[PATCH v2 3/5] PCI: iproc: Disable MSI parsing in certain PAXC blocks

Ray Jui
2018-06-12T00:21:38Z

The internal MSI parsing logic in certain revisions of PAXC root
complexes does not work properly and can casue corruptions on the
writes. They need to be disabled

Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
---
drivers/pci/host/pcie-iproc.c | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
index 680f6b1..0804aa2 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -1197,10 +1197,22 @@ static int iproc_pcie_paxb_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr)
return ret;
}

-static void iproc_pcie_paxc_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr)
+static void iproc_pcie_paxc_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr,
+ bool enable)
{
u32 val;

+ if (!enable) {
+ /*
+ * Disable PAXC MSI steering. All write transfers will be
+ * treated as non-MSI transfers
+ */
+ val = iproc_pcie_read_reg(pcie, IPROC_PCIE_MSI_EN_CFG);
+ val &= ~MSI_ENABLE_CFG;
+ iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_EN_CFG, val);
+ return;
+ }
+
/*
* Program bits [43:13] of address of GITS_TRANSLATER register into
* bits [30:0] of the MSI base address register. In fact, in all iProc
@@ -1254,7 +1266,7 @@ static int iproc_pcie_msi_steer(struct iproc_pcie *pcie,
return ret;
break;
case IPROC_PCIE_PAXC_V2:
- iproc_pcie_paxc_v2_msi_steer(pcie, msi_addr);
+ iproc_pcie_paxc_v2_msi_steer(pcie, msi_addr, true);
break;
default:
return -EINVAL;
@@ -1480,6 +1492,24 @@ int iproc_pcie_remove(struct iproc_pcie *pcie)
}
EXPORT_SYMBOL(iproc_pcie_remove);

+/*
+ * The MSI parsing logic in certain revisions of Broadcom PAXC based root
+ * complex does not work and needs to be disabled
+ */
+static void quirk_paxc_disable_msi_parsing(struct pci_dev *pdev)
+{
+ struct iproc_pcie *pcie = iproc_data(pdev->bus);
+
+ if (pdev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
+ iproc_pcie_paxc_v2_msi_steer(pcie, 0, false);
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0x16f0,
+ quirk_paxc_disable_msi_parsing);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0xd802,
+ quirk_paxc_disable_msi_parsing);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0xd804,
+ quirk_paxc_disable_msi_parsing);
+
MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
MODULE_DESCRIPTION("Broadcom iPROC PCIe common driver");
MODULE_LICENSE("GPL v2");
--
2.1.4