Create new wrapper function: bus_delayed_attach_children()

Delay the attachment of children, when requested, until after interrutps are
running. This is often needed to allow children to run transactions on i2c or
spi busses. It's a common enough idiom that it will be useful to have its own
wrapper.

Reviewed by: ian
Differential Revision: https://reviews.freebsd.org/D21465

13 files changed, 83 insertions, 19 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 9a79aff4cc25..2981771836f8 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -34,6 +34,7 @@ MAN=	accept_filter.9 \
 	BUS_CHILD_DELETED.9 \
 	BUS_CHILD_DETACHED.9 \
 	BUS_CONFIG_INTR.9 \
+	bus_delayed_attach_children.9 \
 	BUS_DESCRIBE_INTR.9 \
 	bus_dma.9 \
 	bus_generic_attach.9 \
diff --git a/share/man/man9/bus_delayed_attach_children.9 b/share/man/man9/bus_delayed_attach_children.9
new file mode 100644
index 000000000000..724d90096537
--- /dev/null
+++ b/share/man/man9/bus_delayed_attach_children.9
@@ -0,0 +1,55 @@
+.\" -*- nroff -*-
+.\"
+.\" Copyright (c) 2019 M. Warner Losh
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd August 29, 2019
+.Dt BUS_DELAYED_ATTACH_CHILDREN 9
+.Os
+.Sh NAME
+.Nm bus_delayed_attach_children
+.Nd "request that the children be attached when interrupts are enabled"
+.Sh SYNOPSIS
+.In sys/param.h
+.In sys/bus.h
+.Pp
+.Ft int
+.Fn bus_delayed_attach_children "device_t dev"
+.Sh DESCRIPTION
+The
+.Fn bus_delayed_attach_children
+function requests that the children of this device
+be attached when interrupts are running.
+If interrupts are currently running, this happens immediately.
+If interrupts aren't yet running, this happens after interrupts are enabled, but
+before the system mounts root.
+.Sh RETURN VALUES
+A zero return value indicates success.
+.Sh SEE ALSO
+.Xr bus 9 ,
+.Xr device 9 ,
+.Xr driver 9
+.Sh AUTHORS
+This manual page was written by
+.An Warner Losh Aq Mt imp@FreeBSD.org .
diff --git a/sys/arm/broadcom/bcm2835/bcm2835_bsc.c b/sys/arm/broadcom/bcm2835/bcm2835_bsc.c
index 0c68a12a1f43..d4d246db03e8 100644
--- a/sys/arm/broadcom/bcm2835/bcm2835_bsc.c
+++ b/sys/arm/broadcom/bcm2835/bcm2835_bsc.c
@@ -347,7 +347,7 @@ bcm_bsc_attach(device_t dev)
 	}
 
 	/* Probe and attach the iicbus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
+	bus_delayed_attach_children(dev);
 
 	return (0);
 }
diff --git a/sys/arm/freescale/imx/imx_i2c.c b/sys/arm/freescale/imx/imx_i2c.c
index 1d21f7964acb..1811d7a084ad 100644
--- a/sys/arm/freescale/imx/imx_i2c.c
+++ b/sys/arm/freescale/imx/imx_i2c.c
@@ -449,8 +449,7 @@ no_recovery:
 	/* We don't do a hardware reset here because iicbus_attach() does it. */
 
 	/* Probe and attach the iicbus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
-	return (0);
+	return (bus_delayed_attach_children(dev));
 }
 
 static int
diff --git a/sys/arm/freescale/imx/imx_spi.c b/sys/arm/freescale/imx/imx_spi.c
index 21add56cef7f..6624955ff124 100644
--- a/sys/arm/freescale/imx/imx_spi.c
+++ b/sys/arm/freescale/imx/imx_spi.c
@@ -566,9 +566,7 @@ spi_attach(device_t dev)
 	 * their attach. We can't do IO until timers and interrupts are working.
 	 */
 	sc->spibus = device_add_child(dev, "spibus", -1);
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
-
-	return (0);
+	return (bus_delayed_attach_children(dev));
 }
 
 static int
diff --git a/sys/arm/mv/a37x0_spi.c b/sys/arm/mv/a37x0_spi.c
index 69a4ceeac080..6194232464ce 100644
--- a/sys/arm/mv/a37x0_spi.c
+++ b/sys/arm/mv/a37x0_spi.c
@@ -220,7 +220,7 @@ a37x0_spi_attach(device_t dev)
 	device_add_child(dev, "spibus", -1);
 
