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Subject: Re: [PATCH V3 XRT Alveo 07/18] fpga: xrt: management physical
 function driver (root)
To:     Lizhi Hou <lizhi.hou@xilinx.com>, linux-kernel@vger.kernel.org,
        "mdf@kernel.org" <mdf@kernel.org>
Cc:     Lizhi Hou <lizhih@xilinx.com>, linux-fpga@vger.kernel.org,
        maxz@xilinx.com, sonal.santan@xilinx.com, michal.simek@xilinx.com,
        stefanos@xilinx.com, devicetree@vger.kernel.org, mdf@kernel.org,
        robh@kernel.org, Max Zhen <max.zhen@xilinx.com>
References: <20210218064019.29189-1-lizhih@xilinx.com>
 <20210218064019.29189-8-lizhih@xilinx.com>
From:   Tom Rix <trix@redhat.com>
Message-ID: <d0057bee-2cf1-b560-c160-636d8e76cbda@redhat.com>
Date:   Fri, 26 Feb 2021 07:01:05 -0800
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A question i do not know the answer to.

Seems like 'golden' is linked to a manufacturing (diagnostics?) image.

If the public will never see it, should handling it here be done ?

Moritz, do you know ?


On 2/17/21 10:40 PM, Lizhi Hou wrote:
> The PCIE device driver which attaches to management function on Alveo
to the management
> devices. It instantiates one or more partition drivers which in turn
more fpga partition / group ?
> instantiate platform drivers. The instantiation of partition and platform
> drivers is completely data driven.
data driven ? everything is data driven.  do you mean dtb driven ?
>
> Signed-off-by: Sonal Santan <sonal.santan@xilinx.com>
> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
> Signed-off-by: Lizhi Hou <lizhih@xilinx.com>
> ---
>  drivers/fpga/xrt/include/xroot.h | 114 +++++++++++
>  drivers/fpga/xrt/mgmt/root.c     | 342 +++++++++++++++++++++++++++++++
>  2 files changed, 456 insertions(+)
>  create mode 100644 drivers/fpga/xrt/include/xroot.h
>  create mode 100644 drivers/fpga/xrt/mgmt/root.c
>
> diff --git a/drivers/fpga/xrt/include/xroot.h b/drivers/fpga/xrt/include/xroot.h
> new file mode 100644
> index 000000000000..752e10daa85e
> --- /dev/null
> +++ b/drivers/fpga/xrt/include/xroot.h
> @@ -0,0 +1,114 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Header file for Xilinx Runtime (XRT) driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Cheng Zhen <maxz@xilinx.com>
> + */
> +
> +#ifndef _XRT_ROOT_H_
> +#define _XRT_ROOT_H_
> +
> +#include <linux/pci.h>
> +#include "subdev_id.h"
> +#include "events.h"
> +
> +typedef bool (*xrt_subdev_match_t)(enum xrt_subdev_id,
> +	struct platform_device *, void *);
> +#define XRT_SUBDEV_MATCH_PREV	((xrt_subdev_match_t)-1)
> +#define XRT_SUBDEV_MATCH_NEXT	((xrt_subdev_match_t)-2)
> +
> +/*
> + * Root IOCTL calls.
> + */
> +enum xrt_root_ioctl_cmd {
> +	/* Leaf actions. */
> +	XRT_ROOT_GET_LEAF = 0,
> +	XRT_ROOT_PUT_LEAF,
> +	XRT_ROOT_GET_LEAF_HOLDERS,
> +
> +	/* Group actions. */
> +	XRT_ROOT_CREATE_GROUP,
> +	XRT_ROOT_REMOVE_GROUP,
> +	XRT_ROOT_LOOKUP_GROUP,
> +	XRT_ROOT_WAIT_GROUP_BRINGUP,
> +
> +	/* Event actions. */
> +	XRT_ROOT_EVENT,
should this be XRT_ROOT_EVENT_SYNC ?
> +	XRT_ROOT_EVENT_ASYNC,
> +
> +	/* Device info. */
> +	XRT_ROOT_GET_RESOURCE,
> +	XRT_ROOT_GET_ID,
> +
> +	/* Misc. */
> +	XRT_ROOT_HOT_RESET,
> +	XRT_ROOT_HWMON,
> +};
> +
> +struct xrt_root_ioctl_get_leaf {
> +	struct platform_device *xpigl_pdev; /* caller's pdev */
xpigl_ ? unneeded suffix in element names
> +	xrt_subdev_match_t xpigl_match_cb;
> +	void *xpigl_match_arg;
> +	struct platform_device *xpigl_leaf; /* target leaf pdev */
> +};
> +
> +struct xrt_root_ioctl_put_leaf {
> +	struct platform_device *xpipl_pdev; /* caller's pdev */
> +	struct platform_device *xpipl_leaf; /* target's pdev */

caller_pdev;

target_pdev;

