1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Copyright 2015 IBM Corp. 4 */ 5 6 #ifndef _MISC_CXL_H 7 #define _MISC_CXL_H 8 9 #include <linux/pci.h> 10 #include <linux/poll.h> 11 #include <linux/interrupt.h> 12 #include <uapi/misc/cxl.h> 13 14 /* 15 * This documents the in kernel API for driver to use CXL. It allows kernel 16 * drivers to bind to AFUs using an AFU configuration record exposed as a PCI 17 * configuration record. 18 * 19 * This API enables control over AFU and contexts which can't be part of the 20 * generic PCI API. This API is agnostic to the actual AFU. 21 */ 22 23 /* Get the AFU associated with a pci_dev */ 24 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev); 25 26 /* Get the AFU conf record number associated with a pci_dev */ 27 unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev); 28 29 30 /* 31 * Context lifetime overview: 32 * 33 * An AFU context may be inited and then started and stopped multiple times 34 * before it's released. ie. 35 * - cxl_dev_context_init() 36 * - cxl_start_context() 37 * - cxl_stop_context() 38 * - cxl_start_context() 39 * - cxl_stop_context() 40 * ...repeat... 41 * - cxl_release_context() 42 * Once released, a context can't be started again. 43 * 44 * One context is inited by the cxl driver for every pci_dev. This is to be 45 * used as a default kernel context. cxl_get_context() will get this 46 * context. This context will be released by PCI hot unplug, so doesn't need to 47 * be released explicitly by drivers. 48 * 49 * Additional kernel contexts may be inited using cxl_dev_context_init(). 50 * These must be released using cxl_context_detach(). 51 * 52 * Once a context has been inited, IRQs may be configured. Firstly these IRQs 53 * must be allocated (cxl_allocate_afu_irqs()), then individually mapped to 54 * specific handlers (cxl_map_afu_irq()). 55 * 56 * These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released 57 * (cxl_free_afu_irqs()). 58 * 59 * The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU 60 * hardware to lose track of all contexts. It's upto the caller of 61 * cxl_afu_reset() to restart these contexts. 62 */ 63 64 /* 65 * On pci_enabled_device(), the cxl driver will init a single cxl context for 66 * use by the driver. It doesn't start this context (as that will likely 67 * generate DMA traffic for most AFUs). 68 * 69 * This gets the default context associated with this pci_dev. This context 70 * doesn't need to be released as this will be done by the PCI subsystem on hot 71 * unplug. 72 */ 73 struct cxl_context *cxl_get_context(struct pci_dev *dev); 74 /* 75 * Allocate and initalise a context associated with a AFU PCI device. This 76 * doesn't start the context in the AFU. 77 */ 78 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev); 79 /* 80 * Release and free a context. Context should be stopped before calling. 81 */ 82 int cxl_release_context(struct cxl_context *ctx); 83 84 /* 85 * Set and get private data associated with a context. Allows drivers to have a 86 * back pointer to some useful structure. 87 */ 88 int cxl_set_priv(struct cxl_context *ctx, void *priv); 89 void *cxl_get_priv(struct cxl_context *ctx); 90 91 /* 92 * Allocate AFU interrupts for this context. num=0 will allocate the default 93 * for this AFU as given in the AFU descriptor. This number doesn't include the 94 * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be 95 * used must map a handler with cxl_map_afu_irq. 96 */ 97 int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num); 98 /* Free allocated interrupts */ 99 void cxl_free_afu_irqs(struct cxl_context *cxl); 100 101 /* 102 * Map a handler for an AFU interrupt associated with a particular context. AFU 103 * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie 104 * is private data is that will be provided to the interrupt handler. 105 */ 106 int cxl_map_afu_irq(struct cxl_context *cxl, int num, 107 irq_handler_t handler, void *cookie, char *name); 108 /* unmap mapped IRQ handlers */ 109 void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie); 110 111 /* 112 * Start work on the AFU. This starts an cxl context and associates it with a 113 * task. task == NULL will make it a kernel context. 114 */ 115 int cxl_start_context(struct cxl_context *ctx, u64 wed, 116 struct task_struct *task); 117 /* 118 * Stop a context and remove it from the PSL 119 */ 120 int cxl_stop_context(struct cxl_context *ctx); 121 122 /* Reset the AFU */ 123 int cxl_afu_reset(struct cxl_context *ctx); 124 125 /* 126 * Set a context as a master context. 127 * This sets the default problem space area mapped as the full space, rather 128 * than just the per context area (for slaves). 129 */ 130 void cxl_set_master(struct cxl_context *ctx); 131 132 /* 133 * Map and unmap the AFU Problem Space area. The amount and location mapped 134 * depends on if this context is a master or slave. 135 */ 136 void __iomem *cxl_psa_map(struct cxl_context *ctx); 137 void cxl_psa_unmap(void __iomem *addr); 138 139 /* Get the process element for this context */ 140 int cxl_process_element(struct cxl_context *ctx); 141 142 /* 143 * These calls allow drivers to create their own file descriptors and make them 144 * identical to the cxl file descriptor user API. An example use case: 145 * 146 * struct file_operations cxl_my_fops = {}; 147 * ...... 