mpc85xx: revert the napi polling code to the one from an older kernel version to fix stability issues (#14020)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38409 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 162 insertions, 0 deletions

diff --git a/target/linux/mpc85xx/patches-3.10/200-gianfar_napi_poll_revert.patch b/target/linux/mpc85xx/patches-3.10/200-gianfar_napi_poll_revert.patch
new file mode 100644
index 0000000000..9f2b727580
--- /dev/null
+++ b/target/linux/mpc85xx/patches-3.10/200-gianfar_napi_poll_revert.patch
@@ -0,0 +1,162 @@
+--- a/drivers/net/ethernet/freescale/gianfar.c
++++ b/drivers/net/ethernet/freescale/gianfar.c
+@@ -132,7 +132,7 @@ static int gfar_poll(struct napi_struct 
+ static void gfar_netpoll(struct net_device *dev);
+ #endif
+ int gfar_clean_rx_ring(struct gfar_priv_rx_q *rx_queue, int rx_work_limit);
+-static void gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue);
++static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue);
+ static void gfar_process_frame(struct net_device *dev, struct sk_buff *skb,
+ 			       int amount_pull, struct napi_struct *napi);
+ void gfar_halt(struct net_device *dev);
+@@ -2475,7 +2475,7 @@ static void gfar_align_skb(struct sk_buf
+ }
+ 
+ /* Interrupt Handler for Transmit complete */
+-static void gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue)
++static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue)
+ {
+ 	struct net_device *dev = tx_queue->dev;
+ 	struct netdev_queue *txq;
+@@ -2575,6 +2575,8 @@ static void gfar_clean_tx_ring(struct gf
+ 	tx_queue->dirty_tx = bdp;
+ 
+ 	netdev_tx_completed_queue(txq, howmany, bytes_sent);
++
++	return howmany;
+ }
+ 
+ static void gfar_schedule_cleanup(struct gfar_priv_grp *gfargrp)
+@@ -2833,82 +2835,62 @@ static int gfar_poll(struct napi_struct 
+ 	struct gfar __iomem *regs = gfargrp->regs;
+ 	struct gfar_priv_tx_q *tx_queue = NULL;
+ 	struct gfar_priv_rx_q *rx_queue = NULL;
+-	int work_done = 0, work_done_per_q = 0;
+-	int i, budget_per_q = 0;
+-	int has_tx_work;
+-	unsigned long rstat_rxf;
+-	int num_act_queues;
++	int rx_cleaned = 0, budget_per_queue = 0, rx_cleaned_per_queue = 0;
++	int tx_cleaned = 0, i, left_over_budget = budget;
++	unsigned long serviced_queues = 0;
++	int num_queues = 0;
++
++	num_queues = gfargrp->num_rx_queues;
++	budget_per_queue = budget/num_queues;
+ 
+ 	/* Clear IEVENT, so interrupts aren't called again
+ 	 * because of the packets that have already arrived
+ 	 */
+ 	gfar_write(&regs->ievent, IEVENT_RTX_MASK);
+ 
+-	rstat_rxf = gfar_read(&regs->rstat) & RSTAT_RXF_MASK;
+-
+-	num_act_queues = bitmap_weight(&rstat_rxf, MAX_RX_QS);
+-	if (num_act_queues)
+-		budget_per_q = budget/num_act_queues;
+-
+-	while (1) {
+-		has_tx_work = 0;
+-		for_each_set_bit(i, &gfargrp->tx_bit_map, priv->num_tx_queues) {
+-			tx_queue = priv->tx_queue[i];
+-			/* run Tx cleanup to completion */
+-			if (tx_queue->tx_skbuff[tx_queue->skb_dirtytx]) {
+-				gfar_clean_tx_ring(tx_queue);
+-				has_tx_work = 1;
+-			}
+-		}
++	while (num_queues && left_over_budget) {
++		budget_per_queue = left_over_budget/num_queues;
++		left_over_budget = 0;
+ 
+ 		for_each_set_bit(i, &gfargrp->rx_bit_map, priv->num_rx_queues) {
+-			/* skip queue if not active */
+-			if (!(rstat_rxf & (RSTAT_CLEAR_RXF0 >> i)))
++			if (test_bit(i, &serviced_queues))
+ 				continue;
+-
+ 			rx_queue = priv->rx_queue[i];
+-			work_done_per_q =
+-				gfar_clean_rx_ring(rx_queue, budget_per_q);
+-			work_done += work_done_per_q;
+-
+-			/* finished processing this queue */
+-			if (work_done_per_q < budget_per_q) {
+-				/* clear active queue hw indication */
+-				gfar_write(&regs->rstat,
+-					   RSTAT_CLEAR_RXF0 >> i);
+-				rstat_rxf &= ~(RSTAT_CLEAR_RXF0 >> i);
+-				num_act_queues--;
+-
+-				if (!num_act_queues)
+-					break;
+-				/* recompute budget per Rx queue */
+-				budget_per_q =
+-					(budget - work_done) / num_act_queues;
++			tx_queue = priv->tx_queue[rx_queue->qindex];
++
++			tx_cleaned += gfar_clean_tx_ring(tx_queue);
++			rx_cleaned_per_queue =
++				gfar_clean_rx_ring(rx_queue, budget_per_queue);
++			rx_cleaned += rx_cleaned_per_queue;
++			if (rx_cleaned_per_queue < budget_per_queue) {
++				left_over_budget = left_over_budget +
++					(budget_per_queue -
++					 rx_cleaned_per_queue);
++				set_bit(i, &serviced_queues);
++				num_queues--;
+ 			}
+ 		}
++	}
+ 
+-		if (work_done >= budget)
+-			break;
+-
+-		if (!num_act_queues && !has_tx_work) {
++	if (tx_cleaned)
++		return budget;
+ 
+-			napi_complete(napi);
++	if (rx_cleaned < budget) {
++		napi_complete(napi);
+ 
+-			/* Clear the halt bit in RSTAT */
+-			gfar_write(&regs->rstat, gfargrp->rstat);
++		/* Clear the halt bit in RSTAT */
++		gfar_write(&regs->rstat, gfargrp->rstat);
+ 
+-			gfar_write(&regs->imask, IMASK_DEFAULT);
++		gfar_write(&regs->imask, IMASK_DEFAULT);
+ 
+-			/* If we are coalescing interrupts, update the timer
+-			 * Otherwise, clear it
+-			 */
+-			gfar_configure_coalescing(priv, gfargrp->rx_bit_map,
+-						  gfargrp->tx_bit_map);
+-			break;
+-		}
++		/* If we are coalescing interrupts, update the timer
++		 * Otherwise, clear it
++		 */
++		gfar_configure_coalescing(priv, gfargrp->rx_bit_map,
++					  gfargrp->tx_bit_map);
+ 	}
+ 
+-	return work_done;
++	return rx_cleaned;
+ }
+ 
+ #ifdef CONFIG_NET_POLL_CONTROLLER
+--- a/drivers/net/ethernet/freescale/gianfar.h
++++ b/drivers/net/ethernet/freescale/gianfar.h
+@@ -291,9 +291,7 @@ extern const char gfar_driver_version[];
+ #define RCTRL_PADDING(x)	((x << 16) & RCTRL_PAL_MASK)
+ 
+ 
+-#define RSTAT_CLEAR_RHALT	0x00800000
+-#define RSTAT_CLEAR_RXF0	0x00000080
+-#define RSTAT_RXF_MASK		0x000000ff
++#define RSTAT_CLEAR_RHALT       0x00800000
+ 
+ #define TCTRL_IPCSEN		0x00004000
+ #define TCTRL_TUCSEN		0x00002000