Date:   Mon, 3 May 2021 06:49:44 -0700
From:   Tom Rix <trix@...hat.com>
To:     Lizhi Hou <lizhi.hou@...inx.com>, linux-kernel@...r.kernel.org
Cc:     linux-fpga@...r.kernel.org, maxz@...inx.com,
        sonal.santan@...inx.com, yliu@...inx.com, michal.simek@...inx.com,
        stefanos@...inx.com, devicetree@...r.kernel.org, mdf@...nel.org,
        robh@...nel.org, Max Zhen <max.zhen@...inx.com>
Subject: Re: [PATCH V5 XRT Alveo 09/20] fpga: xrt: management physical
 function driver (root)


On 4/27/21 1:54 PM, Lizhi Hou wrote:
> The PCIE device driver which attaches to management function on Alveo
> devices. It instantiates one or more group drivers which, in turn,
> instantiate xrt drivers. The instantiation of group and xrt drivers is
> completely dtb driven.
>
> Signed-off-by: Sonal Santan <sonal.santan@...inx.com>
> Signed-off-by: Max Zhen <max.zhen@...inx.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@...inx.com>
Reviewed-by: Tom Rix <trix@...hat.com>
> ---
>   drivers/fpga/xrt/mgnt/root.c | 419 +++++++++++++++++++++++++++++++++++
>   1 file changed, 419 insertions(+)
>   create mode 100644 drivers/fpga/xrt/mgnt/root.c
>
> diff --git a/drivers/fpga/xrt/mgnt/root.c b/drivers/fpga/xrt/mgnt/root.c
> new file mode 100644
> index 000000000000..6e362e9d4b59
> --- /dev/null
> +++ b/drivers/fpga/xrt/mgnt/root.c
> @@ -0,0 +1,419 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo Management Function Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Cheng Zhen <maxz@...inx.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/aer.h>
> +#include <linux/vmalloc.h>
> +#include <linux/delay.h>
> +
> +#include "xroot.h"
> +#include "xmgnt.h"
> +#include "metadata.h"
> +
> +#define XMGNT_MODULE_NAME	"xrt-mgnt"
> +#define XMGNT_DRIVER_VERSION	"4.0.0"
> +
> +#define XMGNT_PDEV(xm)		((xm)->pdev)
> +#define XMGNT_DEV(xm)		(&(XMGNT_PDEV(xm)->dev))
> +#define xmgnt_err(xm, fmt, args...)	\
> +	dev_err(XMGNT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgnt_warn(xm, fmt, args...)	\
> +	dev_warn(XMGNT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgnt_info(xm, fmt, args...)	\
> +	dev_info(XMGNT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgnt_dbg(xm, fmt, args...)	\
> +	dev_dbg(XMGNT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define XMGNT_DEV_ID(_pcidev)			\
> +	({ typeof(_pcidev) (pcidev) = (_pcidev);	\
> +	((pci_domain_nr((pcidev)->bus) << 16) |	\
> +	PCI_DEVID((pcidev)->bus->number, 0)); })
> +#define XRT_VSEC_ID		0x20
> +#define XRT_MAX_READRQ		512
> +
> +static struct class *xmgnt_class;
> +
> +/* PCI Device IDs */
> +/*
> + * Golden image is preloaded on the device when it is shipped to customer.
> + * Then, customer can load other shells (from Xilinx or some other vendor).
> + * If something goes wrong with the shell, customer can always go back to
> + * golden and start over again.
