A number of Linkstation models from Buffalo Technology with PPC, ARM, and
also MIPS (I think) CPUs have a power-management controller connected to a
UART. Among other things that chip controlls power and reset buttons.
Working on a standby support for one of these systems (ppc mpc8241 based),
the only suitable wakeup source there is the power button, which means, I
have to configure one of the two system UARTs to not be suspendsd. Using
the device_*_wakeup API doesn't quite work because both serial ports share
one device. The below patch proposes a new port flag UPF_MAY_WAKEUP to
configure such UARTs. It also adds support for a new "can-wakeup" serial
node property to the legacy_serial driver.
Signed-off-by: Guennadi Liakhovetski <[EMAIL PROTECTED]>
diff --git a/arch/powerpc/kernel/legacy_serial.c
b/arch/powerpc/kernel/legacy_serial.c
index cea8045..888d9bb 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -51,6 +51,9 @@ static int __init add_legacy_port(struct device_node *np, int
want_index,
/* get default speed if present */
spd = of_get_property(np, "current-speed", NULL);
+ if (of_find_property(np, "can-wakeup", NULL))
+ flags |= UPF_MAY_WAKEUP;
+
/* If we have a location index, then try to use it */
if (want_index >= 0 && want_index < MAX_LEGACY_SERIAL_PORTS)
index = want_index;
diff --git a/arch/powerpc/kernel/of_platform.c
b/arch/powerpc/kernel/of_platform.c
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 0b3ec38..77dd552 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -130,6 +130,7 @@ struct uart_8250_port {
unsigned char mcr_mask; /* mask of user bits */
unsigned char mcr_force; /* mask of forced bits */
unsigned char lsr_break_flag;
+ char suspended;
/*
* We provide a per-port pm hook.
@@ -2680,8 +2681,14 @@ static int serial8250_suspend(struct platform_device
*dev, pm_message_t state)
for (i = 0; i < UART_NR; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
- if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
- uart_suspend_port(&serial8250_reg, &up->port);
+ if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
{
+ if (up->port.flags & UPF_MAY_WAKEUP)
+ enable_irq_wake(up->port.irq);
+ else {
+ uart_suspend_port(&serial8250_reg, &up->port);
+ up->suspended = 1;
+ }
+ }
}
return 0;
@@ -2694,8 +2701,13 @@ static int serial8250_resume(struct platform_device *dev)
for (i = 0; i < UART_NR; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
- if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
- serial8250_resume_port(i);
+ if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
{
+ if (up->suspended) {
+ serial8250_resume_port(i);
+ up->suspended = 0;
+ } else
+ disable_irq_wake(up->port.irq);
+ }
}
return 0;
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 773d8d8..d585967 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -272,6 +272,7 @@ struct uart_port {
#define UPF_LOW_LATENCY ((__force upf_t) (1 << 13))
#define UPF_BUGGY_UART ((__force upf_t) (1 << 14))
#define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16))
+#define UPF_MAY_WAKEUP ((__force upf_t) (1 << 17))
#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
#define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
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