powerpc/85xx: workaround for chips with MSI hardware errata

The MPIC version 2.0 has a MSI errata (errata PIC1 of mpc8544), It causes
that neither MSI nor MSI-X can work fine. This is a workaround to allow
MSI-X to function properly.

Signed-off-by: Liu Shuo <soniccat.liu@gmail.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Jia Hongtao <hongtao.jia@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

2 files changed, 28 insertions, 3 deletions

diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index 4bbb4b8dfd09..f086c6f22dc9 100644
--- a/arch/powerpc/sysdev/fsl_msi.c
+++ b/arch/powerpc/sysdev/fsl_msi.c
@@ -162,7 +162,17 @@ static void fsl_compose_msi_msg(struct pci_dev *pdev, int hwirq,
         msg->address_lo = lower_32_bits(address);
         msg->address_hi = upper_32_bits(address);
 
-        msg->data = hwirq;
+        /*
+         * MPIC version 2.0 has erratum PIC1. It causes
+         * that neither MSI nor MSI-X can work fine.
+         * This is a workaround to allow MSI-X to function
+         * properly. It only works for MSI-X, we prevent
+         * MSI on buggy chips in fsl_setup_msi_irqs().
+         */
+        if (msi_data->feature & MSI_HW_ERRATA_ENDIAN)
+                msg->data = __swab32(hwirq);
+        else
+                msg->data = hwirq;
 
         pr_debug("%s: allocated srs: %d, ibs: %d\n", __func__,
                  (hwirq >> msi_data->srs_shift) & MSI_SRS_MASK,
@@ -180,8 +190,16 @@ static int fsl_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
         struct msi_msg msg;
         struct fsl_msi *msi_data;
 
-        if (type == PCI_CAP_ID_MSIX)
-                pr_debug("fslmsi: MSI-X untested, trying anyway.\n");
+        if (type == PCI_CAP_ID_MSI) {
+                /*
+                 * MPIC version 2.0 has erratum PIC1. For now MSI
+                 * could not work. So check to prevent MSI from
+                 * being used on the board with this erratum.
+                 */
+                list_for_each_entry(msi_data, &msi_head, list)
+                        if (msi_data->feature & MSI_HW_ERRATA_ENDIAN)
+                                return -EINVAL;
+        }
 
         /*
          * If the PCI node has an fsl,msi property, then we need to use it
@@ -446,6 +464,11 @@ static int fsl_of_msi_probe(struct platform_device *dev)
 
         msi->feature = features->fsl_pic_ip;
 
+        /* For erratum PIC1 on MPIC version 2.0*/
+        if ((features->fsl_pic_ip & FSL_PIC_IP_MASK) == FSL_PIC_IP_MPIC
+                        && (fsl_mpic_primary_get_version() == 0x0200))
+                msi->feature |= MSI_HW_ERRATA_ENDIAN;
+
         /*
          * Remember the phandle, so that we can match with any PCI nodes
          * that have an "fsl,msi" property.
diff --git a/arch/powerpc/sysdev/fsl_msi.h b/arch/powerpc/sysdev/fsl_msi.h
index 420cfcbdac01..a67359d993e5 100644
--- a/arch/powerpc/sysdev/fsl_msi.h
+++ b/arch/powerpc/sysdev/fsl_msi.h
@@ -27,6 +27,8 @@
 #define FSL_PIC_IP_IPIC   0x00000002
 #define FSL_PIC_IP_VMPIC  0x00000003
 
+#define MSI_HW_ERRATA_ENDIAN 0x00000010
+
 struct fsl_msi_cascade_data;
 
 struct fsl_msi {