drivers/char/ipmi/ipmi_dmi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * A hack to create a platform device from a DMI entry.  This will
   4  * allow autoloading of the IPMI drive based on SMBIOS entries.
   5  */
   6
   7 #include <linux/ipmi.h>
   8 #include <linux/init.h>
   9 #include <linux/dmi.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/property.h>
  12 #include "ipmi_si_sm.h"
  13 #include "ipmi_dmi.h"
  14
  15 #define IPMI_DMI_TYPE_KCS       0x01
  16 #define IPMI_DMI_TYPE_SMIC      0x02
  17 #define IPMI_DMI_TYPE_BT        0x03
  18 #define IPMI_DMI_TYPE_SSIF      0x04
  19
  20 struct ipmi_dmi_info {
  21         enum si_type si_type;
  22         u32 flags;
  23         unsigned long addr;
  24         u8 slave_addr;
  25         struct ipmi_dmi_info *next;
  26 };
  27
  28 static struct ipmi_dmi_info *ipmi_dmi_infos;
  29
  30 static int ipmi_dmi_nr __initdata;
  31
  32 #define set_prop_entry(_p_, _name_, type, val)  \
  33 do {                                    \
  34         struct property_entry *_p = &_p_;       \
  35         _p->name = _name_;                      \
  36         _p->length = sizeof(type);              \
  37         _p->is_string = false;                  \
  38         _p->value.type##_data = val;            \
  39 } while(0)
  40
  41 static void __init dmi_add_platform_ipmi(unsigned long base_addr,
  42                                          u32 flags,
  43                                          u8 slave_addr,
  44                                          int irq,
  45                                          int offset,
  46                                          int type)
  47 {
  48         struct platform_device *pdev;
  49         struct resource r[4];
  50         unsigned int num_r = 1, size;
  51         struct property_entry p[5];
  52         unsigned int pidx = 0;
  53         char *name, *override;
  54         int rv;
  55         enum si_type si_type;
  56         struct ipmi_dmi_info *info;
  57
  58         memset(p, 0, sizeof(p));
  59
  60         name = "dmi-ipmi-si";
  61         override = "ipmi_si";
  62         switch (type) {
  63         case IPMI_DMI_TYPE_SSIF:
  64                 name = "dmi-ipmi-ssif";
  65                 override = "ipmi_ssif";
  66                 offset = 1;
  67                 size = 1;
  68                 si_type = SI_TYPE_INVALID;
  69                 break;
  70         case IPMI_DMI_TYPE_BT:
  71                 size = 3;
  72                 si_type = SI_BT;
  73                 break;
  74         case IPMI_DMI_TYPE_KCS:
  75                 size = 2;
  76                 si_type = SI_KCS;
  77                 break;
  78         case IPMI_DMI_TYPE_SMIC:
  79                 size = 2;
  80                 si_type = SI_SMIC;
  81                 break;
  82         default:
  83                 pr_err("ipmi:dmi: Invalid IPMI type: %d\n", type);
  84                 return;
  85         }
  86
  87         if (si_type != SI_TYPE_INVALID)
  88                 set_prop_entry(p[pidx++], "ipmi-type", u8, si_type);
  89         set_prop_entry(p[pidx++], "slave-addr", u8, slave_addr);
  90         set_prop_entry(p[pidx++], "addr-source", u8, SI_SMBIOS);
  91
  92         info = kmalloc(sizeof(*info), GFP_KERNEL);
  93         if (!info) {
  94                 pr_warn("ipmi:dmi: Could not allocate dmi info\n");
  95         } else {
  96                 info->si_type = si_type;
  97                 info->flags = flags;
  98                 info->addr = base_addr;
  99                 info->slave_addr = slave_addr;
 100                 info->next = ipmi_dmi_infos;
 101                 ipmi_dmi_infos = info;
 102         }
 103
 104         pdev = platform_device_alloc(name, ipmi_dmi_nr);
 105         if (!pdev) {
 106                 pr_err("ipmi:dmi: Error allocation IPMI platform device\n");
 107                 return;
 108         }
 109         pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
 110                                           override);
 111         if (!pdev->driver_override)
 112                 goto err;
 113
 114         if (type == IPMI_DMI_TYPE_SSIF) {
 115                 set_prop_entry(p[pidx++], "i2c-addr", u16, base_addr);
 116                 goto add_properties;
 117         }
 118
 119         memset(r, 0, sizeof(r));
 120
 121         r[0].start = base_addr;
 122         r[0].end = r[0].start + offset - 1;
 123         r[0].name = "IPMI Address 1";
 124         r[0].flags = flags;
 125
 126         if (size > 1) {
 127                 r[1].start = r[0].start + offset;
 128                 r[1].end = r[1].start + offset - 1;
 129                 r[1].name = "IPMI Address 2";
 130                 r[1].flags = flags;
 131                 num_r++;
 132         }
 133
 134         if (size > 2) {
 135                 r[2].start = r[1].start + offset;
 136                 r[2].end = r[2].start + offset - 1;
 137                 r[2].name = "IPMI Address 3";
 138                 r[2].flags = flags;
 139                 num_r++;
 140         }
 141
 142         if (irq) {
 143                 r[num_r].start = irq;
 144                 r[num_r].end = irq;
 145                 r[num_r].name = "IPMI IRQ";
 146                 r[num_r].flags = IORESOURCE_IRQ;
 147                 num_r++;
 148         }
 149
 150         rv = platform_device_add_resources(pdev, r, num_r);
 151         if (rv) {
 152                 dev_err(&pdev->dev,
 153                         "ipmi:dmi: Unable to add resources: %d\n", rv);
 154                 goto err;
 155         }
 156
 157 add_properties:
 158         rv = platform_device_add_properties(pdev, p);
 159         if (rv) {
 160                 dev_err(&pdev->dev,
 161                         "ipmi:dmi: Unable to add properties: %d\n", rv);
 162                 goto err;
 163         }
 164
 165         rv = platform_device_add(pdev);
 166         if (rv) {
 167                 dev_err(&pdev->dev, "ipmi:dmi: Unable to add device: %d\n", rv);
 168                 goto err;
 169         }
 170
 171         ipmi_dmi_nr++;
 172         return;
 173
 174 err:
 175         platform_device_put(pdev);
 176 }
 177
 178 /*
 179  * Look up the slave address for a given interface.  This is here
 180  * because ACPI doesn't have a slave address while SMBIOS does, but we
 181  * prefer using ACPI so the ACPI code can use the IPMI namespace.
