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Date: Fri, 08 Aug 2008 18:36:11 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: jeff@...zik.org
Cc: netdev@...r.kernel.org, davem@...emloft.net,
akpm@...ux-foundation.org, Bruce Allan <bruce.w.allan@...el.com>,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [PATCH 6/7] e1000e: test for unusable MSI support
From: Bruce Allan <bruce.w.allan@...el.com>
Some systems do not like 82571/2 use of 16-bit MSI messages and some
other systems claim to support MSI, but neither really works. Setup a
test MSI handler to detect whether or not MSI is working properly, and
if not, fallback to legacy INTx interrupts.
Signed-off-by: Bruce Allan <bruce.w.allan@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/e1000e/defines.h | 2
drivers/net/e1000e/e1000.h | 1
drivers/net/e1000e/netdev.c | 172 ++++++++++++++++++++++++++++++++++++++++--
3 files changed, 164 insertions(+), 11 deletions(-)
diff --git a/drivers/net/e1000e/defines.h b/drivers/net/e1000e/defines.h
index f823b8b..14b0e6c 100644
--- a/drivers/net/e1000e/defines.h
+++ b/drivers/net/e1000e/defines.h
@@ -389,7 +389,7 @@
/* Interrupt Cause Set */
#define E1000_ICS_LSC E1000_ICR_LSC /* Link Status Change */
-#define E1000_ICS_RXDMT0 E1000_ICR_RXDMT0 /* rx desc min. threshold */
+#define E1000_ICS_RXSEQ E1000_ICR_RXSEQ /* Rx sequence error */
#define E1000_ICS_RXDMT0 E1000_ICR_RXDMT0 /* Rx desc min. threshold */
/* Transmit Descriptor Control */
diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index cf57050..ac4e506 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -326,6 +326,7 @@ struct e1000_info {
#define FLAG_RX_CSUM_ENABLED (1 << 28)
#define FLAG_TSO_FORCE (1 << 29)
#define FLAG_RX_RESTART_NOW (1 << 30)
+#define FLAG_MSI_TEST_FAILED (1 << 31)
#define E1000_RX_DESC_PS(R, i) \
(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index b8b26cf..d266510 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -1236,26 +1236,36 @@ static irqreturn_t e1000_intr(int irq, void *data)
return IRQ_HANDLED;
}
+/**
+ * e1000_request_irq - initialize interrupts
+ *
+ * Attempts to configure interrupts using the best available
+ * capabilities of the hardware and kernel.
+ **/
static int e1000_request_irq(struct e1000_adapter *adapter)
{
struct net_device *netdev = adapter->netdev;
- irq_handler_t handler = e1000_intr;
int irq_flags = IRQF_SHARED;
int err;
- if (!pci_enable_msi(adapter->pdev)) {
- adapter->flags |= FLAG_MSI_ENABLED;
- handler = e1000_intr_msi;
- irq_flags = 0;
+ if (!(adapter->flags & FLAG_MSI_TEST_FAILED)) {
+ err = pci_enable_msi(adapter->pdev);
+ if (!err) {
+ adapter->flags |= FLAG_MSI_ENABLED;
+ irq_flags = 0;
+ }
}
- err = request_irq(adapter->pdev->irq, handler, irq_flags, netdev->name,
- netdev);
+ err = request_irq(adapter->pdev->irq,
+ ((adapter->flags & FLAG_MSI_ENABLED) ?