> +};
> +
> +struct xrt_root_ioctl_lookup_group {
> +	struct platform_device *xpilp_pdev; /* caller's pdev */
> +	xrt_subdev_match_t xpilp_match_cb;
> +	void *xpilp_match_arg;
> +	int xpilp_grp_inst;
> +};
> +
> +struct xrt_root_ioctl_get_holders {
> +	struct platform_device *xpigh_pdev; /* caller's pdev */
> +	char *xpigh_holder_buf;
> +	size_t xpigh_holder_buf_len;
> +};
> +
> +struct xrt_root_ioctl_get_res {
> +	struct resource *xpigr_res;
> +};
> +
> +struct xrt_root_ioctl_get_id {
> +	unsigned short  xpigi_vendor_id;
> +	unsigned short  xpigi_device_id;
> +	unsigned short  xpigi_sub_vendor_id;
> +	unsigned short  xpigi_sub_device_id;
> +};
> +
> +struct xrt_root_ioctl_hwmon {
> +	bool xpih_register;
> +	const char *xpih_name;
> +	void *xpih_drvdata;
> +	const struct attribute_group **xpih_groups;
> +	struct device *xpih_hwmon_dev;
> +};
> +
> +typedef int (*xrt_subdev_root_cb_t)(struct device *, void *, u32, void *);
This function pointer type is important, please add a comment about its use and expected parameters
> +int xrt_subdev_root_request(struct platform_device *self, u32 cmd, void *arg);
> +
> +/*
> + * Defines physical function (MPF / UPF) specific operations
> + * needed in common root driver.
> + */
> +struct xroot_pf_cb {
> +	void (*xpc_hot_reset)(struct pci_dev *pdev);
This is only ever set to xmgmt_root_hot_reset, why is this abstraction needed ?
> +};
> +
> +int xroot_probe(struct pci_dev *pdev, struct xroot_pf_cb *cb, void **root);
> +void xroot_remove(void *root);
> +bool xroot_wait_for_bringup(void *root);
> +int xroot_add_vsec_node(void *root, char *dtb);
> +int xroot_create_group(void *xr, char *dtb);
> +int xroot_add_simple_node(void *root, char *dtb, const char *endpoint);
> +void xroot_broadcast(void *root, enum xrt_events evt);
> +
> +#endif	/* _XRT_ROOT_H_ */
> diff --git a/drivers/fpga/xrt/mgmt/root.c b/drivers/fpga/xrt/mgmt/root.c
> new file mode 100644
> index 000000000000..583a37c9d30c
> --- /dev/null
> +++ b/drivers/fpga/xrt/mgmt/root.c
> @@ -0,0 +1,342 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo Management Function Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Cheng Zhen <maxz@xilinx.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 "main-impl.h"
> +#include "metadata.h"
> +
> +#define XMGMT_MODULE_NAME	"xmgmt"
The xrt modules would be more easily identified with a 'xrt' prefix instead of 'x'
> +#define XMGMT_DRIVER_VERSION	"4.0.0"
> +
> +#define XMGMT_PDEV(xm)		((xm)->pdev)
> +#define XMGMT_DEV(xm)		(&(XMGMT_PDEV(xm)->dev))
> +#define xmgmt_err(xm, fmt, args...)	\
> +	dev_err(XMGMT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgmt_warn(xm, fmt, args...)	\
> +	dev_warn(XMGMT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgmt_info(xm, fmt, args...)	\
> +	dev_info(XMGMT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define xmgmt_dbg(xm, fmt, args...)	\
> +	dev_dbg(XMGMT_DEV(xm), "%s: " fmt, __func__, ##args)
> +#define XMGMT_DEV_ID(_pcidev)			\
> +	({ typeof(_pcidev) (pcidev) = (_pcidev);	\
> +	((pci_domain_nr((pcidev)->bus) << 16) |	\
> +	PCI_DEVID((pcidev)->bus->number, 0)); })
> +
> +static struct class *xmgmt_class;
> +static const struct pci_device_id xmgmt_pci_ids[] = {
> +	{ PCI_DEVICE(0x10EE, 0xd020), }, /* Alveo U50 (golden image) */
> +	{ PCI_DEVICE(0x10EE, 0x5020), }, /* Alveo U50 */

demagic this table, look at dfl-pci for how to use existing #define for the vendor and create a new on for the device.  If there are vf's add them at the same time.

