4.14-stable review patch. If anyone has any objections, please let me know.
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From: Michal Simek michal.simek@xilinx.com
commit 814453adea7d081ad8917aa0f32d6a14165a3563 upstream.
On DT based platforms when current-speed property is present baudrate is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16 value. Drivers like uartps/ns16550 contain logic when baudrate and uartclk is used for baudrate calculation.
The patch is reading optional clock-frequency property to replace bogus BASE_BAUD * 16 calculation to have proper baudrate calculation.
[-stable comment: commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") has changed 8250_early.c behavior which now tries to setup UART speed. Ignoring clock-frequency results in wrong value of calculated divisor & malformed early console output.]
Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Signed-off-by: Michal Simek michal.simek@xilinx.com [rmilecki: add -stable comment and Fixes tag] Signed-off-by: Rafał Miłecki rafal@milecki.pl Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/serial/earlycon.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -289,6 +289,10 @@ int __init of_setup_earlycon(const struc if (val) early_console_dev.baud = be32_to_cpu(*val);
+ val = of_get_flat_dt_prop(node, "clock-frequency", NULL); + if (val) + port->uartclk = be32_to_cpu(*val); + if (options) { early_console_dev.baud = simple_strtoul(options, NULL, 0); strlcpy(early_console_dev.options, options,