dvma.c

Go to the documentation of this file.

/*
 * Virtual DMA allocation
 *
 * (C) 1999 Thomas Bogendoerfer ([email protected])
 *
 * 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 ([email protected])
 *
 */

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

#include <asm/sun3x.h>
#include <asm/dvma.h>
#include <asm/io.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.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)))

#undef DEBUG

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

        unsigned long index;

        index = dvma_addr >> DVMA_PAGE_SHIFT;

        printk("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;
    unsigned long end;
    int ret = 0;

    kaddr &= PAGE_MASK;
    vaddr &= PAGE_MASK;

    end = PAGE_ALIGN(vaddr + len);

#ifdef DEBUG
    printk("dvma: mapping kern %08lx to virt %08lx\n",
           kaddr, vaddr);
#endif
    pgd = pgd_offset_k(vaddr);

    do {
        pmd_t *pmd;
        unsigned long end2;

        if((pmd = pmd_alloc(&init_mm, pgd, 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 {
#ifdef DEBUG
                printk("mapping %08lx phys to %08lx\n",
                       __pa(kaddr), vaddr);
#endif
                set_pte(pte, pfn_pte(virt_to_pfn(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;
}


inline 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();
//      printk("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++) {
#ifdef DEBUG
        printk("freeing bus mapping %08x\n", index << DVMA_PAGE_SHIFT);
#endif
#if 0
        if(!dvma_entry_use(index))
            printk("dvma_unmap freeing unused entry %04x\n",
                   index);
        else
            dvma_entry_dec(index);
#endif
        dvma_entry_clr(index);
    }

}