d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Disable decoding of BARs by devices before we trash the value in the BAR

Browse Source 
by writing all 1's to it to determine its length.  This fixes issues with
MCFG on at least some machines where a trashed BAR claimed subsequent
attempts at PCI config transactions because the addresses in the MCFG
window fell in the decoding range of the BAR.

In general it is a bad idea to leave the BARs enabled while we are
frobbing with them in this manner.

Sleuthing by:  tegge
MFC after:     1 week
This commit is contained in:
John Baldwin 2009-01-16 22:22:30 +00:00
parent 1149b79dac
commit 589d604bf9
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sys/dev/pci/pci.c
View File

@ -2291,9 +2291,27 @@ pci_add_map(device_t pcib, device_t bus, device_t dev,
struct resource *res;
map = PCIB_READ_CONFIG(pcib, b, s, f, reg, 4);
/*
* Disable decoding via the command register before
* determining the BARs length since we will be placing them
* in a weird state.
*/
cmd = PCIB_READ_CONFIG(pcib, b, s, f, PCIR_COMMAND, 2);
PCIB_WRITE_CONFIG(pcib, b, s, f, PCIR_COMMAND,
cmd & ~(PCI_BAR_MEM(map) ? PCIM_CMD_MEMEN : PCIM_CMD_PORTEN), 2);
/*
* Determine the BAR's length by writing all 1's. The bottom
* log_2(size) bits of the BAR will stick as 0 when we read
* the value back.
*/
PCIB_WRITE_CONFIG(pcib, b, s, f, reg, 0xffffffff, 4);
testval = PCIB_READ_CONFIG(pcib, b, s, f, reg, 4);
/* Restore the BAR and command register. */
PCIB_WRITE_CONFIG(pcib, b, s, f, reg, map, 4);
PCIB_WRITE_CONFIG(pcib, b, s, f, PCIR_COMMAND, cmd, 2);
if (PCI_BAR_MEM(map))
type = SYS_RES_MEMORY;