blob: c09762aee6c96b9764843f06a84f6a6f87cad2d7 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2015 Google, Inc
*
* Based on code from the coreboot file of the same name
*/
#include <common.h>
#include <cpu.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <qfw.h>
#include <asm/atomic.h>
#include <asm/cpu.h>
#include <asm/global_data.h>
#include <asm/interrupt.h>
#include <asm/io.h>
#include <asm/lapic.h>
#include <asm/microcode.h>
#include <asm/mp.h>
#include <asm/msr.h>
#include <asm/mtrr.h>
#include <asm/processor.h>
#include <asm/sipi.h>
#include <dm/device-internal.h>
#include <dm/uclass-internal.h>
#include <dm/lists.h>
#include <dm/root.h>
#include <linux/delay.h>
#include <linux/linkage.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* Setting up multiprocessing
*
* See https://www.intel.com/content/www/us/en/intelligent-systems/intel-boot-loader-development-kit/minimal-intel-architecture-boot-loader-paper.html
*
* Note that this file refers to the boot CPU (the one U-Boot is running on) as
* the BSP (BootStrap Processor) and the others as APs (Application Processors).
*
* This module works by loading some setup code into RAM at AP_DEFAULT_BASE and
* telling each AP to execute it. The code that each AP runs is in
* sipi_vector.S (see ap_start16) which includes a struct sipi_params at the
* end of it. Those parameters are set up by the C code.
* Setting up is handled by load_sipi_vector(). It inits the common block of
* parameters (sipi_params) which tell the APs what to do. This block includes
* microcode and the MTTRs (Memory-Type-Range Registers) from the main CPU.
* There is also an ap_count which each AP increments as it starts up, so the
* BSP can tell how many checked in.
*
* The APs are started with a SIPI (Startup Inter-Processor Interrupt) which
* tells an AP to start executing at a particular address, in this case
* AP_DEFAULT_BASE which contains the code copied from ap_start16. This protocol
* is handled by start_aps().
*
* After being started, each AP runs the code in ap_start16, switches to 32-bit
* mode, runs the code at ap_start, then jumps to c_handler which is ap_init().
* This runs a very simple 'flight plan' described in mp_steps(). This sets up
* the CPU and waits for further instructions by looking at its entry in
* ap_callbacks[]. Note that the flight plan is only actually run for each CPU
* in bsp_do_flight_plan(): once the BSP completes each flight record, it sets
* mp_flight_record->barrier to 1 to allow the APs to executed the record one
* by one.
*
* CPUS are numbered sequentially from 0 using the device tree:
*
* cpus {
* u-boot,dm-pre-reloc;
* #address-cells = <1>;
* #size-cells = <0>;
*
* cpu@0 {
* u-boot,dm-pre-reloc;
* device_type = "cpu";
* compatible = "intel,apl-cpu";
* reg = <0>;
* intel,apic-id = <0>;
* };
*
* cpu@1 {
* device_type = "cpu";
* compatible = "intel,apl-cpu";
* reg = <1>;
* intel,apic-id = <2>;
* };
*
* Here the 'reg' property is the CPU number and then is placed in dev_seq(cpu)
* so that we can index into ap_callbacks[] using that. The APIC ID is different
* and may not be sequential (it typically is if hyperthreading is supported).
*
* Once APs are inited they wait in ap_wait_for_instruction() for instructions.
* Instructions come in the form of a function to run. This logic is in
* mp_run_on_cpus() which supports running on any one AP, all APs, just the BSP
* or all CPUs. The BSP logic is handled directly in mp_run_on_cpus(), by
* calling the function. For the APs, callback information is stored in a
* single, common struct mp_callback and a pointer to this is written to each
* AP's slot in ap_callbacks[] by run_ap_work(). All APs get the message even
* if it is only for one of them. When an AP notices a message it checks whether
* it should call the function (see check in ap_wait_for_instruction()) and then
* does so if needed. After that it sets its slot to NULL to indicate it is
* done.
*
* While U-Boot is running it can use mp_run_on_cpus() to run code on the APs.
* An example of this is the 'mtrr' command which allows reading and changing
* the MTRRs on all CPUs.
*
* Before U-Boot exits it calls mp_park_aps() which tells all CPUs to halt by
* executing a 'hlt' instruction. That allows them to be used by Linux when it
* starts up.
