Date:	Thu, 15 Feb 2007 17:08:57 -0600
From:	linas@...tin.ibm.com (Linas Vepstas)
To:	Ramkrishna Vepa <Ramkrishna.Vepa@...erion.com>,
	Raghavendra Koushik <raghavendra.koushik@...erion.com>,
	Ananda Raju <Ananda.Raju@...erion.com>
Cc:	Wen Xiong <wenxiong@...ibm.com>, linux-kernel@...r.kernel.org,
	linux-pci@...ey.karlin.mff.cuni.cz, netdev@...r.kernel.org,
	Jeff Garzik <jgarzik@...ox.com>, Andrew Morton <akpm@...l.org>
Subject: [PATCH] s2io: add PCI error recovery support


Koushik, Raju,

Please review, comment, and if you find this acceptable, 
please forward upstream. This patch incorporates all of 
fixes resulting from the last set of discussions, circa 
November 2006.

--linas

This patch adds PCI error recovery support to the 
s2io 10-Gigabit ethernet device driver. Fourth revision,
blocks interrupts and the watchdog. Adds a flag to 
s2io_down(), to avoid doing I/O when PCI bus is offline.

Tested, seems to work well.

Signed-off-by: Linas Vepstas <linas@...tin.ibm.com>
Acked-by: Ramkrishna Vepa <Ramkrishna.Vepa@...erion.com>
Cc: Raghavendra Koushik <raghavendra.koushik@...erion.com>
Cc: Ananda Raju <Ananda.Raju@...erion.com>
Cc: Wen Xiong <wenxiong@...ibm.com>

----
 drivers/net/s2io.c |  116 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 drivers/net/s2io.h |    5 ++
 2 files changed, 116 insertions(+), 5 deletions(-)

Index: linux-2.6.20-git4/drivers/net/s2io.c
===================================================================
--- linux-2.6.20-git4.orig/drivers/net/s2io.c	2007-02-15 15:39:35.000000000 -0600
+++ linux-2.6.20-git4/drivers/net/s2io.c	2007-02-15 16:15:10.000000000 -0600
@@ -435,11 +435,18 @@ static struct pci_device_id s2io_tbl[] _
 
 MODULE_DEVICE_TABLE(pci, s2io_tbl);
 
+static struct pci_error_handlers s2io_err_handler = {
+	.error_detected = s2io_io_error_detected,
+	.slot_reset = s2io_io_slot_reset,
+	.resume = s2io_io_resume,
+};
+
 static struct pci_driver s2io_driver = {
       .name = "S2IO",
       .id_table = s2io_tbl,
       .probe = s2io_init_nic,
       .remove = __devexit_p(s2io_rem_nic),
+      .err_handler = &s2io_err_handler,
 };
 
 /* A simplifier macro used both by init and free shared_mem Fns(). */
@@ -2577,6 +2584,9 @@ static void s2io_netpoll(struct net_devi
 	u64 val64 = 0xFFFFFFFFFFFFFFFFULL;
 	int i;
 
+	if (pci_channel_offline(nic->pdev))
+		return;
+
 	disable_irq(dev->irq);
 
 	atomic_inc(&nic->isr_cnt);
@@ -3079,6 +3089,8 @@ static void alarm_intr_handler(struct s2
 	int i;
 	if (atomic_read(&nic->card_state) == CARD_DOWN)
 		return;
+	if (pci_channel_offline(nic->pdev))
+		return;
 	nic->mac_control.stats_info->sw_stat.ring_full_cnt = 0;
 	/* Handling the XPAK counters update */
 	if(nic->mac_control.stats_info->xpak_stat.xpak_timer_count < 72000) {
@@ -4117,6 +4129,10 @@ static irqreturn_t s2io_isr(int irq, voi
 	struct mac_info *mac_control;
 	struct config_param *config;
 
+	/* Pretend we handled any irq's from a disconnected card */
+	if (pci_channel_offline(sp->pdev))
+		return IRQ_NONE;
+
 	atomic_inc(&sp->isr_cnt);
 	mac_control = &sp->mac_control;
 	config = &sp->config;
@@ -6188,7 +6204,7 @@ static void s2io_rem_isr(struct s2io_nic
 	} while(cnt < 5);
 }
 
-static void s2io_card_down(struct s2io_nic * sp)
+static void do_s2io_card_down(struct s2io_nic * sp, int do_io)
 {
 	int cnt = 0;
 	struct XENA_dev_config __iomem *bar0 = sp->bar0;
@@ -6203,7 +6219,8 @@ static void s2io_card_down(struct s2io_n
 	atomic_set(&sp->card_state, CARD_DOWN);
 
 	/* disable Tx and Rx traffic on the NIC */
-	stop_nic(sp);
+	if (do_io)
+		stop_nic(sp);
 
 	s2io_rem_isr(sp);
 