 182  * This function allows an ACPI-specified IPMI device to look up the
 183  * slave address from the DMI table.
 184  */
 185 int ipmi_dmi_get_slave_addr(enum si_type si_type, u32 flags,
 186                             unsigned long base_addr)
 187 {
 188         struct ipmi_dmi_info *info = ipmi_dmi_infos;
 189
 190         while (info) {
 191                 if (info->si_type == si_type &&
 192                     info->flags == flags &&
 193                     info->addr == base_addr)
 194                         return info->slave_addr;
 195                 info = info->next;
 196         }
 197
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
 201
 202 #define DMI_IPMI_MIN_LENGTH     0x10
 203 #define DMI_IPMI_VER2_LENGTH    0x12
 204 #define DMI_IPMI_TYPE           4
 205 #define DMI_IPMI_SLAVEADDR      6
 206 #define DMI_IPMI_ADDR           8
 207 #define DMI_IPMI_ACCESS         0x10
 208 #define DMI_IPMI_IRQ            0x11
 209 #define DMI_IPMI_IO_MASK        0xfffe
 210
 211 static void __init dmi_decode_ipmi(const struct dmi_header *dm)
 212 {
 213         const u8        *data = (const u8 *) dm;
 214         u32             flags = IORESOURCE_IO;
 215         unsigned long   base_addr;
 216         u8              len = dm->length;
 217         u8              slave_addr;
 218         int             irq = 0, offset;
 219         int             type;
 220
 221         if (len < DMI_IPMI_MIN_LENGTH)
 222                 return;
 223
 224         type = data[DMI_IPMI_TYPE];
 225         slave_addr = data[DMI_IPMI_SLAVEADDR];
 226
 227         memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
 228         if (len >= DMI_IPMI_VER2_LENGTH) {
 229                 if (type == IPMI_DMI_TYPE_SSIF) {
 230                         offset = 0;
 231                         flags = 0;
 232                         base_addr = data[DMI_IPMI_ADDR] >> 1;
 233                         if (base_addr == 0) {
 234                                 /*
 235                                  * Some broken systems put the I2C address in
 236                                  * the slave address field.  We try to
 237                                  * accommodate them here.
 238                                  */
 239                                 base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
 240                                 slave_addr = 0;
 241                         }
 242                 } else {
 243                         if (base_addr & 1) {
 244                                 /* I/O */
 245                                 base_addr &= DMI_IPMI_IO_MASK;
 246                         } else {
 247                                 /* Memory */
 248                                 flags = IORESOURCE_MEM;
 249                         }
 250
 251                         /*
 252                          * If bit 4 of byte 0x10 is set, then the lsb
 253                          * for the address is odd.
 254                          */
 255                         base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
 256
 257                         irq = data[DMI_IPMI_IRQ];
 258
 259                         /*
 260                          * The top two bits of byte 0x10 hold the
 261                          * register spacing.
 262                          */
 263                         switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
 264                         case 0: /* Byte boundaries */
 265                                 offset = 1;
 266                                 break;
 267                         case 1: /* 32-bit boundaries */
 268                                 offset = 4;
 269                                 break;
 270                         case 2: /* 16-byte boundaries */
 271                                 offset = 16;
 272                                 break;
 273                         default:
 274                                 pr_err("ipmi:dmi: Invalid offset: 0\n");
 275                                 return;
 276                         }
 277                 }
 278         } else {
 279                 /* Old DMI spec. */
 280                 /*
 281                  * Note that technically, the lower bit of the base
 282                  * address should be 1 if the address is I/O and 0 if
 283                  * the address is in memory.  So many systems get that
 284                  * wrong (and all that I have seen are I/O) so we just
 285                  * ignore that bit and assume I/O.  Systems that use
 286                  * memory should use the newer spec, anyway.
 287                  */
 288                 base_addr = base_addr & DMI_IPMI_IO_MASK;
 289                 offset = 1;
 290         }
 291
 292         dmi_add_platform_ipmi(base_addr, flags, slave_addr, irq,
 293                               offset, type);
 294 }
 295
 296 static int __init scan_for_dmi_ipmi(void)
 297 {
 298         const struct dmi_device *dev = NULL;
 299
 300         while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
 301                 dmi_decode_ipmi((const struct dmi_header *) dev->device_data);
 302
 303         return 0;
 304 }
 305 subsys_initcall(scan_for_dmi_ipmi);