+ &e1000_intr_msi : &e1000_intr),
+ irq_flags, netdev->name, netdev);
if (err) {
- e_err("Unable to allocate %s interrupt (return: %d)\n",
- adapter->flags & FLAG_MSI_ENABLED ? "MSI":"INTx", err);
- if (adapter->flags & FLAG_MSI_ENABLED)
+ if (adapter->flags & FLAG_MSI_ENABLED) {
pci_disable_msi(adapter->pdev);
+ adapter->flags &= ~FLAG_MSI_ENABLED;
+ }
+ e_err("Unable to allocate interrupt, Error: %d\n", err);
}
return err;
@@ -2595,6 +2605,135 @@ err:
}
/**
+ * e1000_intr_msi_test - Interrupt Handler
+ * @irq: interrupt number
+ * @data: pointer to a network interface device structure
+ **/
+static irqreturn_t e1000_intr_msi_test(int irq, void *data)
+{
+ struct net_device *netdev = data;
+ struct e1000_adapter *adapter = netdev_priv(netdev);
+ struct e1000_hw *hw = &adapter->hw;
+ u32 icr = er32(ICR);
+
+ e_dbg("%s: icr is %08X\n", netdev->name, icr);
+ if (icr & E1000_ICR_RXSEQ) {
+ adapter->flags &= ~FLAG_MSI_TEST_FAILED;
+ wmb();
+ }
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * e1000_test_msi_interrupt - Returns 0 for successful test
+ * @adapter: board private struct
+ *
+ * code flow taken from tg3.c
+ **/
+static int e1000_test_msi_interrupt(struct e1000_adapter *adapter)
+{
+ struct net_device *netdev = adapter->netdev;
+ struct e1000_hw *hw = &adapter->hw;
+ int err;
+
+ /* poll_enable hasn't been called yet, so don't need disable */
+ /* clear any pending events */
+ er32(ICR);
+
+ /* free the real vector and request a test handler */
+ e1000_free_irq(adapter);
+
+ /* Assume that the test fails, if it succeeds then the test
+ * MSI irq handler will unset this flag */
+ adapter->flags |= FLAG_MSI_TEST_FAILED;
+
+ err = pci_enable_msi(adapter->pdev);
+ if (err)
+ goto msi_test_failed;
+
+ err = request_irq(adapter->pdev->irq, &e1000_intr_msi_test, 0,
+ netdev->name, netdev);
+ if (err) {
+ pci_disable_msi(adapter->pdev);
+ goto msi_test_failed;
+ }
+
+ wmb();
+
+ e1000_irq_enable(adapter);
+
+ /* fire an unusual interrupt on the test handler */
+ ew32(ICS, E1000_ICS_RXSEQ);
+ e1e_flush();
+ msleep(50);
+
+ e1000_irq_disable(adapter);
+
+ rmb();
+
+ if (adapter->flags & FLAG_MSI_TEST_FAILED) {
+ err = -EIO;
+ e_info("MSI interrupt test failed!\n");
+ }
+
+ free_irq(adapter->pdev->irq, netdev);
+ pci_disable_msi(adapter->pdev);
+
+ if (err == -EIO)
+ goto msi_test_failed;
+
+ /* okay so the test worked, restore settings */
+ e_dbg("%s: MSI interrupt test succeeded!\n", netdev->name);
+msi_test_failed:
+ /* restore the original vector, even if it failed */
+ e1000_request_irq(adapter);
+ return err;
+}
+
+/**
+ * e1000_test_msi - Returns 0 if MSI test succeeds or INTx mode is restored
+ * @adapter: board private struct
+ *
+ * code flow taken from tg3.c, called with e1000 interrupts disabled.
+ **/
+static int e1000_test_msi(struct e1000_adapter *adapter)
+{
+ int err;
+ u16 pci_cmd;
+
+ if (!(adapter->flags & FLAG_MSI_ENABLED))
+ return 0;
+
+ /* disable SERR in case the MSI write causes a master abort */
+ pci_read_config_word(adapter->pdev, PCI_COMMAND, &pci_cmd);
+ pci_write_config_word(adapter->pdev, PCI_COMMAND,
+ pci_cmd & ~PCI_COMMAND_SERR);
+
+ err = e1000_test_msi_interrupt(adapter);
+
+ /* restore previous setting of command word */
+ pci_write_config_word(adapter->pdev, PCI_COMMAND, pci_cmd);
+
+ /* success ! */
+ if (!err)
+ return 0;
+
+ /* EIO means MSI test failed */
+ if (err != -EIO)
+ return err;
+
+ /* back to INTx mode */
+ e_warn("MSI interrupt test failed, using legacy interrupt.\n");
+
+ e1000_free_irq(adapter);
+
+ err = e1000_request_irq(adapter);
+
+ return err;
+}
+
+/**
* e1000_open - Called when a network interface is made active
* @netdev: network interface device structure
*
@@ -2652,6 +2791,19 @@ static int e1000_open(struct net_device *netdev)
if (err)
goto err_req_irq;
+ /*
+ * Work around PCIe errata with MSI interrupts causing some chipsets to
+ * ignore e1000e MSI messages, which means we need to test our MSI
+ * interrupt now
+ */
+ {
+ err = e1000_test_msi(adapter);
+ if (err) {
+ e_err("Interrupt allocation failed\n");
+ goto err_req_irq;
+ }
+ }
+
/* From here on the code is the same as e1000e_up() */
clear_bit(__E1000_DOWN, &adapter->state);
--
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