*/
/* This also needs to match the sipi.S assembly code for saved MSR encoding */
struct __packed saved_msr {
uint32_t index;
uint32_t lo;
uint32_t hi;
};
/**
* struct mp_flight_plan - Holds the flight plan
*
* @num_records: Number of flight records
* @records: Pointer to each record
*/
struct mp_flight_plan {
int num_records;
struct mp_flight_record *records;
};
/**
* struct mp_callback - Callback information for APs
*
* @func: Function to run
* @arg: Argument to pass to the function
* @logical_cpu_number: Either a CPU number (i.e. dev_seq(cpu) or a special
* value like MP_SELECT_BSP. It tells the AP whether it should process this
* callback
*/
struct mp_callback {
mp_run_func func;
void *arg;
int logical_cpu_number;
};
/* Stores the flight plan so that APs can find it */
static struct mp_flight_plan mp_info;
/*
* ap_callbacks - Callback mailbox array
*
* Array of callback, one entry for each available CPU, indexed by the CPU
* number, which is dev_seq(cpu). The entry for the main CPU is never used.
* When this is NULL, there is no pending work for the CPU to run. When
* non-NULL it points to the mp_callback structure. This is shared between all
* CPUs, so should only be written by the main CPU.
*/
static struct mp_callback **ap_callbacks;
static inline void barrier_wait(atomic_t *b)
{
while (atomic_read(b) == 0)
asm("pause");
mfence();
}
static inline void release_barrier(atomic_t *b)
{
mfence();
atomic_set(b, 1);
}
static inline void stop_this_cpu(void)
{
/* Called by an AP when it is ready to halt and wait for a new task */
for (;;)
cpu_hlt();
}
/* Returns 1 if timeout waiting for APs. 0 if target APs found */
static int wait_for_aps(atomic_t *val, int target, int total_delay,
int delay_step)
{
int timeout = 0;
int delayed = 0;
while (atomic_read(val) != target) {
udelay(delay_step);
delayed += delay_step;
if (delayed >= total_delay) {
timeout = 1;
break;
}
}
return timeout;
}
static void ap_do_flight_plan(struct udevice *cpu)
{
int i;
for (i = 0; i < mp_info.num_records; i++) {
struct mp_flight_record *rec = &mp_info.records[i];
atomic_inc(&rec->cpus_entered);
barrier_wait(&rec->barrier);
if (rec->ap_call != NULL)
rec->ap_call(cpu, rec->ap_arg);
}
}
static int find_cpu_by_apic_id(int apic_id, struct udevice **devp)
{
struct udevice *dev;
*devp = NULL;
for (uclass_find_first_device(UCLASS_CPU, &dev);
dev;
uclass_find_next_device(&dev)) {
struct cpu_plat *plat = dev_get_parent_plat(dev);
if (plat->cpu_id == apic_id) {
*devp = dev;
return 0;
}
}
return -ENOENT;
}
/*
* By the time APs call ap_init() caching has been setup, and microcode has
* been loaded
*/
static void ap_init(unsigned int cpu_index)
{
struct udevice *dev;
int apic_id;
int ret;
/* Ensure the local apic is enabled */
enable_lapic();
apic_id = lapicid();
ret = find_cpu_by_apic_id(apic_id, &dev);
if (ret) {
debug("Unknown CPU apic_id %x\n", apic_id);
goto done;
}
debug("AP: slot %d apic_id %x, dev %s\n", cpu_index, apic_id,
dev ? dev->name : "(apic_id not found)");
/*
* Walk the flight plan, which only returns if CONFIG_SMP_AP_WORK is not
* enabled
*/
ap_do_flight_plan(dev);
done:
stop_this_cpu();
}
static const unsigned int fixed_mtrrs[NUM_FIXED_MTRRS] = {
MTRR_FIX_64K_00000_MSR, MTRR_FIX_16K_80000_MSR, MTRR_FIX_16K_A0000_MSR,
MTRR_FIX_4K_C0000_MSR, MTRR_FIX_4K_C8000_MSR, MTRR_FIX_4K_D0000_MSR,
MTRR_FIX_4K_D8000_MSR, MTRR_FIX_4K_E0000_MSR, MTRR_FIX_4K_E8000_MSR,
MTRR_FIX_4K_F0000_MSR, MTRR_FIX_4K_F8000_MSR,
