kernel.git/drivers/tty/serial/meson_uart.c, branch linux-4.11.y

tty: serial: meson: allow baud-rates higher than 115200

2017-01-19T13:38:57Z

The vendor driver allows setting baud-rates higher than 115200 baud. There is a check in the vendor driver which prevents using more than 115200 baud during startup, however it does not have such a check in .set_termios. Higher baud-rates are often used by the bluetooth modules embedded into the SDIO wifi chips (Amlogic devices use brcmfmac based wifi chips quite often, 2000000 baud seems to be a common value for the UART baud-rate in Amlogic's "libbt"). I have tested this on a Meson GXL device with uart_A (to which the bluetooth module is connected, where initialization times out with 115200 baud) and uart_AO (which I manually set to 2000000 baud and then connected with my USB UART adapter to that). Signed-off-by: Martin Blumenstingl Acked-by: Kevin Hilman Tested-by: Andreas Färber Signed-off-by: Greg Kroah-Hartman

tty: serial: meson: Implement earlycon support

2016-04-30T16:26:55Z

Split off the bulk of the existing meson_serial_console_write() implementation into meson_serial_port_write() for implementing meson_serial_early_console_write(). Use "meson" as the earlycon driver name, courtesy of Nicolas. Signed-off-by: Nicolas Saenz Julienne Acked-by: Carlo Caione Signed-off-by: Andreas Färber Signed-off-by: Greg Kroah-Hartman

tty: serial: meson: Add support for XTAL clock input

2016-02-15T01:39:36Z

Fix the baudrate calculation for 24 MHz XTAL clock found on gxbb platforms. Signed-off-by: Andreas Färber Acked-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: check for tx-irq enabled in irq code

2015-12-14T03:59:48Z

Ensure that if the interrupt handler is entered then only try and do tx work if the tx irq is enabled. Signed-off-by: Ben Dooks Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: ensure tx irq on if more work to do

2015-12-14T03:59:48Z

The tx_stop() call turns the interrupt off, but the tx_start() does not check if the interrupt is enabled. Switch it back on if there is more work to do. Signed-off-by: Ben Dooks Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: disable rx/tx irqs during console write

2015-12-14T03:59:48Z

As an attempt to stop issues with bad console output, ensure that both the rx and tx interrupts are disabled during the console write to avoid any problems with console and non-console being called together. This should help with the SMP case as it should stop other cores being signalled during the console write. Signed-off-by: Ben Dooks Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: use meson_uart_tx_empty() to wait for empty

2015-12-14T03:59:48Z

Use the meson_uart_tx_empty() instead of a direct read of the status register. This is easier to read and will ensure the UART's transmit state machine is idle when trying to update the baud rate. Signed-off-by: Ben Dooks Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: only disable tx irq on stop

2015-12-14T03:59:48Z

Since disabling the transmit state machine still allows characters to be transmitted when written to the UART write FIFO, simply disable the transmit interrupt when the UART port is stopped. This has not shown an improvement with the console issues when running systemd, but seems like it should be done. Signed-off-by: Ben Dooks Reported-by: Edward Cragg Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: ensure console port uart enabled

2015-12-14T03:59:48Z

Ensure the UART's transmitter is enabled when meson_console_putchar is called. If not, then the console output is corrupt (the hardware seems to try and send /something/ even if the TX is disabled). This fixes corrupt console output on events such as trying to reboot the system since the console tx may be called after drivers shutdown method has been called. Signed-off-by: Ben Dooks Reported-by: Edward Cragg Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman

ARM: meson: serial: tx_empty fails to check for transmitter busy

2015-12-14T03:59:48Z

The tx_empty() uart_op should only return empty if both the transmit fifo and the transmit state-machine are both idle. Add a test for the hardware's XMIT_BUSY flag. Note, this is possibly related to an issue where the port is being shutdown with paritally transmitted characters in it. Signed-off-by: Ben Dooks Reported-by: Edward Cragg Tested-by: Carlo Caione Signed-off-by: Greg Kroah-Hartman