Re: [PATCH] serial: pmac_zilog: don't init if zilog is not available

Finn Thain
2020-10-20T23:43:39Z

On Tue, 20 Oct 2020, Brad Boyer wrote:

>
> Wouldn't it be better to rearrange this code to only run if the devices
> are present? This is a macio driver on pmac and a platform driver on
> mac, so shouldn't it be possible to only run this code when the
> appropriate entries are present in the right data structures?
>
> I didn't look at a lot of the other serial drivers, but some other mac
> drivers have recently been updated to no longer have MACH_IS_MAC checks
> due to being converted to platform drivers.
>

Actually, it's not simply a platform driver or macio driver. I think the
console is supposed to be registered before the normal bus matching takes
place. Hence this comment in pmac_zilog.c,

/*
* First, we need to do a direct OF-based probe pass. We
* do that because we want serial console up before the
* macio stuffs calls us back, and since that makes it
* easier to pass the proper number of channels to
* uart_register_driver()
*/

Laurent, can we avoid the irq == 0 warning splat like this?

diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index 96e7aa479961..7db600cd8cc7 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -1701,8 +1701,10 @@ static int __init pmz_init_port(struct uart_pmac_port *uap)
int irq;

r_ports = platform_get_resource(uap->pdev, IORESOURCE_MEM, 0);
+ if (!r_ports)
+ return -ENODEV;
irq = platform_get_irq(uap->pdev, 0);
- if (!r_ports || irq <= 0)
+ if (irq <= 0)
return -ENODEV;

uap->port.mapbase = r_ports->start;