148 * // Init the context 149 * ctx = cxl_dev_context_init(dev); 150 * if (IS_ERR(ctx)) 151 * return PTR_ERR(ctx); 152 * // Create and attach a new file descriptor to my file ops 153 * file = cxl_get_fd(ctx, &cxl_my_fops, &fd); 154 * // Start context 155 * rc = cxl_start_work(ctx, &work.work); 156 * if (rc) { 157 * fput(file); 158 * put_unused_fd(fd); 159 * return -ENODEV; 160 * } 161 * // No error paths after installing the fd 162 * fd_install(fd, file); 163 * return fd; 164 * 165 * This inits a context, and gets a file descriptor and associates some file 166 * ops to that file descriptor. If the file ops are blank, the cxl driver will 167 * fill them in with the default ones that mimic the standard user API. Once 168 * completed, the file descriptor can be installed. Once the file descriptor is 169 * installed, it's visible to the user so no errors must occur past this point. 170 * 171 * If cxl_fd_release() file op call is installed, the context will be stopped 172 * and released when the fd is released. Hence the driver won't need to manage 173 * this itself. 174 */ 175 176 /* 177 * Take a context and associate it with my file ops. Returns the associated 178 * file and file descriptor. Any file ops which are blank are filled in by the 179 * cxl driver with the default ops to mimic the standard API. 180 */ 181 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops, 182 int *fd); 183 /* Get the context associated with this file */ 184 struct cxl_context *cxl_fops_get_context(struct file *file); 185 /* 186 * Start a context associated a struct cxl_ioctl_start_work used by the 187 * standard cxl user API. 188 */ 189 int cxl_start_work(struct cxl_context *ctx, 190 struct cxl_ioctl_start_work *work); 191 /* 192 * Export all the existing fops so drivers can use them 193 */ 194 int cxl_fd_open(struct inode *inode, struct file *file); 195 int cxl_fd_release(struct inode *inode, struct file *file); 196 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 197 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm); 198 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll); 199 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count, 200 loff_t *off); 201 202 /* 203 * For EEH, a driver may want to assert a PERST will reload the same image 204 * from flash into the FPGA. 205 * 206 * This is a property of the entire adapter, not a single AFU, so drivers 207 * should set this property with care! 208 */ 209 void cxl_perst_reloads_same_image(struct cxl_afu *afu, 210 bool perst_reloads_same_image); 211 212 /* 213 * Read the VPD for the card where the AFU resides 214 */ 215 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count); 216 217 /* 218 * AFU driver ops allow an AFU driver to create their own events to pass to 219 * userspace through the file descriptor as a simpler alternative to overriding 220 * the read() and poll() calls that works with the generic cxl events. These 221 * events are given priority over the generic cxl events, so they will be 222 * delivered first if multiple types of events are pending. 223 * 224 * The AFU driver must call cxl_context_events_pending() to notify the cxl 225 * driver that new events are ready to be delivered for a specific context. 226 * cxl_context_events_pending() will adjust the current count of AFU driver 227 * events for this context, and wake up anyone waiting on the context wait 228 * queue. 229 * 230 * The cxl driver will then call fetch_event() to get a structure defining 231 * the size and address of the driver specific event data. The cxl driver 232 * will build a cxl header with type and process_element fields filled in, 233 * and header.size set to sizeof(struct cxl_event_header) + data_size. 234 * The total size of the event is limited to CXL_READ_MIN_SIZE (4K). 235 * 236 * fetch_event() is called with a spin lock held, so it must not sleep. 237 * 238 * The cxl driver will then deliver the event to userspace, and finally 239 * call event_delivered() to return the status of the operation, identified 240 * by cxl context and AFU driver event data pointers. 241 * 0 Success 242 * -EFAULT copy_to_user() has failed 243 * -EINVAL Event data pointer is NULL, or event size is greater than 244 * CXL_READ_MIN_SIZE. 245 */ 246 struct cxl_afu_driver_ops { 247 struct cxl_event_afu_driver_reserved *(*fetch_event) ( 248 struct cxl_context *ctx); 249 void (*event_delivered) (struct cxl_context *ctx, 250 struct cxl_event_afu_driver_reserved *event, 251 int rc); 252 }; 253 254 /* 255 * Associate the above driver ops with a specific context. 256 * Reset the current count of AFU driver events. 257 */ 258 void cxl_set_driver_ops(struct cxl_context *ctx, 259 struct cxl_afu_driver_ops *ops); 260 261 /* Notify cxl driver that new events are ready to be delivered for context */ 262 void cxl_context_events_pending(struct cxl_context *ctx, 263 unsigned int new_events); 264 265 #endif /* _MISC_CXL_H */ 266