Add system tunable to turn off power state changes. Default to off until

we get the resource allocation stuff hammered out.

Fix and off by one error that caused unnecessary filtering of valid
BARs for only 4 bytes than ICH3 and other PCI IDE controllers have.
Andrew Gallatin submitted this, although it doesn't solve the problems
ICH3 controllers have with the new code, it does restore the former
resource list on the probe line.

1 files changed, 48 insertions, 15 deletions

diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index cf9ffe2..63ae28b 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -176,6 +176,14 @@ SYSCTL_INT(_hw_pci, OID_AUTO, enable_io_modes, CTLFLAG_RW,
 enable these bits correctly.  We'd like to do this all the time, but there\n\
 are some peripherals that this causes problems with.");
 
+static int pci_do_powerstate = 0;
+TUNABLE_INT("hw.pci.do_powerstate", (int *)&pci_do_powerstate);
+SYSCTL_INT(_hw_pci, OID_AUTO, do_powerstate, CTLFLAG_RW,
+    &pci_do_powerstate, 0,
+    "Enable setting the power states of the PCI devices.  This means that we\n\
+set devices into D0 before probe/attach, and D3 if they fail to attach.  It\n\
+also means we set devices into D3 state before shutdown.");
+
 /* Find a device_t by bus/slot/function */
 
 device_t
@@ -484,6 +492,12 @@ pci_set_powerstate_method(device_t dev, device_t child, int state)
 	uint16_t status;
 	int result;
 
+	/*
+	 * Dx -> Dx is a nop always.
+	 */
+	if (pci_get_powerstate(dev) == state)
+		return (0);
+
 	if (cfg->pp.pp_cap != 0) {
 		status = PCI_READ_CONFIG(dev, child, cfg->pp.pp_status, 2)
 		    & ~PCIM_PSTAT_DMASK;
@@ -752,13 +766,14 @@ pci_add_map(device_t pcib, device_t bus, device_t dev,
 	 * For I/O registers, if bottom bit is set, and the next bit up
 	 * isn't clear, we know we have a BAR that doesn't conform to the
 	 * spec, so ignore it.  Also, sanity check the size of the data
-	 * areas to the type of memory involved.
+	 * areas to the type of memory involved.  Memory must be at least
+	 * 32 bytes in size, while I/O ranges must be at least 4.
 	 */
 	if ((testval & 0x1) == 0x1 &&
 	    (testval & 0x2) != 0)
 		return (1);
 	if ((type == SYS_RES_MEMORY && ln2size < 5) ||
-	    (type == SYS_RES_IOPORT && ln2size < 3))
+	    (type == SYS_RES_IOPORT && ln2size < 2))
 		return (1);
 
 	if (ln2range == 64)
@@ -1696,16 +1711,26 @@ pci_cfg_restore(device_t dev, struct pci_devinfo *dinfo)
 	int i;
 
 	/*
-	 * Only do header type 0 devices.  Type 1 devices are bridges, which
-	 * we know need special treatment.  Type 2 devices are cardbus bridges
-	 * which also require special treatment.  Other types are unknown, and
-	 * we err on the side of safety by ignoring them.
+	 * Only do header type 0 devices.  Type 1 devices are bridges,
+	 * which we know need special treatment.  Type 2 devices are
+	 * cardbus bridges which also require special treatment.
+	 * Other types are unknown, and we err on the side of safety
+	 * by ignoring them.
 	 */
 	if (dinfo->cfg.hdrtype != 0)
 		return;
-	if (pci_get_powerstate(dev) != PCI_POWERSTATE_D0) {
-		printf("pci%d:%d:%d: setting power state D0\n", dinfo->cfg.bus,
-		    dinfo->cfg.slot, dinfo->cfg.func);
+	/*
+	 * Restore the device to full power mode.  We must do this
+	 * before we restore the registers because moving from D3 to
+	 * D0 will cause the chip's BARs and some other registers to
+	 * be reset to some unknown power on reset values.  Cut down
+	 * the noise on boot by doing nothing if we are already in
+	 * state D0.
+	 */
+	if (pci_do_powerstate && (pci_get_powerstate(dev) != PCI_POWERSTATE_D0)) {
+		printf("pci%d:%d:%d: Transition from D%d to D0\n", dinfo->cfg.bus,
+		    dinfo->cfg.slot, dinfo->cfg.func,
+		    pci_get_powerstate(dev));
 		pci_set_powerstate(dev, PCI_POWERSTATE_D0);
 	}
 	for (i = 0; i < dinfo->cfg.nummaps; i++)
@@ -1725,6 +1750,7 @@ pci_cfg_save(device_t dev, struct pci_devinfo *dinfo, int setstate)
 {
 	int i;
 	uint32_t cls;
+	int ps;
 
 	/*
 	 * Only do header type 0 devices.  Type 1 devices are bridges, which
@@ -1763,15 +1789,22 @@ pci_cfg_save(device_t dev, struct pci_devinfo *dinfo, int setstate)
 	 * detach and (b) use generic drivers for these devices so that some
 	 * device actually attaches.  We need to make sure that when we
 	 * implement (a) we don't power the device down on a reattach.
-	 *
-	 * John and Nate also tell me that we should be running the power up
-	 * and power down hooks when we change power state for those nodes
-	 * that have ACPI hooks in the tree.
 	 */
 	cls = pci_get_class(dev);
-	if (setstate && cls != PCIC_DISPLAY && cls != PCIC_MEMORY) {
+	if (pci_do_powerstate && setstate && cls != PCIC_DISPLAY && cls != PCIC_MEMORY) {
+		/*
+		 * PCI spec is clear that we can only go into D3 state from
+		 * D0 state.  Transition from D[12] into D0 before going
+		 * to D3 state.
+		 */
+		ps = pci_get_powerstate(dev);
+		if (ps != PCI_POWERSTATE_D0 && ps != PCI_POWERSTATE_D3) {
+			printf("pci%d:%d:%d: Transition from D%d to D0\n", dinfo->cfg.bus,
+			    dinfo->cfg.slot, dinfo->cfg.func, ps);
+			pci_set_powerstate(dev, PCI_POWERSTATE_D0);
+		}
 		if (pci_get_powerstate(dev) != PCI_POWERSTATE_D3) {
-			printf("pci%d:%d:%d: setting power state D3\n", dinfo->cfg.bus,
+			printf("pci%d:%d:%d: Transition from D0 to D3\n", dinfo->cfg.bus,
 			    dinfo->cfg.slot, dinfo->cfg.func);
 			pci_set_powerstate(dev, PCI_POWERSTATE_D3);
 		}