include/misc/cxl.h

   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 #define CXL_SLOT_FLAG_DMA 0x1
  28
  29 /*
  30  * Checks if the given card is in a cxl capable slot. Pass CXL_SLOT_FLAG_DMA if
  31  * the card requires CAPP DMA mode to also check if the system supports it.
  32  * This is intended to be used by bi-modal devices to determine if they can use
  33  * cxl mode or if they should continue running in PCI mode.
  34  *
  35  * Note that this only checks if the slot is cxl capable - it does not
  36  * currently check if the CAPP is currently available for chips where it can be
  37  * assigned to different PHBs on a first come first serve basis (i.e. P8)
  38  */
  39 bool cxl_slot_is_supported(struct pci_dev *dev, int flags);
  40
  41
  42 #define CXL_BIMODE_CXL 1
  43 #define CXL_BIMODE_PCI 2
  44
  45 /*
  46  * Check the mode that the given bi-modal CXL adapter is currently in and
  47  * change it if necessary. This does not apply to AFU drivers.
  48  *
  49  * If the mode matches the requested mode this function will return 0 - if the
  50  * driver was expecting the generic CXL driver to have bound to the adapter and
  51  * it gets this return value it should fail the probe function to give the CXL
  52  * driver a chance to probe it.
  53  *
  54  * If the mode does not match it will start a background task to unplug the
  55  * device from Linux and switch its mode, and will return -EBUSY. At this
  56  * point the calling driver should make sure it has released the device and
  57  * fail its probe function.
  58  *
  59  * The offset of the CXL VSEC can be provided to this function. If 0 is passed,
  60  * this function will search for a CXL VSEC with ID 0x1280 and return -ENODEV
  61  * if it is not found.
  62  */
  63 #ifdef CONFIG_CXL_BIMODAL
  64 int cxl_check_and_switch_mode(struct pci_dev *dev, int mode, int vsec);
  65 #endif
  66
  67 /* Get the AFU associated with a pci_dev */
  68 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);
  69
  70 /* Get the AFU conf record number associated with a pci_dev */
  71 unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev);
  72
  73
  74 /*
  75  * Context lifetime overview:
  76  *
  77  * An AFU context may be inited and then started and stoppped multiple times
  78  * before it's released. ie.
  79  *    - cxl_dev_context_init()
  80  *      - cxl_start_context()
  81  *      - cxl_stop_context()
  82  *      - cxl_start_context()
  83  *      - cxl_stop_context()
  84  *     ...repeat...
  85  *    - cxl_release_context()
  86  * Once released, a context can't be started again.
  87  *
  88  * One context is inited by the cxl driver for every pci_dev. This is to be
  89  * used as a default kernel context. cxl_get_context() will get this
  90  * context. This context will be released by PCI hot unplug, so doesn't need to
  91  * be released explicitly by drivers.
  92  *
  93  * Additional kernel contexts may be inited using cxl_dev_context_init().
  94  * These must be released using cxl_context_detach().
  95  *
  96  * Once a context has been inited, IRQs may be configured. Firstly these IRQs
  97  * must be allocated (cxl_allocate_afu_irqs()), then individually mapped to
  98  * specific handlers (cxl_map_afu_irq()).
  99  *
 100  * These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released
 101  * (cxl_free_afu_irqs()).
 102  *
 103  * The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU
 104  * hardware to lose track of all contexts. It's upto the caller of
 105  * cxl_afu_reset() to restart these contexts.
 106  */
 107
 108 /*
 109  * On pci_enabled_device(), the cxl driver will init a single cxl context for
 110  * use by the driver. It doesn't start this context (as that will likely
 111  * generate DMA traffic for most AFUs).
 112  *
 113  * This gets the default context associated with this pci_dev.  This context
 114  * doesn't need to be released as this will be done by the PCI subsystem on hot
 115  * unplug.
 116  */
 117 struct cxl_context *cxl_get_context(struct pci_dev *dev);
 118 /*
 119  * Allocate and initalise a context associated with a AFU PCI device. This
 120  * doesn't start the context in the AFU.
 121  */
 122 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev);
 123 /*
 124  * Release and free a context. Context should be stopped before calling.
 125  */
 126 int cxl_release_context(struct cxl_context *ctx);
 127
 128 /*
 129  * Set and get private data associated with a context. Allows drivers to have a
 130  * back pointer to some useful structure.
