linux/drivers/cdx/cdx.c

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// SPDX-License-Identifier: GPL-2.0
/*
* CDX bus driver.
*
* Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
*/
/*
* Architecture Overview
* =====================
* CDX is a Hardware Architecture designed for AMD FPGA devices. It
* consists of sophisticated mechanism for interaction between FPGA,
* Firmware and the APUs (Application CPUs).
*
* Firmware resides on RPU (Realtime CPUs) which interacts with
* the FPGA program manager and the APUs. The RPU provides memory-mapped
* interface (RPU if) which is used to communicate with APUs.
*
* The diagram below shows an overview of the CDX architecture:
*
* +--------------------------------------+
* | Application CPUs (APU) |
* | |
* | CDX device drivers|
* | Linux OS | |
* | CDX bus |
* | | |
* | CDX controller |
* | | |
* +-----------------------------|--------+
* | (discover, config,
* | reset, rescan)
* |
* +------------------------| RPU if |----+
* | | |
* | V |
* | Realtime CPUs (RPU) |
* | |
* +--------------------------------------+
* |
* +---------------------|----------------+
* | FPGA | |
* | +-----------------------+ |
* | | | | |
* | +-------+ +-------+ +-------+ |
* | | dev 1 | | dev 2 | | dev 3 | |
* | +-------+ +-------+ +-------+ |
* +--------------------------------------+
*
* The RPU firmware extracts the device information from the loaded FPGA
* image and implements a mechanism that allows the APU drivers to
* enumerate such devices (device personality and resource details) via
* a dedicated communication channel. RPU mediates operations such as
* discover, reset and rescan of the FPGA devices for the APU. This is
* done using memory mapped interface provided by the RPU to APU.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/idr.h>
#include <linux/cdx/cdx_bus.h>
#include <linux/iommu.h>
#include <linux/dma-map-ops.h>
#include "cdx.h"
/* Default DMA mask for devices on a CDX bus */
#define CDX_DEFAULT_DMA_MASK (~0ULL)
#define MAX_CDX_CONTROLLERS 16
/* IDA for CDX controllers registered with the CDX bus */
static DEFINE_IDA(cdx_controller_ida);
/* Lock to protect controller ops */
static DEFINE_MUTEX(cdx_controller_lock);
static char *compat_node_name = "xlnx,versal-net-cdx";
/**
* cdx_dev_reset - Reset a CDX device
* @dev: CDX device
*
* Return: -errno on failure, 0 on success.
*/
int cdx_dev_reset(struct device *dev)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
struct cdx_controller *cdx = cdx_dev->cdx;
struct cdx_device_config dev_config = {0};
struct cdx_driver *cdx_drv;
int ret;
cdx_drv = to_cdx_driver(dev->driver);
/* Notify driver that device is being reset */
if (cdx_drv && cdx_drv->reset_prepare)
cdx_drv->reset_prepare(cdx_dev);
dev_config.type = CDX_DEV_RESET_CONF;
ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
cdx_dev->dev_num, &dev_config);
if (ret)
dev_err(dev, "cdx device reset failed\n");
/* Notify driver that device reset is complete */
if (cdx_drv && cdx_drv->reset_done)
cdx_drv->reset_done(cdx_dev);
return ret;
}
EXPORT_SYMBOL_GPL(cdx_dev_reset);
/**
* cdx_unregister_device - Unregister a CDX device
* @dev: CDX device
* @data: This is always passed as NULL, and is not used in this API,
* but is required here as the bus_for_each_dev() API expects
* the passed function (cdx_unregister_device) to have this
* as an argument.
*
* Return: 0 on success.
*/
static int cdx_unregister_device(struct device *dev,
void *data)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
kfree(cdx_dev->driver_override);
cdx_dev->driver_override = NULL;
/*
* Do not free cdx_dev here as it would be freed in
* cdx_device_release() called from within put_device().
