. The TI version uses a newer API for controlling the PRU and the Bone version has the same API as the 3.8 kernel and the prussdrv_open() function should work fine. To install the 4.1 "bone" kernel, you can do:

cd /opt/scripts/tools
sudo ./update_kernel.sh --bone-rt-kernel --lts-4_1

More info: https://groups.google.com/forum/#!topic/beagleboard/cyM3f935wMA

Upvotes: 1

fyhertz
fyhertz

Reputation: 83

You could try to use the 4.1.5-ti-r10 version of the kernel. Apparently pruss_uio does not work for some 4.1.x kernels.

Moreover, the dts file you are using was not working for me either (don't know why). I used the following, and prussdrv_open does not fail:

/dts-v1/; 
/plugin/; 

/ { 
    compatible = "ti,beaglebone", "ti,beaglebone-black"; 

    /* identification */ 
    part-number = "BB-ENABLE-PRU"; 

    /* version */ 
    version = "00A0"; 

        fragment@1 {         // Enable the PRUSS 
                target = <&pruss>; 
                __overlay__ { 
                    status = "okay"; 
                }; 
        }; 
};

If found all this out on that thread: https://groups.google.com/forum/#!category-topic/beagleboard/VBNEoCbEHUQ

Upvotes: 0

Kelu124
Kelu124

Reputation: 54

Hmmm looks similar to a previous issue.. The problem was that the PRU was not enabled, and I quote : echo BB-BONE-PRU-01 > /sys/devices/bone_capemgr.8/slots fixed it.

Upvotes: 0

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