DM: cleanup resource for uart.

Add deinit function for uart.
Another work is add resource cleanup functions which is called
by other components when they are using uart.

Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>

devicemodel/hw/pci/uart.c

@@ -106,9 +106,22 @@ pci_uart_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 	return 0;
 }
 
+static void
+pci_uart_deinit(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
+{
+	struct uart_vdev *uart = (struct uart_vdev *)dev->arg;
+
+	if (uart == NULL)
+		return;
+
+	uart_release_backend(uart, opts);
+	uart_deinit(uart);
+}
+
 struct pci_vdev_ops pci_ops_com = {
 	.class_name	= "uart",
 	.vdev_init	= pci_uart_init,
+	.vdev_deinit	= pci_uart_deinit,
 	.vdev_barwrite	= pci_uart_write,
 	.vdev_barread	= pci_uart_read
 };

devicemodel/hw/platform/uart_core.c

@@ -274,6 +274,18 @@ uart_opentty(struct uart_vdev *uart)
 	}
 }
 
+static void
+uart_closetty(struct uart_vdev *uart)
+{
+	if (uart->tty.fd != STDIN_FILENO)
+		mevent_delete_close(uart->mev);
+	else
+		mevent_delete(uart->mev);
+
+	uart->mev = 0;
+	ttyclose();
+}
+
 static uint8_t
 modem_status(uint8_t mcr)
 {
@@ -692,3 +704,19 @@ uart_set_backend(struct uart_vdev *uart, const char *opts)
 
 	return retval;
 }
+
+void
+uart_release_backend(struct uart_vdev *uart, const char *opts)
+{
+	if (opts == NULL)
+		return;
+
+	uart_closetty(uart);
+	if (strcmp("stdio", opts) == 0) {
+		stdio_in_use = false;
+	} else
+		close(uart->tty.fd);
+
+	uart->tty.fd = 0;
+	uart->tty.opened = false;
+}

devicemodel/include/uart_core.h

@@ -44,4 +44,5 @@ void	uart_legacy_dealloc(int which);
 uint8_t	uart_read(struct uart_vdev *uart, int offset);
 void	uart_write(struct uart_vdev *uart, int offset, uint8_t value);
 int	uart_set_backend(struct uart_vdev *uart, const char *opt);
+void	uart_release_backend(struct uart_vdev *uart, const char *opts);
 #endif