rtase: Implement pci_driver suspend and resume function

Implement the pci_driver suspend function to enable the device
to sleep, and implement the resume function to enable the device
to resume operation.

Signed-off-by: Justin Lai <justinlai0215@realtek.com>
Link: https://patch.msgid.link/20240904032114.247117-10-justinlai0215@realtek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Justin Lai

drivers/net/ethernet/realtek/rtase/rtase_main.c

@@ -2151,12 +2151,63 @@ static void rtase_shutdown(struct pci_dev *pdev)
 	rtase_reset_interrupt(pdev, tp);
 }
 
+static int rtase_suspend(struct device *device)
+{
+	struct net_device *dev = dev_get_drvdata(device);
+
+	if (netif_running(dev)) {
+		netif_device_detach(dev);
+		rtase_hw_reset(dev);
+	}
+
+	return 0;
+}
+
+static int rtase_resume(struct device *device)
+{
+	struct net_device *dev = dev_get_drvdata(device);
+	struct rtase_private *tp = netdev_priv(dev);
+	int ret;
+
+	/* restore last modified mac address */
+	rtase_rar_set(tp, dev->dev_addr);
+
+	if (!netif_running(dev))
+		goto out;
+
+	rtase_wait_for_quiescence(dev);
+
+	rtase_tx_clear(tp);
+	rtase_rx_clear(tp);
+
+	ret = rtase_init_ring(dev);
+	if (ret) {
+		netdev_err(dev, "unable to init ring\n");
+		rtase_free_desc(tp);
+		return -ENOMEM;
+	}
+
+	rtase_hw_config(dev);
+	/* always link, so start to transmit & receive */
+	rtase_hw_start(dev);
+
+	netif_device_attach(dev);
+out:
+
+	return 0;
+}
+
+static const struct dev_pm_ops rtase_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(rtase_suspend, rtase_resume)
+};
+
 static struct pci_driver rtase_pci_driver = {
 	.name = KBUILD_MODNAME,
 	.id_table = rtase_pci_tbl,
 	.probe = rtase_init_one,
 	.remove = rtase_remove_one,
 	.shutdown = rtase_shutdown,
+	.driver.pm = pm_ptr(&rtase_pm_ops),
 };
 
 module_pci_driver(rtase_pci_driver);