Tool: Vivado 2014.4
chip: zc7z020
linux: xlnl-linux tag v2014.4 (3.17)
u-boot: tag v2014.v
Hi,
I have built a simple zynq PS with "spi 0" turned on, working as a SPI master. The slave is trf7970a (a TI NFC chip).
The NFC chip (trf7970a) need an interrupt (IRQ request) line to connect with. So I routed the trf7970a's irq line to a MIO pin (work as a GPIO pin).
At first, I couldn't insmod trf7970a driver (trf7970a.ko), because it failed requesting irq.
I noted that the spi 0's irq number (58) was already registerd. But I don't know what it meant and whether I can use it?
So I modified the device-tree, added a custom attribue named "int-gpio" in "nfc0" node (which in spi0) with value "<&gpio0 48 0>". Then I modified the interrupt register's function in trf7970a's driver, invoked "gpio_to_irq()" to get a valid irq number, and registered the irq. (I also referred to "<KERNEL_PATH>/driver/input/keyboard/gpio_keys.c" ). After that, I succeeded in loading (insmod) driver.
I can see the interrupt registered.
zynq:~# cat /proc/interrupts
CPU0 CPU1
144: 0 0 zynq-gpio 48 trf7970a
When I open nfc application which controls the driver to power on (send a command to trf7970a chip), the linux system will hang.
Sometimes the following messages presented on the console:
INFO: rcu_preempt self_detected stall on CPU { 0} (t=0001 jiffies g=76 c=75 1=527)
Task dump for CPU0:
[<40014764>] (unwind_backtrack) from .....
[....] (show_stack) from ....
[....] (rcu_dump_cpu_stacks) from ....
[....] (rcu_check_callbacks) from ....
[....] (updae_process_times) from ...
[....] (tick_sched_timer) from ...
....
[....] (handle_percpu_devid_irq_) from ...
[....] (generic_handle_irq) from ...
[....] (handle_IRQ) from ...
[....] (gic_handle_irq) from ...
...
Any help will be greatly appreciated.
Regards,
