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authorChris Wright <chrisw@sous-sol.org>2009-12-04 23:15:21 +0300
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-12-05 03:19:24 +0300
commit5d990b627537e59a3a2f039ff588a4750e9c1a6a (patch)
tree8c0e723c3f9146da52b30c087a80fc417df2b41b /drivers/pci/pci.c
parentb26a34aa4792b3db2500b8a98cb7702765c1a92e (diff)
downloadlinux-5d990b627537e59a3a2f039ff588a4750e9c1a6a.tar.xz
PCI: add pci_request_acs
Commit ae21ee65e8bc228416bbcc8a1da01c56a847a60c "PCI: acs p2p upsteram forwarding enabling" doesn't actually enable ACS. Add a function to pci core to allow an IOMMU to request that ACS be enabled. The existing mechanism of using iommu_found() in the pci core to know when ACS should be enabled doesn't actually work due to initialization order; iommu has only been detected not initialized. Have Intel and AMD IOMMUs request ACS, and Xen does as well during early init of dom0. Cc: Allen Kay <allen.m.kay@intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r--drivers/pci/pci.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6af212c509c5..cd9b375f49d5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1550,6 +1550,16 @@ void pci_enable_ari(struct pci_dev *dev)
bridge->ari_enabled = 1;
}
+static int pci_acs_enable;
+
+/**
+ * pci_request_acs - ask for ACS to be enabled if supported
+ */
+void pci_request_acs(void)
+{
+ pci_acs_enable = 1;
+}
+
/**
* pci_enable_acs - enable ACS if hardware support it
* @dev: the PCI device
@@ -1560,6 +1570,9 @@ void pci_enable_acs(struct pci_dev *dev)
u16 cap;
u16 ctrl;
+ if (!pci_acs_enable)
+ return;
+
if (!pci_is_pcie(dev))
return;