Handle HRESP error by doing a SW reset of RX and TX and
re-initializing the descriptors, RX and TX queue pointers.

Signed-off-by: Harini Katakam <hari...@xilinx.com>
---
 drivers/net/ethernet/cadence/macb.c |   48 ++++++++++++++++++++++++++++++++---
 drivers/net/ethernet/cadence/macb.h |    2 ++
 2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.c 
b/drivers/net/ethernet/cadence/macb.c
index 89c0cfa..8ffb863 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -1070,6 +1070,46 @@ static int macb_poll(struct napi_struct *napi, int 
budget)
        return work_done;
 }
 
+static void macb_hresp_error_task(unsigned long data)
+{
+       struct macb *bp = (struct macb *)data;
+       struct net_device *dev = bp->dev;
+       struct macb_queue *queue = bp->queues;
+       unsigned int q;
+       u32 ctrl;
+
+       for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
+               queue_writel(queue, IDR, MACB_RX_INT_FLAGS |
+                                        MACB_TX_INT_FLAGS |
+                                        MACB_BIT(HRESP));
+       }
+       ctrl = macb_readl(bp, NCR);
+       ctrl &= ~(MACB_BIT(RE) | MACB_BIT(TE));
+       macb_writel(bp, NCR, ctrl);
+
+       netif_tx_stop_all_queues(dev);
+       netif_carrier_off(dev);
+
+       bp->macbgem_ops.mog_init_rings(bp);
+
+       macb_writel(bp, RBQP, bp->rx_ring_dma);
+       for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
+               queue_writel(queue, TBQP, queue->tx_ring_dma);
+
+               /* Enable interrupts */
+               queue_writel(queue, IER,
+                            MACB_RX_INT_FLAGS |
+                            MACB_TX_INT_FLAGS |
+                            MACB_BIT(HRESP));
+       }
+
+       ctrl |= MACB_BIT(RE) | MACB_BIT(TE);
+       macb_writel(bp, NCR, ctrl);
+
+       netif_carrier_on(dev);
+       netif_tx_start_all_queues(dev);
+}
+
 static irqreturn_t macb_interrupt(int irq, void *dev_id)
 {
        struct macb_queue *queue = dev_id;
@@ -1158,10 +1198,7 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
                }
 
                if (status & MACB_BIT(HRESP)) {
-                       /* TODO: Reset the hardware, and maybe move the
-                        * netdev_err to a lower-priority context as well
-                        * (work queue?)
-                        */
+                       tasklet_schedule(&bp->hresp_err_tasklet);
                        netdev_err(dev, "DMA bus error: HRESP not OK\n");
 
                        if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
@@ -2998,6 +3035,9 @@ static int macb_probe(struct platform_device *pdev)
 
        phy_attached_info(phydev);
 
+       tasklet_init(&bp->hresp_err_tasklet, macb_hresp_error_task,
+                    (unsigned long)bp);
+
        netdev_info(dev, "Cadence %s rev 0x%08x at 0x%08lx irq %d (%pM)\n",
                    macb_is_gem(bp) ? "GEM" : "MACB", macb_readl(bp, MID),
                    dev->base_addr, dev->irq, dev->dev_addr);
diff --git a/drivers/net/ethernet/cadence/macb.h 
b/drivers/net/ethernet/cadence/macb.h
index 36893d8..8393068 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -845,6 +845,8 @@ struct macb {
        unsigned int            jumbo_max_len;
 
        u32                     wol;
+
+       struct tasklet_struct   hresp_err_tasklet;
 };
 
 static inline bool macb_is_gem(struct macb *bp)
-- 
1.7.9.5

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