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Revert r276949 and redo the fix for PCIe/PCI bridges, which do not

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follow specification and do not provide PCIe capability.

Verify if the port above such bridge is downstream PCIe (or root port)
and treat the bridge as PCIe/PCI then.  This allows to avoid
maintaining the table of device ids for bridges without capability,
while still calculate correct request originator for devices behind
the bridge.

Submitted by:	Jason Harmening <jason.harmening@gmail.com>
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2015-02-21 22:38:32 +00:00
parent c06167fbd3
commit af02586229
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=279117
1 changed files with 26 additions and 6 deletions
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32
sys/x86/iommu/busdma_dmar.c
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@ -98,6 +98,8 @@ dmar_get_requester(device_t dev, uint16_t *rid)
devclass_t pci_class;
device_t l, pci, pcib, pcip, pcibp, requester;
int cap_offset;
uint16_t pcie_flags;
bool bridge_is_pcie;
pci_class = devclass_find("pci");
l = requester = dev;
@ -144,13 +146,30 @@ dmar_get_requester(device_t dev, uint16_t *rid)
} else {
/*
* Device is not PCIe, it cannot be seen as a
* requester by DMAR unit.
* requester by DMAR unit. Check whether the
* bridge is PCIe.
*/
requester = pcibp;
bridge_is_pcie = pci_find_cap(pcib, PCIY_EXPRESS,
&cap_offset) == 0;
requester = pcib;
/* Check whether the bus above the bridge is PCIe. */
if (pci_find_cap(pcibp, PCIY_EXPRESS,
&cap_offset) == 0) {
/*
* Check for a buggy PCIe/PCI bridge that
* doesn't report the express capability. If
* the bridge above it is express but isn't a
* PCI bridge, then we know pcib is actually a
* PCIe/PCI bridge.
*/
if (!bridge_is_pcie && pci_find_cap(pcibp,
PCIY_EXPRESS, &cap_offset) == 0) {
pcie_flags = pci_read_config(pcibp,
cap_offset + PCIER_FLAGS, 2);
if ((pcie_flags & PCIEM_FLAGS_TYPE) !=
PCIEM_TYPE_PCI_BRIDGE)
bridge_is_pcie = true;
}
if (bridge_is_pcie) {
/*
* The current device is not PCIe, but
* the bridge above it is. This is a
@ -168,6 +187,7 @@ dmar_get_requester(device_t dev, uint16_t *rid)
* non-taken transactions.
*/
*rid = PCI_RID(pci_get_bus(l), 0, 0);
l = pcibp;
} else {
/*
* Neither the device nor the bridge
@ -177,8 +197,8 @@ dmar_get_requester(device_t dev, uint16_t *rid)
* requester ID.
*/
*rid = pci_get_rid(pcib);
l = pcib;
}
l = pcibp;
}
}
return (requester);