pds_core: initial framework for pds_core PF driver

This is the initial PCI driver framework for the new pds_core device
driver and its family of devices.  This does the very basics of
registering for the new PF PCI device 1dd8:100c, setting up debugfs
entries, and registering with devlink.
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/device_drivers/ethernet/amd/pds_core.rst

+.. SPDX-License-Identifier: GPL-2.0+
+
+========================================================
+Linux Driver for the AMD/Pensando(R) DSC adapter family
+========================================================
+
+Copyright(c) 2023 Advanced Micro Devices, Inc
+
+Identifying the Adapter
+=======================
+
+To find if one or more AMD/Pensando PCI Core devices are installed on the
+host, check for the PCI devices::
+
+  # lspci -d 1dd8:100c
+  b5:00.0 Processing accelerators: Pensando Systems Device 100c
+  b6:00.0 Processing accelerators: Pensando Systems Device 100c
+
+If such devices are listed as above, then the pds_core.ko driver should find
+and configure them for use.  There should be log entries in the kernel
+messages such as these::
+
+  $ dmesg | grep pds_core
+  pds_core 0000:b5:00.0: 252.048 Gb/s available PCIe bandwidth (16.0 GT/s PCIe x16 link)
+  pds_core 0000:b5:00.0: FW: 1.60.0-73
+  pds_core 0000:b6:00.0: 252.048 Gb/s available PCIe bandwidth (16.0 GT/s PCIe x16 link)
+  pds_core 0000:b6:00.0: FW: 1.60.0-73
+
+Support
+=======
+
+For general Linux networking support, please use the netdev mailing
+list, which is monitored by AMD/Pensando personnel::
+
+  netdev@vger.kernel.org

Documentation/networking/device_drivers/ethernet/index.rst

@@ -14,6 +14,7 @@ Contents:
    3com/vortex
    amazon/ena
    altera/altera_tse
+   amd/pds_core
    aquantia/atlantic
    chelsio/cxgb
    cirrus/cs89x0

drivers/net/ethernet/amd/pds_core/Makefile

+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 Advanced Micro Devices, Inc.
+
+obj-$(CONFIG_PDS_CORE) := pds_core.o
+
+pds_core-y := main.o
+
+pds_core-$(CONFIG_DEBUG_FS) += debugfs.o

drivers/net/ethernet/amd/pds_core/core.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#ifndef _PDSC_H_
+#define _PDSC_H_
+
+#include <linux/debugfs.h>
+#include <net/devlink.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_core_if.h>
+
+#define PDSC_DRV_DESCRIPTION	"AMD/Pensando Core Driver"
+
+struct pdsc_dev_bar {
+	void __iomem *vaddr;
+	phys_addr_t bus_addr;
+	unsigned long len;
+	int res_index;
+};
+
+/* No state flags set means we are in a steady running state */
+enum pdsc_state_flags {
+	PDSC_S_FW_DEAD,		    /* stopped, wait on startup or recovery */
+	PDSC_S_INITING_DRIVER,	    /* initial startup from probe */
+	PDSC_S_STOPPING_DRIVER,	    /* driver remove */
+
+	/* leave this as last */
+	PDSC_S_STATE_SIZE
+};
+
+struct pdsc {
+	struct pci_dev *pdev;
+	struct dentry *dentry;
+	struct device *dev;
+	struct pdsc_dev_bar bars[PDS_CORE_BARS_MAX];
+	int hw_index;
+	int uid;
+
+	unsigned long state;
+
+	struct pds_core_dev_info_regs __iomem *info_regs;
+	struct pds_core_dev_cmd_regs __iomem *cmd_regs;
+	struct pds_core_intr __iomem *intr_ctrl;
+	u64 __iomem *intr_status;
+	u64 __iomem *db_pages;
+	dma_addr_t phy_db_pages;
+	u64 __iomem *kern_dbpage;
+};
+
+void pdsc_debugfs_create(void);
+void pdsc_debugfs_destroy(void);
+void pdsc_debugfs_add_dev(struct pdsc *pdsc);
+void pdsc_debugfs_del_dev(struct pdsc *pdsc);
+
+#endif /* _PDSC_H_ */

drivers/net/ethernet/amd/pds_core/debugfs.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#include <linux/pci.h>
+
+#include "core.h"
+
+static struct dentry *pdsc_dir;
+
+void pdsc_debugfs_create(void)
+{
+	pdsc_dir = debugfs_create_dir(PDS_CORE_DRV_NAME, NULL);
+}
+
+void pdsc_debugfs_destroy(void)
+{
+	debugfs_remove_recursive(pdsc_dir);
+}
+
+void pdsc_debugfs_add_dev(struct pdsc *pdsc)
+{
+	pdsc->dentry = debugfs_create_dir(pci_name(pdsc->pdev), pdsc_dir);
+
+	debugfs_create_ulong("state", 0400, pdsc->dentry, &pdsc->state);
+}
+
+void pdsc_debugfs_del_dev(struct pdsc *pdsc)
+{
+	debugfs_remove_recursive(pdsc->dentry);
+	pdsc->dentry = NULL;
+}

