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