Re: [Xen-devel] [for-4.7 1/5] drivers/pl011: ACPI: The interrupt should always be high level triggered

[Shannon Zhao <zhaoshenglong@xxxxxxxxxx>]

On 2016/4/7 18:59, Julien Grall wrote:
> The SPCR does not specify if the interrupt is edge or level triggered.
> So the configuration needs to be hardcoded in the code.
> 
> Based on the PL011 TRM (see 2.2.8 in ARM DDI 0183G), the interrupt generated
> will be active high. This wording implies the interrupt should be high level
> triggered.
I think active high can stand rising edge triggered for edge triggered
interrupt.

E.g. see "Table 5-118 Flag Definitions: Virtual Timer, EL2 timers, and
Secure & Non-Secure EL1 timers" in ACPI SPEC 6.0.

> Note that a rising edge triggered interrupt would be described as
> "high going edge".
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> ---
>  xen/drivers/char/pl011.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
> index fa22edf..88d8488 100644
> --- a/xen/drivers/char/pl011.c
> +++ b/xen/drivers/char/pl011.c
> @@ -327,7 +327,7 @@ static int __init pl011_acpi_uart_init(const void *data)
>      }
>  
>      /* trigger/polarity information is not available in spcr */
> -    irq_set_type(spcr->interrupt, IRQ_TYPE_EDGE_BOTH);
> +    irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_MASK);
>  
>      res = pl011_uart_init(spcr->interrupt, spcr->serial_port.address,
>                            PAGE_SIZE);
> 

-- 
Shannon


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