On 2018-05-23 07:25, C Smith wrote: > I'm not familiar with the chaining of shared interrupts in the RTDM > architecture. I think the EOI should somehow be done in the very last > invocation of rt_16550_interrupt() by the last peripheral needing service. >
Just like under Linux, the driver does not have to worry about that details. Xenomai will EOI the IRQ when needed. The driver handler just need to tell if a particular invocation was (also) triggered by the device it drives. > > I read this from an old interrupt handler: > (assuming IBM PC (Intel) architecture) > An interrupt handler issues an EOI by writing the value 0x20 to the PIC at > address 0x20. If the interrupt was number 8-15, do the same thing again, > write 0x20 to address 0x20. > > So perhaps something like this at the end of rt_16550_interrupt() ? > > if (ctx->irq_handle.irq <= 7) /* non-specific EOI to 8259 */ > rt_16550_reg_out(mode, 0, 0x20, 0x20); > if (ctx->irq_handle.irq <= 15) /* extra EOI for upper ISA IRQs */ > rt_16550_reg_out(mode, 0, 0x20, 0x20); > > But again I don't know if that will work with shared interrupts. Surely > RTDM implements some "master" handler which is already doing an EOI? > Remember lower interrupts like IRQ 5 work fine with the xeno_16550A driver As noted in the other thread, IRQ 5 is most probably wrong. Check what Linux uses when you attach the device to a normal Linux driver. Jan > unless another port is sharing the same IRQ. > > -C Smith > -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux _______________________________________________ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
