ipmi_dmi.c
// SPDX-License-Identifier: GPL-2.0+
/*
* A hack to create a platform device from a DMI entry. This will
* allow autoloading of the IPMI drive based on SMBIOS entries.
*/
#define pr_fmt(fmt) "%s" fmt, "ipmi:dmi: "
#define dev_fmt pr_fmt
#include <linux/ipmi.h>
#include <linux/init.h>
#include <linux/dmi.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include "ipmi_dmi.h"
#include "ipmi_plat_data.h"
#define IPMI_DMI_TYPE_KCS 0x01
#define IPMI_DMI_TYPE_SMIC 0x02
#define IPMI_DMI_TYPE_BT 0x03
#define IPMI_DMI_TYPE_SSIF 0x04
struct ipmi_dmi_info {
enum si_type si_type;
unsigned int space; /* addr space for si, intf# for ssif */
unsigned long addr;
u8 slave_addr;
struct ipmi_dmi_info *next;
};
static struct ipmi_dmi_info *ipmi_dmi_infos;
static int ipmi_dmi_nr __initdata;
static void __init dmi_add_platform_ipmi(unsigned long base_addr,
unsigned int space,
u8 slave_addr,
int irq,
int offset,
int type)
{
const char *name;
struct ipmi_dmi_info *info;
struct ipmi_plat_data p;
memset(&p, 0, sizeof(p));
name = "dmi-ipmi-si";
p.iftype = IPMI_PLAT_IF_SI;
switch (type) {
case IPMI_DMI_TYPE_SSIF:
name = "dmi-ipmi-ssif";
p.iftype = IPMI_PLAT_IF_SSIF;
p.type = SI_TYPE_INVALID;
break;
case IPMI_DMI_TYPE_BT:
p.type = SI_BT;
break;
case IPMI_DMI_TYPE_KCS:
p.type = SI_KCS;
break;
case IPMI_DMI_TYPE_SMIC:
p.type = SI_SMIC;
break;
default:
pr_err("Invalid IPMI type: %d\n", type);
return;
}
p.addr = base_addr;
p.space = space;
p.regspacing = offset;
p.irq = irq;
p.slave_addr = slave_addr;
p.addr_source = SI_SMBIOS;
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
pr_warn("Could not allocate dmi info\n");
} else {
info->si_type = p.type;
info->space = space;
info->addr = base_addr;
info->slave_addr = slave_addr;
info->next = ipmi_dmi_infos;
ipmi_dmi_infos = info;
}
if (ipmi_platform_add(name, ipmi_dmi_nr, &p))
ipmi_dmi_nr++;
}
/*
* Look up the slave address for a given interface. This is here
* because ACPI doesn't have a slave address while SMBIOS does, but we
* prefer using ACPI so the ACPI code can use the IPMI namespace.
* This function allows an ACPI-specified IPMI device to look up the
* slave address from the DMI table.
*/
int ipmi_dmi_get_slave_addr(enum si_type si_type, unsigned int space,
unsigned long base_addr)
{
struct ipmi_dmi_info *info = ipmi_dmi_infos;
while (info) {
if (info->si_type == si_type &&
info->space == space &&
info->addr == base_addr)
return info->slave_addr;
info = info->next;
}
return 0;
}
EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
#define DMI_IPMI_MIN_LENGTH 0x10
#define DMI_IPMI_VER2_LENGTH 0x12
#define DMI_IPMI_TYPE 4
#define DMI_IPMI_SLAVEADDR 6
#define DMI_IPMI_ADDR 8
#define DMI_IPMI_ACCESS 0x10
#define DMI_IPMI_IRQ 0x11
#define DMI_IPMI_IO_MASK 0xfffe
static void __init dmi_decode_ipmi(const struct dmi_header *dm)
{
const u8 *data = (const u8 *) dm;
int space = IPMI_IO_ADDR_SPACE;
unsigned long base_addr;
u8 len = dm->length;
u8 slave_addr;
int irq = 0, offset = 0;
int type;
if (len < DMI_IPMI_MIN_LENGTH)
return;
type = data[DMI_IPMI_TYPE];
slave_addr = data[DMI_IPMI_SLAVEADDR];
memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
if (!base_addr) {
pr_err("Base address is zero, assuming no IPMI interface\n");
return;
}
if (len >= DMI_IPMI_VER2_LENGTH) {
if (type == IPMI_DMI_TYPE_SSIF) {
space = 0; /* Match I2C interface 0. */
base_addr = data[DMI_IPMI_ADDR] >> 1;
if (base_addr == 0) {
/*
* Some broken systems put the I2C address in
* the slave address field. We try to
* accommodate them here.
*/
base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
slave_addr = 0;
}
} else {
if (base_addr & 1) {
/* I/O */
base_addr &= DMI_IPMI_IO_MASK;
} else {
/* Memory */
space = IPMI_MEM_ADDR_SPACE;
}
/*
* If bit 4 of byte 0x10 is set, then the lsb
* for the address is odd.
*/
base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
irq = data[DMI_IPMI_IRQ];
/*
* The top two bits of byte 0x10 hold the
* register spacing.
*/
switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
case 0: /* Byte boundaries */
offset = 1;
break;
case 1: /* 32-bit boundaries */
offset = 4;
break;
case 2: /* 16-byte boundaries */
offset = 16;
break;
default:
pr_err("Invalid offset: 0\n");
return;
}
}
} else {
/* Old DMI spec. */
/*
* Note that technically, the lower bit of the base
* address should be 1 if the address is I/O and 0 if
* the address is in memory. So many systems get that
* wrong (and all that I have seen are I/O) so we just
* ignore that bit and assume I/O. Systems that use
* memory should use the newer spec, anyway.
*/
base_addr = base_addr & DMI_IPMI_IO_MASK;
offset = 1;
}
dmi_add_platform_ipmi(base_addr, space, slave_addr, irq,
offset, type);
}
static int __init scan_for_dmi_ipmi(void)
{
const struct dmi_device *dev = NULL;
while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
dmi_decode_ipmi((const struct dmi_header *) dev->device_data);
return 0;
}
subsys_initcall(scan_for_dmi_ipmi);