char/ipmi/ipmi_dmi.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * A hack to create a platform device from a DMI entry.  This will
0004  * allow autoloading of the IPMI drive based on SMBIOS entries.
0005  */
0006
0007 #define pr_fmt(fmt) "%s" fmt, "ipmi:dmi: "
0008 #define dev_fmt pr_fmt
0009
0010 #include <linux/ipmi.h>
0011 #include <linux/init.h>
0012 #include <linux/dmi.h>
0013 #include <linux/platform_device.h>
0014 #include <linux/property.h>
0015 #include "ipmi_dmi.h"
0016 #include "ipmi_plat_data.h"
0017
0018 #define IPMI_DMI_TYPE_KCS   0x01
0019 #define IPMI_DMI_TYPE_SMIC  0x02
0020 #define IPMI_DMI_TYPE_BT    0x03
0021 #define IPMI_DMI_TYPE_SSIF  0x04
0022
0023 struct ipmi_dmi_info {
0024     enum si_type si_type;
0025     unsigned int space; /* addr space for si, intf# for ssif */
0026     unsigned long addr;
0027     u8 slave_addr;
0028     struct ipmi_dmi_info *next;
0029 };
0030
0031 static struct ipmi_dmi_info *ipmi_dmi_infos;
0032
0033 static int ipmi_dmi_nr __initdata;
0034
0035 static void __init dmi_add_platform_ipmi(unsigned long base_addr,
0036                      unsigned int space,
0037                      u8 slave_addr,
0038                      int irq,
0039                      int offset,
0040                      int type)
0041 {
0042     const char *name;
0043     struct ipmi_dmi_info *info;
0044     struct ipmi_plat_data p;
0045
0046     memset(&p, 0, sizeof(p));
0047
0048     name = "dmi-ipmi-si";
0049     p.iftype = IPMI_PLAT_IF_SI;
0050     switch (type) {
0051     case IPMI_DMI_TYPE_SSIF:
0052         name = "dmi-ipmi-ssif";
0053         p.iftype = IPMI_PLAT_IF_SSIF;
0054         p.type = SI_TYPE_INVALID;
0055         break;
0056     case IPMI_DMI_TYPE_BT:
0057         p.type = SI_BT;
0058         break;
0059     case IPMI_DMI_TYPE_KCS:
0060         p.type = SI_KCS;
0061         break;
0062     case IPMI_DMI_TYPE_SMIC:
0063         p.type = SI_SMIC;
0064         break;
0065     default:
0066         pr_err("Invalid IPMI type: %d\n", type);
0067         return;
0068     }
0069
0070     p.addr = base_addr;
0071     p.space = space;
0072     p.regspacing = offset;
0073     p.irq = irq;
0074     p.slave_addr = slave_addr;
0075     p.addr_source = SI_SMBIOS;
0076
0077     info = kmalloc(sizeof(*info), GFP_KERNEL);
0078     if (!info) {
0079         pr_warn("Could not allocate dmi info\n");
0080     } else {
0081         info->si_type = p.type;
0082         info->space = space;
0083         info->addr = base_addr;
0084         info->slave_addr = slave_addr;
0085         info->next = ipmi_dmi_infos;
0086         ipmi_dmi_infos = info;
0087     }
0088
0089     if (ipmi_platform_add(name, ipmi_dmi_nr, &p))
0090         ipmi_dmi_nr++;
0091 }
0092
0093 /*
0094  * Look up the slave address for a given interface.  This is here
0095  * because ACPI doesn't have a slave address while SMBIOS does, but we
0096  * prefer using ACPI so the ACPI code can use the IPMI namespace.
0097  * This function allows an ACPI-specified IPMI device to look up the
0098  * slave address from the DMI table.
