diff options
Diffstat (limited to 'drivers/cdx/cdx.c')
| -rw-r--r-- | drivers/cdx/cdx.c | 535 |
1 files changed, 535 insertions, 0 deletions
diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c new file mode 100644 index 000000000000..67c32cb2c006 --- /dev/null +++ b/drivers/cdx/cdx.c @@ -0,0 +1,535 @@ +// 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/xarray.h> +#include <linux/cdx/cdx_bus.h> +#include "cdx.h" + +/* Default DMA mask for devices on a CDX bus */ +#define CDX_DEFAULT_DMA_MASK (~0ULL) +#define MAX_CDX_CONTROLLERS 16 + +/* CDX controllers registered with the CDX bus */ +static DEFINE_XARRAY_ALLOC(cdx_controllers); + +/** + * 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_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; + } + + return 0; +} + +/* 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(struct bus_type *bus, + const char *buf, size_t count) +{ + struct cdx_controller *cdx; + unsigned long index; + bool val; + + if (kstrtobool(buf, &val) < 0) + return -EINVAL; + + if (!val) + return -EINVAL; + + /* Unregister all the devices on the bus */ + cdx_unregister_devices(&cdx_bus_type); + + /* Rescan all the devices */ + xa_for_each(&cdx_controllers, index, cdx) { + int ret; + + ret = cdx->ops->scan(cdx); + if (ret) + dev_err(cdx->dev, "cdx bus scanning failed\n"); + } + + 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, + .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 = xa_alloc(&cdx_controllers, &cdx->id, cdx, + XA_LIMIT(0, MAX_CDX_CONTROLLERS - 1), GFP_KERNEL); + if (ret) { + dev_err(cdx->dev, + "No free index available. Maximum controllers already registered\n"); + cdx->id = (u8)MAX_CDX_CONTROLLERS; + return ret; + } + + /* Scan all the devices */ + cdx->ops->scan(cdx); + + return 0; +} +EXPORT_SYMBOL_GPL(cdx_register_controller); + +void cdx_unregister_controller(struct cdx_controller *cdx) +{ + if (cdx->id >= MAX_CDX_CONTROLLERS) + return; + + device_for_each_child(cdx->dev, NULL, cdx_unregister_device); + xa_erase(&cdx_controllers, cdx->id); +} +EXPORT_SYMBOL_GPL(cdx_unregister_controller); + +static int __init cdx_bus_init(void) +{ + return bus_register(&cdx_bus_type); +} +postcore_initcall(cdx_bus_init); |