tty: serial: qcom-geni-serial: Add support for Hibernation feature

Added changes to support the hibernation feature for serial UART.
Added support for freeze, restore and thaw callbacks to put the
device into hibernation.

Signed-off-by: Aniket Randive <quic_arandive@quicinc.com>
Link: https://lore.kernel.org/r/1665123780-20557-1-git-send-email-quic_arandive@quicinc.com
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 83b66b73303afde411c03690a2303a7395888dc3..b487823f0e61724ba8cdb38ff11f8e5c28bfbf6a 100644 (file)
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -924,6 +924,7 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
                               false, true, true);
        geni_se_init(&port->se, UART_RX_WM, port->rx_fifo_depth - 2);
        geni_se_select_mode(&port->se, GENI_SE_FIFO);
+       qcom_geni_serial_start_rx(uport);
        port->setup = true;
 
        return 0;
@@ -1547,9 +1548,43 @@ static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
        return ret;
 }
 
+static int qcom_geni_serial_sys_hib_resume(struct device *dev)
+{
+       int ret = 0;
+       struct uart_port *uport;
+       struct qcom_geni_private_data *private_data;
+       struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
+
+       uport = &port->uport;
+       private_data = uport->private_data;
+
+       if (uart_console(uport)) {
+               geni_icc_set_tag(&port->se, 0x7);
+               geni_icc_set_bw(&port->se);
+               ret = uart_resume_port(private_data->drv, uport);
+               /*
+                * For hibernation usecase clients for
+                * console UART won't call port setup during restore,
+                * hence call port setup for console uart.
+                */
+               qcom_geni_serial_port_setup(uport);
+       } else {
+               /*
+                * Peripheral register settings are lost during hibernation.
+                * Update setup flag such that port setup happens again
+                * during next session. Clients of HS-UART will close and
+                * open the port during hibernation.
+                */
+               port->setup = false;
+       }
+       return ret;
+}
+
 static const struct dev_pm_ops qcom_geni_serial_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(qcom_geni_serial_sys_suspend,
                                        qcom_geni_serial_sys_resume)
+       .restore = qcom_geni_serial_sys_hib_resume,
+       .thaw = qcom_geni_serial_sys_hib_resume,
 };
 
 static const struct of_device_id qcom_geni_serial_match_table[] = {