};
static inline struct saved_msr *save_msr(int index, struct saved_msr *entry)
{
msr_t msr;
msr = msr_read(index);
entry->index = index;
entry->lo = msr.lo;
entry->hi = msr.hi;
/* Return the next entry */
entry++;
return entry;
}
static int save_bsp_msrs(char *start, int size)
{
int msr_count;
int num_var_mtrrs;
struct saved_msr *msr_entry;
int i;
msr_t msr;
/* Determine number of MTRRs need to be saved */
msr = msr_read(MTRR_CAP_MSR);
num_var_mtrrs = msr.lo & 0xff;
/* 2 * num_var_mtrrs for base and mask. +1 for IA32_MTRR_DEF_TYPE */
msr_count = 2 * num_var_mtrrs + NUM_FIXED_MTRRS + 1;
if ((msr_count * sizeof(struct saved_msr)) > size) {
printf("Cannot mirror all %d msrs\n", msr_count);
return -ENOSPC;
}
msr_entry = (void *)start;
for (i = 0; i < NUM_FIXED_MTRRS; i++)
msr_entry = save_msr(fixed_mtrrs[i], msr_entry);
for (i = 0; i < num_var_mtrrs; i++) {
msr_entry = save_msr(MTRR_PHYS_BASE_MSR(i), msr_entry);
msr_entry = save_msr(MTRR_PHYS_MASK_MSR(i), msr_entry);
}
msr_entry = save_msr(MTRR_DEF_TYPE_MSR, msr_entry);
return msr_count;
}
static int load_sipi_vector(atomic_t **ap_countp, int num_cpus)
{
struct sipi_params_16bit *params16;
struct sipi_params *params;
static char msr_save[512];
char *stack;
ulong addr;
int code_len;
int size;
int ret;
/* Copy in the code */
code_len = ap_start16_code_end - ap_start16;
debug("Copying SIPI code to %x: %d bytes\n", AP_DEFAULT_BASE,
code_len);
memcpy((void *)AP_DEFAULT_BASE, ap_start16, code_len);
addr = AP_DEFAULT_BASE + (ulong)sipi_params_16bit - (ulong)ap_start16;
params16 = (struct sipi_params_16bit *)addr;
params16->ap_start = (uint32_t)ap_start;
params16->gdt = (uint32_t)gd->arch.gdt;
params16->gdt_limit = X86_GDT_SIZE - 1;
debug("gdt = %x, gdt_limit = %x\n", params16->gdt, params16->gdt_limit);
params = (struct sipi_params *)sipi_params;
debug("SIPI 32-bit params at %p\n", params);
params->idt_ptr = (uint32_t)x86_get_idt();
params->stack_size = CONFIG_AP_STACK_SIZE;
size = params->stack_size * num_cpus;
stack = memalign(4096, size);
if (!stack)
return -ENOMEM;
params->stack_top = (u32)(stack + size);
#if !defined(CONFIG_QEMU) && !defined(CONFIG_HAVE_FSP) && \
!defined(CONFIG_INTEL_MID)
params->microcode_ptr = ucode_base;
debug("Microcode at %x\n", params->microcode_ptr);
#endif
params->msr_table_ptr = (u32)msr_save;
ret = save_bsp_msrs(msr_save, sizeof(msr_save));
if (ret < 0)
return ret;
params->msr_count = ret;
params->c_handler = (uint32_t)&ap_init;
*ap_countp = &params->ap_count;
atomic_set(*ap_countp, 0);
debug("SIPI vector is ready\n");
return 0;
}
static int check_cpu_devices(int expected_cpus)
{
int i;
for (i = 0; i < expected_cpus; i++) {
struct udevice *dev;
int ret;
ret = uclass_find_device(UCLASS_CPU, i, &dev);
if (ret) {
debug("Cannot find CPU %d in device tree\n", i);
return ret;
}
}
return 0;
}
/* Returns 1 for timeout. 0 on success */
static int apic_wait_timeout(int total_delay, const char *msg)
{
int total = 0;
if (!(lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY))
return 0;
debug("Waiting for %s...", msg);
while (lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY) {
udelay(50);
total += 50;
if (total >= total_delay) {
debug("timed out: aborting\n");
return -ETIMEDOUT;
}
}
debug("done\n");
return 0;
}
/**
* start_aps() - Start up the APs and count how many we find
*
* This is called on the boot processor to start up all the other processors
* (here called APs).
