/*
 * NOOP APIC driver.
 *
 * Does almost nothing and should be substituted by a real apic driver via
 * probe routine.
 *
 * Though in case if apic is disabled (for some reason) we try
 * to not uglify the caller's code and allow to call (some) apic routines
 * like self-ipi, etc...
 */

#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <asm/fixmap.h>
#include <asm/mpspec.h>
#include <asm/apicdef.h>
#include <asm/apic.h>
#include <asm/setup.h>

#include <linux/smp.h>
#include <asm/ipi.h>

#include <linux/interrupt.h>
#include <asm/acpi.h>
#include <asm/e820.h>

static void noop_init_apic_ldr(void) { }
static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_allbutself(int vector) { }
static void noop_send_IPI_all(int vector) { }
static void noop_send_IPI_self(int vector) { }
static void noop_apic_wait_icr_idle(void) { }
static void noop_apic_icr_write(u32 low, u32 id) { }

static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
{
        return -1;
}

static u32 noop_safe_apic_wait_icr_idle(void)
{
        return 0;
}

static u64 noop_apic_icr_read(void)
{
        return 0;
}

static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
{
        return 0;
}

static unsigned int noop_get_apic_id(unsigned long x)
{
        return 0;
}

static int noop_probe(void)
{
        /*
         * NOOP apic should not ever be
         * enabled via probe routine
         */
        return 0;
}

static int noop_apic_id_registered(void)
{
        /*
         * if we would be really "pedantic"
         * we should pass read_apic_id() here
         * but since NOOP suppose APIC ID = 0
         * lets save a few cycles
         */
        return physid_isset(0, phys_cpu_present_map);
}

static const struct cpumask *noop_target_cpus(void)
{
        /* only BSP here */
        return cpumask_of(0);
}

static unsigned long noop_check_apicid_used(physid_mask_t *map, int apicid)
{
        return physid_isset(apicid, *map);
}

static unsigned long noop_check_apicid_present(int bit)
{
        return physid_isset(bit, phys_cpu_present_map);
}

static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask,
                                          const struct cpumask *mask)
{
        if (cpu != 0)
                pr_warning("APIC: Vector allocated for non-BSP cpu\n");
        cpumask_copy(retmask, cpumask_of(cpu));
}

static u32 noop_apic_read(u32 reg)
{
        WARN_ON_ONCE((cpu_has_apic && !disable_apic));
        return 0;
}

static void noop_apic_write(u32 reg, u32 v)
{
        WARN_ON_ONCE(cpu_has_apic && !disable_apic);
}

struct apic apic_noop = {
        .name                           = "noop",
        .probe                          = noop_probe,
        .acpi_madt_oem_check            = NULL,

        .apic_id_valid                  = default_apic_id_valid,
        .apic_id_registered             = noop_apic_id_registered,

        .irq_delivery_mode              = dest_LowestPrio,
        /* logical delivery broadcast to all CPUs: */
        .irq_dest_mode                  = 1,

        .target_cpus                    = noop_target_cpus,
        .disable_esr                    = 0,
        .dest_logical                   = APIC_DEST_LOGICAL,
        .check_apicid_used              = noop_check_apicid_used,
        .check_apicid_present           = noop_check_apicid_present,

        .vector_allocation_domain       = noop_vector_allocation_domain,
        .init_apic_ldr                  = noop_init_apic_ldr,

        .ioapic_phys_id_map             = default_ioapic_phys_id_map,
        .setup_apic_routing             = NULL,
        .multi_timer_check              = NULL,

        .cpu_present_to_apicid          = default_cpu_present_to_apicid,
        .apicid_to_cpu_present          = physid_set_mask_of_physid,

        .setup_portio_remap             = NULL,
        .check_phys_apicid_present      = default_check_phys_apicid_present,
        .enable_apic_mode               = NULL,

        .phys_pkg_id                    = noop_phys_pkg_id,

        .mps_oem_check                  = NULL,

        .get_apic_id                    = noop_get_apic_id,
        .set_apic_id                    = NULL,
        .apic_id_mask                   = 0x0F << 24,

        .cpu_mask_to_apicid_and         = flat_cpu_mask_to_apicid_and,

        .send_IPI_mask                  = noop_send_IPI_mask,
        .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
        .send_IPI_allbutself            = noop_send_IPI_allbutself,
        .send_IPI_all                   = noop_send_IPI_all,
        .send_IPI_self                  = noop_send_IPI_self,

        .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,

        /* should be safe */
        .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
        .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,

        .wait_for_init_deassert         = NULL,

        .smp_callin_clear_local_apic    = NULL,
        .inquire_remote_apic            = NULL,

        .read                           = noop_apic_read,
        .write                          = noop_apic_write,
        .eoi_write                      = noop_apic_write,
        .icr_read                       = noop_apic_icr_read,
        .icr_write                      = noop_apic_icr_write,
        .wait_icr_idle                  = noop_apic_wait_icr_idle,
        .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,

#ifdef CONFIG_X86_32
        .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
#endif
};