@@ -6211,7 +6228,7 @@ static void s2io_card_down(struct s2io_n
 	tasklet_kill(&sp->task);
 
 	/* Check if the device is Quiescent and then Reset the NIC */
-	do {
+	while(do_io) {
 		/* As per the HW requirement we need to replenish the
 		 * receive buffer to avoid the ring bump. Since there is
 		 * no intention of processing the Rx frame at this pointwe are
@@ -6236,8 +6253,9 @@ static void s2io_card_down(struct s2io_n
 				  (unsigned long long) val64);
 			break;
 		}
-	} while (1);
-	s2io_reset(sp);
+	}
+	if (do_io)
+		s2io_reset(sp);
 
 	spin_lock_irqsave(&sp->tx_lock, flags);
 	/* Free all Tx buffers */
@@ -6252,6 +6270,11 @@ static void s2io_card_down(struct s2io_n
 	clear_bit(0, &(sp->link_state));
 }
 
+static void s2io_card_down(struct s2io_nic * sp)
+{
+	do_s2io_card_down(sp, 1);
+}
+
 static int s2io_card_up(struct s2io_nic * sp)
 {
 	int i, ret = 0;
@@ -7536,3 +7559,86 @@ static void lro_append_pkt(struct s2io_n
 	sp->mac_control.stats_info->sw_stat.clubbed_frms_cnt++;
 	return;
 }
+
+/**
+ * s2io_io_error_detected - called when PCI error is detected
+ * @pdev: Pointer to PCI device
+ * @state: The current pci conneection state
+ *
+ * This function is called after a PCI bus error affecting
+ * this device has been detected.
+ */
+static pci_ers_result_t s2io_io_error_detected(struct pci_dev *pdev,
+                                               pci_channel_state_t state)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct s2io_nic *sp = netdev->priv;
+
+	netif_device_detach(netdev);
+
+	if (netif_running(netdev)) {
+		/* Bring down the card, while avoiding PCI I/O */
+		do_s2io_card_down(sp, 0);
+		sp->device_close_flag = TRUE;	/* Device is shut down. */
+	}
+	pci_disable_device(pdev);
+
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+/**
+ * s2io_io_slot_reset - called after the pci bus has been reset.
+ * @pdev: Pointer to PCI device
+ *
+ * Restart the card from scratch, as if from a cold-boot.
+ * At this point, the card has exprienced a hard reset,
+ * followed by fixups by BIOS, and has its config space
+ * set up identically to what it was at cold boot.
+ */
+static pci_ers_result_t s2io_io_slot_reset(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct s2io_nic *sp = netdev->priv;
+
+	if (pci_enable_device(pdev)) {
+		printk(KERN_ERR "s2io: "
+		       "Cannot re-enable PCI device after reset.\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
+	pci_set_master(pdev);
+	s2io_reset(sp);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+/**
+ * s2io_io_resume - called when traffic can start flowing again.
+ * @pdev: Pointer to PCI device
+ *
+ * This callback is called when the error recovery driver tells
+ * us that its OK to resume normal operation.
+ */
+static void s2io_io_resume(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct s2io_nic *sp = netdev->priv;
+
+	if (netif_running(netdev)) {
+		if (s2io_card_up(sp)) {
+			printk(KERN_ERR "s2io: "
+			       "Can't bring device back up after reset.\n");
+			return;
+		}
+
+		if (s2io_set_mac_addr(netdev, netdev->dev_addr) == FAILURE) {
+			s2io_card_down(sp);
+			printk(KERN_ERR "s2io: "
+			       "Can't resetore mac addr after reset.\n");
+			return;
+		}
+	}
+
+	netif_device_attach(netdev);
+	netif_wake_queue(netdev);
+}
Index: linux-2.6.20-git4/drivers/net/s2io.h
===================================================================
--- linux-2.6.20-git4.orig/drivers/net/s2io.h	2007-02-15 15:39:35.000000000 -0600
+++ linux-2.6.20-git4/drivers/net/s2io.h	2007-02-15 16:59:40.000000000 -0600
@@ -1020,6 +1020,11 @@ static void update_L3L4_header(struct s2
 static void lro_append_pkt(struct s2io_nic *sp, struct lro *lro,
 			   struct sk_buff *skb, u32 tcp_len);
 
+static pci_ers_result_t s2io_io_error_detected(struct pci_dev *pdev,
+			                      pci_channel_state_t state);
+static pci_ers_result_t s2io_io_slot_reset(struct pci_dev *pdev);
+static void s2io_io_resume(struct pci_dev *pdev);
+
 #define s2io_tcp_mss(skb) skb_shinfo(skb)->gso_size
 #define s2io_udp_mss(skb) skb_shinfo(skb)->gso_size
 #define s2io_offload_type(skb) skb_shinfo(skb)->gso_type
-
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