[PATCH 07/16] xen/char: implement suspend/resume calls for SCIF driver

[Mykola Kvach]

From: Mykola Kvach <mykola_kv...@epam.com>

The changes have been tested only on the Renesas R-Car-H3 Starter Kit board.

Signed-off-by: Volodymyr Babchuk <volodymyr_babc...@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
Signed-off-by: Mykola Kvach <mykola_kv...@epam.com>
---
 xen/drivers/char/scif-uart.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/xen/drivers/char/scif-uart.c b/xen/drivers/char/scif-uart.c
index 757793ca45..e166fb0f36 100644
--- a/xen/drivers/char/scif-uart.c
+++ b/xen/drivers/char/scif-uart.c
@@ -139,7 +139,7 @@ static void scif_uart_interrupt(int irq, void *data)
     }
 }
 
-static void __init scif_uart_init_preirq(struct serial_port *port)
+static void scif_uart_init_preirq(struct serial_port *port)
 {
     struct scif_uart *uart = port->uart;
     const struct port_params *params = uart->params;
@@ -271,6 +271,33 @@ static void scif_uart_stop_tx(struct serial_port *port)
     scif_writew(uart, SCIF_SCSCR, scif_readw(uart, SCIF_SCSCR) & ~SCSCR_TIE);
 }
 
+static void scif_uart_suspend(struct serial_port *port)
+{
+    struct scif_uart *uart = port->uart;
+
+    scif_uart_stop_tx(port);
+
+    /* Wait until last bit has been transmitted. */
+    while ( !(scif_readw(uart, SCIF_SCFSR) & SCFSR_TEND) );
+
+    /* Disable TX/RX parts and all interrupts */
+    scif_writew(uart, SCIF_SCSCR, 0);
+
+    /* Reset TX/RX FIFOs */
+    scif_writew(uart, SCIF_SCFCR, SCFCR_RFRST | SCFCR_TFRST);
+}
+
+static void scif_uart_resume(struct serial_port *port)
+{
+    struct scif_uart *uart = port->uart;
+
+    scif_uart_init_preirq(port);
+
+    /* Enable TX/RX and Error Interrupts  */
+    scif_writew(uart, SCIF_SCSCR, scif_readw(uart, SCIF_SCSCR) |
+                SCSCR_TIE | SCSCR_RIE | SCSCR_REIE);
+}
+
 static struct uart_driver __read_mostly scif_uart_driver = {
     .init_preirq  = scif_uart_init_preirq,
     .init_postirq = scif_uart_init_postirq,
@@ -281,6 +308,8 @@ static struct uart_driver __read_mostly scif_uart_driver = {
     .start_tx     = scif_uart_start_tx,
     .stop_tx      = scif_uart_stop_tx,
     .vuart_info   = scif_vuart_info,
+    .suspend      = scif_uart_suspend,
+    .resume       = scif_uart_resume,
 };
 
 static const struct dt_device_match scif_uart_dt_match[] __initconst =
-- 
2.43.0