0099  */
0100 int ipmi_dmi_get_slave_addr(enum si_type si_type, unsigned int space,
0101                 unsigned long base_addr)
0102 {
0103     struct ipmi_dmi_info *info = ipmi_dmi_infos;
0104
0105     while (info) {
0106         if (info->si_type == si_type &&
0107             info->space == space &&
0108             info->addr == base_addr)
0109             return info->slave_addr;
0110         info = info->next;
0111     }
0112
0113     return 0;
0114 }
0115 EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
0116
0117 #define DMI_IPMI_MIN_LENGTH 0x10
0118 #define DMI_IPMI_VER2_LENGTH    0x12
0119 #define DMI_IPMI_TYPE       4
0120 #define DMI_IPMI_SLAVEADDR  6
0121 #define DMI_IPMI_ADDR       8
0122 #define DMI_IPMI_ACCESS     0x10
0123 #define DMI_IPMI_IRQ        0x11
0124 #define DMI_IPMI_IO_MASK    0xfffe
0125
0126 static void __init dmi_decode_ipmi(const struct dmi_header *dm)
0127 {
0128     const u8 *data = (const u8 *) dm;
0129     int space = IPMI_IO_ADDR_SPACE;
0130     unsigned long base_addr;
0131     u8 len = dm->length;
0132     u8 slave_addr;
0133     int irq = 0, offset = 0;
0134     int type;
0135
0136     if (len < DMI_IPMI_MIN_LENGTH)
0137         return;
0138
0139     type = data[DMI_IPMI_TYPE];
0140     slave_addr = data[DMI_IPMI_SLAVEADDR];
0141
0142     memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
0143     if (!base_addr) {
0144         pr_err("Base address is zero, assuming no IPMI interface\n");
0145         return;
0146     }
0147     if (len >= DMI_IPMI_VER2_LENGTH) {
0148         if (type == IPMI_DMI_TYPE_SSIF) {
0149             space = 0; /* Match I2C interface 0. */
0150             base_addr = data[DMI_IPMI_ADDR] >> 1;
0151             if (base_addr == 0) {
0152                 /*
0153                  * Some broken systems put the I2C address in
0154                  * the slave address field.  We try to
0155                  * accommodate them here.
0156                  */
0157                 base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
0158                 slave_addr = 0;
0159             }
0160         } else {
0161             if (base_addr & 1) {
0162                 /* I/O */
0163                 base_addr &= DMI_IPMI_IO_MASK;
0164             } else {
0165                 /* Memory */
0166                 space = IPMI_MEM_ADDR_SPACE;
0167             }
0168
0169             /*
0170              * If bit 4 of byte 0x10 is set, then the lsb
0171              * for the address is odd.
0172              */
0173             base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
0174
0175             irq = data[DMI_IPMI_IRQ];
0176
0177             /*
0178              * The top two bits of byte 0x10 hold the
0179              * register spacing.
0180              */
0181             switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
0182             case 0: /* Byte boundaries */
0183                 offset = 1;
0184                 break;
0185             case 1: /* 32-bit boundaries */
0186                 offset = 4;
0187                 break;
0188             case 2: /* 16-byte boundaries */
0189                 offset = 16;
0190                 break;
0191             default:
0192                 pr_err("Invalid offset: 0\n");
0193                 return;
0194             }
0195         }
0196     } else {
0197         /* Old DMI spec. */
0198         /*
0199          * Note that technically, the lower bit of the base
0200          * address should be 1 if the address is I/O and 0 if
0201          * the address is in memory.  So many systems get that
0202          * wrong (and all that I have seen are I/O) so we just
0203          * ignore that bit and assume I/O.  Systems that use
0204          * memory should use the newer spec, anyway.
0205          */
0206         base_addr = base_addr & DMI_IPMI_IO_MASK;
0207         offset = 1;
0208     }
0209
0210     dmi_add_platform_ipmi(base_addr, space, slave_addr, irq,
0211                   offset, type);
0212 }
0213
0214 static int __init scan_for_dmi_ipmi(void)
0215 {
0216     const struct dmi_device *dev = NULL;
0217
0218     while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
0219         dmi_decode_ipmi((const struct dmi_header *) dev->device_data);
0220
0221     return 0;
0222 }
0223 subsys_initcall(scan_for_dmi_ipmi);