[PATCH v2] net: macb: Handle HRESP error

[harinikatakamlinux.com]

From: Harini Katakam <harini.katakam@xxxxxxxxxx>

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 <harinik@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
---
v2:
Rebased on top of latest net-next and reinitialized
all rx queues.

 drivers/net/ethernet/cadence/macb.h      |  3 ++
 drivers/net/ethernet/cadence/macb_main.c | 59 +++++++++++++++++++++++++++++---
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index c50c5ec..8665982 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -13,6 +13,7 @@
 #include <linux/phy.h>
 #include <linux/ptp_clock_kernel.h>
 #include <linux/net_tstamp.h>
+#include <linux/interrupt.h>

 #if defined(CONFIG_ARCH_DMA_ADDR_T_64BIT) || defined(CONFIG_MACB_USE_HWSTAMP)
 #define MACB_EXT_DESC
@@ -1200,6 +1201,8 @@ struct macb {
        struct ethtool_rx_fs_list rx_fs_list;
        spinlock_t rx_fs_lock;
        unsigned int max_tuples;
+
+       struct tasklet_struct   hresp_err_tasklet;
 };

 #ifdef CONFIG_MACB_USE_HWSTAMP
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 234667e..e84afcf 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -1258,6 +1258,57 @@ 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);
+
+       /* Initialize TX and RX buffers */
+       for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
+               queue_writel(queue, RBQP, lower_32_bits(queue->rx_ring_dma));
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+               if (bp->hw_dma_cap & HW_DMA_CAP_64B)
+                       queue_writel(queue, RBQPH,
+                                    upper_32_bits(queue->rx_ring_dma));
+#endif
+               queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma));
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+               if (bp->hw_dma_cap & HW_DMA_CAP_64B)
+                       queue_writel(queue, TBQPH,
+                                    upper_32_bits(queue->tx_ring_dma));
+#endif
+
+               /* 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;
@@ -1347,10 +1398,7 @@ 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)
@@ -3937,6 +3985,9 @@ static int macb_probe(struct platform_device *pdev)
                goto err_out_unregister_mdio;
        }

+       tasklet_init(&bp->hresp_err_tasklet, macb_hresp_error_task,
+                    (unsigned long)bp);
+
        phy_attached_info(phydev);

        netdev_info(dev, "Cadence %s rev 0x%08x at 0x%08lx irq %d (%pM)\n",
--
2.7.4

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