drivers/platform/x86/intel_pmt_class.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Intel Platform Monitory Technology Telemetry driver
   4  *
   5  * Copyright (c) 2020, Intel Corporation.
   6  * All Rights Reserved.
   7  *
   8  * Author: "Alexander Duyck" <[email protected]>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mm.h>
  14 #include <linux/pci.h>
  15
  16 #include "intel_pmt_class.h"
  17
  18 #define PMT_XA_START            0
  19 #define PMT_XA_MAX              INT_MAX
  20 #define PMT_XA_LIMIT            XA_LIMIT(PMT_XA_START, PMT_XA_MAX)
  21
  22 /*
  23  * sysfs
  24  */
  25 static ssize_t
  26 intel_pmt_read(struct file *filp, struct kobject *kobj,
  27                struct bin_attribute *attr, char *buf, loff_t off,
  28                size_t count)
  29 {
  30         struct intel_pmt_entry *entry = container_of(attr,
  31                                                      struct intel_pmt_entry,
  32                                                      pmt_bin_attr);
  33
  34         if (off < 0)
  35                 return -EINVAL;
  36
  37         if (off >= entry->size)
  38                 return 0;
  39
  40         if (count > entry->size - off)
  41                 count = entry->size - off;
  42
  43         memcpy_fromio(buf, entry->base + off, count);
  44
  45         return count;
  46 }
  47
  48 static int
  49 intel_pmt_mmap(struct file *filp, struct kobject *kobj,
  50                 struct bin_attribute *attr, struct vm_area_struct *vma)
  51 {
  52         struct intel_pmt_entry *entry = container_of(attr,
  53                                                      struct intel_pmt_entry,
  54                                                      pmt_bin_attr);
  55         unsigned long vsize = vma->vm_end - vma->vm_start;
  56         struct device *dev = kobj_to_dev(kobj);
  57         unsigned long phys = entry->base_addr;
  58         unsigned long pfn = PFN_DOWN(phys);
  59         unsigned long psize;
  60
  61         if (vma->vm_flags & (VM_WRITE | VM_MAYWRITE))
  62                 return -EROFS;
  63
  64         psize = (PFN_UP(entry->base_addr + entry->size) - pfn) * PAGE_SIZE;
  65         if (vsize > psize) {
  66                 dev_err(dev, "Requested mmap size is too large\n");
  67                 return -EINVAL;
  68         }
  69
  70         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  71         if (io_remap_pfn_range(vma, vma->vm_start, pfn,
  72                 vsize, vma->vm_page_prot))
  73                 return -EAGAIN;
  74
  75         return 0;
  76 }
  77
  78 static ssize_t
  79 guid_show(struct device *dev, struct device_attribute *attr, char *buf)
  80 {
  81         struct intel_pmt_entry *entry = dev_get_drvdata(dev);
  82
  83         return sprintf(buf, "0x%x\n", entry->guid);
  84 }
  85 static DEVICE_ATTR_RO(guid);
  86
  87 static ssize_t size_show(struct device *dev, struct device_attribute *attr,
  88                          char *buf)
  89 {
  90         struct intel_pmt_entry *entry = dev_get_drvdata(dev);
  91
  92         return sprintf(buf, "%zu\n", entry->size);
  93 }
  94 static DEVICE_ATTR_RO(size);
  95
  96 static ssize_t
  97 offset_show(struct device *dev, struct device_attribute *attr, char *buf)
  98 {
  99         struct intel_pmt_entry *entry = dev_get_drvdata(dev);
 100
 101         return sprintf(buf, "%lu\n", offset_in_page(entry->base_addr));
 102 }
 103 static DEVICE_ATTR_RO(offset);
 104
 105 static struct attribute *intel_pmt_attrs[] = {
 106         &dev_attr_guid.attr,
 107         &dev_attr_size.attr,
 108         &dev_attr_offset.attr,
 109         NULL
 110 };
 111 ATTRIBUTE_GROUPS(intel_pmt);
 112
 113 static struct class intel_pmt_class = {
 114         .name = "intel_pmt",
 115         .owner = THIS_MODULE,
 116         .dev_groups = intel_pmt_groups,
 117 };
 118
 119 static int intel_pmt_populate_entry(struct intel_pmt_entry *entry,
 120                                     struct intel_pmt_header *header,
 121                                     struct device *dev,
 122                                     struct resource *disc_res)
 123 {
 124         struct pci_dev *pci_dev = to_pci_dev(dev->parent);
 125         u8 bir;
 126
 127         /*
 128          * The base offset should always be 8 byte aligned.
 129          *
 130          * For non-local access types the lower 3 bits of base offset
 131          * contains the index of the base address register where the
 132          * telemetry can be found.
 133          */
 134         bir = GET_BIR(header->base_offset);
 135
 136         /* Local access and BARID only for now */
 137         switch (header->access_type) {
 138         case ACCESS_LOCAL:
 139                 if (bir) {
 140                         dev_err(dev,
 141                                 "Unsupported BAR index %d for access type %d\n",
 142                                 bir, header->access_type);
 143                         return -EINVAL;
 144                 }
 145                 /*
 146                  * For access_type LOCAL, the base address is as follows:
 147                  * base address = end of discovery region + base offset
 148                  */
 149                 entry->base_addr = disc_res->end + 1 + header->base_offset;
 150                 break;
 151         case ACCESS_BARID:
 152                 /*
 153                  * If another BAR was specified then the base offset
 154                  * represents the offset within that BAR. SO retrieve the
 155                  * address from the parent PCI device and add offset.
