AM37xx: spurious interrupt problem connecting to WiFi

Prateek Bansal

Expert 4510 points

Hi,

My customer is experiencing an issue when talking to Wi-Fi chip to SD/MMC2 port. they see this message:

Spurious irq 95: 0xffffffdf, please flush posted write for irq 86

http://e2e.ti.com/support/dsp/sitara_arm174_microprocessors/f/416/t/100963.aspx

http://comments.gmane.org/gmane.linux.ports.arm.omap/66288

As I looked at number of forums, this issue has been experienced by many and the recommendation was to have read-back call in irq 86 handler.

The customer did have this in their code and it doesn't fix the issue. Further looking at TRM, irq 86 is set to MMC2_IRQ and irq 95 is reserved. Considering irq 95 is not even registered, what could cause this spurious interrupt 95? Any guidance on things that can be tried would be greatly appreciated.

Thanks in advance.

Prateek

over 13 years ago

0 Tom Wheeler over 13 years ago

Prodigy 10 points

Irq 95 is asserted when there is a spurious interrupt. The omap_check_spurious function is only called when the irq is irq95.

0 Prateek Bansal over 13 years ago in reply to Tom Wheeler

TI__Expert 4510 points

Thanks for explanation Tom. Now we understand irq 95 is used for spurious interrupts now and irq 86 is interrupt handler where this spurious interrupt is generated from.

Now, the question is how can we resolve this spurious interrupt issue considering read back of interrupt status register or revision register right after write acking the interrupt does not work?

Prateek

0 Prateek Bansal over 13 years ago in reply to Prateek Bansal

TI__Expert 4510 points

Hi Tom,

I was told by team to try memory barrier function if read back of interrupt status register does not work. Let me know if this helps.

http://en.wikipedia.org/wiki/Memory_barrier

Prateek

Processors

Processors forum

AM37xx: spurious interrupt problem connecting to WiFi