*/
device_del(&cdx_dev->dev);
put_device(&cdx_dev->dev);
return 0;
}
static void cdx_unregister_devices(struct bus_type *bus)
{
/* Reset all the devices attached to cdx bus */
bus_for_each_dev(bus, NULL, NULL, cdx_unregister_device);
}
/**
* cdx_match_one_device - Tell if a CDX device structure has a matching
* CDX device id structure
* @id: single CDX device id structure to match
* @dev: the CDX device structure to match against
*
* Return: matching cdx_device_id structure or NULL if there is no match.
*/
static inline const struct cdx_device_id *
cdx_match_one_device(const struct cdx_device_id *id,
const struct cdx_device *dev)
{
/* Use vendor ID and device ID for matching */
if ((id->vendor == CDX_ANY_ID || id->vendor == dev->vendor) &&
(id->device == CDX_ANY_ID || id->device == dev->device))
return id;
return NULL;
}
/**
* cdx_match_id - See if a CDX device matches a given cdx_id table
* @ids: array of CDX device ID structures to search in
* @dev: the CDX device structure to match against.
*
* Used by a driver to check whether a CDX device is in its list of
* supported devices. Returns the matching cdx_device_id structure or
* NULL if there is no match.
*
* Return: matching cdx_device_id structure or NULL if there is no match.
*/
static inline const struct cdx_device_id *
cdx_match_id(const struct cdx_device_id *ids, struct cdx_device *dev)
{
if (ids) {
while (ids->vendor || ids->device) {
if (cdx_match_one_device(ids, dev))
return ids;
ids++;
}
}
return NULL;
}
/**
* cdx_bus_match - device to driver matching callback
* @dev: the cdx device to match against
* @drv: the device driver to search for matching cdx device
* structures
*
* Return: true on success, false otherwise.
*/
static int cdx_bus_match(struct device *dev, struct device_driver *drv)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
struct cdx_driver *cdx_drv = to_cdx_driver(drv);
const struct cdx_device_id *found_id = NULL;
const struct cdx_device_id *ids;
ids = cdx_drv->match_id_table;
/* When driver_override is set, only bind to the matching driver */
if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name))
return false;
found_id = cdx_match_id(ids, cdx_dev);
if (!found_id)
return false;
do {
/*
* In case override_only was set, enforce driver_override
* matching.
*/
if (!found_id->override_only)
return true;
if (cdx_dev->driver_override)
return true;
ids = found_id + 1;
found_id = cdx_match_id(ids, cdx_dev);
} while (found_id);
return false;
}
static int cdx_probe(struct device *dev)
{
struct cdx_driver *cdx_drv = to_cdx_driver(dev->driver);
struct cdx_device *cdx_dev = to_cdx_device(dev);
int error;
error = cdx_drv->probe(cdx_dev);
if (error) {
dev_err_probe(dev, error, "%s failed\n", __func__);
return error;
}
return 0;
}
static void cdx_remove(struct device *dev)
{
struct cdx_driver *cdx_drv = to_cdx_driver(dev->driver);
struct cdx_device *cdx_dev = to_cdx_device(dev);
if (cdx_drv && cdx_drv->remove)
cdx_drv->remove(cdx_dev);
}
static void cdx_shutdown(struct device *dev)
{
struct cdx_driver *cdx_drv = to_cdx_driver(dev->driver);
struct cdx_device *cdx_dev = to_cdx_device(dev);
if (cdx_drv && cdx_drv->shutdown)
cdx_drv->shutdown(cdx_dev);
}
static int cdx_dma_configure(struct device *dev)
