uart: add resume method and enable it for attachments on the most common

x86 buses

Otherwise the uart hardware could be in such a state after the resume
where IER is cleared and thus no interrupts are generated.

This behavior is observed and tested with QEMU, so I am comitting this
change to help with my debugging.
There has been no feedback from users of serial ports on real hardware.

MFC after:	20 days

5 files changed, 13 insertions, 0 deletions

diff --git a/sys/dev/uart/uart_bus.h b/sys/dev/uart/uart_bus.h
index 01752d0..322e9a8 100644
--- a/sys/dev/uart/uart_bus.h
+++ b/sys/dev/uart/uart_bus.h
@@ -138,6 +138,7 @@ extern char uart_driver_name[];
 
 int uart_bus_attach(device_t dev);
 int uart_bus_detach(device_t dev);
+int uart_bus_resume(device_t dev);
 serdev_intr_t *uart_bus_ihand(device_t dev, int ipend);
 int uart_bus_ipend(device_t dev);
 int uart_bus_probe(device_t dev, int regshft, int rclk, int rid, int chan);
diff --git a/sys/dev/uart/uart_bus_acpi.c b/sys/dev/uart/uart_bus_acpi.c
index 756f7f2..ccd213d 100644
--- a/sys/dev/uart/uart_bus_acpi.c
+++ b/sys/dev/uart/uart_bus_acpi.c
@@ -47,6 +47,7 @@ static device_method_t uart_acpi_methods[] = {
 	DEVMETHOD(device_probe,		uart_acpi_probe),
 	DEVMETHOD(device_attach,	uart_bus_attach),
 	DEVMETHOD(device_detach,	uart_bus_detach),
+	DEVMETHOD(device_resume,	uart_bus_resume),
 	{ 0, 0 }
 };
 
diff --git a/sys/dev/uart/uart_bus_isa.c b/sys/dev/uart/uart_bus_isa.c
index 1836663..1fda15f 100644
--- a/sys/dev/uart/uart_bus_isa.c
+++ b/sys/dev/uart/uart_bus_isa.c
@@ -50,6 +50,7 @@ static device_method_t uart_isa_methods[] = {
 	DEVMETHOD(device_probe,		uart_isa_probe),
 	DEVMETHOD(device_attach,	uart_bus_attach),
 	DEVMETHOD(device_detach,	uart_bus_detach),
+	DEVMETHOD(device_resume,	uart_bus_resume),
 	{ 0, 0 }
 };
 
diff --git a/sys/dev/uart/uart_bus_pci.c b/sys/dev/uart/uart_bus_pci.c
index 307ee340..4237fa4 100644
--- a/sys/dev/uart/uart_bus_pci.c
+++ b/sys/dev/uart/uart_bus_pci.c
@@ -51,6 +51,7 @@ static device_method_t uart_pci_methods[] = {
 	DEVMETHOD(device_probe,		uart_pci_probe),
 	DEVMETHOD(device_attach,	uart_bus_attach),
 	DEVMETHOD(device_detach,	uart_bus_detach),
+	DEVMETHOD(device_resume,	uart_bus_resume),
 	{ 0, 0 }
 };
 
diff --git a/sys/dev/uart/uart_core.c b/sys/dev/uart/uart_core.c
index 47d5f3d..f5a9a1c 100644
--- a/sys/dev/uart/uart_core.c
+++ b/sys/dev/uart/uart_core.c
@@ -590,3 +590,12 @@ uart_bus_detach(device_t dev)
 
 	return (0);
 }
+
+int
+uart_bus_resume(device_t dev)
+{
+	struct uart_softc *sc;
+
+	sc = device_get_softc(dev);
+	return (UART_ATTACH(sc));
+}