*
* @num_aps: Number of APs we expect to find
* @ap_count: Initially zero. Incremented by this function for each AP found
* @return 0 if all APs were set up correctly or there are none to set up,
* -ENOSPC if the SIPI vector is too high in memory,
* -ETIMEDOUT if the ICR is busy or the second SIPI fails to complete
* -EIO if not all APs check in correctly
*/
static int start_aps(int num_aps, atomic_t *ap_count)
{
int sipi_vector;
/* Max location is 4KiB below 1MiB */
const int max_vector_loc = ((1 << 20) - (1 << 12)) >> 12;
if (num_aps == 0)
return 0;
/* The vector is sent as a 4k aligned address in one byte */
sipi_vector = AP_DEFAULT_BASE >> 12;
if (sipi_vector > max_vector_loc) {
printf("SIPI vector too large! 0x%08x\n",
sipi_vector);
return -ENOSPC;
}
debug("Attempting to start %d APs\n", num_aps);
if (apic_wait_timeout(1000, "ICR not to be busy"))
return -ETIMEDOUT;
/* Send INIT IPI to all but self */
lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
LAPIC_DM_INIT);
debug("Waiting for 10ms after sending INIT\n");
mdelay(10);
/* Send 1st SIPI */
if (apic_wait_timeout(1000, "ICR not to be busy"))
return -ETIMEDOUT;
lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
LAPIC_DM_STARTUP | sipi_vector);
if (apic_wait_timeout(10000, "first SIPI to complete"))
return -ETIMEDOUT;
/* Wait for CPUs to check in up to 200 us */
wait_for_aps(ap_count, num_aps, 200, 15);
/* Send 2nd SIPI */
if (apic_wait_timeout(1000, "ICR not to be busy"))
return -ETIMEDOUT;
lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
LAPIC_DM_STARTUP | sipi_vector);
if (apic_wait_timeout(10000, "second SIPI to complete"))
return -ETIMEDOUT;
/* Wait for CPUs to check in */
if (wait_for_aps(ap_count, num_aps, 10000, 50)) {
debug("Not all APs checked in: %d/%d\n",
atomic_read(ap_count), num_aps);
return -EIO;
}
return 0;
}
/**
* bsp_do_flight_plan() - Do the flight plan on the BSP
*
* This runs the flight plan on the main CPU used to boot U-Boot
*
* @cpu: Device for the main CPU
* @plan: Flight plan to run
* @num_aps: Number of APs (CPUs other than the BSP)
* @returns 0 on success, -ETIMEDOUT if an AP failed to come up
*/
static int bsp_do_flight_plan(struct udevice *cpu, struct mp_flight_plan *plan,
int num_aps)
{
int i;
int ret = 0;
const int timeout_us = 100000;
const int step_us = 100;
for (i = 0; i < plan->num_records; i++) {
struct mp_flight_record *rec = &plan->records[i];
/* Wait for APs if the record is not released */
if (atomic_read(&rec->barrier) == 0) {
/* Wait for the APs to check in */
if (wait_for_aps(&rec->cpus_entered, num_aps,
timeout_us, step_us)) {
debug("MP record %d timeout\n", i);
ret = -ETIMEDOUT;
}
}
if (rec->bsp_call != NULL)
rec->bsp_call(cpu, rec->bsp_arg);
release_barrier(&rec->barrier);
}
return ret;
}
/**
* get_bsp() - Get information about the bootstrap processor
*
* @devp: If non-NULL, returns CPU device corresponding to the BSP
* @cpu_countp: If non-NULL, returns the total number of CPUs
* @return CPU number of the BSP, or -ve on error. If multiprocessing is not
* enabled, returns 0
*/
static int get_bsp(struct udevice **devp, int *cpu_countp)
{
char processor_name[CPU_MAX_NAME_LEN];
struct udevice *dev;
int apic_id;
int ret;
cpu_get_name(processor_name);
debug("CPU: %s\n", processor_name);
apic_id = lapicid();
ret = find_cpu_by_apic_id(apic_id, &dev);
if (ret < 0) {
printf("Cannot find boot CPU, APIC ID %d\n", apic_id);
return ret;
}
ret = cpu_get_count(dev);
if (ret < 0)
return log_msg_ret("count", ret);
if (devp)
*devp = dev;
if (cpu_countp)
*cpu_countp = ret;
return dev_seq(dev) >= 0 ? dev_seq(dev) : 0;
}
/**
* read_callback() - Read the pointer in a callback slot
*
* This is called by APs to read their callback slot to see if there is a
* pointer to new instructions
*
* @slot: Pointer to the AP's callback slot
* @return value of that pointer
*/
static struct mp_callback *read_callback(struct mp_callback **slot)
{
dmb();
return *slot;
}
/**
* store_callback() - Store a pointer to the callback slot
*
* This is called by APs to write NULL into the callback slot when they have
* finished the work requested by the BSP.