{
struct cdx_driver *cdx_drv = to_cdx_driver(dev->driver);
struct cdx_device *cdx_dev = to_cdx_device(dev);
u32 input_id = cdx_dev->req_id;
int ret;
ret = of_dma_configure_id(dev, dev->parent->of_node, 0, &input_id);
if (ret && ret != -EPROBE_DEFER) {
dev_err(dev, "of_dma_configure_id() failed\n");
return ret;
}
if (!ret && !cdx_drv->driver_managed_dma) {
ret = iommu_device_use_default_domain(dev);
if (ret)
arch_teardown_dma_ops(dev);
}
return 0;
}
static void cdx_dma_cleanup(struct device *dev)
{
struct cdx_driver *cdx_drv = to_cdx_driver(dev->driver);
if (!cdx_drv->driver_managed_dma)
iommu_device_unuse_default_domain(dev);
}
/* show configuration fields */
#define cdx_config_attr(field, format_string) \
static ssize_t \
field##_show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct cdx_device *cdx_dev = to_cdx_device(dev); \
return sysfs_emit(buf, format_string, cdx_dev->field); \
} \
static DEVICE_ATTR_RO(field)
cdx_config_attr(vendor, "0x%04x\n");
cdx_config_attr(device, "0x%04x\n");
static ssize_t remove_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
bool val;
if (kstrtobool(buf, &val) < 0)
return -EINVAL;
if (!val)
return -EINVAL;
if (device_remove_file_self(dev, attr)) {
int ret;
ret = cdx_unregister_device(dev, NULL);
if (ret)
return ret;
}
return count;
}
static DEVICE_ATTR_WO(remove);
static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
bool val;
int ret;
if (kstrtobool(buf, &val) < 0)
return -EINVAL;
if (!val)
return -EINVAL;
ret = cdx_dev_reset(dev);
if (ret)
return ret;
return count;
}
static DEVICE_ATTR_WO(reset);
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
int ret;
if (WARN_ON(dev->bus != &cdx_bus_type))
return -EINVAL;
ret = driver_set_override(dev, &cdx_dev->driver_override, buf, count);
if (ret)
return ret;
return count;
}
static ssize_t driver_override_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
return sysfs_emit(buf, "%s\n", cdx_dev->driver_override);
}
static DEVICE_ATTR_RW(driver_override);
static struct attribute *cdx_dev_attrs[] = {
&dev_attr_remove.attr,
&dev_attr_reset.attr,
&dev_attr_vendor.attr,
&dev_attr_device.attr,
&dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(cdx_dev);
static ssize_t rescan_store(const struct bus_type *bus,
const char *buf, size_t count)
{
struct cdx_controller *cdx;
struct platform_device *pd;
struct device_node *np;
bool val;
if (kstrtobool(buf, &val) < 0)
return -EINVAL;
if (!val)
return -EINVAL;
mutex_lock(&cdx_controller_lock);
/* Unregister all the devices on the bus */
cdx_unregister_devices(&cdx_bus_type);
/* Rescan all the devices */
for_each_compatible_node(np, NULL, compat_node_name) {
if (!np)
return -EINVAL;
pd = of_find_device_by_node(np);
if (!pd)
return -EINVAL;
cdx = platform_get_drvdata(pd);
if (cdx && cdx->controller_registered && cdx->ops->scan)
cdx->ops->scan(cdx);
put_device(&pd->dev);
}
mutex_unlock(&cdx_controller_lock);
return count;
}
static BUS_ATTR_WO(rescan);
static struct attribute *cdx_bus_attrs[] = {
&bus_attr_rescan.attr,
NULL,
};
ATTRIBUTE_GROUPS(cdx_bus);
struct bus_type cdx_bus_type = {
.name = "cdx",
.match = cdx_bus_match,
.probe = cdx_probe,
.remove = cdx_remove,
.shutdown = cdx_shutdown,
