// SPDX-License-Identifier: GPL-2.0
/*
 * Virtual DMA allocation
 *
 * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
 *
 * 11/26/2000 -- disabled the existing code because it didn't work for
 * me in 2.4.  Replaced with a significantly more primitive version
 * similar to the sun3 code.  the old functionality was probably more
 * desirable, but....   -- Sam Creasey (sammy@oh.verio.com)
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/vmalloc.h>

#include <asm/sun3x.h>
#include <asm/dvma.h>
#include <asm/io.h>
#include <asm/page.h>
#include <asm/tlbflush.h>

/* IOMMU support */

#define IOMMU_ADDR_MASK            0x03ffe000
#define IOMMU_CACHE_INHIBIT        0x00000040
#define IOMMU_FULL_BLOCK           0x00000020
#define IOMMU_MODIFIED             0x00000010
#define IOMMU_USED                 0x00000008
#define IOMMU_WRITE_PROTECT        0x00000004
#define IOMMU_DT_MASK              0x00000003
#define IOMMU_DT_INVALID           0x00000000
#define IOMMU_DT_VALID             0x00000001
#define IOMMU_DT_BAD               0x00000002


static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;


#define dvma_entry_paddr(index)         (iommu_pte[index] & IOMMU_ADDR_MASK)
#define dvma_entry_vaddr(index,paddr)   ((index << DVMA_PAGE_SHIFT) |  \
                                         (paddr & (DVMA_PAGE_SIZE-1)))
#if 0
#define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
                                            (addr & IOMMU_ADDR_MASK) | \
                                             IOMMU_DT_VALID | IOMMU_CACHE_INHIBIT)
#else
#define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
                                            (addr & IOMMU_ADDR_MASK) | \
                                             IOMMU_DT_VALID)
#endif
#define dvma_entry_clr(index)           (iommu_pte[index] = IOMMU_DT_INVALID)
#define dvma_entry_hash(addr)           ((addr >> DVMA_PAGE_SHIFT) ^ \
                                         ((addr & 0x03c00000) >>     \
                                                (DVMA_PAGE_SHIFT+4)))

#ifdef DEBUG
/* code to print out a dvma mapping for debugging purposes */
static void dvma_print (unsigned long dvma_addr)
{

        unsigned long index;

        index = dvma_addr >> DVMA_PAGE_SHIFT;

        pr_info("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
                dvma_entry_paddr(index));
}
#endif


/* create a virtual mapping for a page assigned within the IOMMU
   so that the cpu can reach it easily */
inline int dvma_map_cpu(unsigned long kaddr,
                               unsigned long vaddr, int len)
{
        pgd_t *pgd;
        p4d_t *p4d;
        pud_t *pud;
        unsigned long end;
        int ret = 0;

        kaddr &= PAGE_MASK;
        vaddr &= PAGE_MASK;

        end = PAGE_ALIGN(vaddr + len);

        pr_debug("dvma: mapping kern %08lx to virt %08lx\n", kaddr, vaddr);
        pgd = pgd_offset_k(vaddr);
        p4d = p4d_offset(pgd, vaddr);
        pud = pud_offset(p4d, vaddr);

        do {
                pmd_t *pmd;
                unsigned long end2;

                if((pmd = pmd_alloc(&init_mm, pud, vaddr)) == NULL) {
                        ret = -ENOMEM;
                        goto out;
                }

                if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
                        end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
                else
                        end2 = end;

                do {
                        pte_t *pte;
                        unsigned long end3;

                        if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
                                ret = -ENOMEM;
                                goto out;
                        }

                        if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
                                end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
                        else
                                end3 = end2;

                        do {
                                pr_debug("mapping %08lx phys to %08lx\n",
                                         __pa(kaddr), vaddr);
                                set_pte(pte, pfn_pte(virt_to_pfn((void *)kaddr),
                                                     PAGE_KERNEL));
                                pte++;
                                kaddr += PAGE_SIZE;
                                vaddr += PAGE_SIZE;
                        } while(vaddr < end3);

                } while(vaddr < end2);

        } while(vaddr < end);

        flush_tlb_all();

 out:
        return ret;
}


int dvma_map_iommu(unsigned long kaddr, unsigned long baddr, int len)
{
        unsigned long end, index;

        index = baddr >> DVMA_PAGE_SHIFT;
        end = ((baddr+len) >> DVMA_PAGE_SHIFT);

        if(len & ~DVMA_PAGE_MASK)
                end++;

        for(; index < end ; index++) {
//              if(dvma_entry_use(index))
//                      BUG();
//              pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
//                      index << DVMA_PAGE_SHIFT);

                dvma_entry_set(index, __pa(kaddr));

                iommu_pte[index] |= IOMMU_FULL_BLOCK;
//              dvma_entry_inc(index);

                kaddr += DVMA_PAGE_SIZE;
        }

#ifdef DEBUG
        for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
                dvma_print(index << DVMA_PAGE_SHIFT);
#endif
        return 0;

}

void dvma_unmap_iommu(unsigned long baddr, int len)
{

        int index, end;


        index = baddr >> DVMA_PAGE_SHIFT;
        end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);

        for(; index < end ; index++) {
                pr_debug("freeing bus mapping %08x\n",
                         index << DVMA_PAGE_SHIFT);
#if 0
                if(!dvma_entry_use(index))
                        pr_info("dvma_unmap freeing unused entry %04x\n",
                                index);
                else
                        dvma_entry_dec(index);
#endif
                dvma_entry_clr(index);
        }

}