Not able to run Openocd for rp2040 on rpi5

[pranjalchanda08]

I am stuck with the following screen state on rpi5:

sudo openocd -f interface/raspberrypi-swd.cfg -f target/rp2040.cfg
Open On-Chip Debugger 0.11.0-g8e3c38f (2023-12-23-19:52)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
adapter speed: 1000 kHz

Info : Hardware thread awareness created
Info : Hardware thread awareness created
Info : RP2040 Flash Bank Command
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : BCM2835 GPIO JTAG/SWD bitbang driver
Info : clock speed 1001 kHz

**** Stuck after this ****

[lurch]

I've not tried it myself yet, but does raspberrypi/pico-setup#28 help?

[pranjalchanda08]

I will have to try and get back to you

[pranjalchanda08]

Now I have got this issue:

sudo openocd -f interface/raspberrypi-swd.cfg -f target/rp2040.cfg
Open On-Chip Debugger 0.12.0-g4d87f6d (2023-12-23-23:46)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
WARNING: Unknown type of the host SoC. Expect JTAG/SWD clock slower than requested.
Warn : TMS/SWDIO moved to GPIO 8 (pin 24). Check the wiring please!
adapter speed: 5000 kHz

Info : Hardware thread awareness created
Info : Hardware thread awareness created
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : BCM2835 GPIO JTAG/SWD bitbang driver
Info : clock speed 5000 kHz
Error: Failed to connect multidrop rp2040.dap0

Keeping the following warning in mind: Warn : TMS/SWDIO moved to GPIO 8 (pin 24). Check the wiring please!

SWCLK -> GPIO25
GND -> Pin20
SWDIO -> GPIO8

[pranjalchanda08]

@lurch any updates on this. As I need this info to create some CI/CD Setups

[lurch]

I'm afraid you'll have to wait until all the RPi engineers are back from holiday in the New Year.

[pranjalchanda08]

Oh yeah Happy new year!

[cleverca22]

i got it working fairly easily on my pi5:

clever@raspberrypi:~ $ cat test.cfg
adapter driver linuxgpiod
adapter gpio swclk 20 -chip 4
adapter gpio swdio 21 -chip 4
clever@raspberrypi:~ $ openocd -f test.cfg -f target/rp2040.cfg
Open On-Chip Debugger 0.12.0-g4d87f6dca (2024-01-05-00:08)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : Hardware thread awareness created
Info : Hardware thread awareness created
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Warn : An adapter speed is not selected in the init scripts. OpenOCD will try to run the adapter at the low speed (100 kHz)
Warn : To remove this warnings and achieve reasonable communication speed with the target, set "adapter speed" or "jtag_rclk" in the init scripts.
Info : Linux GPIOD JTAG/SWD bitbang driver
Info : This adapter doesn't support configurable speed
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x00000001
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x10000001
Info : [rp2040.core0] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core0] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core1] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core1] target has 4 breakpoints, 2 watchpoints
Info : starting gdb server for rp2040.core0 on 3333
Info : Listening on port 3333 for gdb connections

all it needs now, is to drop that into the interface folder and name it well, and maybe change the pins to match the other examples

[pranjalchanda08]

Ok I get now. My config was using the old rpi interface. Need to switch to Linuxgpiod adapter

[pranjalchanda08]

I think this info needs a released documentation somewhere from rpi team.

[pranjalchanda08]

Few questions:

1. Is 100KHz limit of linuxgpiod.
2. How do we determine on rpi5 that the script is being run on rp5 or older version. This info is needed to maintain cross platform debug scripts.
3. And what does -chip 4 means here?
   @cleverca22

[cleverca22]

And what does -chip 4 means here?

clever@raspberrypi:~ $ gpiodetect
gpiochip0 [gpio-brcmstb@107d508500] (32 lines)
gpiochip1 [gpio-brcmstb@107d508520] (4 lines)
gpiochip2 [gpio-brcmstb@107d517c00] (17 lines)
gpiochip3 [gpio-brcmstb@107d517c20] (6 lines)
gpiochip4 [pinctrl-rp1] (54 lines)

the pi5 has 5 gpio controllers
the 40 pin header is on the 4th one

the debug port on the pi5 is on another, and a simple 3 pin JST-SH cable could link a pi5 directly to the pico with no fuss

How do we determine on rpi5 that the script
tcl/interface/raspberrypi-native.cfg has code to read /proc/device-tree/compatible and check for strings like bcm2712

i'm not sure where the speed would be set

[CamDavidsonPilon]

FYI this works on older Pis:

adapter driver linuxgpiod
adapter gpio swclk 20 -chip 0
adapter gpio swdio 21 -chip 0

[cleverca22]

ah good catch, so we could just use gpiod on every model
and then all you need to do is change the chip#

[pranjalchanda08]

And what does -chip 4 means here?

clever@raspberrypi:~ $ gpiodetect
gpiochip0 [gpio-brcmstb@107d508500] (32 lines)
gpiochip1 [gpio-brcmstb@107d508520] (4 lines)
gpiochip2 [gpio-brcmstb@107d517c00] (17 lines)
gpiochip3 [gpio-brcmstb@107d517c20] (6 lines)
gpiochip4 [pinctrl-rp1] (54 lines)

the pi5 has 5 gpio controllers the 40 pin header is on the 4th one

the debug port on the pi5 is on another, and a simple 3 pin JST-SH cable could link a pi5 directly to the pico with no fuss

How do we determine on rpi5 that the script
tcl/interface/raspberrypi-native.cfg has code to read /proc/device-tree/compatible and check for strings like bcm2712

i'm not sure where the speed would be set

I guess "adapter_speed xxxx" sets of the adapter speed in xxxx KHz. Currently as nothing is given it is setting to 100KHz by default.
But 100KHz and that too it says "Info : This adapter doesn't support configurable" is kinda bothering me. Since 100KHz is very low specially when it comes to over network remote debugging.
Else this solution is kind of just a workaround then, than what rp5 is really capable of.

[cleverca22]

But 100KHz and that too it says "Info : This adapter doesn't support configurable" is kinda bothering me. Since 100KHz is very low specially when it comes to over network remote debugging.

static int adapter_set_speed(int speed)
{
        /* this command can be called during CONFIG,
         * in which case adapter isn't initialized */
        return is_adapter_initialized() ? adapter_driver->speed(speed) : ERROR_OK;
}

at the end, its just calling a speed function within a function pointer table

struct adapter_driver linuxgpiod_adapter_driver = {
        .name = "linuxgpiod",
        .transports = linuxgpiod_transport,

        .init = linuxgpiod_init,
        .quit = linuxgpiod_quit,
        .reset = linuxgpiod_reset,
 
        .jtag_ops = &linuxgpiod_interface,
        .swd_ops = &bitbang_swd,
};

and the linuxgpiod driver lacks a speed function

struct adapter_driver bcm2835gpio_adapter_driver = {
        .name = "bcm2835gpio",
        .transports = bcm2835_transports,
        .commands = bcm2835gpio_command_handlers,

        .init = bcm2835gpio_init,
        .quit = bcm2835gpio_quit,
        .reset = bcm2835gpio_reset,
        .speed = bcm2835gpio_speed,
        .khz = bcm2835gpio_khz,
        .speed_div = bcm2835gpio_speed_div,
 
        .jtag_ops = &bcm2835gpio_interface,
        .swd_ops = &bitbang_swd,
};

while the bcm2835 one does have one
so somebody will need to port that over

edit:
but reading the source more, i can see that all speed does on bcm2835, is make write's delay a bit

while linuxgpiod doesnt delay, so its actually ignoring the speed and going full tilt?
will need to dig more, and confirm