.dma_configure = cdx_dma_configure,
.dma_cleanup = cdx_dma_cleanup,
.bus_groups = cdx_bus_groups,
.dev_groups = cdx_dev_groups,
};
EXPORT_SYMBOL_GPL(cdx_bus_type);
int __cdx_driver_register(struct cdx_driver *cdx_driver,
struct module *owner)
{
int error;
cdx_driver->driver.owner = owner;
cdx_driver->driver.bus = &cdx_bus_type;
error = driver_register(&cdx_driver->driver);
if (error) {
pr_err("driver_register() failed for %s: %d\n",
cdx_driver->driver.name, error);
return error;
}
return 0;
}
EXPORT_SYMBOL_GPL(__cdx_driver_register);
void cdx_driver_unregister(struct cdx_driver *cdx_driver)
{
driver_unregister(&cdx_driver->driver);
}
EXPORT_SYMBOL_GPL(cdx_driver_unregister);
static void cdx_device_release(struct device *dev)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
kfree(cdx_dev);
}
int cdx_device_add(struct cdx_dev_params *dev_params)
{
struct cdx_controller *cdx = dev_params->cdx;
struct device *parent = cdx->dev;
struct cdx_device *cdx_dev;
int ret;
cdx_dev = kzalloc(sizeof(*cdx_dev), GFP_KERNEL);
if (!cdx_dev)
return -ENOMEM;
/* Populate resource */
memcpy(cdx_dev->res, dev_params->res, sizeof(struct resource) *
dev_params->res_count);
cdx_dev->res_count = dev_params->res_count;
/* Populate CDX dev params */
cdx_dev->req_id = dev_params->req_id;
cdx_dev->vendor = dev_params->vendor;
cdx_dev->device = dev_params->device;
cdx_dev->bus_num = dev_params->bus_num;
cdx_dev->dev_num = dev_params->dev_num;
cdx_dev->cdx = dev_params->cdx;
cdx_dev->dma_mask = CDX_DEFAULT_DMA_MASK;
/* Initialize generic device */
device_initialize(&cdx_dev->dev);
cdx_dev->dev.parent = parent;
cdx_dev->dev.bus = &cdx_bus_type;
cdx_dev->dev.dma_mask = &cdx_dev->dma_mask;
cdx_dev->dev.release = cdx_device_release;
/* Set Name */
dev_set_name(&cdx_dev->dev, "cdx-%02x:%02x",
((cdx->id << CDX_CONTROLLER_ID_SHIFT) | (cdx_dev->bus_num & CDX_BUS_NUM_MASK)),
cdx_dev->dev_num);
ret = device_add(&cdx_dev->dev);
if (ret) {
dev_err(&cdx_dev->dev,
"cdx device add failed: %d", ret);
goto fail;
}
return 0;
fail:
/*
* Do not free cdx_dev here as it would be freed in
* cdx_device_release() called from put_device().
*/
put_device(&cdx_dev->dev);
return ret;
}
EXPORT_SYMBOL_GPL(cdx_device_add);
int cdx_register_controller(struct cdx_controller *cdx)
{
int ret;
ret = ida_alloc_range(&cdx_controller_ida, 0, MAX_CDX_CONTROLLERS - 1, GFP_KERNEL);
if (ret < 0) {
dev_err(cdx->dev,
"No free index available. Maximum controllers already registered\n");
cdx->id = (u8)MAX_CDX_CONTROLLERS;
return ret;
}
mutex_lock(&cdx_controller_lock);
cdx->id = ret;
/* Scan all the devices */
if (cdx->ops->scan)
cdx->ops->scan(cdx);
cdx->controller_registered = true;
mutex_unlock(&cdx_controller_lock);
return 0;
}
EXPORT_SYMBOL_GPL(cdx_register_controller);
void cdx_unregister_controller(struct cdx_controller *cdx)
{
if (cdx->id >= MAX_CDX_CONTROLLERS)
return;
mutex_lock(&cdx_controller_lock);
cdx->controller_registered = false;
device_for_each_child(cdx->dev, NULL, cdx_unregister_device);
ida_free(&cdx_controller_ida, cdx->id);
mutex_unlock(&cdx_controller_lock);
}
EXPORT_SYMBOL_GPL(cdx_unregister_controller);
static int __init cdx_bus_init(void)
{
return bus_register(&cdx_bus_type);
}
postcore_initcall(cdx_bus_init);