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/*
* Virtual DMA allocation
*
* (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <asm/sun3x.h>
#include <asm/dvma.h>
#include <asm/io.h>
#include <asm/page.h>
/* IOMMU support */
#define IOMMU_ENTRIES 2048
#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
#define DVMA_PAGE_SHIFT 13
#define DVMA_PAGE_SIZE (1UL << DVMA_PAGE_SHIFT)
#define DVMA_PAGE_MASK (~(DVMA_PAGE_SIZE-1))
static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;
static unsigned long iommu_use[IOMMU_ENTRIES];
static unsigned long iommu_bitmap[IOMMU_ENTRIES/32];
#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)))
#define dvma_entry_set(index,addr) (iommu_pte[index] = \
(addr & IOMMU_ADDR_MASK) | \
IOMMU_DT_VALID)
#define dvma_entry_clr(index) (iommu_pte[index] = IOMMU_DT_INVALID)
#define dvma_entry_use(index) (iommu_use[index])
#define dvma_entry_inc(index) (iommu_use[index]++)
#define dvma_entry_dec(index) (iommu_use[index]--)
#define dvma_entry_hash(addr) ((addr >> DVMA_PAGE_SHIFT) ^ \
((addr & 0x03c00000) >> \
(DVMA_PAGE_SHIFT+4)))
#define dvma_map iommu_bitmap
#define dvma_map_size (IOMMU_ENTRIES/2)
#define dvma_slow_offset (IOMMU_ENTRIES/2)
#define dvma_is_slow(addr) ((addr) & \
(dvma_slow_offset << DVMA_PAGE_SHIFT))
static int fixed_dvma;
void __init dvma_init(void)
{
unsigned long tmp;
if ((unsigned long)high_memory < (IOMMU_ENTRIES << DVMA_PAGE_SHIFT)) {
printk ("Sun3x fixed DVMA mapping\n");
fixed_dvma = 1;
for (tmp = 0; tmp < (unsigned long)high_memory; tmp += DVMA_PAGE_SIZE)
dvma_entry_set (tmp >> DVMA_PAGE_SHIFT, virt_to_phys((void *)tmp));
fixed_dvma = 1;
} else {
printk ("Sun3x variable DVMA mapping\n");
for (tmp = 0; tmp < IOMMU_ENTRIES; tmp++)
dvma_entry_clr (tmp);
fixed_dvma = 0;
}
}
unsigned long dvma_slow_alloc (unsigned long paddr, int npages)
{
int scan, base;
scan = 0;
for (;;) {
scan = find_next_zero_bit(dvma_map, dvma_map_size, scan);
if ((base = scan) + npages > dvma_map_size) {
printk ("dvma_slow_alloc failed for %d pages\n",npages);
return 0;
}
for (;;) {
if (scan >= base + npages) goto found;
if (test_bit(scan, dvma_map)) break;
scan++;
}
}
found:
for (scan = base; scan < base+npages; scan++) {
dvma_entry_set(scan+dvma_slow_offset, paddr);
paddr += DVMA_PAGE_SIZE;
set_bit(scan, dvma_map);
}
return (dvma_entry_vaddr((base+dvma_slow_offset),paddr));
}
unsigned long dvma_alloc (unsigned long paddr, unsigned long size)
{
int index;
int pages = ((paddr & ~DVMA_PAGE_MASK) + size + (DVMA_PAGE_SIZE-1)) >>
DVMA_PAGE_SHIFT;
if (fixed_dvma)
return ((unsigned long)phys_to_virt (paddr));
if (pages > 1) /* multi page, allocate from slow pool */
return dvma_slow_alloc (paddr, pages);
index = dvma_entry_hash (paddr);
if (dvma_entry_use(index)) {
if (dvma_entry_paddr(index) == (paddr & DVMA_PAGE_MASK)) {
dvma_entry_inc(index);
return dvma_entry_vaddr(index,paddr);
}
/* collision, allocate from slow pool */
return dvma_slow_alloc (paddr, pages);
}
dvma_entry_set(index,paddr);
dvma_entry_inc(index);
return dvma_entry_vaddr(index,paddr);
}
void dvma_free (unsigned long dvma_addr, unsigned long size)
{
int npages;
int index;
if (fixed_dvma)
return;
if (!dvma_is_slow(dvma_addr)) {
index = (dvma_addr >> DVMA_PAGE_SHIFT);
if (dvma_entry_use(index) == 0) {
printk ("dvma_free: %lx entry already free\n",dvma_addr);
return;
}
dvma_entry_dec(index);
if (dvma_entry_use(index) == 0)
dvma_entry_clr(index);
return;
}
/* free in slow pool */
npages = ((dvma_addr & ~DVMA_PAGE_MASK) + size + (DVMA_PAGE_SIZE-1)) >>
DVMA_PAGE_SHIFT;
for (index = (dvma_addr >> DVMA_PAGE_SHIFT); npages--; index++) {
dvma_entry_clr(index);
clear_bit (index,dvma_map);
}
}
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