AppliedMicro X-Gene based boards don't use the "standard"
16550 clock rate so supplying a baud rate makes it change
to a random baud rate.
I suggest to introduce a new value '0' for the "Baud
Rate" field of SPCR (now this value is reserved).
This patch introduces a check for this value. In this case
the code does not emit baud rate specification for initialization
of the console.
Signed-off-by: Aleksey Makarov <aleksey.makarov@xxxxxxxxxx>
---
drivers/acpi/spcr.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 6c6710b..2bf338c 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -37,7 +37,7 @@ int __init parse_spcr(bool earlycon)
acpi_status status;
char *uart;
char *iotype;
- int baud_rate;
+ char *baud_rate_string;
int err;
if (acpi_disabled)
@@ -82,25 +82,33 @@ int __init parse_spcr(bool earlycon)
}
switch (table->baud_rate) {
+ case 0:
+ /*
+ * This value is not standaritzed by ACPI SPCR for now.
+ * It means that hardware should not be re-initialized with
+ * new speed.
+ */
+ baud_rate_string = "";
+ break;
case 3:
- baud_rate = 9600;
+ baud_rate_string = ",9600";
break;
case 4:
- baud_rate = 19200;
+ baud_rate_string = ",19200";
break;
case 6:
- baud_rate = 57600;
+ baud_rate_string = ",57600";
break;
case 7:
- baud_rate = 115200;
+ baud_rate_string = ",115200";
break;
default:
err = -ENOENT;
goto done;
}
- snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
- table->serial_port.address, baud_rate);
+ snprintf(opts, sizeof(opts), "%s,%s,0x%llx%s", uart, iotype,
+ table->serial_port.address, baud_rate_string);
pr_info("console: %s\n", opts);
--
2.10.2
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