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 static void __init dmi_add_platform_ipmi(unsigned long base_addr,
  33                                          u32 flags,
  34                                          u8 slave_addr,
  35                                          int irq,
  36                                          int offset,
  37                                          int type)
  38 {
  39         struct platform_device *pdev;
  40         struct resource r[4];
  41         unsigned int num_r = 1, size;
  42         struct property_entry p[5];
  43         unsigned int pidx = 0;
  44         char *name, *override;
  45         int rv;
  46         enum si_type si_type;
  47         struct ipmi_dmi_info *info;
  48
  49         memset(p, 0, sizeof(p));
  50
  51         name = "dmi-ipmi-si";
  52         override = "ipmi_si";
  53         switch (type) {
  54         case IPMI_DMI_TYPE_SSIF:
  55                 name = "dmi-ipmi-ssif";
  56                 override = "ipmi_ssif";
  57                 offset = 1;
  58                 size = 1;
  59                 si_type = SI_TYPE_INVALID;
  60                 break;
  61         case IPMI_DMI_TYPE_BT:
  62                 size = 3;
  63                 si_type = SI_BT;
  64                 break;
  65         case IPMI_DMI_TYPE_KCS:
  66                 size = 2;
  67                 si_type = SI_KCS;
  68                 break;
  69         case IPMI_DMI_TYPE_SMIC:
  70                 size = 2;
  71                 si_type = SI_SMIC;
  72                 break;
  73         default:
  74                 pr_err("ipmi:dmi: Invalid IPMI type: %d\n", type);
  75                 return;
  76         }
  77
  78         if (si_type != SI_TYPE_INVALID)
  79                 p[pidx++] = PROPERTY_ENTRY_U8("ipmi-type", si_type);
  80
  81         p[pidx++] = PROPERTY_ENTRY_U8("slave-addr", slave_addr);
  82         p[pidx++] = PROPERTY_ENTRY_U8("addr-source", SI_SMBIOS);
  83
  84         info = kmalloc(sizeof(*info), GFP_KERNEL);
  85         if (!info) {
  86                 pr_warn("ipmi:dmi: Could not allocate dmi info\n");
  87         } else {
  88                 info->si_type = si_type;
  89                 info->flags = flags;
  90                 info->addr = base_addr;
  91                 info->slave_addr = slave_addr;
  92                 info->next = ipmi_dmi_infos;
  93                 ipmi_dmi_infos = info;
  94         }
  95
  96         pdev = platform_device_alloc(name, ipmi_dmi_nr);
  97         if (!pdev) {
  98                 pr_err("ipmi:dmi: Error allocation IPMI platform device\n");
  99                 return;
 100         }
 101         pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
 102                                           override);
 103         if (!pdev->driver_override)
 104                 goto err;
 105
 106         if (type == IPMI_DMI_TYPE_SSIF) {
 107                 p[pidx++] = PROPERTY_ENTRY_U16("i2c-addr", base_addr);
 108                 goto add_properties;
 109         }
 110
 111         memset(r, 0, sizeof(r));
 112
 113         r[0].start = base_addr;
 114         r[0].end = r[0].start + offset - 1;
 115         r[0].name = "IPMI Address 1";
 116         r[0].flags = flags;
 117
 118         if (size > 1) {
 119                 r[1].start = r[0].start + offset;
 120                 r[1].end = r[1].start + offset - 1;
 121                 r[1].name = "IPMI Address 2";
 122                 r[1].flags = flags;
 123                 num_r++;
 124         }
 125
 126         if (size > 2) {
 127                 r[2].start = r[1].start + offset;
 128                 r[2].end = r[2].start + offset - 1;
 129                 r[2].name = "IPMI Address 3";
 130                 r[2].flags = flags;
 131                 num_r++;
 132         }
 133
 134         if (irq) {
 135                 r[num_r].start = irq;
 136                 r[num_r].end = irq;
 137                 r[num_r].name = "IPMI IRQ";
 138                 r[num_r].flags = IORESOURCE_IRQ;
 139                 num_r++;
 140         }
 141
 142         rv = platform_device_add_resources(pdev, r, num_r);
 143         if (rv) {
 144                 dev_err(&pdev->dev,
 145                         "ipmi:dmi: Unable to add resources: %d\n", rv);
 146                 goto err;
 147         }
 148
 149 add_properties:
 150         rv = platform_device_add_properties(pdev, p);
 151         if (rv) {
 152                 dev_err(&pdev->dev,
 153                         "ipmi:dmi: Unable to add properties: %d\n", rv);
 154                 goto err;
 155         }
 156
 157         rv = platform_device_add(pdev);
 158         if (rv) {
 159                 dev_err(&pdev->dev, "ipmi:dmi: Unable to add device: %d\n", rv);
 160                 goto err;
 161         }
 162
 163         ipmi_dmi_nr++;
 164         return;
 165
 166 err:
 167         platform_device_put(pdev);
 168 }
 169
 170 /*
 171  * Look up the slave address for a given interface.  This is here
 172  * because ACPI doesn't have a slave address while SMBIOS does, but we
 173  * prefer using ACPI so the ACPI code can use the IPMI namespace.
