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 */ 28 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev); 29 30 /* Get the AFU conf record number associated with a pci_dev */ 31 unsigned 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 */ 77 struct 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 */ 82 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev); 83 /* 84 * Release and free a context. Context should be stopped before calling. 85 */ 86 int cxl_release_context(struct cxl_context *ctx); 87 88 /* 89 * Set and get private data associated with a context. Allows drivers to have a 90 * back pointer to some useful structure. 91 */ 92 int cxl_set_priv(struct cxl_context *ctx, void *priv); 93 void *cxl_get_priv(struct cxl_context *ctx); 94 95 /* 96 * Allocate AFU interrupts for this context. num=0 will allocate the default 97 * for this AFU as given in the AFU descriptor. This number doesn't include the 98 * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be 99 * used must map a handler with cxl_map_afu_irq. 100 */ 101 int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num); 102 /* Free allocated interrupts */ 103 void cxl_free_afu_irqs(struct cxl_context *cxl); 104 105 /* 106 * Map a handler for an AFU interrupt associated with a particular context. AFU 107 * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie 108 * is private data is that will be provided to the interrupt handler. 109 */ 110 int cxl_map_afu_irq(struct cxl_context *cxl, int num, 111 irq_handler_t handler, void *cookie, char *name); 112 /* unmap mapped IRQ handlers */ 113 void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie); 114 115 /* 116 * Start work on the AFU. This starts an cxl context and associates it with a 117 * task. task == NULL will make it a kernel context. 118 */ 119 int cxl_start_context(struct cxl_context *ctx, u64 wed, 120 struct task_struct *task); 121 /* 122 * Stop a context and remove it from the PSL 123 */ 124 int cxl_stop_context(struct cxl_context *ctx); 125 126 /* Reset the AFU */ 127 int cxl_afu_reset(struct cxl_context *ctx); 128 129 /* 130 * Set a context as a master context. 131 * This sets the default problem space area mapped as the full space, rather 132 * than just the per context area (for slaves). 133 */ 134 void cxl_set_master(struct cxl_context *ctx); 135 136 /* 137 * Sets the context to use real mode memory accesses to operate with 138 * translation disabled. Note that this only makes sense for kernel contexts 139 * under bare metal, and will not work with virtualisation. May only be 140 * performed on stopped contexts. 141 */ 142 int cxl_set_translation_mode(struct cxl_context *ctx, bool real_mode); 143 144 /* 145 * Map and unmap the AFU Problem Space area. The amount and location mapped 146 * depends on if this context is a master or slave. 147 */ 148 void __iomem *cxl_psa_map(struct cxl_context *ctx); 149 void cxl_psa_unmap(void __iomem *addr); 150 151 /* Get the process element for this context */ 152 int cxl_process_element(struct cxl_context *ctx); 153 154 155 /* 156 * These calls allow drivers to create their own file descriptors and make them 157 * identical to the cxl file descriptor user API. An example use case: 158 * 159 * struct file_operations cxl_my_fops = {}; 160 * ...... 161 * // Init the context 162 * ctx = cxl_dev_context_init(dev); 163 * if (IS_ERR(ctx)) 164 * return PTR_ERR(ctx); 165 * // Create and attach a new file descriptor to my file ops 166 * file = cxl_get_fd(ctx, &cxl_my_fops, &fd); 167 * // Start context 168 * rc = cxl_start_work(ctx, &work.work); 169 * if (rc) { 170 * fput(file); 171 * put_unused_fd(fd); 172 * return -ENODEV; 173 * } 174 * // No error paths after installing the fd 175 * fd_install(fd, file); 176 * return fd; 177 * 178 * This inits a context, and gets a file descriptor and associates some file 179 * ops to that file descriptor. If the file ops are blank, the cxl driver will 180 * fill them in with the default ones that mimic the standard user API. Once 181 * completed, the file descriptor can be installed. Once the file descriptor is 182 * installed, it's visible to the user so no errors must occur past this point. 183 * 184 * If cxl_fd_release() file op call is installed, the context will be stopped 185 * and released when the fd is released. Hence the driver won't need to manage 186 * this itself. 187 */ 188 189 /* 190 * Take a context and associate it with my file ops. Returns the associated 191 * file and file descriptor. Any file ops which are blank are filled in by the 192 * cxl driver with the default ops to mimic the standard API. 193 */ 194 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops, 195 int *fd); 196 /* Get the context associated with this file */ 197 struct cxl_context *cxl_fops_get_context(struct file *file); 198 /* 199 * Start a context associated a struct cxl_ioctl_start_work used by the 200 * standard cxl user API. 201 */ 202 int cxl_start_work(struct cxl_context *ctx, 203 struct cxl_ioctl_start_work *work); 204 /* 205 * Export all the existing fops so drivers can use them 206 */ 207 int cxl_fd_open(struct inode *inode, struct file *file); 208 int cxl_fd_release(struct inode *inode, struct file *file); 209 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 210 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm); 211 unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll); 212 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count, 213 loff_t *off); 214 215 /* 216 * For EEH, a driver may want to assert a PERST will reload the same image 217 * from flash into the FPGA. 218 * 219 * This is a property of the entire adapter, not a single AFU, so drivers 220 * should set this property with care! 221 */ 222 void cxl_perst_reloads_same_image(struct cxl_afu *afu, 223 bool perst_reloads_same_image); 224 225 /* 226 * Read the VPD for the card where the AFU resides 227 */ 228 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count); 229 230 /* 231 * AFU driver ops allow an AFU driver to create their own events to pass to 232 * userspace through the file descriptor as a simpler alternative to overriding 233 * the read() and poll() calls that works with the generic cxl events. These 234 * events are given priority over the generic cxl events, so they will be 235 * delivered first if multiple types of events are pending. 236 * 237 * The AFU driver must call cxl_context_events_pending() to notify the cxl 238 * driver that new events are ready to be delivered for a specific context. 239 * cxl_context_events_pending() will adjust the current count of AFU driver 240 * events for this context, and wake up anyone waiting on the context wait 241 * queue. 242 * 243 * The cxl driver will then call fetch_event() to get a structure defining 244 * the size and address of the driver specific event data. The cxl driver 245 * will build a cxl header with type and process_element fields filled in, 246 * and header.size set to sizeof(struct cxl_event_header) + data_size. 247 * The total size of the event is limited to CXL_READ_MIN_SIZE (4K). 248 * 249 * fetch_event() is called with a spin lock held, so it must not sleep. 250 * 251 * The cxl driver will then deliver the event to userspace, and finally 252 * call event_delivered() to return the status of the operation, identified 253 * by cxl context and AFU driver event data pointers. 254 * 0 Success 255 * -EFAULT copy_to_user() has failed 256 * -EINVAL Event data pointer is NULL, or event size is greater than 257 * CXL_READ_MIN_SIZE. 258 */ 259 struct cxl_afu_driver_ops { 260 struct cxl_event_afu_driver_reserved *(*fetch_event) ( 261 struct cxl_context *ctx); 262 void (*event_delivered) (struct cxl_context *ctx, 263 struct cxl_event_afu_driver_reserved *event, 264 int rc); 265 }; 266 267 /* 268 * Associate the above driver ops with a specific context. 269 * Reset the current count of AFU driver events. 270 */ 271 void cxl_set_driver_ops(struct cxl_context *ctx, 272 struct cxl_afu_driver_ops *ops); 273 274 /* Notify cxl driver that new events are ready to be delivered for context */ 275 void cxl_context_events_pending(struct cxl_context *ctx, 276 unsigned int new_events); 277 278 #endif /* _MISC_CXL_H */ 279