PCI: designware-ep: Fix ->get_msi() to check MSI_EN bit

->get_msi() now checks MSI_EN bit in the MSI CAPABILITY register to
find whether the host supports MSI instead of using the
MSI ADDRESS in the MSI CAPABILITY register.

This fixes the issue with the following sequence
  'modprobe pci_endpoint_test' enables MSI
  'rmmod pci_endpoint_test' disables MSI but MSI address (in EP's
	capability register) has a valid value
  'modprobe pci_endpoint_test no_msi=1' - Since MSI address (in EP's
	capability register) has a valid value (set during the previous
	insertion of the module), EP thinks host supports MSI.

Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index d5eb143040e3d7a12c77d07ff573041be7aacead..0989946df32c96ddbff1af452457acf3e4545e4c 100644 (file)
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -195,20 +195,14 @@ static int dw_pcie_ep_map_addr(struct pci_epc *epc, phys_addr_t addr,
 static int dw_pcie_ep_get_msi(struct pci_epc *epc)
 {
        int val;
-       u32 lower_addr;
-       u32 upper_addr;
        struct dw_pcie_ep *ep = epc_get_drvdata(epc);
        struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-       val = dw_pcie_readb_dbi(pci, MSI_MESSAGE_CONTROL);
-       val = (val & MSI_CAP_MME_MASK) >> MSI_CAP_MME_SHIFT;
-
-       lower_addr = dw_pcie_readl_dbi(pci, MSI_MESSAGE_ADDR_L32);
-       upper_addr = dw_pcie_readl_dbi(pci, MSI_MESSAGE_ADDR_U32);
-
-       if (!(lower_addr || upper_addr))
+       val = dw_pcie_readw_dbi(pci, MSI_MESSAGE_CONTROL);
+       if (!(val & MSI_CAP_MSI_EN_MASK))
                return -EINVAL;
 
+       val = (val & MSI_CAP_MME_MASK) >> MSI_CAP_MME_SHIFT;
        return val;
 }
 

diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index e6fd0b024b216263c2bc43023d3c7ecab3ac37ab..8700ba12c130148f82b7115e915fa5839ba8146a 100644 (file)
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -101,6 +101,7 @@
 #define MSI_MESSAGE_CONTROL            0x52
 #define MSI_CAP_MMC_SHIFT              1
 #define MSI_CAP_MME_SHIFT              4
+#define MSI_CAP_MSI_EN_MASK            0x1
 #define MSI_CAP_MME_MASK               (7 << MSI_CAP_MME_SHIFT)
 #define MSI_MESSAGE_ADDR_L32           0x54
 #define MSI_MESSAGE_ADDR_U32           0x58