// SPDX-License-Identifier: GPL-2.0-only
/*
 *  RISC-V Specific Low-Level ACPI Boot Support
 *
 *  Copyright (C) 2013-2014, Linaro Ltd.
 *      Author: Al Stone <al.stone@linaro.org>
 *      Author: Graeme Gregory <graeme.gregory@linaro.org>
 *      Author: Hanjun Guo <hanjun.guo@linaro.org>
 *      Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
 *      Author: Naresh Bhat <naresh.bhat@linaro.org>
 *
 *  Copyright (C) 2021-2023, Ventana Micro Systems Inc.
 *      Author: Sunil V L <sunilvl@ventanamicro.com>
 */

#include <linux/acpi.h>
#include <linux/efi-bgrt.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/pci.h>
#include <linux/serial_core.h>

int acpi_noirq = 1;             /* skip ACPI IRQ initialization */
int acpi_disabled = 1;
EXPORT_SYMBOL(acpi_disabled);

int acpi_pci_disabled = 1;      /* skip ACPI PCI scan and IRQ initialization */
EXPORT_SYMBOL(acpi_pci_disabled);

static bool param_acpi_off __initdata;
static bool param_acpi_on __initdata;
static bool param_acpi_force __initdata;

static struct acpi_madt_rintc cpu_madt_rintc[NR_CPUS];

static int __init parse_acpi(char *arg)
{
        if (!arg)
                return -EINVAL;

        /* "acpi=off" disables both ACPI table parsing and interpreter */
        if (strcmp(arg, "off") == 0)
                param_acpi_off = true;
        else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
                param_acpi_on = true;
        else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
                param_acpi_force = true;
        else
                return -EINVAL; /* Core will print when we return error */

        return 0;
}
early_param("acpi", parse_acpi);

/*
 * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
 *                            checks on it
 *
 * Return 0 on success,  <0 on failure
 */
static int __init acpi_fadt_sanity_check(void)
{
        struct acpi_table_header *table;
        struct acpi_table_fadt *fadt;
        acpi_status status;
        int ret = 0;

        /*
         * FADT is required on riscv; retrieve it to check its presence
         * and carry out revision and ACPI HW reduced compliancy tests
         */
        status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
        if (ACPI_FAILURE(status)) {
                const char *msg = acpi_format_exception(status);

                pr_err("Failed to get FADT table, %s\n", msg);
                return -ENODEV;
        }

        fadt = (struct acpi_table_fadt *)table;

        /*
         * The revision in the table header is the FADT's Major revision. The
         * FADT also has a minor revision, which is stored in the FADT itself.
         *
         * TODO: Currently, we check for 6.5 as the minimum version to check
         * for HW_REDUCED flag. However, once RISC-V updates are released in
         * the ACPI spec, we need to update this check for exact minor revision
         */
        if (table->revision < 6 || (table->revision == 6 && fadt->minor_revision < 5))
                pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 6.5+\n",
                       table->revision, fadt->minor_revision);

        if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
                pr_err("FADT not ACPI hardware reduced compliant\n");
                ret = -EINVAL;
        }

        /*
         * acpi_get_table() creates FADT table mapping that
         * should be released after parsing and before resuming boot
         */
        acpi_put_table(table);
        return ret;
}

/*
 * acpi_boot_table_init() called from setup_arch(), always.
 *      1. find RSDP and get its address, and then find XSDT
 *      2. extract all tables and checksums them all
 *      3. check ACPI FADT HW reduced flag
 *
 * We can parse ACPI boot-time tables such as MADT after
 * this function is called.
 *
 * On return ACPI is enabled if either:
 *
 * - ACPI tables are initialized and sanity checks passed
 * - acpi=force was passed in the command line and ACPI was not disabled
 *   explicitly through acpi=off command line parameter
 *
 * ACPI is disabled on function return otherwise
 */
void __init acpi_boot_table_init(void)
{
        /*
         * Enable ACPI instead of device tree unless
         * - ACPI has been disabled explicitly (acpi=off), or
         * - firmware has not populated ACPI ptr in EFI system table
         *   and ACPI has not been [force] enabled (acpi=on|force)
         */
        if (param_acpi_off ||
            (!param_acpi_on && !param_acpi_force &&
             efi.acpi20 == EFI_INVALID_TABLE_ADDR))
                goto done;

        /*
         * ACPI is disabled at this point. Enable it in order to parse
         * the ACPI tables and carry out sanity checks
         */
        enable_acpi();

