Date: Fri, 16 Jan 2009 22:22:30 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r187348 - head/sys/dev/pci Message-ID: <200901162222.n0GMMUs1020195@svn.freebsd.org>
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Author: jhb Date: Fri Jan 16 22:22:30 2009 New Revision: 187348 URL: http://svn.freebsd.org/changeset/base/187348 Log: Disable decoding of BARs by devices before we trash the value in the BAR 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 Modified: head/sys/dev/pci/pci.c Modified: head/sys/dev/pci/pci.c ============================================================================== --- head/sys/dev/pci/pci.c Fri Jan 16 22:16:54 2009 (r187347) +++ head/sys/dev/pci/pci.c Fri Jan 16 22:22:30 2009 (r187348) @@ -2291,9 +2291,27 @@ pci_add_map(device_t pcib, device_t bus, 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;
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