// SPDX-License-Identifier: GPL-2.0-only
/*
 * Default generic APIC driver. This handles up to 8 CPUs.
 *
 * Copyright 2003 Andi Kleen, SuSE Labs.
 *
 * Generic x86 APIC driver probe layer.
 */
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/smp.h>

#include <asm/io_apic.h>
#include <asm/apic.h>
#include <asm/acpi.h>

#include "local.h"

static int default_x86_32_early_logical_apicid(int cpu)
{
        return 1 << cpu;
}

static void setup_apic_flat_routing(void)
{
#ifdef CONFIG_X86_IO_APIC
        printk(KERN_INFO
                "Enabling APIC mode:  Flat.  Using %d I/O APICs\n",
                nr_ioapics);
#endif
}

static int default_apic_id_registered(void)
{
        return physid_isset(read_apic_id(), phys_cpu_present_map);
}

/*
 * Set up the logical destination ID.  Intel recommends to set DFR, LDR and
 * TPR before enabling an APIC.  See e.g. "AP-388 82489DX User's Manual"
 * (Intel document number 292116).
 */
static void default_init_apic_ldr(void)
{
        unsigned long val;

        apic_write(APIC_DFR, APIC_DFR_VALUE);
        val = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
        val |= SET_APIC_LOGICAL_ID(1UL << smp_processor_id());
        apic_write(APIC_LDR, val);
}

static int default_phys_pkg_id(int cpuid_apic, int index_msb)
{
        return cpuid_apic >> index_msb;
}

/* should be called last. */
static int probe_default(void)
{
        return 1;
}

static struct apic apic_default __ro_after_init = {

        .name                           = "default",
        .probe                          = probe_default,
        .acpi_madt_oem_check            = NULL,
        .apic_id_valid                  = default_apic_id_valid,
        .apic_id_registered             = default_apic_id_registered,

        .delivery_mode                  = APIC_DELIVERY_MODE_FIXED,
        .dest_mode_logical              = true,

        .disable_esr                    = 0,

        .check_apicid_used              = default_check_apicid_used,
        .init_apic_ldr                  = default_init_apic_ldr,
        .ioapic_phys_id_map             = default_ioapic_phys_id_map,
        .setup_apic_routing             = setup_apic_flat_routing,
        .cpu_present_to_apicid          = default_cpu_present_to_apicid,
        .apicid_to_cpu_present          = physid_set_mask_of_physid,
        .check_phys_apicid_present      = default_check_phys_apicid_present,
        .phys_pkg_id                    = default_phys_pkg_id,

        .get_apic_id                    = default_get_apic_id,
        .set_apic_id                    = NULL,

        .calc_dest_apicid               = apic_flat_calc_apicid,

        .send_IPI                       = default_send_IPI_single,
        .send_IPI_mask                  = default_send_IPI_mask_logical,
        .send_IPI_mask_allbutself       = default_send_IPI_mask_allbutself_logical,
        .send_IPI_allbutself            = default_send_IPI_allbutself,
        .send_IPI_all                   = default_send_IPI_all,
        .send_IPI_self                  = default_send_IPI_self,

        .inquire_remote_apic            = default_inquire_remote_apic,

        .read                           = native_apic_mem_read,
        .write                          = native_apic_mem_write,
        .eoi_write                      = native_apic_mem_write,
        .icr_read                       = native_apic_icr_read,
        .icr_write                      = native_apic_icr_write,
        .wait_icr_idle                  = native_apic_wait_icr_idle,
        .safe_wait_icr_idle             = native_safe_apic_wait_icr_idle,

        .x86_32_early_logical_apicid    = default_x86_32_early_logical_apicid,
};

apic_driver(apic_default);

struct apic *apic __ro_after_init = &apic_default;
EXPORT_SYMBOL_GPL(apic);

static int cmdline_apic __initdata;
static int __init parse_apic(char *arg)
{
        struct apic **drv;

        if (!arg)
                return -EINVAL;

        for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
                if (!strcmp((*drv)->name, arg)) {
                        apic = *drv;
                        cmdline_apic = 1;
                        return 0;
                }
        }

        /* Parsed again by __setup for debug/verbose */
        return 0;
}
early_param("apic", parse_apic);

void __init default_setup_apic_routing(void)
{
        int version = boot_cpu_apic_version;

        if (num_possible_cpus() > 8) {
                switch (boot_cpu_data.x86_vendor) {
                case X86_VENDOR_INTEL:
                        if (!APIC_XAPIC(version)) {
                                def_to_bigsmp = 0;
                                break;
                        }
                        /* P4 and above */
                        fallthrough;
                case X86_VENDOR_HYGON:
                case X86_VENDOR_AMD:
                        def_to_bigsmp = 1;
                }
        }

#ifdef CONFIG_X86_BIGSMP
        /*
         * This is used to switch to bigsmp mode when
         * - There is no apic= option specified by the user
         * - generic_apic_probe() has chosen apic_default as the sub_arch
         * - we find more than 8 CPUs in acpi LAPIC listing with xAPIC support
         */

        if (!cmdline_apic && apic == &apic_default)
                generic_bigsmp_probe();
#endif

        if (apic->setup_apic_routing)
                apic->setup_apic_routing();
}

void __init generic_apic_probe(void)
{
        if (!cmdline_apic) {
                struct apic **drv;

                for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
                        if ((*drv)->probe()) {
                                apic = *drv;
                                break;
                        }
                }
                /* Not visible without early console */
                if (drv == __apicdrivers_end)
                        panic("Didn't find an APIC driver");
        }
        printk(KERN_INFO "Using APIC driver %s\n", apic->name);
}

/* This function can switch the APIC even after the initial ->probe() */
int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
        struct apic **drv;

        for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
                if (!(*drv)->acpi_madt_oem_check)
                        continue;
                if (!(*drv)->acpi_madt_oem_check(oem_id, oem_table_id))
                        continue;

                if (!cmdline_apic) {
                        apic = *drv;
                        printk(KERN_INFO "Switched to APIC driver `%s'.\n",
                               apic->name);
                }
                return 1;
        }
        return 0;
}