        /*
         * If ACPI tables are initialized and FADT sanity checks passed,
         * leave ACPI enabled and carry on booting; otherwise disable ACPI
         * on initialization error.
         * If acpi=force was passed on the command line it forces ACPI
         * to be enabled even if its initialization failed.
         */
        if (acpi_table_init() || acpi_fadt_sanity_check()) {
                pr_err("Failed to init ACPI tables\n");
                if (!param_acpi_force)
                        disable_acpi();
        }

done:
        if (acpi_disabled) {
                if (earlycon_acpi_spcr_enable)
                        early_init_dt_scan_chosen_stdout();
        } else {
                acpi_parse_spcr(earlycon_acpi_spcr_enable, true);
                if (IS_ENABLED(CONFIG_ACPI_BGRT))
                        acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
        }
}

static int acpi_parse_madt_rintc(union acpi_subtable_headers *header, const unsigned long end)
{
        struct acpi_madt_rintc *rintc = (struct acpi_madt_rintc *)header;
        int cpuid;

        if (!(rintc->flags & ACPI_MADT_ENABLED))
                return 0;

        cpuid = riscv_hartid_to_cpuid(rintc->hart_id);
        /*
         * When CONFIG_SMP is disabled, mapping won't be created for
         * all cpus.
         * CPUs more than num_possible_cpus, will be ignored.
         */
        if (cpuid >= 0 && cpuid < num_possible_cpus())
                cpu_madt_rintc[cpuid] = *rintc;

        return 0;
}

/*
 * Instead of parsing (and freeing) the ACPI table, cache
 * the RINTC structures since they are frequently used
 * like in  cpuinfo.
 */
void __init acpi_init_rintc_map(void)
{
        if (acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_madt_rintc, 0) <= 0) {
                pr_err("No valid RINTC entries exist\n");
                BUG();
        }
}

struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
{
        return &cpu_madt_rintc[cpu];
}

/*
 * __acpi_map_table() will be called before paging_init(), so early_ioremap()
 * or early_memremap() should be called here to for ACPI table mapping.
 */
void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
{
        if (!size)
                return NULL;

        return early_memremap(phys, size);
}

void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
{
        if (!map || !size)
                return;

        early_memunmap(map, size);
}

void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
{
        efi_memory_desc_t *md, *region = NULL;
        pgprot_t prot;

        if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))
                return NULL;

        for_each_efi_memory_desc(md) {
                u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);

                if (phys < md->phys_addr || phys >= end)
                        continue;

                if (phys + size > end) {
                        pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");
                        return NULL;
                }
                region = md;
                break;
        }

        /*
         * It is fine for AML to remap regions that are not represented in the
         * EFI memory map at all, as it only describes normal memory, and MMIO
         * regions that require a virtual mapping to make them accessible to
         * the EFI runtime services.
         */
        prot = PAGE_KERNEL_IO;
        if (region) {
                switch (region->type) {
                case EFI_LOADER_CODE:
                case EFI_LOADER_DATA:
                case EFI_BOOT_SERVICES_CODE:
                case EFI_BOOT_SERVICES_DATA:
                case EFI_CONVENTIONAL_MEMORY:
                case EFI_PERSISTENT_MEMORY:
                        if (memblock_is_map_memory(phys) ||
                            !memblock_is_region_memory(phys, size)) {
                                pr_warn(FW_BUG "requested region covers kernel memory\n");
                                return NULL;
                        }

                        /*
                         * Mapping kernel memory is permitted if the region in
                         * question is covered by a single memblock with the
                         * NOMAP attribute set: this enables the use of ACPI
                         * table overrides passed via initramfs.
                         * This particular use case only requires read access.
                         */
                        fallthrough;

                case EFI_RUNTIME_SERVICES_CODE:
                        /*
                         * This would be unusual, but not problematic per se,
                         * as long as we take care not to create a writable
                         * mapping for executable code.
                         */
                        prot = PAGE_KERNEL_RO;
                        break;

                case EFI_ACPI_RECLAIM_MEMORY:
                        /*
                         * ACPI reclaim memory is used to pass firmware tables
                         * and other data that is intended for consumption by
                         * the OS only, which may decide it wants to reclaim
                         * that memory and use it for something else. We never
                         * do that, but we usually add it to the linear map
                         * anyway, in which case we should use the existing
                         * mapping.
                         */
                        if (memblock_is_map_memory(phys))
                                return (void __iomem *)__va(phys);
                        fallthrough;

                default:
                        if (region->attribute & EFI_MEMORY_WB)
                                prot = PAGE_KERNEL;
                        else if ((region->attribute & EFI_MEMORY_WC) ||
                                 (region->attribute & EFI_MEMORY_WT))
                                prot = pgprot_writecombine(PAGE_KERNEL);
                }
        }

        return ioremap_prot(phys, size, prot);
}

#ifdef CONFIG_PCI

/*
 * raw_pci_read/write - Platform-specific PCI config space access.
 */
int raw_pci_read(unsigned int domain, unsigned int bus,
                 unsigned int devfn, int reg, int len, u32 *val)
{
        struct pci_bus *b = pci_find_bus(domain, bus);

        if (!b)
                return PCIBIOS_DEVICE_NOT_FOUND;
        return b->ops->read(b, devfn, reg, len, val);
}

int raw_pci_write(unsigned int domain, unsigned int bus,
                  unsigned int devfn, int reg, int len, u32 val)
{
        struct pci_bus *b = pci_find_bus(domain, bus);

        if (!b)
                return PCIBIOS_DEVICE_NOT_FOUND;
        return b->ops->write(b, devfn, reg, len, val);
}

#endif  /* CONFIG_PCI */