Add locking to ppc and ppbus and mark the whole lot MPSAFE:

- To avoid having a bunch of locks that end up always getting acquired as
  a group, give each ppc(4) device a mutex which it shares with all the
  child devices including ppbus(4), lpt(4), plip(4), etc.  This mutex
  is then used for all the locking.
- Rework the interrupt handling stuff yet again.  Now ppbus drivers setup
  their interrupt handler during attach and tear it down during detach
  like most other drivers.  ppbus(4) only invokes the interrupt handler
  of the device that currently owns the bus (if any) when an interrupt
  occurs, however.  Also, interrupt handlers in general now accept their
  softc pointers as their argument rather than the device_t.  Another
  feature of the ppbus interrupt handlers is that they are called with
  the parent ppc device's lock already held.  This minimizes the number
  of lock operations during an interrupt.
- Mark plip(4), lpt(4), pcfclock(4), ppi(4), vpo(4) MPSAFE.
- lpbb(4) uses the ppc lock instead of Giant.
- Other plip(4) changes:
  - Add a mutex to protect the global tables in plip(4) and free them on
    module unload.
  - Add a detach routine.
  - Split out the init/stop code from the ioctl routine into separate
    functions.
- Other lpt(4) changes:
  - Use device_printf().
  - Use a dedicated callout for the lptout timer.
  - Allocate the I/O buffers at attach and detach rather than during
    open and close as this simplifies the locking at the cost of
    1024+32 bytes when the driver is attached.
- Other ppi(4) changes:
  - Use an sx lock to serialize open and close.
  - Remove unused HADBUS flag.
  - Add a detach routine.
  - Use a malloc'd buffer for each read and write to avoid races with
    concurrent read/write.
- Other pps(4) changes:
  - Use a callout rather than a callout handle with timeout().
  - Conform to the new ppbus requirements (regular mutex, non-filter
    interrupt handler).  pps(4) is probably going to have to become a
    standalone driver that doesn't use ppbus(4) to satisfy it's
    requirements for low latency as a result.
  - Use an sx lock to serialize open and close.
- Other vpo(4) changes:
  - Use the parent ppc device's lock to create the CAM sim instead of
    Giant.
- Other ppc(4) changes:
  - Fix ppc_isa's detach method to detach instead of calling attach.

Tested by:	  no one :-(

1 files changed, 76 insertions, 44 deletions

diff --git a/sys/dev/ppbus/ppbconf.c b/sys/dev/ppbus/ppbconf.c
index 196e2b8..a3617be 100644
--- a/sys/dev/ppbus/ppbconf.c
+++ b/sys/dev/ppbus/ppbconf.c
@@ -33,7 +33,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
+#include <sys/lock.h>
 #include <sys/module.h>
+#include <sys/mutex.h>
 #include <sys/bus.h>
 #include <sys/malloc.h>
 #include <sys/rman.h>
@@ -50,6 +52,8 @@ __FBSDID("$FreeBSD$");
 static MALLOC_DEFINE(M_PPBUSDEV, "ppbusdev", "Parallel Port bus device");
 
 
+static int	ppbus_intr(void *arg);
+
 /*
  * Device methods
  */
@@ -375,13 +379,36 @@ end_scan:
 static int
 ppbus_attach(device_t dev)
 {
+	struct ppb_data *ppb = device_get_softc(dev);
+	int error, rid;
+
+	error = BUS_READ_IVAR(device_get_parent(dev), dev, PPC_IVAR_LOCK,
+	    (uintptr_t *)&ppb->ppc_lock);
+	if (error) {
+		device_printf(dev, "Unable to fetch parent's lock\n");
+		return (error);
+	}
+
+	rid = 0;
+	ppb->ppc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
+	    RF_SHAREABLE);
+	if (ppb->ppc_irq_res != NULL) {
+		error = BUS_WRITE_IVAR(device_get_parent(dev), dev,
+		    PPC_IVAR_INTR_HANDLER, (uintptr_t)&ppbus_intr);
+		if (error) {
+			device_printf(dev, "Unable to set interrupt handler\n");
+			return (error);
+		}
+	}
 
 	/* Locate our children */
 	bus_generic_probe(dev);
 
 #ifndef DONTPROBE_1284
 	/* detect IEEE1284 compliant devices */
+	mtx_lock(ppb->ppc_lock);
 	ppb_scan_bus(dev);
+	mtx_unlock(ppb->ppc_lock);
 #endif /* !DONTPROBE_1284 */
 
 	/* launch attachment of the added children */
@@ -412,26 +439,43 @@ ppbus_detach(device_t dev)
 }
 
 static int
+ppbus_intr(void *arg)
+{
+	struct ppb_device *ppbdev;
+	struct ppb_data *ppb = arg;
+
+	mtx_assert(ppb->ppc_lock, MA_OWNED);
+	if (ppb->ppb_owner == NULL)
+		return (ENOENT);
+
+	ppbdev = device_get_ivars(ppb->ppb_owner);
+	if (ppbdev->intr_hook == NULL)
+		return (ENOENT);
+
+	ppbdev->intr_hook(ppbdev->intr_arg);
+	return (0);
+}
+
+static int
 ppbus_setup_intr(device_t bus, device_t child, struct resource *r, int flags,
     driver_filter_t *filt, void (*ihand)(void *), void *arg, void **cookiep)
 {
-	int error;
-	struct ppb_data *ppb = DEVTOSOFTC(bus);
 	struct ppb_device *ppbdev = device_get_ivars(child);
+	struct ppb_data *ppb = DEVTOSOFTC(bus);
 
