mirror_ubuntu-kernels/arch/x86/kernel/amd_nb.c

544 lines
16 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Shared support code for AMD K8 northbridges and derivatives.
* Copyright 2006 Andi Kleen, SUSE Labs.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/pci_ids.h>
#include <asm/amd_nb.h>
#define PCI_DEVICE_ID_AMD_17H_ROOT 0x1450
#define PCI_DEVICE_ID_AMD_17H_M10H_ROOT 0x15d0
#define PCI_DEVICE_ID_AMD_17H_M30H_ROOT 0x1480
#define PCI_DEVICE_ID_AMD_17H_M60H_ROOT 0x1630
#define PCI_DEVICE_ID_AMD_17H_MA0H_ROOT 0x14b5
#define PCI_DEVICE_ID_AMD_19H_M10H_ROOT 0x14a4
#define PCI_DEVICE_ID_AMD_19H_M40H_ROOT 0x14b5
#define PCI_DEVICE_ID_AMD_19H_M60H_ROOT 0x14d8
#define PCI_DEVICE_ID_AMD_19H_M70H_ROOT 0x14e8
#define PCI_DEVICE_ID_AMD_1AH_M00H_ROOT 0x153a
#define PCI_DEVICE_ID_AMD_1AH_M20H_ROOT 0x1507
#define PCI_DEVICE_ID_AMD_MI200_ROOT 0x14bb
#define PCI_DEVICE_ID_AMD_MI300_ROOT 0x14f8
#define PCI_DEVICE_ID_AMD_17H_DF_F4 0x1464
#define PCI_DEVICE_ID_AMD_17H_M10H_DF_F4 0x15ec
#define PCI_DEVICE_ID_AMD_17H_M30H_DF_F4 0x1494
#define PCI_DEVICE_ID_AMD_17H_M60H_DF_F4 0x144c
#define PCI_DEVICE_ID_AMD_17H_M70H_DF_F4 0x1444
#define PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4 0x1728
#define PCI_DEVICE_ID_AMD_19H_DF_F4 0x1654
#define PCI_DEVICE_ID_AMD_19H_M10H_DF_F4 0x14b1
#define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4 0x167d
#define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4 0x166e
#define PCI_DEVICE_ID_AMD_19H_M60H_DF_F4 0x14e4
#define PCI_DEVICE_ID_AMD_19H_M70H_DF_F4 0x14f4
#define PCI_DEVICE_ID_AMD_19H_M78H_DF_F4 0x12fc
#define PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4 0x12c4
#define PCI_DEVICE_ID_AMD_MI200_DF_F4 0x14d4
#define PCI_DEVICE_ID_AMD_MI300_DF_F4 0x152c
/* Protect the PCI config register pairs used for SMN. */
static DEFINE_MUTEX(smn_mutex);
static u32 *flush_words;
static const struct pci_device_id amd_root_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_ROOT) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_ROOT) },
{}
};
#define PCI_DEVICE_ID_AMD_CNB17H_F4 0x1704
static const struct pci_device_id amd_nb_misc_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M10H_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F3) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F3) },
{}
};
static const struct pci_device_id amd_nb_link_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F4) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F4) },
{}
};
static const struct pci_device_id hygon_root_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_ROOT) },
{}
};
static const struct pci_device_id hygon_nb_misc_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) },
{}
};
static const struct pci_device_id hygon_nb_link_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F4) },
{}
};
const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[] __initconst = {
{ 0x00, 0x18, 0x20 },
{ 0xff, 0x00, 0x20 },
{ 0xfe, 0x00, 0x20 },
{ }
};
static struct amd_northbridge_info amd_northbridges;
u16 amd_nb_num(void)
{
return amd_northbridges.num;
}
EXPORT_SYMBOL_GPL(amd_nb_num);
bool amd_nb_has_feature(unsigned int feature)
{
return ((amd_northbridges.flags & feature) == feature);
}
EXPORT_SYMBOL_GPL(amd_nb_has_feature);
struct amd_northbridge *node_to_amd_nb(int node)
{
return (node < amd_northbridges.num) ? &amd_northbridges.nb[node] : NULL;
}
EXPORT_SYMBOL_GPL(node_to_amd_nb);
static struct pci_dev *next_northbridge(struct pci_dev *dev,
const struct pci_device_id *ids)
{
do {
dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
if (!dev)
break;
} while (!pci_match_id(ids, dev));
return dev;
}
static int __amd_smn_rw(u16 node, u32 address, u32 *value, bool write)
{
struct pci_dev *root;
int err = -ENODEV;
if (node >= amd_northbridges.num)
goto out;
root = node_to_amd_nb(node)->root;
if (!root)
goto out;
mutex_lock(&smn_mutex);
err = pci_write_config_dword(root, 0x60, address);
