Author: jhb
Date: Thu Jun 27 20:35:39 2013
New Revision: 252317
URL: http://svnweb.freebsd.org/changeset/base/252317
Log:
MFC 250418,252166:
Revision 233677 broke certain machines. Specifically, if the firmware/BIOS
assigned conflicting ranges to BARs then leaving the BARs alone could
result in one device stealing mmio accesses intended to go to a second
device. Prior to 233677 the PCI bus driver attempted to handle this case
by clearing the BAR to 0 depending on BARs based at 0 not decoding (which
is not guaranteed to be true). Now when a conflicting BAR is detected the
following steps are taken:
1) If hw.pci.realloc_bars (a new tunable) is enabled (default is disabled),
then ignore the current BAR setting from the firmware and attempt to
allocate a fresh resource range for the BAR.
2) If 1) failed (or was disabled), disable decoding for the relevant
BAR type (e.g. disable mem decoding for a memory BAR) and emit a
warning if booting verbose.
Modified:
stable/9/sys/dev/pci/pci.c
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/dev/ (props changed)
Modified: stable/9/sys/dev/pci/pci.c
==============================================================================
--- stable/9/sys/dev/pci/pci.c Thu Jun 27 20:27:34 2013 (r252316)
+++ stable/9/sys/dev/pci/pci.c Thu Jun 27 20:35:39 2013 (r252317)
@@ -289,6 +289,12 @@ SYSCTL_INT(_hw_pci, OID_AUTO, enable_io_
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_realloc_bars = 0;
+TUNABLE_INT("hw.pci.realloc_bars", &pci_do_realloc_bars);
+SYSCTL_INT(_hw_pci, OID_AUTO, realloc_bars, CTLFLAG_RW,
+ &pci_do_realloc_bars, 0,
+ "Attempt to allocate a new range for any BARs whose original
firmware-assigned ranges fail to allocate during the initial device scan.");
+
static int pci_do_power_nodriver = 0;
TUNABLE_INT("hw.pci.do_power_nodriver", &pci_do_power_nodriver);
SYSCTL_INT(_hw_pci, OID_AUTO, do_power_nodriver, CTLFLAG_RW,
@@ -2745,13 +2751,34 @@ pci_add_map(device_t bus, device_t dev,
*/
res = resource_list_reserve(rl, bus, dev, type, ®, start, end, count,
prefetch ? RF_PREFETCHABLE : 0);
+ if (pci_do_realloc_bars && res == NULL && (start != 0 || end != ~0ul)) {
+ /*
+ * If the allocation fails, try to allocate a resource for
+ * this BAR using any available range. The firmware felt
+ * it was important enough to assign a resource, so don't
+ * disable decoding if we can help it.
+ */
+ resource_list_delete(rl, type, reg);
+ resource_list_add(rl, type, reg, 0, ~0ul, count);
+ res = resource_list_reserve(rl, bus, dev, type, ®, 0, ~0ul,
+ count, prefetch ? RF_PREFETCHABLE : 0);
+ }
if (res == NULL) {
/*
* If the allocation fails, delete the resource list entry
- * to force pci_alloc_resource() to allocate resources
- * from the parent.
+ * and disable decoding for this device.
+ *
+ * If the driver requests this resource in the future,
+ * pci_reserve_map() will try to allocate a fresh
+ * resource range.
*/
resource_list_delete(rl, type, reg);
+ pci_disable_io(dev, type);
+ if (bootverbose)
+ device_printf(bus,
+ "pci%d:%d:%d:%d bar %#x failed to allocate\n",
+ pci_get_domain(dev), pci_get_bus(dev),
+ pci_get_slot(dev), pci_get_function(dev), reg);
} else {
start = rman_get_start(res);
pci_write_bar(dev, pm, start);
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