Re: [PATCH 1/2] serial: 8250: Let drivers request full 16550A feature probing

From: Maciej W. Rozycki
Date: Mon Sep 19 2022 - 04:23:41 EST


On Mon, 19 Sep 2022, Jiri Slaby wrote:

> > --- linux-macro.orig/include/linux/serial_core.h
> > +++ linux-macro/include/linux/serial_core.h
> > @@ -414,7 +414,7 @@ struct uart_icount {
> > __u32 buf_overrun;
> > };
> > -typedef unsigned int __bitwise upf_t;
> > +typedef __u64 __bitwise upf_t;
>
> Why __u64 and not u64?

For consistency as there's `__u32' used elsewhere in this file. It's not
clear to me what our rules WRT the use of `s*'/`u*' vs `__s*'/`__u*' are.
I don't think we have it mentioned under Documentation/. Please clarify
if you know and I can update the change accordingly.

> > @@ -522,6 +522,7 @@ struct uart_port {
> > #define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
> > #define UPF_DEAD ((__force upf_t) (1 << 30))
> > #define UPF_IOREMAP ((__force upf_t) (1 << 31))
> > +#define UPF_FULL_PROBE ((__force upf_t) (1ULL << 32))
>
> This looks like a perfect time to switch them all to BIT_ULL().

Good point, I keep forgetting about that macro. I'll keep this part
unchanged for the purpose of backporting and add 3/3 to switch all the
macros over.

Maciej