1/*
  2 * Copyright 2015 IBM Corp.
  3 *
  4 * This program is free software; you can redistribute it and/or
  5 * modify it under the terms of the GNU General Public License
  6 * as published by the Free Software Foundation; either version
  7 * 2 of the License, or (at your option) any later version.
  8 */
  9
 10#ifndef _MISC_CXL_H
 11#define _MISC_CXL_H
 12
 13#include <linux/pci.h>
 14#include <linux/poll.h>
 15#include <linux/interrupt.h>
 16#include <uapi/misc/cxl.h>
 17
 18/*
 19 * This documents the in kernel API for driver to use CXL. It allows kernel
 20 * drivers to bind to AFUs using an AFU configuration record exposed as a PCI
 21 * configuration record.
 22 *
 23 * This API enables control over AFU and contexts which can't be part of the
 24 * generic PCI API. This API is agnostic to the actual AFU.
 25 */
 26
 27/* Get the AFU associated with a pci_dev */
 28struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);
 29
 30/* Get the AFU conf record number associated with a pci_dev */
 31unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev);
 32
 33
 34/*
 35 * Context lifetime overview:
 36 *
 37 * An AFU context may be inited and then started and stoppped multiple times
 38 * before it's released. ie.
 39 *    - cxl_dev_context_init()
 40 *      - cxl_start_context()
 41 *      - cxl_stop_context()
 42 *      - cxl_start_context()
 43 *      - cxl_stop_context()
 44 *     ...repeat...
 45 *    - cxl_release_context()
 46 * Once released, a context can't be started again.
 47 *
 48 * One context is inited by the cxl driver for every pci_dev. This is to be
 49 * used as a default kernel context. cxl_get_context() will get this
 50 * context. This context will be released by PCI hot unplug, so doesn't need to
 51 * be released explicitly by drivers.
 52 *
 53 * Additional kernel contexts may be inited using cxl_dev_context_init().
 54 * These must be released using cxl_context_detach().
 55 *
 56 * Once a context has been inited, IRQs may be configured. Firstly these IRQs
 57 * must be allocated (cxl_allocate_afu_irqs()), then individually mapped to
 58 * specific handlers (cxl_map_afu_irq()).
 59 *
 60 * These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released
 61 * (cxl_free_afu_irqs()).
 62 *
 63 * The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU
 64 * hardware to lose track of all contexts. It's upto the caller of
 65 * cxl_afu_reset() to restart these contexts.
 66 */
 67
 68/*
 69 * On pci_enabled_device(), the cxl driver will init a single cxl context for
 70 * use by the driver. It doesn't start this context (as that will likely
 71 * generate DMA traffic for most AFUs).
 72 *
 73 * This gets the default context associated with this pci_dev.  This context
 74 * doesn't need to be released as this will be done by the PCI subsystem on hot
 75 * unplug.
 76 */
 77struct cxl_context *cxl_get_context(struct pci_dev *dev);
 78/*
 79 * Allocate and initalise a context associated with a AFU PCI device. This
 80 * doesn't start the context in the AFU.
 81 */
 82struct cxl_context *cxl_dev_context_init(struct pci_dev *dev);
 83/*
 84 * Release and free a context. Context should be stopped before calling.
 85 */
 86int cxl_release_context(struct cxl_context *ctx);
 87
 88/*
 89 * Allocate AFU interrupts for this context. num=0 will allocate the default
 90 * for this AFU as given in the AFU descriptor. This number doesn't include the
 91 * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be
 92 * used must map a handler with cxl_map_afu_irq.
 93 */
 94int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num);
 95/* Free allocated interrupts */
 96void cxl_free_afu_irqs(struct cxl_context *cxl);
 97
 98/*
 99 * Map a handler for an AFU interrupt associated with a particular context. AFU
100 * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie
101 * is private data is that will be provided to the interrupt handler.
