From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pierre-Loup Gosse <pierre-loup.gosse@smile.fr>
Subject: ipipe: IRQ not received on i.MX8 (linux-imx)
Message-ID: <a57774b8-46af-5db9-1ab4-163210bc1396@smile.fr>
Date: Mon, 5 Jul 2021 09:10:58 +0200
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To: xenomai@xenomai.org

Hi,

For a client project I try to port Xenomai 3.1 + I-pipe to the kernel 
linux-imx 5.4.70 for arm64 (i.MX8 Mini). I adapted the I-pipe patch 
(5.4.72-arm64). The kernel boots and works well.

However, for the non-regression test, I run a client test that uses 
Xenomai and UDD (to register a PCIe driver). The test waits for a 
hardware IRQ from a PCIe device. This IRQ is never received which lead 
the test to fail. To be more precise, after running the test, Xenomai 
show that no IRQs was received for this device:

# cat /proc/xenomai/irq
   IRQ         CPU0        CPU1 CPU2        CPU3
     3:        4027       14050 3708        4488         [timer/0]
**223:           0           0 0           0         netx00
  1031:           0           0 0           0         [sync]
  1032:           1           1 1           0         [timer-ipi]
  1033:           0           0 0           0         [reschedule]
  1037:           0          44 0           0         [virtual]

'netx00' is our device with the IRQ 223.
/proc/xenomai/irq simply reads the irqall counter per CPU per IRQ 
(/__ipipe_cpudata_irq_hits/). This means that no IRQ 223 went through 
the I-pipe, or worse, not even sent.

But in comparison, I reproduced this test with the old client image 
(Xenomai 3.1 + I-pipe on the kernel linux-imx 4.14.98) on the same 
hardware (arm64 i.MX8 Mini). The test passed and Xenomai received IRQs 
for 'next00'.

This leads me to the conclusion that on the new kernel our IRQ is sent 
but does not pass through the I-pipe.

I noticed that some irq handler functions from driver do not use the 
/ipipe_handle_domain_irq/ or /ipipe_handle_demuxed_irq/ but the generic 
function, respectively /handle_domain_irq/ and /generic_handle_irq/. 
Especially for the imx irqchip (_drivers/irqchip/irq-imx-intmux.c_ and 
_drivers/irqchip/irq-imx-irqsteer.c_). I patched these files to use 
/ipipe_handle_demuxed_irq/ rather than /generic_handle_irq/. But 
/proc/xenomai/irq still shows 0 IRQs and the test still fails.

Am I doing things right ? Or am I missing something ?

Best regards,

-- 
Pierre-Loup.