eth: fbnic: Add scaffolding for Meta's NIC driver

Create a bare-bones PCI driver for Meta's NIC.
Subsequent changes will flesh it out.

Signed-off-by: Alexander Duyck <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

MAINTAINERS

···
 F:	Documentation/devicetree/bindings/media/amlogic,gx-vdec.yaml
 F:	drivers/staging/media/meson/vdec/
 
+META ETHERNET DRIVERS
+M:	Alexander Duyck <[e-mail]>
+M:	Jakub Kicinski <[e-mail]>
+R:	[e-mail]
+S:	Supported
+F:	drivers/net/ethernet/meta/
+
 METHODE UDPU SUPPORT
 M:	Robert Marko <[e-mail]>
 S:	Maintained

drivers/net/ethernet/Kconfig

···
 source "drivers/net/ethernet/marvell/Kconfig"
 source "drivers/net/ethernet/mediatek/Kconfig"
 source "drivers/net/ethernet/mellanox/Kconfig"
+source "drivers/net/ethernet/meta/Kconfig"
 source "drivers/net/ethernet/micrel/Kconfig"
 source "drivers/net/ethernet/microchip/Kconfig"
 source "drivers/net/ethernet/mscc/Kconfig"

drivers/net/ethernet/Makefile

···
 obj-$(CONFIG_NET_VENDOR_MARVELL) += marvell/
 obj-$(CONFIG_NET_VENDOR_MEDIATEK) += mediatek/
 obj-$(CONFIG_NET_VENDOR_MELLANOX) += mellanox/
+obj-$(CONFIG_NET_VENDOR_META) += meta/
 obj-$(CONFIG_NET_VENDOR_MICREL) += micrel/
 obj-$(CONFIG_NET_VENDOR_MICROCHIP) += microchip/
 obj-$(CONFIG_NET_VENDOR_MICROSEMI) += mscc/

drivers/net/ethernet/meta/Kconfig

···
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Meta Platforms network device configuration
+#
+
+config NET_VENDOR_META
+	bool "Meta Platforms devices"
+	default y
+	help
+	  If you have a network (Ethernet) card designed by Meta, say Y.
+	  That's Meta as in the parent company of Facebook.
+
+	  Note that the answer to this question doesn't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  the questions about Meta cards. If you say Y, you will be asked for
+	  your specific card in the following questions.
+
+if NET_VENDOR_META
+
+config FBNIC
+	tristate "Meta Platforms Host Network Interface"
+	depends on X86_64 || COMPILE_TEST
+	depends on PCI_MSI
+	help
+	  This driver supports Meta Platforms Host Network Interface.
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called fbnic.  MSI-X interrupt support is required.
+
+endif # NET_VENDOR_META

drivers/net/ethernet/meta/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Meta Platforms network device drivers.
+#
+
+obj-$(CONFIG_FBNIC) += fbnic/

drivers/net/ethernet/meta/fbnic/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+
+#
+# Makefile for the Meta(R) Host Network Interface
+#
+
+obj-$(CONFIG_FBNIC) += fbnic.o
+
+fbnic-y := fbnic_pci.o

drivers/net/ethernet/meta/fbnic/fbnic.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#ifndef _FBNIC_H_
+#define _FBNIC_H_
+
+#include "fbnic_csr.h"
+
+extern char fbnic_driver_name[];
+
+enum fbnic_boards {
+	fbnic_board_asic
+};
+
+struct fbnic_info {
+	unsigned int bar_mask;
+};
+
+#endif /* _FBNIC_H_ */

drivers/net/ethernet/meta/fbnic/fbnic_csr.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#ifndef _FBNIC_CSR_H_
+#define _FBNIC_CSR_H_
+
+#define PCI_DEVICE_ID_META_FBNIC_ASIC		0x0013
+
+#endif /* _FBNIC_CSR_H_ */

drivers/net/ethernet/meta/fbnic/fbnic_drvinfo.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#define DRV_NAME "fbnic"
+#define DRV_SUMMARY "Meta(R) Host Network Interface Driver"