> + */
> +#define PCI_DEVICE_ID_U50_GOLDEN	0xD020
> +#define PCI_DEVICE_ID_U50		0x5020
> +static const struct pci_device_id xmgnt_pci_ids[] = {
> +	{ PCI_DEVICE(PCI_VENDOR_ID_XILINX, PCI_DEVICE_ID_U50_GOLDEN), }, /* Alveo U50 (golden) */
> +	{ PCI_DEVICE(PCI_VENDOR_ID_XILINX, PCI_DEVICE_ID_U50), }, /* Alveo U50 */
> +	{ 0, }
> +};
> +
> +struct xmgnt {
> +	struct pci_dev *pdev;
> +	void *root;
> +
> +	bool ready;
> +};
> +
> +static int xmgnt_config_pci(struct xmgnt *xm)
> +{
> +	struct pci_dev *pdev = XMGNT_PDEV(xm);
> +	int rc;
> +
> +	rc = pcim_enable_device(pdev);
> +	if (rc < 0) {
> +		xmgnt_err(xm, "failed to enable device: %d", rc);
> +		return rc;
> +	}
> +
> +	rc = pci_enable_pcie_error_reporting(pdev);
> +	if (rc)
> +		xmgnt_warn(xm, "failed to enable AER: %d", rc);
> +
> +	pci_set_master(pdev);
> +
> +	rc = pcie_get_readrq(pdev);
> +	if (rc > XRT_MAX_READRQ)
> +		pcie_set_readrq(pdev, XRT_MAX_READRQ);
> +	return 0;
> +}
> +
> +static int xmgnt_match_slot_and_save(struct device *dev, void *data)
> +{
> +	struct xmgnt *xm = data;
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +
> +	if (XMGNT_DEV_ID(pdev) == XMGNT_DEV_ID(xm->pdev)) {
> +		pci_cfg_access_lock(pdev);
> +		pci_save_state(pdev);
> +	}
> +
> +	return 0;
> +}
> +
> +static void xmgnt_pci_save_config_all(struct xmgnt *xm)
> +{
> +	bus_for_each_dev(&pci_bus_type, NULL, xm, xmgnt_match_slot_and_save);
> +}
> +
> +static int xmgnt_match_slot_and_restore(struct device *dev, void *data)
> +{
> +	struct xmgnt *xm = data;
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +
> +	if (XMGNT_DEV_ID(pdev) == XMGNT_DEV_ID(xm->pdev)) {
> +		pci_restore_state(pdev);
> +		pci_cfg_access_unlock(pdev);
> +	}
> +
> +	return 0;
> +}
> +
> +static void xmgnt_pci_restore_config_all(struct xmgnt *xm)
> +{
> +	bus_for_each_dev(&pci_bus_type, NULL, xm, xmgnt_match_slot_and_restore);
> +}
> +
> +static void xmgnt_root_hot_reset(struct device *dev)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct pci_bus *bus;
> +	u16 pci_cmd, devctl;
> +	struct xmgnt *xm;
> +	u8 pci_bctl;
> +	int i, ret;
> +
> +	xm = pci_get_drvdata(pdev);
> +	xmgnt_info(xm, "hot reset start");
> +	xmgnt_pci_save_config_all(xm);
> +	pci_disable_device(pdev);
> +	bus = pdev->bus;
> +
> +	/*
> +	 * When flipping the SBR bit, device can fall off the bus. This is
> +	 * usually no problem at all so long as drivers are working properly
> +	 * after SBR. However, some systems complain bitterly when the device
> +	 * falls off the bus.
> +	 * The quick solution is to temporarily disable the SERR reporting of
> +	 * switch port during SBR.
> +	 */
> +
> +	pci_read_config_word(bus->self, PCI_COMMAND, &pci_cmd);
> +	pci_write_config_word(bus->self, PCI_COMMAND, (pci_cmd & ~PCI_COMMAND_SERR));
> +	pcie_capability_read_word(bus->self, PCI_EXP_DEVCTL, &devctl);
> +	pcie_capability_write_word(bus->self, PCI_EXP_DEVCTL, (devctl & ~PCI_EXP_DEVCTL_FERE));
> +	pci_read_config_byte(bus->self, PCI_BRIDGE_CONTROL, &pci_bctl);
> +	pci_write_config_byte(bus->self, PCI_BRIDGE_CONTROL, pci_bctl | PCI_BRIDGE_CTL_BUS_RESET);
> +	msleep(100);
> +	pci_write_config_byte(bus->self, PCI_BRIDGE_CONTROL, pci_bctl);
> +	ssleep(1);
> +
> +	pcie_capability_write_word(bus->self, PCI_EXP_DEVCTL, devctl);
> +	pci_write_config_word(bus->self, PCI_COMMAND, pci_cmd);
> +
> +	ret = pci_enable_device(pdev);
> +	if (ret)
> +		xmgnt_err(xm, "failed to enable device, ret %d", ret);
> +
> +	for (i = 0; i < 300; i++) {