 131  */
 132 int cxl_set_priv(struct cxl_context *ctx, void *priv);
 133 void *cxl_get_priv(struct cxl_context *ctx);
 134
 135 /*
 136  * Allocate AFU interrupts for this context. num=0 will allocate the default
 137  * for this AFU as given in the AFU descriptor. This number doesn't include the
 138  * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be
 139  * used must map a handler with cxl_map_afu_irq.
 140  */
 141 int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num);
 142 /* Free allocated interrupts */
 143 void cxl_free_afu_irqs(struct cxl_context *cxl);
 144
 145 /*
 146  * Map a handler for an AFU interrupt associated with a particular context. AFU
 147  * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie
 148  * is private data is that will be provided to the interrupt handler.
 149  */
 150 int cxl_map_afu_irq(struct cxl_context *cxl, int num,
 151                     irq_handler_t handler, void *cookie, char *name);
 152 /* unmap mapped IRQ handlers */
 153 void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie);
 154
 155 /*
 156  * Start work on the AFU. This starts an cxl context and associates it with a
 157  * task. task == NULL will make it a kernel context.
 158  */
 159 int cxl_start_context(struct cxl_context *ctx, u64 wed,
 160                       struct task_struct *task);
 161 /*
 162  * Stop a context and remove it from the PSL
 163  */
 164 int cxl_stop_context(struct cxl_context *ctx);
 165
 166 /* Reset the AFU */
 167 int cxl_afu_reset(struct cxl_context *ctx);
 168
 169 /*
 170  * Set a context as a master context.
 171  * This sets the default problem space area mapped as the full space, rather
 172  * than just the per context area (for slaves).
 173  */
 174 void cxl_set_master(struct cxl_context *ctx);
 175
 176 /*
 177  * Sets the context to use real mode memory accesses to operate with
 178  * translation disabled. Note that this only makes sense for kernel contexts
 179  * under bare metal, and will not work with virtualisation. May only be
 180  * performed on stopped contexts.
 181  */
 182 int cxl_set_translation_mode(struct cxl_context *ctx, bool real_mode);
 183
 184 /*
 185  * Map and unmap the AFU Problem Space area. The amount and location mapped
 186  * depends on if this context is a master or slave.
 187  */
 188 void __iomem *cxl_psa_map(struct cxl_context *ctx);
 189 void cxl_psa_unmap(void __iomem *addr);
 190
 191 /*  Get the process element for this context */
 192 int cxl_process_element(struct cxl_context *ctx);
 193
 194 /*
 195  * Limit the number of interrupts that a single context can allocate via
 196  * cxl_start_work. If using the api with a real phb, this may be used to
 197  * request that additional default contexts be created when allocating
 198  * interrupts via pci_enable_msix_range. These will be set to the same running
 199  * state as the default context, and if that is running it will reuse the
 200  * parameters previously passed to cxl_start_context for the default context.
 201  */
 202 int cxl_set_max_irqs_per_process(struct pci_dev *dev, int irqs);
 203 int cxl_get_max_irqs_per_process(struct pci_dev *dev);
 204
 205 /*
 206  * Use to simultaneously iterate over hardware interrupt numbers, contexts and
 207  * afu interrupt numbers allocated for the device via pci_enable_msix_range and
 208  * is a useful convenience function when working with hardware that has
 209  * limitations on the number of interrupts per process. *ctx and *afu_irq
 210  * should be NULL and 0 to start the iteration.
 211  */
 212 int cxl_next_msi_hwirq(struct pci_dev *pdev, struct cxl_context **ctx, int *afu_irq);
 213
 214 /*
 215  * These calls allow drivers to create their own file descriptors and make them
 216  * identical to the cxl file descriptor user API. An example use case:
 217  *
 218  * struct file_operations cxl_my_fops = {};
 219  * ......
 220  *      // Init the context
 221  *      ctx = cxl_dev_context_init(dev);
 222  *      if (IS_ERR(ctx))
 223  *              return PTR_ERR(ctx);
 224  *      // Create and attach a new file descriptor to my file ops
 225  *      file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
 226  *      // Start context
 227  *      rc = cxl_start_work(ctx, &work.work);
 228  *      if (rc) {
 229  *              fput(file);
 230  *              put_unused_fd(fd);
 231  *              return -ENODEV;
 232  *      }
 233  *      // No error paths after installing the fd
 234  *      fd_install(fd, file);
 235  *      return fd;
 236  *
 237  * This inits a context, and gets a file descriptor and associates some file
 238  * ops to that file descriptor. If the file ops are blank, the cxl driver will
 239  * fill them in with the default ones that mimic the standard user API.  Once
 240  * completed, the file descriptor can be installed. Once the file descriptor is
 241  * installed, it's visible to the user so no errors must occur past this point.
