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 | |