Update PCI drivers to no longer look at the MEMIO-enabled bit in the PCI

command register.  The lazy BAR allocation code in FreeBSD sometimes
disables this bit when it detects a range conflict, and will re-enable
it on demand when a driver allocates the BAR.  Thus, the bit is no longer
a reliable indication of capability, and should not be checked.  This
results in the elimination of a lot of code from drivers, and also gives
the opportunity to simplify a lot of drivers to use a helper API to set
the busmaster enable bit.

This changes fixes some recent reports of disk controllers and their
associated drives/enclosures disappearing during boot.

Submitted by:	jhb
Reviewed by:	jfv, marius, achadd, achim
MFC after:	1 day

1 files changed, 2 insertions, 14 deletions

diff --git a/sys/dev/mfi/mfi_pci.c b/sys/dev/mfi/mfi_pci.c
index 5f757da..6572893 100644
--- a/sys/dev/mfi/mfi_pci.c
+++ b/sys/dev/mfi/mfi_pci.c
@@ -187,7 +187,6 @@ mfi_pci_attach(device_t dev)
 {
 	struct mfi_softc *sc;
 	struct mfi_ident *m;
-	uint32_t command;
 	int count, error;
 
 	sc = device_get_softc(dev);
@@ -196,19 +195,8 @@ mfi_pci_attach(device_t dev)
 	m = mfi_find_ident(dev);
 	sc->mfi_flags = m->flags;
 
-	/* Verify that the adapter can be set up in PCI space */
-	command = pci_read_config(dev, PCIR_COMMAND, 2);
-	command |= PCIM_CMD_BUSMASTEREN;
-	pci_write_config(dev, PCIR_COMMAND, command, 2);
-	command = pci_read_config(dev, PCIR_COMMAND, 2);
-	if ((command & PCIM_CMD_BUSMASTEREN) == 0) {
-		device_printf(dev, "Can't enable PCI busmaster\n");
-		return (ENXIO);
-	}
-	if ((command & PCIM_CMD_MEMEN) == 0) {
-		device_printf(dev, "PCI memory window not available\n");
-		return (ENXIO);
-	}
+	/* Ensure busmastering is enabled */
+	pci_enable_busmaster(dev);
 
 	/* Allocate PCI registers */
 	if ((sc->mfi_flags & MFI_FLAGS_1064R) ||