*
* @slot: Pointer to the AP's callback slot
* @val: Value to write (e.g. NULL)
*/
static void store_callback(struct mp_callback **slot, struct mp_callback *val)
{
*slot = val;
dmb();
}
/**
* run_ap_work() - Run a callback on selected APs
*
* This writes @callback to all APs and waits for them all to acknowledge it,
* Note that whether each AP actually calls the callback depends on the value
* of logical_cpu_number (see struct mp_callback). The logical CPU number is
* the CPU device's req->seq value.
*
* @callback: Callback information to pass to all APs
* @bsp: CPU device for the BSP
* @num_cpus: The number of CPUs in the system (= number of APs + 1)
* @expire_ms: Timeout to wait for all APs to finish, in milliseconds, or 0 for
* no timeout
* @return 0 if OK, -ETIMEDOUT if one or more APs failed to respond in time
*/
static int run_ap_work(struct mp_callback *callback, struct udevice *bsp,
int num_cpus, uint expire_ms)
{
int cur_cpu = dev_seq(bsp);
int num_aps = num_cpus - 1; /* number of non-BSPs to get this message */
int cpus_accepted;
ulong start;
int i;
if (!IS_ENABLED(CONFIG_SMP_AP_WORK)) {
printf("APs already parked. CONFIG_SMP_AP_WORK not enabled\n");
return -ENOTSUPP;
}
/* Signal to all the APs to run the func. */
for (i = 0; i < num_cpus; i++) {
if (cur_cpu != i)
store_callback(&ap_callbacks[i], callback);
}
mfence();
/* Wait for all the APs to signal back that call has been accepted. */
start = get_timer(0);
do {
mdelay(1);
cpus_accepted = 0;
for (i = 0; i < num_cpus; i++) {
if (cur_cpu == i)
continue;
if (!read_callback(&ap_callbacks[i]))
cpus_accepted++;
}
if (expire_ms && get_timer(start) >= expire_ms) {
log(UCLASS_CPU, LOGL_CRIT,
"AP call expired; %d/%d CPUs accepted\n",
cpus_accepted, num_aps);
return -ETIMEDOUT;
}
} while (cpus_accepted != num_aps);
/* Make sure we can see any data written by the APs */
mfence();
return 0;
}
/**
* ap_wait_for_instruction() - Wait for and process requests from the main CPU
*
* This is called by APs (here, everything other than the main boot CPU) to
* await instructions. They arrive in the form of a function call and argument,
* which is then called. This uses a simple mailbox with atomic read/set
*
* @cpu: CPU that is waiting
* @unused: Optional argument provided by struct mp_flight_record, not used here
* @return Does not return
*/
static int ap_wait_for_instruction(struct udevice *cpu, void *unused)
{
struct mp_callback lcb;
struct mp_callback **per_cpu_slot;
if (!IS_ENABLED(CONFIG_SMP_AP_WORK))
return 0;
per_cpu_slot = &ap_callbacks[dev_seq(cpu)];
while (1) {
struct mp_callback *cb = read_callback(per_cpu_slot);
if (!cb) {
asm ("pause");
continue;
}
/* Copy to local variable before using the value */
memcpy(&lcb, cb, sizeof(lcb));
mfence();
if (lcb.logical_cpu_number == MP_SELECT_ALL ||
lcb.logical_cpu_number == MP_SELECT_APS ||
dev_seq(cpu) == lcb.logical_cpu_number)
lcb.func(lcb.arg);
/* Indicate we are finished */
store_callback(per_cpu_slot, NULL);
}
return 0;
}
static int mp_init_cpu(struct udevice *cpu, void *unused)
{
struct cpu_plat *plat = dev_get_parent_plat(cpu);
plat->ucode_version = microcode_read_rev();
plat->device_id = gd->arch.x86_device;
return device_probe(cpu);
}
static struct mp_flight_record mp_steps[] = {
MP_FR_BLOCK_APS(mp_init_cpu, NULL, mp_init_cpu, NULL),
MP_FR_BLOCK_APS(ap_wait_for_instruction, NULL, NULL, NULL),
};
int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg)
{
struct mp_callback lcb = {
.func = func,
.arg = arg,
.logical_cpu_number = cpu_select,
};
struct udevice *dev;
int num_cpus;
