[Skiboot] [PATCH v2] Fix hvc console issue by using OPAL event.

[Alistair Popple]

Hi Pridhiviraj,

There were some subtlties here with different kernel versions that
unfortunately I only vaguely recall. Which specific kernel versions
and systems have you tested this on? Sam do you think this will cause
issues on Firenze when there is data on the second serial console?

Regards,

Alistair

On Wed, 22 Feb 2017 11:32:42 AM ppaidipe at linux.vnet.ibm.com wrote:
> From: Pridhiviraj Paidipeddi <ppaidipe at linux.vnet.ibm.com>
>
> This reverts part of commit 583c8203dcb26b42cea81e4734ea926dae05dbb9.
>
> Below is the WARNING in pre 4.2 linux kernels which is raised in firenze
> systems due to interrupts mapping failure.
>
> [    0.947741] irq: irq-62==>hwirq-0x3e mapping failed: -22
> [    0.947793] ------------[ cut here ]------------
> [    0.947838] WARNING: at kernel/irq/irqdomain.c:485
>
> So this commit 583c8203dcb26b42cea81e4734ea926dae05dbb9 is causing
> the above kernel WARNING(found by git-bisect).
>
> As per suggestion by Alistair, Use OPAL event instead of interrupts
> to avoid the warning. Tested on RHEL and Ubuntu OS's, not seen any
> kernel warning's.
>
> [    1.745145] hvc0: raw protocol on /ibm,opal/consoles/serial at 0 (boot console)
> [    1.745223] hvc0: No interrupts property, using OPAL event
> [    1.745556] hvc1: hvsi protocol on /ibm,opal/consoles/serial at 1
> [    1.745622] hvc1: No interrupts property, using OPAL event
>
> Signed-off-by: Pridhiviraj Paidipeddi <ppaidipe at linux.vnet.ibm.com>
> ---
> Changes since v1:
>
> 	Use OPAL event instead of interrupts to avoid the
> 	kernel warning.
>
>  hw/fsp/fsp-console.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/hw/fsp/fsp-console.c b/hw/fsp/fsp-console.c
> index 6683679..2785a82 100644
> --- a/hw/fsp/fsp-console.c
> +++ b/hw/fsp/fsp-console.c
> @@ -929,10 +929,8 @@ void fsp_console_reset(void)
>
>  void fsp_console_add_nodes(void)
>  {
> -	struct dt_node *opal_event;
>  	unsigned int i;
>
> -	opal_event = dt_find_by_name(opal_node, "event");
>
>  	for (i = 0; i < MAX_SERIAL; i++) {
>  		struct fsp_serial *fs = &fsp_serials[i];
> @@ -951,10 +949,6 @@ void fsp_console_add_nodes(void)
>
>  		fs->irq = opal_dynamic_event_alloc();
>  		dt_add_property_cells(fs_node, "interrupts", ilog2(fs->irq));
> -
> -		if (opal_event)
> -			dt_add_property_cells(fs_node, "interrupt-parent",
> -					      opal_event->phandle);
>  	}
>  }
>
>