From a12f1b406f2d3c3e3bba5300b6e420d004ca263b Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 29 Oct 2014 18:47:01 -0700 Subject: [PATCH] tty: serial: msm: Reset uartdm after baud rate change We need to issue a reset if we ever change the value of the IPR register on DM hardware. If we don't reset the hardware the RX stale interrupt never triggers and the only way to trigger an RX handling event is by filling up the fifo. This causes things like getty to not work so well considering it might change the baud rate a few times. Fix this by moving the reset on startup and any reprogramming required after the reset to be after we change the baud rate. Signed-off-by: Stephen Boyd Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/msm_serial.c | 49 ++++++++++------------------------------- 1 file changed, 12 insertions(+), 37 deletions(-) diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index d44c049..b507f5a 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -427,9 +427,6 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud) entry = msm_find_best_baud(port, baud); - if (msm_port->is_uartdm) - msm_write(port, UART_CR_CMD_RESET_RX, UART_CR); - msm_write(port, entry->code, UART_CSR); /* RX stale watermark */ @@ -446,6 +443,18 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud) /* set TX watermark */ msm_write(port, 10, UART_TFWR); + msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR); + msm_reset(port); + + /* Enable RX and TX */ + msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR); + + /* turn on RX and CTS interrupts */ + msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE | + UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START; + + msm_write(port, msm_port->imr, UART_IMR); + if (msm_port->is_uartdm) { msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR); msm_write(port, 0xFFFFFF, UARTDM_DMRX); @@ -492,40 +501,6 @@ static int msm_startup(struct uart_port *port) data |= UART_MR1_AUTO_RFR_LEVEL1 & (rfr_level << 2); data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level; msm_write(port, data, UART_MR1); - - /* make sure that RXSTALE count is non-zero */ - data = msm_read(port, UART_IPR); - if (unlikely(!data)) { - data |= UART_IPR_RXSTALE_LAST; - data |= UART_IPR_STALE_LSB; - msm_write(port, data, UART_IPR); - } - - data = 0; - if (!port->cons || (port->cons && !(port->cons->flags & CON_ENABLED))) { - msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR); - msm_reset(port); - data = UART_CR_TX_ENABLE; - } - - data |= UART_CR_RX_ENABLE; - msm_write(port, data, UART_CR); /* enable TX & RX */ - - /* Make sure IPR is not 0 to start with*/ - if (msm_port->is_uartdm) - msm_write(port, UART_IPR_STALE_LSB, UART_IPR); - - /* turn on RX and CTS interrupts */ - msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE | - UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START; - - if (msm_port->is_uartdm) { - msm_write(port, 0xFFFFFF, UARTDM_DMRX); - msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR); - msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR); - } - - msm_write(port, msm_port->imr, UART_IMR); return 0; } -- 2.7.4