 	/* Probe and attach the spibus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
+	bus_delayed_attach_children(dev);
 
 	return (0);
 }
diff --git a/sys/arm/mv/mv_spi.c b/sys/arm/mv/mv_spi.c
index 1ad3b5749da5..95d7d21e85c3 100644
--- a/sys/arm/mv/mv_spi.c
+++ b/sys/arm/mv/mv_spi.c
@@ -174,9 +174,7 @@ mv_spi_attach(device_t dev)
 	device_add_child(dev, "spibus", -1);
 
 	/* Probe and attach the spibus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
-
-	return (0);
+	return (bus_delayed_attach_children(dev));
 }
 
 static int
diff --git a/sys/arm/ti/ti_i2c.c b/sys/arm/ti/ti_i2c.c
index 8f1804493192..4a9313d6f501 100644
--- a/sys/arm/ti/ti_i2c.c
+++ b/sys/arm/ti/ti_i2c.c
@@ -905,7 +905,7 @@ ti_i2c_attach(device_t dev)
 	}
 
 	/* Probe and attach the iicbus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
+	err = bus_delayed_attach_children(dev);
 
 out:
 	if (err) {
diff --git a/sys/dev/glxiic/glxiic.c b/sys/dev/glxiic/glxiic.c
index d5f5f248f4af..e742812824df 100644
--- a/sys/dev/glxiic/glxiic.c
+++ b/sys/dev/glxiic/glxiic.c
@@ -411,8 +411,7 @@ glxiic_attach(device_t dev)
 	glxiic_smb_enable(sc, IIC_FASTEST, 0);
 
 	/* Probe and attach the iicbus when interrupts are available. */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
-	error = 0;
+	error = bus_delayed_attach_children(dev);
 
 out:
 	if (error != 0) {
diff --git a/sys/dev/ichsmb/ichsmb.c b/sys/dev/ichsmb/ichsmb.c
index b69c40089024..5354d5ca94c6 100644
--- a/sys/dev/ichsmb/ichsmb.c
+++ b/sys/dev/ichsmb/ichsmb.c
@@ -131,11 +131,8 @@ ichsmb_attach(device_t dev)
 		goto fail;
 	}
 
-	/* Probe and attach the smbus when interrupts are available */
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
-
-	return (0);
-
+	/* Attach children when interrupts are available */
+	return (bus_delayed_attach_children(dev));
 fail:
 	mtx_destroy(&sc->mutex);
 	return (error);
diff --git a/sys/dev/ow/owc_gpiobus.c b/sys/dev/ow/owc_gpiobus.c
index 621f7b1c6f09..d01d5e6968b8 100644
--- a/sys/dev/ow/owc_gpiobus.c
+++ b/sys/dev/ow/owc_gpiobus.c
@@ -131,7 +131,7 @@ owc_gpiobus_attach(device_t dev)
 		free(kids, M_TEMP);
 	if (nkid == 0)
 		device_add_child(dev, "ow", -1);
-	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
+	bus_delayed_attach_children(dev);
 
 	return (0);
 }
diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index f40a0194ee22..f36cc881f182 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -3753,6 +3753,22 @@ bus_generic_attach(device_t dev)
 }
 
 /**
+ * @brief Helper function for delaying attaching children
+ *
+ * Many buses can't run transactions on the bus which children need to probe and
+ * attach until after interrupts and/or timers are running.  This function
+ * delays their attach until interrupts and timers are enabled.
+ */
+int
+bus_delayed_attach_children(device_t dev)
+{
+	/* Probe and attach the bus children when interrupts are available */
+	config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
+
+	return (0);
+}
+
+/**
  * @brief Helper function for implementing DEVICE_DETACH()
  *
  * This function can be used to help implement the DEVICE_DETACH() for
diff --git a/sys/sys/bus.h b/sys/sys/bus.h
index 508267754e41..a2d22af77277 100644
--- a/sys/sys/bus.h
+++ b/sys/sys/bus.h
@@ -567,6 +567,7 @@ int	bus_child_present(device_t child);
 int	bus_child_pnpinfo_str(device_t child, char *buf, size_t buflen);
 int	bus_child_location_str(device_t child, char *buf, size_t buflen);
 void	bus_enumerate_hinted_children(device_t bus);
+int	bus_delayed_attach_children(device_t bus);
 
 static __inline struct resource *
 bus_alloc_resource_any(device_t dev, int type, int *rid, u_int flags)