netdev - [PATCH net-next 2/3] igbvf: add PCI reset handler functions

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Date:   Tue, 21 Mar 2023 13:00:12 -0700
From:   Tony Nguyen <anthony.l.nguyen@...el.com>
To:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com, netdev@...r.kernel.org
Cc:     Dawid Wesierski <dawidx.wesierski@...el.com>,
        anthony.l.nguyen@...el.com,
        Kamil Maziarz <kamil.maziarz@...el.com>,
        Michal Kubiak <michal.kubiak@...el.com>,
        Marek Szlosek <marek.szlosek@...el.com>
Subject: [PATCH net-next 2/3] igbvf: add PCI reset handler functions

From: Dawid Wesierski <dawidx.wesierski@...el.com>

There was a problem with resuming ping after conducting a PCI reset.
This commit adds two functions, igbvf_io_prepare and igbvf_io_done,
which, after being added to the pci_error_handlers struct,
will prepare the drivers for a PCI reset and then bring the interface up
and reset it after. This will prevent the driver from ending up in
incorrect state. Test_and_set_bit is highly reliable in this context,
so we are not including a timeout in this commit

This introduces 900ms - 1100ms of overhead to this operation but it's in
non-time-critical flow. And also allows the driver to continue
functioning after the reset.

Functionality documented in ethernet-controller-i350-datasheet 4.2.1.3
https://www.intel.com/content/www/us/en/products/details/ethernet/gigabit-controllers/i350-controllers/docs.html

Signed-off-by: Dawid Wesierski <dawidx.wesierski@...el.com>
Signed-off-by: Kamil Maziarz <kamil.maziarz@...el.com>
Reviewed-by: Michal Kubiak <michal.kubiak@...el.com>
Tested-by: Marek Szlosek <marek.szlosek@...el.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@...el.com>
---
 drivers/net/ethernet/intel/igbvf/netdev.c | 29 +++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c
index 3a32809510fc..790383078e0d 100644
--- a/drivers/net/ethernet/intel/igbvf/netdev.c
+++ b/drivers/net/ethernet/intel/igbvf/netdev.c
@@ -2589,6 +2589,33 @@ static void igbvf_io_resume(struct pci_dev *pdev)
 	netif_device_attach(netdev);
 }
 
+/**
+ * igbvf_io_prepare - prepare device driver for PCI reset
+ * @pdev: PCI device information struct
+ */
+static void igbvf_io_prepare(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct igbvf_adapter *adapter = netdev_priv(netdev);
+
+	while (test_and_set_bit(__IGBVF_RESETTING, &adapter->state))
+		usleep_range(1000, 2000);
+	igbvf_down(adapter);
+}
+
+/**
+ * igbvf_io_reset_done - PCI reset done, device driver reset can begin
+ * @pdev: PCI device information struct
+ */
+static void igbvf_io_reset_done(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct igbvf_adapter *adapter = netdev_priv(netdev);
+
+	igbvf_up(adapter);
+	clear_bit(__IGBVF_RESETTING, &adapter->state);
+}
+
 static void igbvf_print_device_info(struct igbvf_adapter *adapter)
 {
 	struct e1000_hw *hw = &adapter->hw;
@@ -2916,6 +2943,8 @@ static const struct pci_error_handlers igbvf_err_handler = {
 	.error_detected = igbvf_io_error_detected,
 	.slot_reset = igbvf_io_slot_reset,
 	.resume = igbvf_io_resume,
+	.reset_prepare = igbvf_io_prepare,
+	.reset_done = igbvf_io_reset_done,
 };
 
 static const struct pci_device_id igbvf_pci_tbl[] = {
-- 
2.38.1