/*
* arch/ppc64/kernel/iommu.c
* Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
*
* Rewrite, cleanup, new allocation schemes, virtual merging:
* Copyright (C) 2004 Olof Johansson, IBM Corporation
* and Ben. Herrenschmidt, IBM Corporation
*
* Dynamic DMA mapping support, bus-independent parts.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/iommu.h>
#include <asm/pci-bridge.h>
#include <asm/machdep.h>
#define DBG(...)
#ifdef CONFIG_IOMMU_VMERGE
static int novmerge = 0;
#else
static int novmerge = 1;
#endif
static int __init setup_iommu(char *str)
{
if (!strcmp(str, "novmerge"))
novmerge = 1;
else if (!strcmp(str, "vmerge"))
novmerge = 0;
return 1;
}
__setup("iommu=", setup_iommu);
static unsigned long iommu_range_alloc(struct iommu_table *tbl,
unsigned long npages,
unsigned long *handle,
unsigned int align_order)
{
unsigned long n, end, i, start;
unsigned long limit;
int largealloc = npages > 15;
int pass = 0;
unsigned long align_mask;
align_mask = 0xffffffffffffffffl >> (64 - align_order);
/* This allocator was derived from x86_64's bit string search */
/* Sanity check */
if (unlikely(npages) == 0) {
if (printk_ratelimit())
WARN_ON(1);
return DMA_ERROR_CODE;
}
if (handle && *handle)
start = *handle;
else
start = largealloc ? tbl->it_largehint : tbl->it_hint;
/* Use only half of the table for small allocs (15 pages or less) */
limit = largealloc ? tbl->it_size : tbl->it_halfpoint;
if (largealloc && start < tbl->it_halfpoint)
start = tbl->it_halfpoint;
/* The case below can happen if we have a small segment appended
* to a large, or when the previous alloc was at the very end of
* the available space. If so, go back to the initial start.
*/
if (start >= limit)
start = largealloc ? tbl->it_largehint : tbl->it_hint;
again:
n = find_next_zero_bit(tbl->it_map, limit, start);
/* Align allocation */
n = (n + align_mask) & ~align_mask;
end = n + npages;
if (unlikely(end >= limit)) {
if (likely(pass < 2)) {
/* First failure, just rescan the half of the table.
* Second failure, rescan the other half of the table.
*/
start = (largealloc ^ pass) ? tbl->it_halfpoint : 0;
limit = pass ? tbl->it_size : limit;
pass++;
goto again;
} else {
/* Third failure, give up */
return DMA_ERROR_CODE;
}
}
for (i = n; i < end; i++)
if (test_bit(i, tbl->it_map)) {
start = i+1;
goto again;
}
for (i = n; i < end; i++)
__set_bit(i, tbl->it_map);
/* Bump the hint to a new block for small allocs. */
if (largealloc) {
/* Don't bump to new block to avoid fragmentation */
tbl->it_largehint = end;
} else {
/* Overflow will be taken care of at the next allocation */
tbl->it_hint = (end + tbl->it_blocksize - 1) &
~(tbl->it_blocksize - 1);
}
/* Update handle for SG allocations */
if (handle)
*handle = end;
return n;
}
static dma_addr_t iommu_alloc(struct iommu_table *tbl, void *page,
unsigned int npages, enum dma_data_direction direction,
unsigned int align_order)
{
unsigned long entry, flags;
dma_addr_t ret = DMA_ERROR_CODE;
spin_lock_irqsave(&(tbl->it_lock), flags);
entry = iommu_range_alloc(tbl, npages, NULL, align_order);
if (unlikely(entry == DMA_ERROR_CODE)) {
spin_unlock_irqrestore(&(tbl->it_lock), flags);
return DMA_ERROR_CODE;
}
entry += tbl->it_offset; /* Offset into real TCE table */
ret = entry << PAGE_SHIFT; /* Set the return dma address */
/* Put the TCEs in the HW table */
ppc_md.tce_build(tbl, entry, npages, (unsigned long)page & PAGE_MASK,
