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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2015 Google, Inc
*
* Taken from coreboot file of the same name
*/
#ifndef _X86_MP_H_
#define _X86_MP_H_
#include <asm/atomic.h>
#include <asm/cache.h>
#include <linux/bitops.h>
struct udevice;
enum {
/*
* Indicates that the function should run on all CPUs. We use a large
* number, above the number of real CPUs we expect to find.
*/
MP_SELECT_ALL = BIT(16),
/* Run on boot CPUs */
MP_SELECT_BSP,
/* Run on non-boot CPUs */
MP_SELECT_APS,
};
typedef int (*mp_callback_t)(struct udevice *cpu, void *arg);
/*
* A mp_flight_record details a sequence of calls for the APs to perform
* along with the BSP to coordinate sequencing. Each flight record either
* provides a barrier for each AP before calling the callback or the APs
* are allowed to perform the callback without waiting. Regardless, each
* record has the cpus_entered field incremented for each record. When
* the BSP observes that the cpus_entered matches the number of APs
* the bsp_call is called with bsp_arg and upon returning releases the
* barrier allowing the APs to make further progress.
*
* Note that ap_call() and bsp_call() can be NULL. In the NULL case the
* callback will just not be called.
*
* @barrier: Ensures that the BSP and AP don't run the flight record at the same
* time
* @cpus_entered: Counts the number of APs that have run this record
* @ap_call: Function for the APs to call
* @ap_arg: Argument to pass to @ap_call
* @bsp_call: Function for the BSP to call
* @bsp_arg: Argument to pass to @bsp_call
*/
struct mp_flight_record {
atomic_t barrier;
atomic_t cpus_entered;
mp_callback_t ap_call;
void *ap_arg;
mp_callback_t bsp_call;
void *bsp_arg;
} __attribute__((aligned(ARCH_DMA_MINALIGN)));
#define MP_FLIGHT_RECORD(barrier_, ap_func_, ap_arg_, bsp_func_, bsp_arg_) \
{ \
.barrier = ATOMIC_INIT(barrier_), \
.cpus_entered = ATOMIC_INIT(0), \
.ap_call = ap_func_, \
.ap_arg = ap_arg_, \
.bsp_call = bsp_func_, \
.bsp_arg = bsp_arg_, \
}
#define MP_FR_BLOCK_APS(ap_func, ap_arg, bsp_func, bsp_arg) \
MP_FLIGHT_RECORD(0, ap_func, ap_arg, bsp_func, bsp_arg)
#define MP_FR_NOBLOCK_APS(ap_func, ap_arg, bsp_func, bsp_arg) \
MP_FLIGHT_RECORD(1, ap_func, ap_arg, bsp_func, bsp_arg)
/*
* mp_init() will set up the SIPI vector and bring up the APs according to
* mp_params. Each flight record will be executed according to the plan. Note
* that the MP infrastructure uses SMM default area without saving it. It's
* up to the chipset or mainboard to either e820 reserve this area or save this
* region prior to calling mp_init() and restoring it after mp_init returns.
*
* At the time mp_init() is called the MTRR MSRs are mirrored into APs then
* caching is enabled before running the flight plan.
*
* The MP init has the following properties:
* 1. APs are brought up in parallel.
* 2. The ordering of cpu number and APIC ids is not deterministic.
* Therefore, one cannot rely on this property or the order of devices in
* the device tree unless the chipset or mainboard know the APIC ids
* a priori.
*
* mp_init() returns < 0 on error, 0 on success.
*/
int mp_init(void);
/**
* x86_mp_init() - Set up additional CPUs
*
* @returns < 0 on error, 0 on success.
*/
int x86_mp_init(void);
/**
* mp_run_func() - Function to call on the AP
*
* @arg: Argument to pass
*/
typedef void (*mp_run_func)(void *arg);
#if CONFIG_IS_ENABLED(SMP) && !CONFIG_IS_ENABLED(X86_64)
/**
* mp_run_on_cpus() - Run a function on one or all CPUs
*
* This does not return until all CPUs have completed the work
*
* Running on anything other than the boot CPU is only supported if
* CONFIG_SMP_AP_WORK is enabled
*
* @cpu_select: CPU to run on (its dev_seq() value), or MP_SELECT_ALL for
* all, or MP_SELECT_BSP for BSP
* @func: Function to run
* @arg: Argument to pass to the function
* @return 0 on success, -ve on error
*/
int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg);
/**
* mp_park_aps() - Park the APs ready for the OS
*
* This halts all CPUs except the main one, ready for the OS to use them
*
* @return 0 if OK, -ve on error
*/
int mp_park_aps(void);
/**
* mp_first_cpu() - Get the first CPU to process, from a selection
*
* This is used to iterate through selected CPUs. Call this function first, then
* call mp_next_cpu() repeatedly (with the same @cpu_select) until it returns
* -EFBIG.
*
* @cpu_select: Selected CPUs (either a CPU number or MP_SELECT_...)
* @return next CPU number to run on (e.g. 0)
*/
int mp_first_cpu(int cpu_select);
/**
* mp_next_cpu() - Get the next CPU to process, from a selection
*
* This is used to iterate through selected CPUs. After first calling
* mp_first_cpu() once, call this function repeatedly until it returns -EFBIG.
*
* The value of @cpu_select must be the same for all calls and must match the
* value passed to mp_first_cpu(), otherwise the behaviour is undefined.
*
* @cpu_select: Selected CPUs (either a CPU number or MP_SELECT_...)
* @prev_cpu: Previous value returned by mp_first_cpu()/mp_next_cpu()
* @return next CPU number to run on (e.g. 0)
*/
int mp_next_cpu(int cpu_select, int prev_cpu);
#else
static inline int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg)
{
/* There is only one CPU, so just call the function here */
func(arg);
return 0;
}
static inline int mp_park_aps(void)
{
/* No APs to park */
return 0;
}
static inline int mp_first_cpu(int cpu_select)
{
/* We cannot run on any APs, nor a selected CPU */
return cpu_select == MP_SELECT_APS ? -EFBIG : MP_SELECT_BSP;
}
static inline int mp_next_cpu(int cpu_select, int prev_cpu)
{
/*
* When MP is not enabled, there is only one CPU and we did it in
* mp_first_cpu()
*/
return -EFBIG;
}
#endif
#endif /* _X86_MP_H_ */
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