 156                  */
 157                 entry->base_addr = pci_resource_start(pci_dev, bir) +
 158                                    GET_ADDRESS(header->base_offset);
 159                 break;
 160         default:
 161                 dev_err(dev, "Unsupported access type %d\n",
 162                         header->access_type);
 163                 return -EINVAL;
 164         }
 165
 166         entry->guid = header->guid;
 167         entry->size = header->size;
 168
 169         return 0;
 170 }
 171
 172 static int intel_pmt_dev_register(struct intel_pmt_entry *entry,
 173                                   struct intel_pmt_namespace *ns,
 174                                   struct device *parent)
 175 {
 176         struct resource res;
 177         struct device *dev;
 178         int ret;
 179
 180         ret = xa_alloc(ns->xa, &entry->devid, entry, PMT_XA_LIMIT, GFP_KERNEL);
 181         if (ret)
 182                 return ret;
 183
 184         dev = device_create(&intel_pmt_class, parent, MKDEV(0, 0), entry,
 185                             "%s%d", ns->name, entry->devid);
 186
 187         if (IS_ERR(dev)) {
 188                 dev_err(parent, "Could not create %s%d device node\n",
 189                         ns->name, entry->devid);
 190                 ret = PTR_ERR(dev);
 191                 goto fail_dev_create;
 192         }
 193
 194         entry->kobj = &dev->kobj;
 195
 196         if (ns->attr_grp) {
 197                 ret = sysfs_create_group(entry->kobj, ns->attr_grp);
 198                 if (ret)
 199                         goto fail_sysfs;
 200         }
 201
 202         /* if size is 0 assume no data buffer, so no file needed */
 203         if (!entry->size)
 204                 return 0;
 205
 206         res.start = entry->base_addr;
 207         res.end = res.start + entry->size - 1;
 208         res.flags = IORESOURCE_MEM;
 209
 210         entry->base = devm_ioremap_resource(dev, &res);
 211         if (IS_ERR(entry->base)) {
 212                 ret = PTR_ERR(entry->base);
 213                 goto fail_ioremap;
 214         }
 215
 216         sysfs_bin_attr_init(&entry->pmt_bin_attr);
 217         entry->pmt_bin_attr.attr.name = ns->name;
 218         entry->pmt_bin_attr.attr.mode = 0440;
 219         entry->pmt_bin_attr.mmap = intel_pmt_mmap;
 220         entry->pmt_bin_attr.read = intel_pmt_read;
 221         entry->pmt_bin_attr.size = entry->size;
 222
 223         ret = sysfs_create_bin_file(&dev->kobj, &entry->pmt_bin_attr);
 224         if (!ret)
 225                 return 0;
 226
 227 fail_ioremap:
 228         if (ns->attr_grp)
 229                 sysfs_remove_group(entry->kobj, ns->attr_grp);
 230 fail_sysfs:
 231         device_unregister(dev);
 232 fail_dev_create:
 233         xa_erase(ns->xa, entry->devid);
 234
 235         return ret;
 236 }
 237
 238 int intel_pmt_dev_create(struct intel_pmt_entry *entry,
 239                          struct intel_pmt_namespace *ns,
 240                          struct platform_device *pdev, int idx)
 241 {
 242         struct intel_pmt_header header;
 243         struct resource *disc_res;
 244         int ret = -ENODEV;
 245
 246         disc_res = platform_get_resource(pdev, IORESOURCE_MEM, idx);
 247         if (!disc_res)
 248                 return ret;
 249
 250         entry->disc_table = devm_platform_ioremap_resource(pdev, idx);
 251         if (IS_ERR(entry->disc_table))
 252                 return PTR_ERR(entry->disc_table);
 253
 254         ret = ns->pmt_header_decode(entry, &header, &pdev->dev);
 255         if (ret)
 256                 return ret;
 257
 258         ret = intel_pmt_populate_entry(entry, &header, &pdev->dev, disc_res);
 259         if (ret)
 260                 return ret;
 261
 262         return intel_pmt_dev_register(entry, ns, &pdev->dev);
 263
 264 }
 265 EXPORT_SYMBOL_GPL(intel_pmt_dev_create);
 266
 267 void intel_pmt_dev_destroy(struct intel_pmt_entry *entry,
 268                            struct intel_pmt_namespace *ns)
 269 {
 270         struct device *dev = kobj_to_dev(entry->kobj);
 271
 272         if (entry->size)
 273                 sysfs_remove_bin_file(entry->kobj, &entry->pmt_bin_attr);
 274
 275         if (ns->attr_grp)
 276                 sysfs_remove_group(entry->kobj, ns->attr_grp);
 277
 278         device_unregister(dev);
 279         xa_erase(ns->xa, entry->devid);
 280 }
 281 EXPORT_SYMBOL_GPL(intel_pmt_dev_destroy);
 282
 283 static int __init pmt_class_init(void)
 284 {
 285         return class_register(&intel_pmt_class);
 286 }
 287
 288 static void __exit pmt_class_exit(void)
 289 {
 290         class_unregister(&intel_pmt_class);
 291 }
 292
 293 module_init(pmt_class_init);
 294 module_exit(pmt_class_exit);
 295
 296 MODULE_AUTHOR("Alexander Duyck <[email protected]>");
 297 MODULE_DESCRIPTION("Intel PMT Class driver");
 298 MODULE_LICENSE("GPL v2");