What is a golden image ?

> +	{ 0, }
> +};
> +
> +struct xmgmt {
> +	struct pci_dev *pdev;
> +	void *root;
> +
> +	bool ready;
> +};
> +
> +static int xmgmt_config_pci(struct xmgmt *xm)
> +{
> +	struct pci_dev *pdev = XMGMT_PDEV(xm);
> +	int rc;
> +
> +	rc = pcim_enable_device(pdev);
> +	if (rc < 0) {
> +		xmgmt_err(xm, "failed to enable device: %d", rc);
> +		return rc;
> +	}
> +
> +	rc = pci_enable_pcie_error_reporting(pdev);
> +	if (rc)
> +		xmgmt_warn(xm, "failed to enable AER: %d", rc);
> +
> +	pci_set_master(pdev);
> +
> +	rc = pcie_get_readrq(pdev);
Review this call, it does not go negative
> +	if (rc < 0) {
> +		xmgmt_err(xm, "failed to read mrrs %d", rc);
> +		return rc;
> +	}
this is a quirk, add a comment.
> +	if (rc > 512) {
> +		rc = pcie_set_readrq(pdev, 512);
> +		if (rc) {
> +			xmgmt_err(xm, "failed to force mrrs %d", rc);
similar calls do not fail here.
> +			return rc;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int xmgmt_match_slot_and_save(struct device *dev, void *data)
> +{
> +	struct xmgmt *xm = data;
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +
> +	if (XMGMT_DEV_ID(pdev) == XMGMT_DEV_ID(xm->pdev)) {
> +		pci_cfg_access_lock(pdev);
> +		pci_save_state(pdev);
> +	}
> +
> +	return 0;
> +}
> +
> +static void xmgmt_pci_save_config_all(struct xmgmt *xm)
> +{
> +	bus_for_each_dev(&pci_bus_type, NULL, xm, xmgmt_match_slot_and_save);

This is a bus call, not a device call.

Can this be changed into something like what hot reset does ?

> +}
> +
> +static int xmgmt_match_slot_and_restore(struct device *dev, void *data)
> +{
> +	struct xmgmt *xm = data;
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +
> +	if (XMGMT_DEV_ID(pdev) == XMGMT_DEV_ID(xm->pdev)) {
> +		pci_restore_state(pdev);
> +		pci_cfg_access_unlock(pdev);
> +	}
> +
> +	return 0;
> +}
> +
> +static void xmgmt_pci_restore_config_all(struct xmgmt *xm)
> +{
> +	bus_for_each_dev(&pci_bus_type, NULL, xm, xmgmt_match_slot_and_restore);
> +}
> +
> +static void xmgmt_root_hot_reset(struct pci_dev *pdev)
> +{
> +	struct xmgmt *xm = pci_get_drvdata(pdev);
> +	struct pci_bus *bus;
> +	u8 pci_bctl;
> +	u16 pci_cmd, devctl;
> +	int i, ret;
> +
> +	xmgmt_info(xm, "hot reset start");
> +
> +	xmgmt_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_bctl |= PCI_BRIDGE_CTL_BUS_RESET;
> +	pci_write_config_byte(bus->self, PCI_BRIDGE_CONTROL, pci_bctl);

how the pci config values are set and cleared should be consistent.

this call should be

pci_write_config_byte (... pci_bctl | PCI_BRIDGE_CTL_BUF_RESET )

and the next &= avoided

> +
> +	msleep(100);
> +	pci_bctl &= ~PCI_BRIDGE_CTL_BUS_RESET;
> +	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)
> +		xmgmt_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)
what happens with i == 300 and pci_cmd is still 0xffff ?
> +			break;
> +		msleep(20);
> +	}
> +
> +	xmgmt_info(xm, "waiting for %d ms", i * 20);
> +	xmgmt_pci_restore_config_all(xm);
> +	xmgmt_config_pci(xm);
> +}
> +
> +static int xmgmt_create_root_metadata(struct xmgmt *xm, char **root_dtb)
> +{
> +	char *dtb = NULL;
> +	int ret;
> +
> +	ret = xrt_md_create(XMGMT_DEV(xm), &dtb);
> +	if (ret) {
> +		xmgmt_err(xm, "create metadata failed, ret %d", ret);
> +		goto failed;
> +	}
> +
> +	ret = xroot_add_vsec_node(xm->root, 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);

Manufacturing diagnostics ?

