/* 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 stoppped 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 */