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TOMOYO Linux Cross Reference
Linux/include/misc/cxl.h

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  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  * Map and unmap the AFU Problem Space area. The amount and location mapped
138  * depends on if this context is a master or slave.
139  */
140 void __iomem *cxl_psa_map(struct cxl_context *ctx);
141 void cxl_psa_unmap(void __iomem *addr);
142 
143 /*  Get the process element for this context */
144 int cxl_process_element(struct cxl_context *ctx);
145 
146 /*
147  * These calls allow drivers to create their own file descriptors and make them
148  * identical to the cxl file descriptor user API. An example use case:
149  *
150  * struct file_operations cxl_my_fops = {};
151  * ......
152  *      // Init the context
153  *      ctx = cxl_dev_context_init(dev);
154  *      if (IS_ERR(ctx))
155  *              return PTR_ERR(ctx);
156  *      // Create and attach a new file descriptor to my file ops
157  *      file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
158  *      // Start context
159  *      rc = cxl_start_work(ctx, &work.work);
160  *      if (rc) {
161  *              fput(file);
162  *              put_unused_fd(fd);
163  *              return -ENODEV;
164  *      }
165  *      // No error paths after installing the fd
166  *      fd_install(fd, file);
167  *      return fd;
168  *
169  * This inits a context, and gets a file descriptor and associates some file
170  * ops to that file descriptor. If the file ops are blank, the cxl driver will
171  * fill them in with the default ones that mimic the standard user API.  Once
172  * completed, the file descriptor can be installed. Once the file descriptor is
173  * installed, it's visible to the user so no errors must occur past this point.
174  *
175  * If cxl_fd_release() file op call is installed, the context will be stopped
176  * and released when the fd is released. Hence the driver won't need to manage
177  * this itself.
178  */
179 
180 /*
181  * Take a context and associate it with my file ops. Returns the associated
182  * file and file descriptor. Any file ops which are blank are filled in by the
183  * cxl driver with the default ops to mimic the standard API.
184  */
185 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
186                         int *fd);
187 /* Get the context associated with this file */
188 struct cxl_context *cxl_fops_get_context(struct file *file);
189 /*
190  * Start a context associated a struct cxl_ioctl_start_work used by the
191  * standard cxl user API.
192  */
193 int cxl_start_work(struct cxl_context *ctx,
194                    struct cxl_ioctl_start_work *work);
195 /*
196  * Export all the existing fops so drivers can use them
197  */
198 int cxl_fd_open(struct inode *inode, struct file *file);
199 int cxl_fd_release(struct inode *inode, struct file *file);
200 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
201 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
202 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
203 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
204                            loff_t *off);
205 
206 /*
207  * For EEH, a driver may want to assert a PERST will reload the same image
208  * from flash into the FPGA.
209  *
210  * This is a property of the entire adapter, not a single AFU, so drivers
211  * should set this property with care!
212  */
213 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
214                                   bool perst_reloads_same_image);
215 
216 /*
217  * Read the VPD for the card where the AFU resides
218  */
219 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
220 
221 /*
222  * AFU driver ops allow an AFU driver to create their own events to pass to
223  * userspace through the file descriptor as a simpler alternative to overriding
224  * the read() and poll() calls that works with the generic cxl events. These
225  * events are given priority over the generic cxl events, so they will be
226  * delivered first if multiple types of events are pending.
227  *
228  * The AFU driver must call cxl_context_events_pending() to notify the cxl
229  * driver that new events are ready to be delivered for a specific context.
230  * cxl_context_events_pending() will adjust the current count of AFU driver
231  * events for this context, and wake up anyone waiting on the context wait
232  * queue.
233  *
234  * The cxl driver will then call fetch_event() to get a structure defining
235  * the size and address of the driver specific event data. The cxl driver
236  * will build a cxl header with type and process_element fields filled in,
237  * and header.size set to sizeof(struct cxl_event_header) + data_size.
238  * The total size of the event is limited to CXL_READ_MIN_SIZE (4K).
239  *
240  * fetch_event() is called with a spin lock held, so it must not sleep.
241  *
242  * The cxl driver will then deliver the event to userspace, and finally
243  * call event_delivered() to return the status of the operation, identified
244  * by cxl context and AFU driver event data pointers.
245  *   0        Success
246  *   -EFAULT  copy_to_user() has failed
247  *   -EINVAL  Event data pointer is NULL, or event size is greater than
248  *            CXL_READ_MIN_SIZE.
249  */
250 struct cxl_afu_driver_ops {
251         struct cxl_event_afu_driver_reserved *(*fetch_event) (
252                                                 struct cxl_context *ctx);
253         void (*event_delivered) (struct cxl_context *ctx,
254                                  struct cxl_event_afu_driver_reserved *event,
255                                  int rc);
256 };
257 
258 /*
259  * Associate the above driver ops with a specific context.
260  * Reset the current count of AFU driver events.
261  */
262 void cxl_set_driver_ops(struct cxl_context *ctx,
263                         struct cxl_afu_driver_ops *ops);
264 
265 /* Notify cxl driver that new events are ready to be delivered for context */
266 void cxl_context_events_pending(struct cxl_context *ctx,
267                                 unsigned int new_events);
268 
269 #endif /* _MISC_CXL_H */
270 

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