int ret;
ret = get_bsp(&dev, &num_cpus);
if (ret < 0)
return log_msg_ret("bsp", ret);
if (cpu_select == MP_SELECT_ALL || cpu_select == MP_SELECT_BSP ||
cpu_select == ret) {
/* Run on BSP first */
func(arg);
}
if (!IS_ENABLED(CONFIG_SMP_AP_WORK) ||
!(gd->flags & GD_FLG_SMP_READY)) {
/* Allow use of this function on the BSP only */
if (cpu_select == MP_SELECT_BSP || !cpu_select)
return 0;
return -ENOTSUPP;
}
/* Allow up to 1 second for all APs to finish */
ret = run_ap_work(&lcb, dev, num_cpus, 1000 /* ms */);
if (ret)
return log_msg_ret("aps", ret);
return 0;
}
static void park_this_cpu(void *unused)
{
stop_this_cpu();
}
int mp_park_aps(void)
{
int ret;
ret = mp_run_on_cpus(MP_SELECT_APS, park_this_cpu, NULL);
if (ret)
return log_ret(ret);
return 0;
}
int mp_first_cpu(int cpu_select)
{
struct udevice *dev;
int num_cpus;
int ret;
/*
* This assumes that CPUs are numbered from 0. This function tries to
* avoid assuming the CPU 0 is the boot CPU
*/
if (cpu_select == MP_SELECT_ALL)
return 0; /* start with the first one */
ret = get_bsp(&dev, &num_cpus);
if (ret < 0)
return log_msg_ret("bsp", ret);
/* Return boot CPU if requested */
if (cpu_select == MP_SELECT_BSP)
return ret;
/* Return something other than the boot CPU, if APs requested */
if (cpu_select == MP_SELECT_APS && num_cpus > 1)
return ret == 0 ? 1 : 0;
/* Try to check for an invalid value */
if (cpu_select < 0 || cpu_select >= num_cpus)
return -EINVAL;
return cpu_select; /* return the only selected one */
}
int mp_next_cpu(int cpu_select, int prev_cpu)
{
struct udevice *dev;
int num_cpus;
int ret;
int bsp;
/* If we selected the BSP or a particular single CPU, we are done */
if (!IS_ENABLED(CONFIG_SMP_AP_WORK) || cpu_select == MP_SELECT_BSP ||
cpu_select >= 0)
return -EFBIG;
/* Must be doing MP_SELECT_ALL or MP_SELECT_APS; return the next CPU */
ret = get_bsp(&dev, &num_cpus);
if (ret < 0)
return log_msg_ret("bsp", ret);
bsp = ret;
/* Move to the next CPU */
assert(prev_cpu >= 0);
ret = prev_cpu + 1;
/* Skip the BSP if needed */
if (cpu_select == MP_SELECT_APS && ret == bsp)
ret++;
if (ret >= num_cpus)
return -EFBIG;
return ret;
}
int mp_init(void)
{
int num_aps, num_cpus;
atomic_t *ap_count;
struct udevice *cpu;
int ret;
if (IS_ENABLED(CONFIG_QFW)) {
ret = qemu_cpu_fixup();
if (ret)
return ret;
}
ret = get_bsp(&cpu, &num_cpus);
if (ret < 0) {
debug("Cannot init boot CPU: err=%d\n", ret);
return ret;
}
if (num_cpus < 2)
debug("Warning: Only 1 CPU is detected\n");
ret = check_cpu_devices(num_cpus);
if (ret)
log_warning("Warning: Device tree does not describe all CPUs. Extra ones will not be started correctly\n");
ap_callbacks = calloc(num_cpus, sizeof(struct mp_callback *));
if (!ap_callbacks)
return -ENOMEM;
/* Copy needed parameters so that APs have a reference to the plan */
mp_info.num_records = ARRAY_SIZE(mp_steps);
mp_info.records = mp_steps;
/* Load the SIPI vector */
ret = load_sipi_vector(&ap_count, num_cpus);
if (ap_count == NULL)
return -ENOENT;
/*
* Make sure SIPI data hits RAM so the APs that come up will see
* the startup code even if the caches are disabled
*/
wbinvd();
/* Start the APs providing number of APs and the cpus_entered field */
num_aps = num_cpus - 1;
ret = start_aps(num_aps, ap_count);
if (ret) {
mdelay(1000);
debug("%d/%d eventually checked in?\n", atomic_read(ap_count),
num_aps);
return ret;
}
/* Walk the flight plan for the BSP */
ret = bsp_do_flight_plan(cpu, &mp_info, num_aps);
if (ret) {
debug("CPU init failed: err=%d\n", ret);
return ret;
}
gd->flags |= GD_FLG_SMP_READY;
return 0;
}