// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
 */
#include <linux/efi.h>
#include <asm/efi.h>

#include "efistub.h"

static efi_guid_t cpu_state_guid = LINUX_EFI_ARM_CPU_STATE_TABLE_GUID;

struct efi_arm_entry_state *efi_entry_state;

static void get_cpu_state(u32 *cpsr, u32 *sctlr)
{
        asm("mrs %0, cpsr" : "=r"(*cpsr));
        if ((*cpsr & MODE_MASK) == HYP_MODE)
                asm("mrc p15, 4, %0, c1, c0, 0" : "=r"(*sctlr));
        else
                asm("mrc p15, 0, %0, c1, c0, 0" : "=r"(*sctlr));
}

efi_status_t check_platform_features(void)
{
        efi_status_t status;
        u32 cpsr, sctlr;
        int block;

        get_cpu_state(&cpsr, &sctlr);

        efi_info("Entering in %s mode with MMU %sabled\n",
                 ((cpsr & MODE_MASK) == HYP_MODE) ? "HYP" : "SVC",
                 (sctlr & 1) ? "en" : "dis");

        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
                             sizeof(*efi_entry_state),
                             (void **)&efi_entry_state);
        if (status != EFI_SUCCESS) {
                efi_err("allocate_pool() failed\n");
                return status;
        }

        efi_entry_state->cpsr_before_ebs = cpsr;
        efi_entry_state->sctlr_before_ebs = sctlr;

        status = efi_bs_call(install_configuration_table, &cpu_state_guid,
                             efi_entry_state);
        if (status != EFI_SUCCESS) {
                efi_err("install_configuration_table() failed\n");
                goto free_state;
        }

        /* non-LPAE kernels can run anywhere */
        if (!IS_ENABLED(CONFIG_ARM_LPAE))
                return EFI_SUCCESS;

        /* LPAE kernels need compatible hardware */
        block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
        if (block < 5) {
                efi_err("This LPAE kernel is not supported by your CPU\n");
                status = EFI_UNSUPPORTED;
                goto drop_table;
        }
        return EFI_SUCCESS;

drop_table:
        efi_bs_call(install_configuration_table, &cpu_state_guid, NULL);
free_state:
        efi_bs_call(free_pool, efi_entry_state);
        return status;
}

void efi_handle_post_ebs_state(void)
{
        get_cpu_state(&efi_entry_state->cpsr_after_ebs,
                      &efi_entry_state->sctlr_after_ebs);
}

efi_status_t handle_kernel_image(unsigned long *image_addr,
                                 unsigned long *image_size,
                                 unsigned long *reserve_addr,
                                 unsigned long *reserve_size,
                                 efi_loaded_image_t *image,
                                 efi_handle_t image_handle)
{
        const int slack = TEXT_OFFSET - 5 * PAGE_SIZE;
        int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN;
        unsigned long alloc_base, kernel_base;
        efi_status_t status;

        /*
         * Allocate space for the decompressed kernel as low as possible.
         * The region should be 16 MiB aligned, but the first 'slack' bytes
         * are not used by Linux, so we allow those to be occupied by the
         * firmware.
         */
        status = efi_low_alloc_above(alloc_size, EFI_PAGE_SIZE, &alloc_base, 0x0);
        if (status != EFI_SUCCESS) {
                efi_err("Unable to allocate memory for uncompressed kernel.\n");
                return status;
        }

        if ((alloc_base % EFI_PHYS_ALIGN) > slack) {
                /*
                 * More than 'slack' bytes are already occupied at the base of
                 * the allocation, so we need to advance to the next 16 MiB block.
                 */
                kernel_base = round_up(alloc_base, EFI_PHYS_ALIGN);
                efi_info("Free memory starts at 0x%lx, setting kernel_base to 0x%lx\n",
                         alloc_base, kernel_base);
        } else {
                kernel_base = round_down(alloc_base, EFI_PHYS_ALIGN);
        }

        *reserve_addr = kernel_base + slack;
        *reserve_size = MAX_UNCOMP_KERNEL_SIZE;

        /* now free the parts that we will not use */
        if (*reserve_addr > alloc_base) {
                efi_bs_call(free_pages, alloc_base,
                            (*reserve_addr - alloc_base) / EFI_PAGE_SIZE);
                alloc_size -= *reserve_addr - alloc_base;
        }
        efi_bs_call(free_pages, *reserve_addr + MAX_UNCOMP_KERNEL_SIZE,
                    (alloc_size - MAX_UNCOMP_KERNEL_SIZE) / EFI_PAGE_SIZE);

        *image_addr = kernel_base + TEXT_OFFSET;
        *image_size = 0;

        efi_debug("image addr == 0x%lx, reserve_addr == 0x%lx\n",
                  *image_addr, *reserve_addr);

        return EFI_SUCCESS;
}