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Diffstat (limited to 'include/misc/cxl.h')
| -rw-r--r-- | include/misc/cxl.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/include/misc/cxl.h b/include/misc/cxl.h new file mode 100644 index 0000000000..d8044299d6 --- /dev/null +++ b/include/misc/cxl.h @@ -0,0 +1,265 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright 2015 IBM Corp. + */ + +#ifndef _MISC_CXL_H +#define _MISC_CXL_H + +#include <linux/pci.h> +#include <linux/poll.h> +#include <linux/interrupt.h> +#include <uapi/misc/cxl.h> + +/* + * This documents the in kernel API for driver to use CXL. It allows kernel + * drivers to bind to AFUs using an AFU configuration record exposed as a PCI + * configuration record. + * + * This API enables control over AFU and contexts which can't be part of the + * generic PCI API. This API is agnostic to the actual AFU. + */ + +/* Get the AFU associated with a pci_dev */ +struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev); + +/* Get the AFU conf record number associated with a pci_dev */ +unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev); + + +/* + * Context lifetime overview: + * + * An AFU context may be inited and then started and stopped multiple times + * before it's released. ie. + * - cxl_dev_context_init() + * - cxl_start_context() + * - cxl_stop_context() + * - cxl_start_context() + * - cxl_stop_context() + * ...repeat... + * - cxl_release_context() + * Once released, a context can't be started again. + * + * One context is inited by the cxl driver for every pci_dev. This is to be + * used as a default kernel context. cxl_get_context() will get this + * context. This context will be released by PCI hot unplug, so doesn't need to + * be released explicitly by drivers. + * + * Additional kernel contexts may be inited using cxl_dev_context_init(). + * These must be released using cxl_context_detach(). + * + * Once a context has been inited, IRQs may be configured. Firstly these IRQs + * must be allocated (cxl_allocate_afu_irqs()), then individually mapped to + * specific handlers (cxl_map_afu_irq()). + * + * These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released + * (cxl_free_afu_irqs()). + * + * The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU + * hardware to lose track of all contexts. It's upto the caller of + * cxl_afu_reset() to restart these contexts. + */ + +/* + * On pci_enabled_device(), the cxl driver will init a single cxl context for + * use by the driver. It doesn't start this context (as that will likely + * generate DMA traffic for most AFUs). + * + * This gets the default context associated with this pci_dev. This context + * doesn't need to be released as this will be done by the PCI subsystem on hot + * unplug. + */ +struct cxl_context *cxl_get_context(struct pci_dev *dev); +/* + * Allocate and initalise a context associated with a AFU PCI device. This + * doesn't start the context in the AFU. + */ +struct cxl_context *cxl_dev_context_init(struct pci_dev *dev); +/* + * Release and free a context. Context should be stopped before calling. + */ +int cxl_release_context(struct cxl_context *ctx); + +/* + * Set and get private data associated with a context. Allows drivers to have a + * back pointer to some useful structure. + */ +int cxl_set_priv(struct cxl_context *ctx, void *priv); +void *cxl_get_priv(struct cxl_context *ctx); + +/* + * Allocate AFU interrupts for this context. num=0 will allocate the default + * for this AFU as given in the AFU descriptor. This number doesn't include the + * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be + * used must map a handler with cxl_map_afu_irq. + */ +int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num); +/* Free allocated interrupts */ +void cxl_free_afu_irqs(struct cxl_context *cxl); + +/* + * Map a handler for an AFU interrupt associated with a particular context. AFU + * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie + * is private data is that will be provided to the interrupt handler. + */ +int cxl_map_afu_irq(struct cxl_context *cxl, int num, + irq_handler_t handler, void *cookie, char *name); +/* unmap mapped IRQ handlers */ +void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie); + +/* + * Start work on the AFU. This starts an cxl context and associates it with a + * task. task == NULL will make it a kernel context. + */ +int cxl_start_context(struct cxl_context *ctx, u64 wed, + struct task_struct *task); +/* + * Stop a context and remove it from the PSL + */ +int cxl_stop_context(struct cxl_context *ctx); + +/* Reset the AFU */ +int cxl_afu_reset(struct cxl_context *ctx); + +/* + * Set a context as a master context. + * This sets the default problem space area mapped as the full space, rather + * than just the per context area (for slaves). + */ +void cxl_set_master(struct cxl_context *ctx); + +/* + * Map and unmap the AFU Problem Space area. The amount and location mapped + * depends on if this context is a master or slave. + */ +void __iomem *cxl_psa_map(struct cxl_context *ctx); +void cxl_psa_unmap(void __iomem *addr); + +/* Get the process element for this context */ +int cxl_process_element(struct cxl_context *ctx); + +/* + * These calls allow drivers to create their own file descriptors and make them + * identical to the cxl file descriptor user API. An example use case: + * + * struct file_operations cxl_my_fops = {}; + * ...... + * // Init the context + * ctx = cxl_dev_context_init(dev); + * if (IS_ERR(ctx)) + * return PTR_ERR(ctx); + * // Create and attach a new file descriptor to my file ops + * file = cxl_get_fd(ctx, &cxl_my_fops, &fd); + * // Start context + * rc = cxl_start_work(ctx, &work.work); + * if (rc) { + * fput(file); + * put_unused_fd(fd); + * return -ENODEV; + * } + * // No error paths after installing the fd + * fd_install(fd, file); + * return fd; + * + * This inits a context, and gets a file descriptor and associates some file + * ops to that file descriptor. If the file ops are blank, the cxl driver will + * fill them in with the default ones that mimic the standard user API. Once + * completed, the file descriptor can be installed. Once the file descriptor is + * installed, it's visible to the user so no errors must occur past this point. + * + * If cxl_fd_release() file op call is installed, the context will be stopped + * and released when the fd is released. Hence the driver won't need to manage + * this itself. + */ + +/* + * Take a context and associate it with my file ops. Returns the associated + * file and file descriptor. Any file ops which are blank are filled in by the + * cxl driver with the default ops to mimic the standard API. + */ +struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops, + int *fd); +/* Get the context associated with this file */ +struct cxl_context *cxl_fops_get_context(struct file *file); +/* + * Start a context associated a struct cxl_ioctl_start_work used by the + * standard cxl user API. + */ +int cxl_start_work(struct cxl_context *ctx, + struct cxl_ioctl_start_work *work); +/* + * Export all the existing fops so drivers can use them + */ +int cxl_fd_open(struct inode *inode, struct file *file); +int cxl_fd_release(struct inode *inode, struct file *file); +long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm); +__poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll); +ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count, + loff_t *off); + +/* + * For EEH, a driver may want to assert a PERST will reload the same image + * from flash into the FPGA. + * + * This is a property of the entire adapter, not a single AFU, so drivers + * should set this property with care! + */ +void cxl_perst_reloads_same_image(struct cxl_afu *afu, + bool perst_reloads_same_image); + +/* + * Read the VPD for the card where the AFU resides + */ +ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count); + +/* + * AFU driver ops allow an AFU driver to create their own events to pass to + * userspace through the file descriptor as a simpler alternative to overriding + * the read() and poll() calls that works with the generic cxl events. These + * events are given priority over the generic cxl events, so they will be + * delivered first if multiple types of events are pending. + * + * The AFU driver must call cxl_context_events_pending() to notify the cxl + * driver that new events are ready to be delivered for a specific context. + * cxl_context_events_pending() will adjust the current count of AFU driver + * events for this context, and wake up anyone waiting on the context wait + * queue. + * + * The cxl driver will then call fetch_event() to get a structure defining + * the size and address of the driver specific event data. The cxl driver + * will build a cxl header with type and process_element fields filled in, + * and header.size set to sizeof(struct cxl_event_header) + data_size. + * The total size of the event is limited to CXL_READ_MIN_SIZE (4K). + * + * fetch_event() is called with a spin lock held, so it must not sleep. + * + * The cxl driver will then deliver the event to userspace, and finally + * call event_delivered() to return the status of the operation, identified + * by cxl context and AFU driver event data pointers. + * 0 Success + * -EFAULT copy_to_user() has failed + * -EINVAL Event data pointer is NULL, or event size is greater than + * CXL_READ_MIN_SIZE. + */ +struct cxl_afu_driver_ops { + struct cxl_event_afu_driver_reserved *(*fetch_event) ( + struct cxl_context *ctx); + void (*event_delivered) (struct cxl_context *ctx, + struct cxl_event_afu_driver_reserved *event, + int rc); +}; + +/* + * Associate the above driver ops with a specific context. + * Reset the current count of AFU driver events. + */ +void cxl_set_driver_ops(struct cxl_context *ctx, + struct cxl_afu_driver_ops *ops); + +/* Notify cxl driver that new events are ready to be delivered for context */ +void cxl_context_events_pending(struct cxl_context *ctx, + unsigned int new_events); + +#endif /* _MISC_CXL_H */ |