The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 679aac5ead2f18d223554a52b543e1195e181811 Mon Sep 17 00:00:00 2001

From: satya priya skakit@codeaurora.org Date: Tue, 11 Feb 2020 15:43:02 +0530 Subject: [PATCH] tty: serial: qcom_geni_serial: Fix RX cancel command failure

RX cancel command fails when BT is switched on and off multiple times.

To handle this, poll for the cancel bit in SE_GENI_S_IRQ_STATUS register instead of SE_GENI_S_CMD_CTRL_REG.

As per the HPG update, handle the RX last bit after cancel command and flush out the RX FIFO buffer.

Signed-off-by: satya priya skakit@codeaurora.org Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/1581415982-8793-1-git-send-email-skakit@codeaurora... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 191abb18fc2a..0bd1684cabb3 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -129,6 +129,7 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop); static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop); static unsigned int qcom_geni_serial_tx_empty(struct uart_port *port); static void qcom_geni_serial_stop_rx(struct uart_port *uport); +static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop);

static const unsigned long root_freq[] = {7372800, 14745600, 19200000, 29491200, 32000000, 48000000, 64000000, 80000000, @@ -599,7 +600,7 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport) u32 irq_en; u32 status; struct qcom_geni_serial_port *port = to_dev_port(uport, uport); - u32 irq_clear = S_CMD_DONE_EN; + u32 s_irq_status;

irq_en = readl(uport->membase + SE_GENI_S_IRQ_EN); irq_en &= ~(S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN); @@ -615,10 +616,19 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport) return;

geni_se_cancel_s_cmd(&port->se); - qcom_geni_serial_poll_bit(uport, SE_GENI_S_CMD_CTRL_REG, - S_GENI_CMD_CANCEL, false); + qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS, + S_CMD_CANCEL_EN, true); + /* + * If timeout occurs secondary engine remains active + * and Abort sequence is executed. + */ + s_irq_status = readl(uport->membase + SE_GENI_S_IRQ_STATUS); + /* Flush the Rx buffer */ + if (s_irq_status & S_RX_FIFO_LAST_EN) + qcom_geni_serial_handle_rx(uport, true); + writel(s_irq_status, uport->membase + SE_GENI_S_IRQ_CLEAR); + status = readl(uport->membase + SE_GENI_STATUS); - writel(irq_clear, uport->membase + SE_GENI_S_IRQ_CLEAR); if (status & S_GENI_CMD_ACTIVE) qcom_geni_serial_abort_rx(uport); }