Hi Jan,
On 13/07/2023 11:08, Jan Beulich wrote:
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.
I wondered the same. On Arm we are fine because the UART will be an SPI
which starts at 32.
That's part why I was suggesting to use a define. Because we don't have
to hardcode the poll value everywhere.
Cheers,
--
Julien Grall
