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serial: earlycon: prefer EARLYCON_DECLARE() variant 

If a driver exposes early consoles with EARLYCON_DECLARE() and
OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it
by
  earlycon=<driver>,<options>

The rationale behind this is that some drivers register multiple setup
functions under the same driver name. Eg.

OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);

It depends on the order of the entries which console_setup() actually
gets called. To make things worse, I guess it also depends on the
compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE()
ones.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200220174607.24285-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Walle 2020-02-20 18:46:07 +01:00 committed by Greg Kroah-Hartman
parent 4f5f588737
commit f8c3686c65
1 changed files with 11 additions and 0 deletions
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11
drivers/tty/serial/earlycon.c
View File

@ -170,6 +170,7 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match)
int __init setup_earlycon(char *buf)
{
const struct earlycon_id **p_match;
bool empty_compatible = true;
if (!buf || !buf[0])
return -EINVAL;
@ -177,6 +178,7 @@ int __init setup_earlycon(char *buf)
if (early_con.flags & CON_ENABLED)
return -EALREADY;
again:
for (p_match = __earlycon_table; p_match < __earlycon_table_end;
p_match++) {
const struct earlycon_id *match = *p_match;
@ -185,6 +187,10 @@ int __init setup_earlycon(char *buf)
if (strncmp(buf, match->name, len))
continue;
/* prefer entries with empty compatible */
if (empty_compatible && *match->compatible)
continue;
if (buf[len]) {
if (buf[len] != ',')
continue;
@ -195,6 +201,11 @@ int __init setup_earlycon(char *buf)
return register_earlycon(buf, match);
}
if (empty_compatible) {
empty_compatible = false;
goto again;
}
return -ENOENT;
}