drivers/net/ethernet/amd/pds_core/main.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/pci.h>
+
+#include <linux/pds/pds_common.h>
+
+#include "core.h"
+
+MODULE_DESCRIPTION(PDSC_DRV_DESCRIPTION);
+MODULE_AUTHOR("Advanced Micro Devices, Inc");
+MODULE_LICENSE("GPL");
+
+/* Supported devices */
+static const struct pci_device_id pdsc_id_table[] = {
+	{ PCI_VDEVICE(PENSANDO, PCI_DEVICE_ID_PENSANDO_CORE_PF) },
+	{ 0, }	/* end of table */
+};
+MODULE_DEVICE_TABLE(pci, pdsc_id_table);
+
+static void pdsc_unmap_bars(struct pdsc *pdsc)
+{
+	struct pdsc_dev_bar *bars = pdsc->bars;
+	unsigned int i;
+
+	for (i = 0; i < PDS_CORE_BARS_MAX; i++) {
+		if (bars[i].vaddr)
+			pci_iounmap(pdsc->pdev, bars[i].vaddr);
+	}
+}
+
+static int pdsc_map_bars(struct pdsc *pdsc)
+{
+	struct pdsc_dev_bar *bar = pdsc->bars;
+	struct pci_dev *pdev = pdsc->pdev;
+	struct device *dev = pdsc->dev;
+	struct pdsc_dev_bar *bars;
+	unsigned int i, j;
+	int num_bars = 0;
+	int err;
+	u32 sig;
+
+	bars = pdsc->bars;
+
+	/* Since the PCI interface in the hardware is configurable,
+	 * we need to poke into all the bars to find the set we're
+	 * expecting.
+	 */
+	for (i = 0, j = 0; i < PDS_CORE_BARS_MAX; i++) {
+		if (!(pci_resource_flags(pdev, i) & IORESOURCE_MEM))
+			continue;
+
+		bars[j].len = pci_resource_len(pdev, i);
+		bars[j].bus_addr = pci_resource_start(pdev, i);
+		bars[j].res_index = i;
+
+		/* only map the whole bar 0 */
+		if (j > 0) {
+			bars[j].vaddr = NULL;
+		} else {
+			bars[j].vaddr = pci_iomap(pdev, i, bars[j].len);
+			if (!bars[j].vaddr) {
+				dev_err(dev, "Cannot map BAR %d, aborting\n", i);
+				return -ENODEV;
+			}
+		}
+
+		j++;
+	}
+	num_bars = j;
+
+	/* BAR0: dev_cmd and interrupts */
+	if (num_bars < 1) {
+		dev_err(dev, "No bars found\n");
+		err = -EFAULT;
+		goto err_out;
+	}
+
+	if (bar->len < PDS_CORE_BAR0_SIZE) {
+		dev_err(dev, "Resource bar size %lu too small\n", bar->len);
+		err = -EFAULT;
+		goto err_out;
+	}
+
+	pdsc->info_regs = bar->vaddr + PDS_CORE_BAR0_DEV_INFO_REGS_OFFSET;
+	pdsc->cmd_regs = bar->vaddr + PDS_CORE_BAR0_DEV_CMD_REGS_OFFSET;
+	pdsc->intr_status = bar->vaddr + PDS_CORE_BAR0_INTR_STATUS_OFFSET;
+	pdsc->intr_ctrl = bar->vaddr + PDS_CORE_BAR0_INTR_CTRL_OFFSET;
+
+	sig = ioread32(&pdsc->info_regs->signature);
+	if (sig != PDS_CORE_DEV_INFO_SIGNATURE) {
+		dev_err(dev, "Incompatible firmware signature %x", sig);
+		err = -EFAULT;
+		goto err_out;
+	}
+
+	/* BAR1: doorbells */
+	bar++;
+	if (num_bars < 2) {
+		dev_err(dev, "Doorbell bar missing\n");
+		err = -EFAULT;
+		goto err_out;
+	}
+
+	pdsc->db_pages = bar->vaddr;
+	pdsc->phy_db_pages = bar->bus_addr;
+
+	return 0;
+
+err_out:
+	pdsc_unmap_bars(pdsc);
+	return err;
+}
+
+static int pdsc_init_vf(struct pdsc *vf)
+{
+	return -1;
+}
+
+static int pdsc_init_pf(struct pdsc *pdsc)
+{
+	struct devlink *dl;
+	int err;
+
+	pcie_print_link_status(pdsc->pdev);
+
+	err = pci_request_regions(pdsc->pdev, PDS_CORE_DRV_NAME);
+	if (err) {
+		dev_err(pdsc->dev, "Cannot request PCI regions: %pe\n",
+			ERR_PTR(err));
+		return err;
+	}
+
+	err = pdsc_map_bars(pdsc);
+	if (err)
+		goto err_out_release_regions;
+
+	dl = priv_to_devlink(pdsc);
+	devl_lock(dl);
+	devl_register(dl);
+	devl_unlock(dl);
+
+	return 0;
+
+err_out_release_regions:
+	pci_release_regions(pdsc->pdev);
+
+	return err;
+}
+
