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 */ 214