 242  *
 243  * If cxl_fd_release() file op call is installed, the context will be stopped
 244  * and released when the fd is released. Hence the driver won't need to manage
 245  * this itself.
 246  */
 247
 248 /*
 249  * Take a context and associate it with my file ops. Returns the associated
 250  * file and file descriptor. Any file ops which are blank are filled in by the
 251  * cxl driver with the default ops to mimic the standard API.
 252  */
 253 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 254                         int *fd);
 255 /* Get the context associated with this file */
 256 struct cxl_context *cxl_fops_get_context(struct file *file);
 257 /*
 258  * Start a context associated a struct cxl_ioctl_start_work used by the
 259  * standard cxl user API.
 260  */
 261 int cxl_start_work(struct cxl_context *ctx,
 262                    struct cxl_ioctl_start_work *work);
 263 /*
 264  * Export all the existing fops so drivers can use them
 265  */
 266 int cxl_fd_open(struct inode *inode, struct file *file);
 267 int cxl_fd_release(struct inode *inode, struct file *file);
 268 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 269 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
 270 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
 271 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 272                            loff_t *off);
 273
 274 /*
 275  * For EEH, a driver may want to assert a PERST will reload the same image
 276  * from flash into the FPGA.
 277  *
 278  * This is a property of the entire adapter, not a single AFU, so drivers
 279  * should set this property with care!
 280  */
 281 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 282                                   bool perst_reloads_same_image);
 283
 284 /*
 285  * Read the VPD for the card where the AFU resides
 286  */
 287 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
 288
 289 /*
 290  * AFU driver ops allow an AFU driver to create their own events to pass to
 291  * userspace through the file descriptor as a simpler alternative to overriding
 292  * the read() and poll() calls that works with the generic cxl events. These
 293  * events are given priority over the generic cxl events, so they will be
 294  * delivered first if multiple types of events are pending.
 295  *
 296  * The AFU driver must call cxl_context_events_pending() to notify the cxl
 297  * driver that new events are ready to be delivered for a specific context.
 298  * cxl_context_events_pending() will adjust the current count of AFU driver
 299  * events for this context, and wake up anyone waiting on the context wait
 300  * queue.
 301  *
 302  * The cxl driver will then call fetch_event() to get a structure defining
 303  * the size and address of the driver specific event data. The cxl driver
 304  * will build a cxl header with type and process_element fields filled in,
 305  * and header.size set to sizeof(struct cxl_event_header) + data_size.
 306  * The total size of the event is limited to CXL_READ_MIN_SIZE (4K).
 307  *
 308  * fetch_event() is called with a spin lock held, so it must not sleep.
 309  *
 310  * The cxl driver will then deliver the event to userspace, and finally
 311  * call event_delivered() to return the status of the operation, identified
 312  * by cxl context and AFU driver event data pointers.
 313  *   0        Success
 314  *   -EFAULT  copy_to_user() has failed
 315  *   -EINVAL  Event data pointer is NULL, or event size is greater than
 316  *            CXL_READ_MIN_SIZE.
 317  */
 318 struct cxl_afu_driver_ops {
 319         struct cxl_event_afu_driver_reserved *(*fetch_event) (
 320                                                 struct cxl_context *ctx);
 321         void (*event_delivered) (struct cxl_context *ctx,
 322                                  struct cxl_event_afu_driver_reserved *event,
 323                                  int rc);
 324 };
 325
 326 /*
 327  * Associate the above driver ops with a specific context.
 328  * Reset the current count of AFU driver events.
 329  */
 330 void cxl_set_driver_ops(struct cxl_context *ctx,
 331                         struct cxl_afu_driver_ops *ops);
 332
 333 /* Notify cxl driver that new events are ready to be delivered for context */
 334 void cxl_context_events_pending(struct cxl_context *ctx,
 335                                 unsigned int new_events);
 336
 337 #endif /* _MISC_CXL_H */