[PATCH v5 40/46] boot: Support IO UARTs for earlycon and console

[Tom Rini]

On Thu, Apr 03, 2025 at 08:22:44AM +1300, Simon Glass wrote:
> Hi Tom,
> 
> On Thu, 3 Apr 2025 at 03:29, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Sat, Mar 15, 2025 at 02:26:00PM +0000, Simon Glass wrote:
> > > Update the string to take account of UARTs which are connected on I/O
> > > ports, as on x86.
> > >
> > > Fix a typo in an error message in the same command, while we are here.
> > >
> > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > ---
> > >
> > > (no changes since v3)
> > >
> > > Changes in v3:
> > > - Add new patch to support IO UARTs for earlycon and console
> > >
> > >  boot/bootflow.c | 7 ++++---
> > >  1 file changed, 4 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/boot/bootflow.c b/boot/bootflow.c
> > > index 58a1afa7a75..4054a966af8 100644
> > > --- a/boot/bootflow.c
> > > +++ b/boot/bootflow.c
> > > @@ -942,8 +942,9 @@ int bootflow_cmdline_auto(struct bootflow *bflow, const char *arg)
> > >       *buf = '\0';
> > >       if (!strcmp("earlycon", arg) && info.type == SERIAL_CHIP_16550_COMPATIBLE) {
> > >               snprintf(buf, sizeof(buf),
> > > -                      "uart8250,mmio32,%#lx,%dn8", info.addr,
> > > -                      info.baudrate);
> > > +                      "uart8250,%s,%#lx,%dn8",
> > > +                      info.addr_space == SERIAL_ADDRESS_SPACE_IO ? "io" :
> > > +                      "mmio", info.addr, info.baudrate);
> > >       } else if (!strcmp("earlycon", arg) && info.type == SERIAL_CHIP_PL01X) {
> > >               snprintf(buf, sizeof(buf),
> > >                        "pl011,mmio32,%#lx,%dn8", info.addr,
> >
> > I suppose we're well past the point where we can delete
> > bootflow_cmdline_auto() itself because that's just going to lead us to
> > trouble down the line (5 years from now when the kernel adopts a new
> > preferred way to pass this info) and grows every platform by some amount
> > of space every time we add something new here.
> 
> Well firstly, why would you want to delete this command? It is very
> useful to be able to change the cmdline.
> 
> This command is only available with BOOTSTD_FULL, which is less than
> 10% of boards.

Because it's automatic non-obvious stuff. We should not be modifying the
command line at all. Is it even documented that we're doing this?

-- 
Tom
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