// SPDX-License-Identifier: GPL-2.0

#include <linux/highmem.h>
#include <linux/genalloc.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>

#if (CONFIG_ITCM_RAM_BASE == 0xffffffff)
#error "You should define ITCM_RAM_BASE"
#endif

#ifdef CONFIG_HAVE_DTCM
#if (CONFIG_DTCM_RAM_BASE == 0xffffffff)
#error "You should define DTCM_RAM_BASE"
#endif

#if (CONFIG_DTCM_RAM_BASE == CONFIG_ITCM_RAM_BASE)
#error "You should define correct DTCM_RAM_BASE"
#endif
#endif

extern char __tcm_start, __tcm_end, __dtcm_start;

static struct gen_pool *tcm_pool;

static void __init tcm_mapping_init(void)
{
        pte_t *tcm_pte;
        unsigned long vaddr, paddr;
        int i;

        paddr = CONFIG_ITCM_RAM_BASE;

        if (pfn_valid(PFN_DOWN(CONFIG_ITCM_RAM_BASE)))
                goto panic;

#ifndef CONFIG_HAVE_DTCM
        for (i = 0; i < TCM_NR_PAGES; i++) {
#else
        for (i = 0; i < CONFIG_ITCM_NR_PAGES; i++) {
#endif
                vaddr = __fix_to_virt(FIX_TCM - i);

                tcm_pte =
                        pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);

                set_pte(tcm_pte, pfn_pte(__phys_to_pfn(paddr), PAGE_KERNEL));

                flush_tlb_one(vaddr);

                paddr = paddr + PAGE_SIZE;
        }

#ifdef CONFIG_HAVE_DTCM
        if (pfn_valid(PFN_DOWN(CONFIG_DTCM_RAM_BASE)))
                goto panic;

        paddr = CONFIG_DTCM_RAM_BASE;

        for (i = 0; i < CONFIG_DTCM_NR_PAGES; i++) {
                vaddr = __fix_to_virt(FIX_TCM - CONFIG_ITCM_NR_PAGES - i);

                tcm_pte =
                        pte_offset_kernel((pmd_t *) pgd_offset_k(vaddr), vaddr);

                set_pte(tcm_pte, pfn_pte(__phys_to_pfn(paddr), PAGE_KERNEL));

                flush_tlb_one(vaddr);

                paddr = paddr + PAGE_SIZE;
        }
#endif

#ifndef CONFIG_HAVE_DTCM
        memcpy((void *)__fix_to_virt(FIX_TCM),
                                &__tcm_start, &__tcm_end - &__tcm_start);

        pr_info("%s: mapping tcm va:0x%08lx to pa:0x%08x\n",
                        __func__, __fix_to_virt(FIX_TCM), CONFIG_ITCM_RAM_BASE);

        pr_info("%s: __tcm_start va:0x%08lx size:%d\n",
                        __func__, (unsigned long)&__tcm_start, &__tcm_end - &__tcm_start);
#else
        memcpy((void *)__fix_to_virt(FIX_TCM),
                                &__tcm_start, &__dtcm_start - &__tcm_start);

        pr_info("%s: mapping itcm va:0x%08lx to pa:0x%08x\n",
                        __func__, __fix_to_virt(FIX_TCM), CONFIG_ITCM_RAM_BASE);

        pr_info("%s: __itcm_start va:0x%08lx size:%d\n",
                        __func__, (unsigned long)&__tcm_start, &__dtcm_start - &__tcm_start);

        memcpy((void *)__fix_to_virt(FIX_TCM - CONFIG_ITCM_NR_PAGES),
                                &__dtcm_start, &__tcm_end - &__dtcm_start);

        pr_info("%s: mapping dtcm va:0x%08lx to pa:0x%08x\n",
                        __func__, __fix_to_virt(FIX_TCM - CONFIG_ITCM_NR_PAGES),
                                                CONFIG_DTCM_RAM_BASE);

        pr_info("%s: __dtcm_start va:0x%08lx size:%d\n",
                        __func__, (unsigned long)&__dtcm_start, &__tcm_end - &__dtcm_start);

#endif
        return;
panic:
        panic("TCM init error");
}

void *tcm_alloc(size_t len)
{
        unsigned long vaddr;

        if (!tcm_pool)
                return NULL;

        vaddr = gen_pool_alloc(tcm_pool, len);
        if (!vaddr)
                return NULL;

        return (void *) vaddr;
}
EXPORT_SYMBOL(tcm_alloc);

void tcm_free(void *addr, size_t len)
{
        gen_pool_free(tcm_pool, (unsigned long) addr, len);
}
EXPORT_SYMBOL(tcm_free);

static int __init tcm_setup_pool(void)
{
#ifndef CONFIG_HAVE_DTCM
        u32 pool_size = (u32) (TCM_NR_PAGES * PAGE_SIZE)
                                - (u32) (&__tcm_end - &__tcm_start);

        u32 tcm_pool_start = __fix_to_virt(FIX_TCM)
                                + (u32) (&__tcm_end - &__tcm_start);
#else
        u32 pool_size = (u32) (CONFIG_DTCM_NR_PAGES * PAGE_SIZE)
                                - (u32) (&__tcm_end - &__dtcm_start);

        u32 tcm_pool_start = __fix_to_virt(FIX_TCM - CONFIG_ITCM_NR_PAGES)
                                + (u32) (&__tcm_end - &__dtcm_start);
#endif
        int ret;

        tcm_pool = gen_pool_create(2, -1);

        ret = gen_pool_add(tcm_pool, tcm_pool_start, pool_size, -1);
        if (ret) {
                pr_err("%s: gen_pool add failed!\n", __func__);
                return ret;
        }

        pr_info("%s: Added %d bytes @ 0x%08x to memory pool\n",
                __func__, pool_size, tcm_pool_start);

        return 0;
}

static int __init tcm_init(void)
{
        tcm_mapping_init();

        tcm_setup_pool();

        return 0;
}
arch_initcall(tcm_init);