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 /* Get the physical device (ie. the PCIe card) which the AFU is attached */
  34 struct device *cxl_get_phys_dev(struct pci_dev *dev);
  35
  36
  37 /*
  38  * Context lifetime overview:
  39  *
  40  * An AFU context may be inited and then started and stoppped multiple times
  41  * before it's released. ie.
  42  *    - cxl_dev_context_init()
  43  *      - cxl_start_context()
  44  *      - cxl_stop_context()
  45  *      - cxl_start_context()
  46  *      - cxl_stop_context()
  47  *     ...repeat...
  48  *    - cxl_release_context()
  49  * Once released, a context can't be started again.
  50  *
  51  * One context is inited by the cxl driver for every pci_dev. This is to be
  52  * used as a default kernel context. cxl_get_context() will get this
  53  * context. This context will be released by PCI hot unplug, so doesn't need to
  54  * be released explicitly by drivers.
  55  *
  56  * Additional kernel contexts may be inited using cxl_dev_context_init().
  57  * These must be released using cxl_context_detach().
  58  *
  59  * Once a context has been inited, IRQs may be configured. Firstly these IRQs
  60  * must be allocated (cxl_allocate_afu_irqs()), then individually mapped to
  61  * specific handlers (cxl_map_afu_irq()).
  62  *
  63  * These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released
  64  * (cxl_free_afu_irqs()).
  65  *
  66  * The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU
  67  * hardware to lose track of all contexts. It's upto the caller of
  68  * cxl_afu_reset() to restart these contexts.
  69  */
  70
  71 /*
  72  * On pci_enabled_device(), the cxl driver will init a single cxl context for
  73  * use by the driver. It doesn't start this context (as that will likely
  74  * generate DMA traffic for most AFUs).
  75  *
  76  * This gets the default context associated with this pci_dev.  This context
  77  * doesn't need to be released as this will be done by the PCI subsystem on hot
  78  * unplug.
  79  */
  80 struct cxl_context *cxl_get_context(struct pci_dev *dev);
  81 /*
  82  * Allocate and initalise a context associated with a AFU PCI device. This
  83  * doesn't start the context in the AFU.
  84  */
  85 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev);
  86 /*
  87  * Release and free a context. Context should be stopped before calling.
  88  */
  89 int cxl_release_context(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 /*
 144  * These calls allow drivers to create their own file descriptors and make them
 145  * identical to the cxl file descriptor user API. An example use case:
 146  *
 147  * struct file_operations cxl_my_fops = {};
 148  * ......
 149  *      // Init the context
 150  *      ctx = cxl_dev_context_init(dev);
 151  *      if (IS_ERR(ctx))
 152  *              return PTR_ERR(ctx);
 153  *      // Create and attach a new file descriptor to my file ops
 154  *      file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
 155  *      // Start context
 156  *      rc = cxl_start_work(ctx, &work.work);
 157  *      if (rc) {
 158  *              fput(file);
 159  *              put_unused_fd(fd);
 160  *              return -ENODEV;
 161  *      }
 162  *      // No error paths after installing the fd
 163  *      fd_install(fd, file);
 164  *      return fd;
 165  *
 166  * This inits a context, and gets a file descriptor and associates some file
 167  * ops to that file descriptor. If the file ops are blank, the cxl driver will
 168  * fill them in with the default ones that mimic the standard user API.  Once
 169  * completed, the file descriptor can be installed. Once the file descriptor is
 170  * installed, it's visible to the user so no errors must occur past this point.
 171  *
 172  * If cxl_fd_release() file op call is installed, the context will be stopped
 173  * and released when the fd is released. Hence the driver won't need to manage
 174  * this itself.
 175  */
 176
 177 /*
 178  * Take a context and associate it with my file ops. Returns the associated
 179  * file and file descriptor. Any file ops which are blank are filled in by the
 180  * cxl driver with the default ops to mimic the standard API.
 181  */
 182 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 183                         int *fd);
 184 /* Get the context associated with this file */
 185 struct cxl_context *cxl_fops_get_context(struct file *file);
 186 /*
 187  * Start a context associated a struct cxl_ioctl_start_work used by the
 188  * standard cxl user API.
 189  */
 190 int cxl_start_work(struct cxl_context *ctx,
 191                    struct cxl_ioctl_start_work *work);
 192 /*
 193  * Export all the existing fops so drivers can use them
 194  */
 195 int cxl_fd_open(struct inode *inode, struct file *file);
 196 int cxl_fd_release(struct inode *inode, struct file *file);
 197 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 198 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
 199 unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
 200 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 201                            loff_t *off);
 202
 203 /*
 204  * For EEH, a driver may want to assert a PERST will reload the same image
 205  * from flash into the FPGA.
 206  *
 207  * This is a property of the entire adapter, not a single AFU, so drivers
 208  * should set this property with care!
 209  */
 210 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 211                                   bool perst_reloads_same_image);
 212
 213 #endif /* _MISC_CXL_H */