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 /* 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  * Allocate AFU interrupts for this context. num=0 will allocate the default
  90  * for this AFU as given in the AFU descriptor. This number doesn't include the
  91  * interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be
  92  * used must map a handler with cxl_map_afu_irq.
  93  */
  94 int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num);
  95 /* Free allocated interrupts */
  96 void cxl_free_afu_irqs(struct cxl_context *cxl);
  97
  98 /*
  99  * Map a handler for an AFU interrupt associated with a particular context. AFU
 100  * IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie
 101  * is private data is that will be provided to the interrupt handler.
 102  */
 103 int cxl_map_afu_irq(struct cxl_context *cxl, int num,
 104                     irq_handler_t handler, void *cookie, char *name);
 105 /* unmap mapped IRQ handlers */
 106 void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie);
 107
 108 /*
 109  * Start work on the AFU. This starts an cxl context and associates it with a
 110  * task. task == NULL will make it a kernel context.
 111  */
 112 int cxl_start_context(struct cxl_context *ctx, u64 wed,
 113                       struct task_struct *task);
 114 /*
 115  * Stop a context and remove it from the PSL
 116  */
 117 int cxl_stop_context(struct cxl_context *ctx);
 118
 119 /* Reset the AFU */
 120 int cxl_afu_reset(struct cxl_context *ctx);
 121
 122 /*
 123  * Set a context as a master context.
 124  * This sets the default problem space area mapped as the full space, rather
 125  * than just the per context area (for slaves).
 126  */
 127 void cxl_set_master(struct cxl_context *ctx);
 128
 129 /*
 130  * Map and unmap the AFU Problem Space area. The amount and location mapped
 131  * depends on if this context is a master or slave.
 132  */
 133 void __iomem *cxl_psa_map(struct cxl_context *ctx);
 134 void cxl_psa_unmap(void __iomem *addr);
 135
 136 /*  Get the process element for this context */
 137 int cxl_process_element(struct cxl_context *ctx);
 138
 139
 140 /*
 141  * These calls allow drivers to create their own file descriptors and make them
 142  * identical to the cxl file descriptor user API. An example use case:
 143  *
 144  * struct file_operations cxl_my_fops = {};
 145  * ......
 146  *      // Init the context
 147  *      ctx = cxl_dev_context_init(dev);
 148  *      if (IS_ERR(ctx))
 149  *              return PTR_ERR(ctx);
 150  *      // Create and attach a new file descriptor to my file ops
 151  *      file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
 152  *      // Start context
 153  *      rc = cxl_start_work(ctx, &work.work);
 154  *      if (rc) {
 155  *              fput(file);
 156  *              put_unused_fd(fd);
 157  *              return -ENODEV;
 158  *      }
 159  *      // No error paths after installing the fd
 160  *      fd_install(fd, file);
 161  *      return fd;
 162  *
 163  * This inits a context, and gets a file descriptor and associates some file
 164  * ops to that file descriptor. If the file ops are blank, the cxl driver will
 165  * fill them in with the default ones that mimic the standard user API.  Once
 166  * completed, the file descriptor can be installed. Once the file descriptor is
 167  * installed, it's visible to the user so no errors must occur past this point.
 168  *
 169  * If cxl_fd_release() file op call is installed, the context will be stopped
 170  * and released when the fd is released. Hence the driver won't need to manage
 171  * this itself.
 172  */
 173
 174 /*
 175  * Take a context and associate it with my file ops. Returns the associated
 176  * file and file descriptor. Any file ops which are blank are filled in by the
 177  * cxl driver with the default ops to mimic the standard API.
 178  */
 179 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 180                         int *fd);
 181 /* Get the context associated with this file */
 182 struct cxl_context *cxl_fops_get_context(struct file *file);
 183 /*
 184  * Start a context associated a struct cxl_ioctl_start_work used by the
 185  * standard cxl user API.
 186  */
 187 int cxl_start_work(struct cxl_context *ctx,
 188                    struct cxl_ioctl_start_work *work);
 189 /*
 190  * Export all the existing fops so drivers can use them
 191  */
 192 int cxl_fd_open(struct inode *inode, struct file *file);
 193 int cxl_fd_release(struct inode *inode, struct file *file);
 194 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 195 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
 196 unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
 197 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 198                            loff_t *off);
 199
 200 /*
 201  * For EEH, a driver may want to assert a PERST will reload the same image
 202  * from flash into the FPGA.
 203  *
 204  * This is a property of the entire adapter, not a single AFU, so drivers
 205  * should set this property with care!
 206  */
 207 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 208                                   bool perst_reloads_same_image);
 209
 210 /*
 211  * Read the VPD for the card where the AFU resides
 212  */
 213 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
 214
 215 #endif /* _MISC_CXL_H */