102 */
103int cxl_map_afu_irq(struct cxl_context *cxl, int num,
104		    irq_handler_t handler, void *cookie, char *name);
105/* unmap mapped IRQ handlers */
106void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie);
107
108/*
109 * Start work on the AFU. This starts an cxl context and associates it with a
110 * task. task == NULL will make it a kernel context.
111 */
112int cxl_start_context(struct cxl_context *ctx, u64 wed,
113		      struct task_struct *task);
114/*
115 * Stop a context and remove it from the PSL
116 */
117int cxl_stop_context(struct cxl_context *ctx);
118
119/* Reset the AFU */
120int cxl_afu_reset(struct cxl_context *ctx);
121
122/*
123 * Set a context as a master context.
124 * This sets the default problem space area mapped as the full space, rather
125 * than just the per context area (for slaves).
126 */
127void cxl_set_master(struct cxl_context *ctx);
128
129/*
130 * Map and unmap the AFU Problem Space area. The amount and location mapped
131 * depends on if this context is a master or slave.
132 */
133void __iomem *cxl_psa_map(struct cxl_context *ctx);
134void cxl_psa_unmap(void __iomem *addr);
135
136/*  Get the process element for this context */
137int cxl_process_element(struct cxl_context *ctx);
138
139
140/*
141 * These calls allow drivers to create their own file descriptors and make them
142 * identical to the cxl file descriptor user API. An example use case:
143 *
144 * struct file_operations cxl_my_fops = {};
145 * ......
146 *	// Init the context
147 *	ctx = cxl_dev_context_init(dev);
148 *	if (IS_ERR(ctx))
149 *		return PTR_ERR(ctx);
150 *	// Create and attach a new file descriptor to my file ops
151 *	file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
152 *	// Start context
153 *	rc = cxl_start_work(ctx, &work.work);
154 *	if (rc) {
155 *		fput(file);
156 *		put_unused_fd(fd);
157 *		return -ENODEV;
158 *	}
159 *	// No error paths after installing the fd
160 *	fd_install(fd, file);
161 *	return fd;
162 *
163 * This inits a context, and gets a file descriptor and associates some file
164 * ops to that file descriptor. If the file ops are blank, the cxl driver will
165 * fill them in with the default ones that mimic the standard user API.  Once
166 * completed, the file descriptor can be installed. Once the file descriptor is
167 * installed, it's visible to the user so no errors must occur past this point.
168 *
169 * If cxl_fd_release() file op call is installed, the context will be stopped
170 * and released when the fd is released. Hence the driver won't need to manage
171 * this itself.
172 */
173
174/*
175 * Take a context and associate it with my file ops. Returns the associated
176 * file and file descriptor. Any file ops which are blank are filled in by the
177 * cxl driver with the default ops to mimic the standard API.
178 */
179struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
180			int *fd);
181/* Get the context associated with this file */
182struct cxl_context *cxl_fops_get_context(struct file *file);
183/*
184 * Start a context associated a struct cxl_ioctl_start_work used by the
185 * standard cxl user API.
186 */
187int cxl_start_work(struct cxl_context *ctx,
188		   struct cxl_ioctl_start_work *work);
189/*
190 * Export all the existing fops so drivers can use them
191 */
192int cxl_fd_open(struct inode *inode, struct file *file);
193int cxl_fd_release(struct inode *inode, struct file *file);
194long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
195int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
196unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
197ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
198			   loff_t *off);
199
200/*
201 * For EEH, a driver may want to assert a PERST will reload the same image
202 * from flash into the FPGA.
203 *
204 * This is a property of the entire adapter, not a single AFU, so drivers
205 * should set this property with care!
206 */
207void cxl_perst_reloads_same_image(struct cxl_afu *afu,
208				  bool perst_reloads_same_image);
209
210/*
211 * Read the VPD for the card where the AFU resides
212 */
213ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
214
215#endif /* _MISC_CXL_H */