+static const struct devlink_ops pdsc_dl_ops = {
+};
+
+static const struct devlink_ops pdsc_dl_vf_ops = {
+};
+
+static DEFINE_IDA(pdsc_ida);
+
+static int pdsc_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	struct device *dev = &pdev->dev;
+	const struct devlink_ops *ops;
+	struct devlink *dl;
+	struct pdsc *pdsc;
+	bool is_pf;
+	int err;
+
+	is_pf = !pdev->is_virtfn;
+	ops = is_pf ? &pdsc_dl_ops : &pdsc_dl_vf_ops;
+	dl = devlink_alloc(ops, sizeof(struct pdsc), dev);
+	if (!dl)
+		return -ENOMEM;
+	pdsc = devlink_priv(dl);
+
+	pdsc->pdev = pdev;
+	pdsc->dev = &pdev->dev;
+	set_bit(PDSC_S_INITING_DRIVER, &pdsc->state);
+	pci_set_drvdata(pdev, pdsc);
+	pdsc_debugfs_add_dev(pdsc);
+
+	err = ida_alloc(&pdsc_ida, GFP_KERNEL);
+	if (err < 0) {
+		dev_err(pdsc->dev, "%s: id alloc failed: %pe\n",
+			__func__, ERR_PTR(err));
+		goto err_out_free_devlink;
+	}
+	pdsc->uid = err;
+
+	/* Query system for DMA addressing limitation for the device. */
+	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(PDS_CORE_ADDR_LEN));
+	if (err) {
+		dev_err(dev, "Unable to obtain 64-bit DMA for consistent allocations, aborting: %pe\n",
+			ERR_PTR(err));
+		goto err_out_free_ida;
+	}
+
+	err = pci_enable_device(pdev);
+	if (err) {
+		dev_err(dev, "Cannot enable PCI device: %pe\n", ERR_PTR(err));
+		goto err_out_free_ida;
+	}
+	pci_set_master(pdev);
+
+	if (is_pf)
+		err = pdsc_init_pf(pdsc);
+	else
+		err = pdsc_init_vf(pdsc);
+	if (err) {
+		dev_err(dev, "Cannot init device: %pe\n", ERR_PTR(err));
+		goto err_out_clear_master;
+	}
+
+	clear_bit(PDSC_S_INITING_DRIVER, &pdsc->state);
+	return 0;
+
+err_out_clear_master:
+	pci_clear_master(pdev);
+	pci_disable_device(pdev);
+err_out_free_ida:
+	ida_free(&pdsc_ida, pdsc->uid);
+err_out_free_devlink:
+	pdsc_debugfs_del_dev(pdsc);
+	devlink_free(dl);
+
+	return err;
+}
+
+static void pdsc_remove(struct pci_dev *pdev)
+{
+	struct pdsc *pdsc = pci_get_drvdata(pdev);
+	struct devlink *dl;
+
+	/* Unhook the registrations first to be sure there
+	 * are no requests while we're stopping.
+	 */
+	dl = priv_to_devlink(pdsc);
+	devl_lock(dl);
+	devl_unregister(dl);
+	devl_unlock(dl);
+
+	pdsc_unmap_bars(pdsc);
+	pci_release_regions(pdev);
+
+	pci_clear_master(pdev);
+	pci_disable_device(pdev);
+
+	ida_free(&pdsc_ida, pdsc->uid);
+	pdsc_debugfs_del_dev(pdsc);
+	devlink_free(dl);
+}
+
+static struct pci_driver pdsc_driver = {
+	.name = PDS_CORE_DRV_NAME,
+	.id_table = pdsc_id_table,
+	.probe = pdsc_probe,
+	.remove = pdsc_remove,
+};
+
+static int __init pdsc_init_module(void)
+{
+	if (strcmp(KBUILD_MODNAME, PDS_CORE_DRV_NAME))
+		return -EINVAL;
+
+	pdsc_debugfs_create();
+	return pci_register_driver(&pdsc_driver);
+}
+
+static void __exit pdsc_cleanup_module(void)
+{
+	pci_unregister_driver(&pdsc_driver);
+	pdsc_debugfs_destroy();
+}
+
+module_init(pdsc_init_module);
+module_exit(pdsc_cleanup_module);

include/linux/pds/pds_common.h

+/* SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB) OR BSD-2-Clause */
+/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
+
+#ifndef _PDS_COMMON_H_
+#define _PDS_COMMON_H_
+
+#define PDS_CORE_DRV_NAME			"pds_core"
+
+/* the device's internal addressing uses up to 52 bits */
+#define PDS_CORE_ADDR_LEN	52
+#define PDS_CORE_ADDR_MASK	(BIT_ULL(PDS_ADDR_LEN) - 1)
+#define PDS_PAGE_SIZE		4096
+
+#endif /* _PDS_COMMON_H_ */