Add sbbc(4), a driver for the BootBus controller found in Serengeti and

StarCat systems which provides time-of-day services for both as well as
console service for Serengeti, i.e. Sun Fire V1280. While the latter is
described with a device type of serial in the OFW device tree, it isn't
actually an UART. Nevertheless the console service is handled by uart(4)
as this allowed to re-use quite a bit of MD and MI code. Actually, this
idea is stolen from Linux which interfaces the sun4v hypervisor console
with the Linux counterpart of uart(4).

sys/conf/files.sparc64

@@ -79,6 +79,7 @@ sparc64/pci/ofw_pcib.c		optional	pci
 sparc64/pci/ofw_pcib_subr.c	optional	pci
 sparc64/pci/ofw_pcibus.c	optional	pci
 sparc64/pci/psycho.c		optional	pci
+sparc64/pci/sbbc.c		optional	uart sbbc
 sparc64/pci/schizo.c		optional	pci
 sparc64/sbus/dma_sbus.c		optional	sbus
 sparc64/sbus/sbus.c		optional	sbus

sys/dev/uart/uart.h

@@ -67,6 +67,7 @@ struct uart_class;
 extern struct uart_class uart_ns8250_class __attribute__((weak));
 extern struct uart_class uart_quicc_class __attribute__((weak));
 extern struct uart_class uart_sab82532_class __attribute__((weak));
+extern struct uart_class uart_sbbc_class __attribute__((weak));
 extern struct uart_class uart_z8530_class __attribute__((weak));
 
 #ifdef PC98

sys/dev/uart/uart_cpu_sparc64.c

@@ -133,6 +133,14 @@ uart_cpu_getdev_console(phandle_t options, char *dev, size_t devsz)
 		return (-1);
 	if (strcmp(buf, "serial") != 0)
 		return (-1);
+	/* For a Serengeti console device point to the bootbus controller. */
+	if (OF_getprop(input, "name", buf, sizeof(buf)) > 0 &&
+	    !strcmp(buf, "sgcn")) {
+		if ((chosen = OF_finddevice("/chosen")) == -1)
+			return (-1);
+		if (OF_getprop(chosen, "iosram", &input, sizeof(input)) == -1)
+			return (-1);
+	}
 	return (input);
 }
 
@@ -258,6 +266,9 @@ uart_cpu_getdev(int devtype, struct uart_devinfo *di)
 	    !strcmp(compat, "su16552")) {
 		class = &uart_ns8250_class;
 		di->bas.chan = 0;
+	} else if (!strcmp(compat, "sgsbbc")) {
+		class = &uart_sbbc_class;
+		di->bas.chan = 0;
 	}
 	if (class == NULL)
 		return (ENXIO);

sys/sparc64/conf/GENERIC

@@ -143,6 +143,9 @@ device		mk48txx		# Mostek MK48Txx clocks
 device		rtc		# rtc (really a front-end for the MC146818)
 device		mc146818	# Motorola MC146818 and compatible clocks
 device		epic		# Sun Fire V215/V245 LEDs
+device		sbbc		# Sun BootBus controller (time-of-day clock for
+				# Serengeti and StarCat, console for Serengeti,
+				# requires device uart)
 
 # Serial (COM) ports
 device		puc		# Multi-channel uarts

sys/sparc64/conf/NOTES

@@ -37,6 +37,7 @@ device		eeprom		# eeprom (really a front-end for the MK48Txx)
 device		mk48txx		# Mostek MK48Txx clocks
 device		rtc		# rtc (really a front-end for the MC146818)
 device		mc146818	# Motorola MC146818 and compatible clocks
+device		sbbc		# Sun BootBus controller
 
 #
 # Optional devices: