diff options
Diffstat (limited to 'target/linux/generic/backport-4.14/180-earlycon-initialize-port-uartclk-based-on-clock-frequency-property.patch')
| -rw-r--r-- | target/linux/generic/backport-4.14/180-earlycon-initialize-port-uartclk-based-on-clock-frequency-property.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.14/180-earlycon-initialize-port-uartclk-based-on-clock-frequency-property.patch b/target/linux/generic/backport-4.14/180-earlycon-initialize-port-uartclk-based-on-clock-frequency-property.patch new file mode 100644 index 0000000000..1b98958af4 --- /dev/null +++ b/target/linux/generic/backport-4.14/180-earlycon-initialize-port-uartclk-based-on-clock-frequency-property.patch @@ -0,0 +1,45 @@ +From 814453adea7d081ad8917aa0f32d6a14165a3563 Mon Sep 17 00:00:00 2001 +From: Michal Simek <michal.simek@xilinx.com> +Date: Tue, 10 Apr 2018 15:32:28 +0200 +Subject: earlycon: Initialize port->uartclk based on clock-frequency property + +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, |