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Re: [PATCH] ns1650: refactor interrupt handling in ns16550_uart_dt_init()
- To: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>, Julien Grall <julien@xxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Thu, 13 Jul 2023 12:08:53 +0200
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- Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Thu, 13 Jul 2023 10:09:11 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 13.07.2023 11:30, Oleksii Kurochko wrote:
> --- a/xen/drivers/char/ns16550.c
> +++ b/xen/drivers/char/ns16550.c
> @@ -1791,8 +1791,16 @@ static int __init ns16550_uart_dt_init(struct
> dt_device_node *dev,
> }
>
> res = platform_get_irq(dev, 0);
> - if ( ! res )
> - return -EINVAL;
> + if ( res == -1 )
> + {
> + printk("ns1650: polling will be used\n");
Nit: Please don't omit one of the two 5-s here.
> + /*
> + * There is the check 'if ( uart->irq > 0 )' in
> ns16550_init_postirq().
> + * If the check is true then interrupt mode will be used otherwise
> + * ( when irq = 0 )polling.
> + */
I wonder in how far that's actually correct outside of x86. On x86 IRQ0 is
always the timer interrupt, but I'm not convinced something similar can be
used as kind of a heuristic on Arm, RISC-V, or basically any other
architecture.
Jan
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