if (err) {
pr_warn("Error programming SMN address 0x%x.\n", address);
goto out_unlock;
}
err = (write ? pci_write_config_dword(root, 0x64, *value)
: pci_read_config_dword(root, 0x64, value));
if (err)
pr_warn("Error %s SMN address 0x%x.\n",
(write ? "writing to" : "reading from"), address);
out_unlock:
mutex_unlock(&smn_mutex);
out:
return err;
}
int amd_smn_read(u16 node, u32 address, u32 *value)
{
return __amd_smn_rw(node, address, value, false);
}
EXPORT_SYMBOL_GPL(amd_smn_read);
int amd_smn_write(u16 node, u32 address, u32 value)
{
return __amd_smn_rw(node, address, &value, true);
}
EXPORT_SYMBOL_GPL(amd_smn_write);
static int amd_cache_northbridges(void)
{
const struct pci_device_id *misc_ids = amd_nb_misc_ids;
const struct pci_device_id *link_ids = amd_nb_link_ids;
const struct pci_device_id *root_ids = amd_root_ids;
struct pci_dev *root, *misc, *link;
struct amd_northbridge *nb;
u16 roots_per_misc = 0;
u16 misc_count = 0;
u16 root_count = 0;
u16 i, j;
if (amd_northbridges.num)
return 0;
if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
root_ids = hygon_root_ids;
misc_ids = hygon_nb_misc_ids;
link_ids = hygon_nb_link_ids;
}
misc = NULL;
while ((misc = next_northbridge(misc, misc_ids)))
misc_count++;
if (!misc_count)
return -ENODEV;
root = NULL;
while ((root = next_northbridge(root, root_ids)))
root_count++;
if (root_count) {
roots_per_misc = root_count / misc_count;
/*
* There should be _exactly_ N roots for each DF/SMN
* interface.
*/
if (!roots_per_misc || (root_count % roots_per_misc)) {
pr_info("Unsupported AMD DF/PCI configuration found\n");
return -ENODEV;
}
}
nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
if (!nb)
return -ENOMEM;
amd_northbridges.nb = nb;
amd_northbridges.num = misc_count;
link = misc = root = NULL;
for (i = 0; i < amd_northbridges.num; i++) {
node_to_amd_nb(i)->root = root =
next_northbridge(root, root_ids);
node_to_amd_nb(i)->misc = misc =
next_northbridge(misc, misc_ids);
node_to_amd_nb(i)->link = link =
next_northbridge(link, link_ids);
/*
* If there are more PCI root devices than data fabric/
* system management network interfaces, then the (N)
* PCI roots per DF/SMN interface are functionally the
* same (for DF/SMN access) and N-1 are redundant. N-1
* PCI roots should be skipped per DF/SMN interface so
* the following DF/SMN interfaces get mapped to
* correct PCI roots.
*/
for (j = 1; j < roots_per_misc; j++)
root = next_northbridge(root, root_ids);
}
if (amd_gart_present())
amd_northbridges.flags |= AMD_NB_GART;
/*
* Check for L3 cache presence.
*/
if (!cpuid_edx(0x80000006))
return 0;
/*
* Some CPU families support L3 Cache Index Disable. There are some
* limitations because of E382 and E388 on family 0x10.
*/
if (boot_cpu_data.x86 == 0x10 &&
boot_cpu_data.x86_model >= 0x8 &&
(boot_cpu_data.x86_model > 0x9 ||
boot_cpu_data.x86_stepping >= 0x1))
amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
if (boot_cpu_data.x86 == 0x15)
amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
/* L3 cache partitioning is supported on family 0x15 */
if (boot_cpu_data.x86 == 0x15)
amd_northbridges.flags |= AMD_NB_L3_PARTITIONING;
return 0;
}
/*
* Ignores subdevice/subvendor but as far as I can figure out
* they're useless anyways
*/
bool __init early_is_amd_nb(u32 device)
{
const struct pci_device_id *misc_ids = amd_nb_misc_ids;
const struct pci_device_id *id;
u32 vendor = device & 0xffff;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
return false;
if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
misc_ids = hygon_nb_misc_ids;
device >>= 16;
for (id = misc_ids; id->vendor; id++)
if (vendor == id->vendor && device == id->device)
return true;
return false;
}
struct resource *amd_get_mmconfig_range(struct resource *res)
{
u32 address;
u64 base, msr;
unsigned int segn_busn_bits;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
return NULL;
/* assume all cpus from fam10h have mmconfig */