 174  * This function allows an ACPI-specified IPMI device to look up the
 175  * slave address from the DMI table.
 176  */
 177 int ipmi_dmi_get_slave_addr(enum si_type si_type, u32 flags,
 178                             unsigned long base_addr)
 179 {
 180         struct ipmi_dmi_info *info = ipmi_dmi_infos;
 181
 182         while (info) {
 183                 if (info->si_type == si_type &&
 184                     info->flags == flags &&
 185                     info->addr == base_addr)
 186                         return info->slave_addr;
 187                 info = info->next;
 188         }
 189
 190         return 0;
 191 }
 192 EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
 193
 194 #define DMI_IPMI_MIN_LENGTH     0x10
 195 #define DMI_IPMI_VER2_LENGTH    0x12
 196 #define DMI_IPMI_TYPE           4
 197 #define DMI_IPMI_SLAVEADDR      6
 198 #define DMI_IPMI_ADDR           8
 199 #define DMI_IPMI_ACCESS         0x10
 200 #define DMI_IPMI_IRQ            0x11
 201 #define DMI_IPMI_IO_MASK        0xfffe
 202
 203 static void __init dmi_decode_ipmi(const struct dmi_header *dm)
 204 {
 205         const u8        *data = (const u8 *) dm;
 206         u32             flags = IORESOURCE_IO;
 207         unsigned long   base_addr;
 208         u8              len = dm->length;
 209         u8              slave_addr;
 210         int             irq = 0, offset;
 211         int             type;
 212
 213         if (len < DMI_IPMI_MIN_LENGTH)
 214                 return;
 215
 216         type = data[DMI_IPMI_TYPE];
 217         slave_addr = data[DMI_IPMI_SLAVEADDR];
 218
 219         memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
 220         if (len >= DMI_IPMI_VER2_LENGTH) {
 221                 if (type == IPMI_DMI_TYPE_SSIF) {
 222                         offset = 0;
 223                         flags = 0;
 224                         base_addr = data[DMI_IPMI_ADDR] >> 1;
 225                         if (base_addr == 0) {
 226                                 /*
 227                                  * Some broken systems put the I2C address in
 228                                  * the slave address field.  We try to
 229                                  * accommodate them here.
 230                                  */
 231                                 base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
 232                                 slave_addr = 0;
 233                         }
 234                 } else {
 235                         if (base_addr & 1) {
 236                                 /* I/O */
 237                                 base_addr &= DMI_IPMI_IO_MASK;
 238                         } else {
 239                                 /* Memory */
 240                                 flags = IORESOURCE_MEM;
 241                         }
 242
 243                         /*
 244                          * If bit 4 of byte 0x10 is set, then the lsb
 245                          * for the address is odd.
 246                          */
 247                         base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
 248
 249                         irq = data[DMI_IPMI_IRQ];
 250
 251                         /*
 252                          * The top two bits of byte 0x10 hold the
 253                          * register spacing.
 254                          */
 255                         switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
 256                         case 0: /* Byte boundaries */
 257                                 offset = 1;
 258                                 break;
 259                         case 1: /* 32-bit boundaries */
 260                                 offset = 4;
 261                                 break;
 262                         case 2: /* 16-byte boundaries */
 263                                 offset = 16;
 264                                 break;
 265                         default:
 266                                 pr_err("ipmi:dmi: Invalid offset: 0\n");
 267                                 return;
 268                         }
 269                 }
 270         } else {
 271                 /* Old DMI spec. */
 272                 /*
 273                  * Note that technically, the lower bit of the base
 274                  * address should be 1 if the address is I/O and 0 if
 275                  * the address is in memory.  So many systems get that
 276                  * wrong (and all that I have seen are I/O) so we just
 277                  * ignore that bit and assume I/O.  Systems that use
 278                  * memory should use the newer spec, anyway.
 279                  */
 280                 base_addr = base_addr & DMI_IPMI_IO_MASK;
 281                 offset = 1;
 282         }
 283
 284         dmi_add_platform_ipmi(base_addr, flags, slave_addr, irq,
 285                               offset, type);
 286 }
 287
 288 static int __init scan_for_dmi_ipmi(void)
 289 {
 290         const struct dmi_device *dev = NULL;
 291
 292         while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
 293                 dmi_decode_ipmi((const struct dmi_header *) dev->device_data);
 294
 295         return 0;
 296 }
 297 subsys_initcall(scan_for_dmi_ipmi);