PCI: rcar: Add error interrupt handling

Add option to enable interrupts to report any errors from the AHB-PCI
bridge to help find any issues with the bridge when in use.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>

1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/pci/host/pci-rcar-gen2.c b/drivers/pci/host/pci-rcar-gen2.c
index 201e4a450340..11e444e79f45 100644
--- a/drivers/pci/host/pci-rcar-gen2.c
+++ b/drivers/pci/host/pci-rcar-gen2.c
@@ -39,9 +39,26 @@
 
 #define RCAR_PCI_INT_ENABLE_REG         (RCAR_AHBPCI_PCICOM_OFFSET + 0x20)
 #define RCAR_PCI_INT_STATUS_REG         (RCAR_AHBPCI_PCICOM_OFFSET + 0x24)
+#define RCAR_PCI_INT_SIGTABORT          (1 << 0)
+#define RCAR_PCI_INT_SIGRETABORT        (1 << 1)
+#define RCAR_PCI_INT_REMABORT           (1 << 2)
+#define RCAR_PCI_INT_PERR               (1 << 3)
+#define RCAR_PCI_INT_SIGSERR            (1 << 4)
+#define RCAR_PCI_INT_RESERR             (1 << 5)
+#define RCAR_PCI_INT_WIN1ERR            (1 << 12)
+#define RCAR_PCI_INT_WIN2ERR            (1 << 13)
 #define RCAR_PCI_INT_A                  (1 << 16)
 #define RCAR_PCI_INT_B                  (1 << 17)
 #define RCAR_PCI_INT_PME                (1 << 19)
+#define RCAR_PCI_INT_ALLERRORS (RCAR_PCI_INT_SIGTABORT          | \
+                                RCAR_PCI_INT_SIGRETABORT        | \
+                                RCAR_PCI_INT_SIGRETABORT        | \
+                                RCAR_PCI_INT_REMABORT           | \
+                                RCAR_PCI_INT_PERR               | \
+                                RCAR_PCI_INT_SIGSERR            | \
+                                RCAR_PCI_INT_RESERR             | \
+                                RCAR_PCI_INT_WIN1ERR            | \
+                                RCAR_PCI_INT_WIN2ERR)
 
 #define RCAR_AHB_BUS_CTR_REG            (RCAR_AHBPCI_PCICOM_OFFSET + 0x30)
 #define RCAR_AHB_BUS_MMODE_HTRANS       (1 << 0)
@@ -164,6 +181,46 @@ static int __init rcar_pci_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
         return priv->irq;
 }
 
+#ifdef CONFIG_PCI_DEBUG
+/* if debug enabled, then attach an error handler irq to the bridge */
+
+static irqreturn_t rcar_pci_err_irq(int irq, void *pw)
+{
+        struct rcar_pci_priv *priv = pw;
+        u32 status = ioread32(priv->reg + RCAR_PCI_INT_STATUS_REG);
+
+        if (status & RCAR_PCI_INT_ALLERRORS) {
+                dev_err(priv->dev, "error irq: status %08x\n", status);
+
+                /* clear the error(s) */
+                iowrite32(status & RCAR_PCI_INT_ALLERRORS,
+                          priv->reg + RCAR_PCI_INT_STATUS_REG);
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
+static void rcar_pci_setup_errirq(struct rcar_pci_priv *priv)
+{
+        int ret;
+        u32 val;
+
+        ret = devm_request_irq(priv->dev, priv->irq, rcar_pci_err_irq,
+                               IRQF_SHARED, "error irq", priv);
+        if (ret) {
+                dev_err(priv->dev, "cannot claim IRQ for error handling\n");
+                return;
+        }
+
+        val = ioread32(priv->reg + RCAR_PCI_INT_ENABLE_REG);
+        val |= RCAR_PCI_INT_ALLERRORS;
+        iowrite32(val, priv->reg + RCAR_PCI_INT_ENABLE_REG);
+}
+#else
+static inline void rcar_pci_setup_errirq(struct rcar_pci_priv *priv) { }
+#endif
+
 /* PCI host controller setup */
 static int __init rcar_pci_setup(int nr, struct pci_sys_data *sys)
 {
@@ -224,6 +281,9 @@ static int __init rcar_pci_setup(int nr, struct pci_sys_data *sys)
         iowrite32(RCAR_PCI_INT_A | RCAR_PCI_INT_B | RCAR_PCI_INT_PME,
                   reg + RCAR_PCI_INT_ENABLE_REG);
 
+        if (priv->irq > 0)
+                rcar_pci_setup_errirq(priv);
+
         /* Add PCI resources */
         pci_add_resource(&sys->resources, &priv->io_res);
         pci_add_resource(&sys->resources, &priv->mem_res);