if (boot_cpu_data.x86 < 0x10)
return NULL;
address = MSR_FAM10H_MMIO_CONF_BASE;
rdmsrl(address, msr);
/* mmconfig is not enabled */
if (!(msr & FAM10H_MMIO_CONF_ENABLE))
return NULL;
base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
segn_busn_bits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
FAM10H_MMIO_CONF_BUSRANGE_MASK;
res->flags = IORESOURCE_MEM;
res->start = base;
res->end = base + (1ULL<<(segn_busn_bits + 20)) - 1;
return res;
}
int amd_get_subcaches(int cpu)
{
struct pci_dev *link = node_to_amd_nb(topology_die_id(cpu))->link;
unsigned int mask;
if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
return 0;
pci_read_config_dword(link, 0x1d4, &mask);
return (mask >> (4 * cpu_data(cpu).topo.core_id)) & 0xf;
}
int amd_set_subcaches(int cpu, unsigned long mask)
{
static unsigned int reset, ban;
struct amd_northbridge *nb = node_to_amd_nb(topology_die_id(cpu));
unsigned int reg;
int cuid;
if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING) || mask > 0xf)
return -EINVAL;
/* if necessary, collect reset state of L3 partitioning and BAN mode */
if (reset == 0) {
pci_read_config_dword(nb->link, 0x1d4, &reset);
pci_read_config_dword(nb->misc, 0x1b8, &ban);
ban &= 0x180000;
}
/* deactivate BAN mode if any subcaches are to be disabled */
if (mask != 0xf) {
pci_read_config_dword(nb->misc, 0x1b8, &reg);
pci_write_config_dword(nb->misc, 0x1b8, reg & ~0x180000);
}
cuid = cpu_data(cpu).topo.core_id;
mask <<= 4 * cuid;
mask |= (0xf ^ (1 << cuid)) << 26;
pci_write_config_dword(nb->link, 0x1d4, mask);
/* reset BAN mode if L3 partitioning returned to reset state */
pci_read_config_dword(nb->link, 0x1d4, &reg);
if (reg == reset) {
pci_read_config_dword(nb->misc, 0x1b8, &reg);
reg &= ~0x180000;
pci_write_config_dword(nb->misc, 0x1b8, reg | ban);
}
return 0;
}
static void amd_cache_gart(void)
{
u16 i;
if (!amd_nb_has_feature(AMD_NB_GART))
return;
flush_words = kmalloc_array(amd_northbridges.num, sizeof(u32), GFP_KERNEL);
if (!flush_words) {
amd_northbridges.flags &= ~AMD_NB_GART;
pr_notice("Cannot initialize GART flush words, GART support disabled\n");
return;
}
for (i = 0; i != amd_northbridges.num; i++)
pci_read_config_dword(node_to_amd_nb(i)->misc, 0x9c, &flush_words[i]);
}
void amd_flush_garts(void)
{
int flushed, i;
unsigned long flags;
static DEFINE_SPINLOCK(gart_lock);
if (!amd_nb_has_feature(AMD_NB_GART))
return;
/*
* Avoid races between AGP and IOMMU. In theory it's not needed
* but I'm not sure if the hardware won't lose flush requests
* when another is pending. This whole thing is so expensive anyways
* that it doesn't matter to serialize more. -AK
*/
spin_lock_irqsave(&gart_lock, flags);
flushed = 0;
for (i = 0; i < amd_northbridges.num; i++) {
pci_write_config_dword(node_to_amd_nb(i)->misc, 0x9c,
flush_words[i] | 1);
flushed++;
}
for (i = 0; i < amd_northbridges.num; i++) {
u32 w;
/* Make sure the hardware actually executed the flush*/
for (;;) {
pci_read_config_dword(node_to_amd_nb(i)->misc,
0x9c, &w);
if (!(w & 1))
break;
cpu_relax();
}
}
spin_unlock_irqrestore(&gart_lock, flags);
if (!flushed)
pr_notice("nothing to flush?\n");
}
EXPORT_SYMBOL_GPL(amd_flush_garts);
static void __fix_erratum_688(void *info)
{
#define MSR_AMD64_IC_CFG 0xC0011021
msr_set_bit(MSR_AMD64_IC_CFG, 3);
msr_set_bit(MSR_AMD64_IC_CFG, 14);
}
/* Apply erratum 688 fix so machines without a BIOS fix work. */
static __init void fix_erratum_688(void)
{
struct pci_dev *F4;
u32 val;
if (boot_cpu_data.x86 != 0x14)
return;
if (!amd_northbridges.num)
return;
F4 = node_to_amd_nb(0)->link;
if (!F4)
return;
if (pci_read_config_dword(F4, 0x164, &val))
return;
if (val & BIT(2))
return;
on_each_cpu(__fix_erratum_688, NULL, 0);
pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");
}
static __init int init_amd_nbs(void)
{
amd_cache_northbridges();
amd_cache_gart();
fix_erratum_688();
return 0;
}
/* This has to go after the PCI subsystem */
fs_initcall(init_amd_nbs);