> +		pci_read_config_word(pdev, PCI_COMMAND, &pci_cmd);
> +		if (pci_cmd != 0xffff)
> +			break;
> +		msleep(20);
> +	}
> +	if (i == 300)
> +		xmgnt_err(xm, "timed out waiting for device to be online after reset");
> +
> +	xmgnt_info(xm, "waiting for %d ms", i * 20);
> +	xmgnt_pci_restore_config_all(xm);
> +	xmgnt_config_pci(xm);
> +}
> +
> +static int xmgnt_add_vsec_node(struct xmgnt *xm, char *dtb)
> +{
> +	u32 off_low, off_high, vsec_bar, header;
> +	struct pci_dev *pdev = XMGNT_PDEV(xm);
> +	struct xrt_md_endpoint ep = { 0 };
> +	struct device *dev = DEV(pdev);
> +	int cap = 0, ret = 0;
> +	u64 vsec_off;
> +
> +	while ((cap = pci_find_next_ext_capability(pdev, cap, PCI_EXT_CAP_ID_VNDR))) {
> +		pci_read_config_dword(pdev, cap + PCI_VNDR_HEADER, &header);
> +		if (PCI_VNDR_HEADER_ID(header) == XRT_VSEC_ID)
> +			break;
> +	}
> +	if (!cap) {
> +		xmgnt_info(xm, "No Vendor Specific Capability.");
> +		return -ENOENT;
> +	}
> +
> +	if (pci_read_config_dword(pdev, cap + 8, &off_low) ||
> +	    pci_read_config_dword(pdev, cap + 12, &off_high)) {
> +		xmgnt_err(xm, "pci_read vendor specific failed.");
> +		return -EINVAL;
> +	}
> +
> +	ep.ep_name = XRT_MD_NODE_VSEC;
> +	ret = xrt_md_add_endpoint(dev, dtb, &ep);
> +	if (ret) {
> +		xmgnt_err(xm, "add vsec metadata failed, ret %d", ret);
> +		goto failed;
> +	}
> +
> +	vsec_bar = cpu_to_be32(off_low & 0xf);
> +	ret = xrt_md_set_prop(dev, dtb, XRT_MD_NODE_VSEC, NULL,
> +			      XRT_MD_PROP_BAR_IDX, &vsec_bar, sizeof(vsec_bar));
> +	if (ret) {
> +		xmgnt_err(xm, "add vsec bar idx failed, ret %d", ret);
> +		goto failed;
> +	}
> +
> +	vsec_off = cpu_to_be64(((u64)off_high << 32) | (off_low & ~0xfU));
> +	ret = xrt_md_set_prop(dev, dtb, XRT_MD_NODE_VSEC, NULL,
> +			      XRT_MD_PROP_OFFSET, &vsec_off, sizeof(vsec_off));
> +	if (ret) {
> +		xmgnt_err(xm, "add vsec offset failed, ret %d", ret);
> +		goto failed;
> +	}
> +
> +failed:
> +	return ret;
> +}
> +
> +static int xmgnt_create_root_metadata(struct xmgnt *xm, char **root_dtb)
> +{
> +	char *dtb = NULL;
> +	int ret;
> +
> +	ret = xrt_md_create(XMGNT_DEV(xm), &dtb);
> +	if (ret) {
> +		xmgnt_err(xm, "create metadata failed, ret %d", ret);
> +		goto failed;
> +	}
> +
> +	ret = xmgnt_add_vsec_node(xm, dtb);
> +	if (ret == -ENOENT) {
> +		/*
> +		 * We may be dealing with a MFG board.
> +		 * Try vsec-golden which will bring up all hard-coded leaves
> +		 * at hard-coded offsets.
> +		 */
> +		ret = xroot_add_simple_node(xm->root, dtb, XRT_MD_NODE_VSEC_GOLDEN);
> +	} else if (ret == 0) {
> +		ret = xroot_add_simple_node(xm->root, dtb, XRT_MD_NODE_MGNT_MAIN);
> +	}
> +	if (ret)
> +		goto failed;
> +
> +	*root_dtb = dtb;
> +	return 0;
> +
> +failed:
> +	vfree(dtb);
> +	return ret;
> +}
> +
> +static ssize_t ready_show(struct device *dev,
> +			  struct device_attribute *da,
> +			  char *buf)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct xmgnt *xm = pci_get_drvdata(pdev);
> +
> +	return sprintf(buf, "%d\n", xm->ready);
> +}
> +static DEVICE_ATTR_RO(ready);
> +
> +static struct attribute *xmgnt_root_attrs[] = {
> +	&dev_attr_ready.attr,
> +	NULL
> +};
> +
> +static struct attribute_group xmgnt_root_attr_group = {
> +	.attrs = xmgnt_root_attrs,
> +};
> +
> +static void xmgnt_root_get_id(struct device *dev, struct xrt_root_get_id *rid)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +
> +	rid->xpigi_vendor_id = pdev->vendor;
> +	rid->xpigi_device_id = pdev->device;
> +	rid->xpigi_sub_vendor_id = pdev->subsystem_vendor;