-	/* a device driver must own the bus to register an interrupt */
-	if (ppb->ppb_owner != child)
+	/* We do not support filters. */
+	if (filt != NULL || ihand == NULL)
 		return (EINVAL);
 
-	if ((error = BUS_SETUP_INTR(device_get_parent(bus), child, r, flags,
-					filt, ihand, arg, cookiep)))
-		return (error);
+	/* Can only attach handlers to the parent device's resource. */
+	if (ppb->ppc_irq_res != r)
+		return (EINVAL);
 
-	/* store the resource and the cookie for eventually forcing
-	 * handler unregistration
-	 */
-	ppbdev->intr_cookie = *cookiep;
-	ppbdev->intr_resource = r;
+	mtx_lock(ppb->ppc_lock);
+	ppbdev->intr_hook = ihand;
+	ppbdev->intr_arg = arg;
+	*cookiep = ppbdev;
+	mtx_unlock(ppb->ppc_lock);
 
 	return (0);
 }
@@ -439,19 +483,19 @@ ppbus_setup_intr(device_t bus, device_t child, struct resource *r, int flags,
 static int
 ppbus_teardown_intr(device_t bus, device_t child, struct resource *r, void *ih)
 {
+	struct ppb_device *ppbdev = device_get_ivars(child);
 	struct ppb_data *ppb = DEVTOSOFTC(bus);
-	struct ppb_device *ppbdev = (struct ppb_device *)device_get_ivars(child);
 
-	/* a device driver must own the bus to unregister an interrupt */
-	if ((ppb->ppb_owner != child) || (ppbdev->intr_cookie != ih) ||
-			(ppbdev->intr_resource != r))
+	mtx_lock(ppb->ppc_lock);
+	if (ppbdev != ih || ppb->ppc_irq_res != r) {
+		mtx_unlock(ppb->ppc_lock);
 		return (EINVAL);
+	}
 
-	ppbdev->intr_cookie = 0;
-	ppbdev->intr_resource = 0;
+	ppbdev->intr_hook = NULL;
+	mtx_unlock(ppb->ppc_lock);
 
-	/* pass unregistration to the upper layer */
-	return (BUS_TEARDOWN_INTR(device_get_parent(bus), child, r, ih));
+	return (0);
 }
 
 /*
@@ -464,27 +508,26 @@ ppbus_teardown_intr(device_t bus, device_t child, struct resource *r, void *ih)
 int
 ppb_request_bus(device_t bus, device_t dev, int how)
 {
-	int s, error = 0;
 	struct ppb_data *ppb = DEVTOSOFTC(bus);
 	struct ppb_device *ppbdev = (struct ppb_device *)device_get_ivars(dev);
+	int error = 0;
 
+	mtx_assert(ppb->ppc_lock, MA_OWNED);
 	while (!error) {
-		s = splhigh();
 		if (ppb->ppb_owner) {
-			splx(s);
-
 			switch (how) {
-			case (PPB_WAIT | PPB_INTR):
-				error = tsleep(ppb, PPBPRI|PCATCH, "ppbreq", 0);
+			case PPB_WAIT | PPB_INTR:
+				error = mtx_sleep(ppb, ppb->ppc_lock,
+				    PPBPRI | PCATCH, "ppbreq", 0);
 				break;
 
-			case (PPB_WAIT | PPB_NOINTR):
-				error = tsleep(ppb, PPBPRI, "ppbreq", 0);
+			case PPB_WAIT | PPB_NOINTR:
+				error = mtx_sleep(ppb, ppb->ppc_lock, PPBPRI,
+				    "ppbreq", 0);
 				break;
 
 			default:
 				return (EWOULDBLOCK);
-				break;
 			}
 
 		} else {
@@ -499,7 +542,6 @@ ppb_request_bus(device_t bus, device_t dev, int how)
 			if (ppbdev->ctx.valid)
 				ppb_set_mode(bus, ppbdev->ctx.mode);
 
-			splx(s);
 			return (0);
 		}
 	}
@@ -515,24 +557,12 @@ ppb_request_bus(device_t bus, device_t dev, int how)
 int
 ppb_release_bus(device_t bus, device_t dev)
 {
-	int s, error;
 	struct ppb_data *ppb = DEVTOSOFTC(bus);
 	struct ppb_device *ppbdev = (struct ppb_device *)device_get_ivars(dev);
 
-	if (ppbdev->intr_resource != 0)
-		/* force interrupt handler unregistration when the ppbus is released */
-		if ((error = BUS_TEARDOWN_INTR(bus, dev, ppbdev->intr_resource,
-					       ppbdev->intr_cookie)))
-			return (error);
-
-	s = splhigh();
-	if (ppb->ppb_owner != dev) {
-		splx(s);
+	mtx_assert(ppb->ppc_lock, MA_OWNED);
+	if (ppb->ppb_owner != dev)
 		return (EACCES);
-	}
-
-	ppb->ppb_owner = 0;
-	splx(s);
 
 	/* save the context of the device */
 	ppbdev->ctx.mode = ppb_get_mode(bus);
@@ -540,6 +570,8 @@ ppb_release_bus(device_t bus, device_t dev)
 	/* ok, now the context of the device is valid */
 	ppbdev->ctx.valid = 1;
 
+	ppb->ppb_owner = 0;
+
 	/* wakeup waiting processes */
 	wakeup(ppb);