Tom

> +	} else if (ret == 0) {
> +		ret = xroot_add_simple_node(xm->root, dtb, XRT_MD_NODE_MGMT_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 xmgmt *xm = pci_get_drvdata(pdev);
> +
> +	return sprintf(buf, "%d\n", xm->ready);
> +}
> +static DEVICE_ATTR_RO(ready);
> +
> +static struct attribute *xmgmt_root_attrs[] = {
> +	&dev_attr_ready.attr,
> +	NULL
> +};
> +
> +static struct attribute_group xmgmt_root_attr_group = {
> +	.attrs = xmgmt_root_attrs,
> +};
> +
> +static struct xroot_pf_cb xmgmt_xroot_pf_cb = {
> +	.xpc_hot_reset = xmgmt_root_hot_reset,
> +};
> +
> +static int xmgmt_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> +{
> +	int ret;
> +	struct device *dev = &pdev->dev;
> +	struct xmgmt *xm = devm_kzalloc(dev, sizeof(*xm), GFP_KERNEL);
> +	char *dtb = NULL;
> +
> +	if (!xm)
> +		return -ENOMEM;
> +	xm->pdev = pdev;
> +	pci_set_drvdata(pdev, xm);
> +
> +	ret = xmgmt_config_pci(xm);
> +	if (ret)
> +		goto failed;
> +
> +	ret = xroot_probe(pdev, &xmgmt_xroot_pf_cb, &xm->root);
> +	if (ret)
> +		goto failed;
> +
> +	ret = xmgmt_create_root_metadata(xm, &dtb);
> +	if (ret)
> +		goto failed_metadata;
> +
> +	ret = xroot_create_group(xm->root, dtb);
> +	vfree(dtb);
> +	if (ret)
> +		xmgmt_err(xm, "failed to create root group: %d", ret);
> +
> +	if (!xroot_wait_for_bringup(xm->root))
> +		xmgmt_err(xm, "failed to bringup all groups");
> +	else
> +		xm->ready = true;
> +
> +	ret = sysfs_create_group(&pdev->dev.kobj, &xmgmt_root_attr_group);
> +	if (ret) {
> +		/* Warning instead of failing the probe. */
> +		xmgmt_warn(xm, "create xmgmt root attrs failed: %d", ret);
> +	}
> +
> +	xroot_broadcast(xm->root, XRT_EVENT_POST_CREATION);
> +	xmgmt_info(xm, "%s started successfully", XMGMT_MODULE_NAME);
> +	return 0;
> +
> +failed_metadata:
> +	(void)xroot_remove(xm->root);
> +failed:
> +	pci_set_drvdata(pdev, NULL);
> +	return ret;
> +}
> +
> +static void xmgmt_remove(struct pci_dev *pdev)
> +{
> +	struct xmgmt *xm = pci_get_drvdata(pdev);
> +
> +	xroot_broadcast(xm->root, XRT_EVENT_PRE_REMOVAL);
> +	sysfs_remove_group(&pdev->dev.kobj, &xmgmt_root_attr_group);
> +	(void)xroot_remove(xm->root);
> +	pci_disable_pcie_error_reporting(xm->pdev);
> +	xmgmt_info(xm, "%s cleaned up successfully", XMGMT_MODULE_NAME);
> +}
> +
> +static struct pci_driver xmgmt_driver = {
> +	.name = XMGMT_MODULE_NAME,
> +	.id_table = xmgmt_pci_ids,
> +	.probe = xmgmt_probe,
> +	.remove = xmgmt_remove,
> +};
> +
> +static int __init xmgmt_init(void)
> +{
> +	int res = 0;
> +
> +	res = xmgmt_main_register_leaf();
> +	if (res)
> +		return res;
> +
> +	xmgmt_class = class_create(THIS_MODULE, XMGMT_MODULE_NAME);
> +	if (IS_ERR(xmgmt_class))
> +		return PTR_ERR(xmgmt_class);
> +
> +	res = pci_register_driver(&xmgmt_driver);
> +	if (res) {
> +		class_destroy(xmgmt_class);
> +		return res;
> +	}
> +
> +	return 0;
> +}
> +
> +static __exit void xmgmt_exit(void)
> +{
> +	pci_unregister_driver(&xmgmt_driver);
> +	class_destroy(xmgmt_class);
> +	xmgmt_main_unregister_leaf();
> +}
> +
> +module_init(xmgmt_init);
> +module_exit(xmgmt_exit);
> +
> +MODULE_DEVICE_TABLE(pci, xmgmt_pci_ids);
> +MODULE_VERSION(XMGMT_DRIVER_VERSION);
> +MODULE_AUTHOR("XRT Team <runtime@xilinx.com>");
> +MODULE_DESCRIPTION("Xilinx Alveo management function driver");
> +MODULE_LICENSE("GPL v2");