> +	rid->xpigi_sub_device_id = pdev->subsystem_device;
> +}
> +
> +static int xmgnt_root_get_resource(struct device *dev, struct xrt_root_get_res *res)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct xmgnt *xm;
> +
> +	xm = pci_get_drvdata(pdev);
> +	if (res->xpigr_region_id > PCI_STD_RESOURCE_END) {
> +		xmgnt_err(xm, "Invalid bar idx %d", res->xpigr_region_id);
> +		return -EINVAL;
> +	}
> +
> +	res->xpigr_res = &pdev->resource[res->xpigr_region_id];
> +	return 0;
> +}
> +
> +static struct xroot_physical_function_callback xmgnt_xroot_pf_cb = {
> +	.xpc_get_id = xmgnt_root_get_id,
> +	.xpc_get_resource = xmgnt_root_get_resource,
> +	.xpc_hot_reset = xmgnt_root_hot_reset,
> +};
> +
> +static int xmgnt_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> +{
> +	int ret;
> +	struct device *dev = &pdev->dev;
> +	struct xmgnt *xm = devm_kzalloc(dev, sizeof(*xm), GFP_KERNEL);
> +	char *dtb = NULL;
> +
> +	if (!xm)
> +		return -ENOMEM;
> +	xm->pdev = pdev;
> +	pci_set_drvdata(pdev, xm);
> +
> +	ret = xmgnt_config_pci(xm);
> +	if (ret)
> +		goto failed;
> +
> +	ret = xroot_probe(&pdev->dev, &xmgnt_xroot_pf_cb, &xm->root);
> +	if (ret)
> +		goto failed;
> +
> +	ret = xmgnt_create_root_metadata(xm, &dtb);
> +	if (ret)
> +		goto failed_metadata;
> +
> +	ret = xroot_create_group(xm->root, dtb);
> +	vfree(dtb);
> +	if (ret)
> +		xmgnt_err(xm, "failed to create root group: %d", ret);
> +
> +	if (!xroot_wait_for_bringup(xm->root))
> +		xmgnt_err(xm, "failed to bringup all groups");
> +	else
> +		xm->ready = true;
> +
> +	ret = sysfs_create_group(&pdev->dev.kobj, &xmgnt_root_attr_group);
> +	if (ret) {
> +		/* Warning instead of failing the probe. */
> +		xmgnt_warn(xm, "create xmgnt root attrs failed: %d", ret);
> +	}
> +
> +	xroot_broadcast(xm->root, XRT_EVENT_POST_CREATION);
> +	xmgnt_info(xm, "%s started successfully", XMGNT_MODULE_NAME);
> +	return 0;
> +
> +failed_metadata:
> +	xroot_remove(xm->root);
> +failed:
> +	pci_set_drvdata(pdev, NULL);
> +	return ret;
> +}
> +
> +static void xmgnt_remove(struct pci_dev *pdev)
> +{
> +	struct xmgnt *xm = pci_get_drvdata(pdev);
> +
> +	xroot_broadcast(xm->root, XRT_EVENT_PRE_REMOVAL);
> +	sysfs_remove_group(&pdev->dev.kobj, &xmgnt_root_attr_group);
> +	xroot_remove(xm->root);
> +	pci_disable_pcie_error_reporting(xm->pdev);
> +	xmgnt_info(xm, "%s cleaned up successfully", XMGNT_MODULE_NAME);
> +}
> +
> +static struct pci_driver xmgnt_driver = {
> +	.name = XMGNT_MODULE_NAME,
> +	.id_table = xmgnt_pci_ids,
> +	.probe = xmgnt_probe,
> +	.remove = xmgnt_remove,
> +};
> +
> +static int __init xmgnt_init(void)
> +{
> +	int res = 0;
> +
> +	res = xmgnt_register_leaf();
> +	if (res)
> +		return res;
> +
> +	xmgnt_class = class_create(THIS_MODULE, XMGNT_MODULE_NAME);
> +	if (IS_ERR(xmgnt_class))
> +		return PTR_ERR(xmgnt_class);
> +
> +	res = pci_register_driver(&xmgnt_driver);
> +	if (res) {
> +		class_destroy(xmgnt_class);
> +		return res;
> +	}
> +
> +	return 0;
> +}
> +
> +static __exit void xmgnt_exit(void)
> +{
> +	pci_unregister_driver(&xmgnt_driver);
> +	class_destroy(xmgnt_class);
> +	xmgnt_unregister_leaf();
> +}
> +
> +module_init(xmgnt_init);
> +module_exit(xmgnt_exit);
> +
> +MODULE_DEVICE_TABLE(pci, xmgnt_pci_ids);
> +MODULE_VERSION(XMGNT_DRIVER_VERSION);
> +MODULE_AUTHOR("XRT Team <runtime@...inx.com>");
> +MODULE_DESCRIPTION("Xilinx Alveo management function driver");
> +MODULE_LICENSE("GPL v2");

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