drivers/net/ethernet/meta/fbnic/fbnic_pci.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+
+#include "fbnic.h"
+#include "fbnic_drvinfo.h"
+
+char fbnic_driver_name[] = DRV_NAME;
+
+MODULE_DESCRIPTION(DRV_SUMMARY);
+MODULE_LICENSE("GPL");
+
+static const struct fbnic_info fbnic_asic_info = {
+	.bar_mask = BIT(0) | BIT(4)
+};
+
+static const struct fbnic_info *fbnic_info_tbl[] = {
+	[fbnic_board_asic] = &fbnic_asic_info,
+};
+
+static const struct pci_device_id fbnic_pci_tbl[] = {
+	{ PCI_DEVICE_DATA(META, FBNIC_ASIC, fbnic_board_asic) },
+	/* Required last entry */
+	{0, }
+};
+MODULE_DEVICE_TABLE(pci, fbnic_pci_tbl);
+
+/**
+ * fbnic_probe - Device Initialization Routine
+ * @pdev: PCI device information struct
+ * @ent: entry in fbnic_pci_tbl
+ *
+ * Initializes a PCI device identified by a pci_dev structure.
+ * The OS initialization, configuring of the adapter private structure,
+ * and a hardware reset occur.
+ *
+ * Return: 0 on success, negative on failure
+ **/
+static int fbnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	const struct fbnic_info *info = fbnic_info_tbl[ent->driver_data];
+	int err;
+
+	if (pdev->error_state != pci_channel_io_normal) {
+		dev_err(&pdev->dev,
+			"PCI device still in an error state. Unable to load...\n");
+		return -EIO;
+	}
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "PCI enable device failed: %d\n", err);
+		return err;
+	}
+
+	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(46));
+	if (err)
+		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	if (err) {
+		dev_err(&pdev->dev, "DMA configuration failed: %d\n", err);
+		return err;
+	}
+
+	err = pcim_iomap_regions(pdev, info->bar_mask, fbnic_driver_name);
+	if (err) {
+		dev_err(&pdev->dev,
+			"pci_request_selected_regions failed: %d\n", err);
+		return err;
+	}
+
+	pci_set_master(pdev);
+	pci_save_state(pdev);
+
+	return 0;
+}
+
+/**
+ * fbnic_remove - Device Removal Routine
+ * @pdev: PCI device information struct
+ *
+ * Called by the PCI subsystem to alert the driver that it should release
+ * a PCI device.  The could be caused by a Hot-Plug event, or because the
+ * driver is going to be removed from memory.
+ **/
+static void fbnic_remove(struct pci_dev *pdev)
+{
+	pci_disable_device(pdev);
+}
+
+static int fbnic_pm_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int __fbnic_pm_resume(struct device *dev)
+{
+	return 0;
+}
+
+static int __maybe_unused fbnic_pm_resume(struct device *dev)
+{
+	int err;
+
+	err = __fbnic_pm_resume(dev);
+
+	return err;
+}
+
+static const struct dev_pm_ops fbnic_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(fbnic_pm_suspend, fbnic_pm_resume)
+};
+
+static void fbnic_shutdown(struct pci_dev *pdev)
+{
+	fbnic_pm_suspend(&pdev->dev);
+}
+
+static pci_ers_result_t fbnic_err_error_detected(struct pci_dev *pdev,
+						 pci_channel_state_t state)
+{
+	/* Disconnect device if failure is not recoverable via reset */
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	fbnic_pm_suspend(&pdev->dev);
+
+	/* Request a slot reset */
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+static pci_ers_result_t fbnic_err_slot_reset(struct pci_dev *pdev)
+{
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+	pci_save_state(pdev);
+
+	if (pci_enable_device_mem(pdev)) {
+		dev_err(&pdev->dev,
+			"Cannot re-enable PCI device after reset.\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void fbnic_err_resume(struct pci_dev *pdev)
+{
+}
+
+static const struct pci_error_handlers fbnic_err_handler = {
+	.error_detected	= fbnic_err_error_detected,
+	.slot_reset	= fbnic_err_slot_reset,
+	.resume		= fbnic_err_resume,
+};
+
+static struct pci_driver fbnic_driver = {
+	.name		= fbnic_driver_name,
+	.id_table	= fbnic_pci_tbl,
+	.probe		= fbnic_probe,
+	.remove		= fbnic_remove,
+	.driver.pm	= &fbnic_pm_ops,
+	.shutdown	= fbnic_shutdown,
+	.err_handler	= &fbnic_err_handler,
+};
+
+/**
+ * fbnic_init_module - Driver Registration Routine
+ *
+ * The first routine called when the driver is loaded.  All it does is
+ * register with the PCI subsystem.
+ *
+ * Return: 0 on success, negative on failure
+ **/
+static int __init fbnic_init_module(void)
+{
+	int err;
+
+	err = pci_register_driver(&fbnic_driver);
+	if (err)
+		goto out;
+
+	pr_info(DRV_SUMMARY " (%s)", fbnic_driver.name);
+out:
+	return err;
+}
+module_init(fbnic_init_module);
+
+/**
+ * fbnic_exit_module - Driver Exit Cleanup Routine
+ *
+ * Called just before the driver is removed from memory.
+ **/
+static void __exit fbnic_exit_module(void)
+{
+	pci_unregister_driver(&fbnic_driver);
+}
+module_exit(fbnic_exit_module);