direction);
/* Flush/invalidate TLB caches if necessary */
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
spin_unlock_irqrestore(&(tbl->it_lock), flags);
/* Make sure updates are seen by hardware */
mb();
return ret;
}
static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
unsigned int npages)
{
unsigned long entry, free_entry;
unsigned long i;
entry = dma_addr >> PAGE_SHIFT;
free_entry = entry - tbl->it_offset;
if (((free_entry + npages) > tbl->it_size) ||
(entry < tbl->it_offset)) {
if (printk_ratelimit()) {
printk(KERN_INFO "iommu_free: invalid entry\n");
printk(KERN_INFO "\tentry = 0x%lx\n", entry);
printk(KERN_INFO "\tdma_addr = 0x%lx\n", (u64)dma_addr);
printk(KERN_INFO "\tTable = 0x%lx\n", (u64)tbl);
printk(KERN_INFO "\tbus# = 0x%lx\n", (u64)tbl->it_busno);
printk(KERN_INFO "\tsize = 0x%lx\n", (u64)tbl->it_size);
printk(KERN_INFO "\tstartOff = 0x%lx\n", (u64)tbl->it_offset);
printk(KERN_INFO "\tindex = 0x%lx\n", (u64)tbl->it_index);
WARN_ON(1);
}
return;
}
ppc_md.tce_free(tbl, entry, npages);
for (i = 0; i < npages; i++)
__clear_bit(free_entry+i, tbl->it_map);
}
static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
unsigned int npages)
{
unsigned long flags;
spin_lock_irqsave(&(tbl->it_lock), flags);
__iommu_free(tbl, dma_addr, npages);
/* Make sure TLB cache is flushed if the HW needs it. We do
* not do an mb() here on purpose, it is not needed on any of
* the current platforms.
*/
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
spin_unlock_irqrestore(&(tbl->it_lock), flags);
}
int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
struct scatterlist *sglist, int nelems,
enum dma_data_direction direction)
{
dma_addr_t dma_next = 0, dma_addr;
unsigned long flags;
struct scatterlist *s, *outs, *segstart;
int outcount, incount;
unsigned long handle;
BUG_ON(direction == DMA_NONE);
if ((nelems == 0) || !tbl)
return 0;
outs = s = segstart = &sglist[0];
outcount = 1;
incount = nelems;
handle = 0;
/* Init first segment length for backout at failure */
outs->dma_length = 0;
DBG("mapping %d elements:\n", nelems);
spin_lock_irqsave(&(tbl->it_lock), flags);
for (s = outs; nelems; nelems--, s++) {
unsigned long vaddr, npages, entry, slen;
slen = s->length;
/* Sanity check */
if (slen == 0) {
dma_next = 0;
continue;
}
/* Allocate iommu entries for that segment */
vaddr = (unsigned long)page_address(s->page) + s->offset;
npages = PAGE_ALIGN(vaddr + slen) - (vaddr & PAGE_MASK);
npages >>= PAGE_SHIFT;
entry = iommu_range_alloc(tbl, npages, &handle, 0);
DBG(" - vaddr: %lx, size: %lx\n", vaddr, slen);
/* Handle failure */
if (unlikely(entry == DMA_ERROR_CODE)) {
if (printk_ratelimit())
printk(KERN_INFO "iommu_alloc failed, tbl %p vaddr %lx"
" npages %lx\n", tbl, vaddr, npages);
goto failure;
}
/* Convert entry to a dma_addr_t */
entry += tbl->it_offset;
dma_addr = entry << PAGE_SHIFT;
dma_addr |= s->offset;
DBG(" - %lx pages, entry: %lx, dma_addr: %lx\n",
npages, entry, dma_addr);
/* Insert into HW table */
ppc_md.tce_build(tbl, entry, npages, vaddr & PAGE_MASK, direction);
/* If we are in an open segment, try merging */
if (segstart != s) {
DBG(" - trying merge...\n");
/* We cannot merge if:
* - allocated dma_addr isn't contiguous to previous allocation
*/
if (novmerge || (dma_addr != dma_next)) {
/* Can't merge: create a new segment */
segstart = s;
outcount++; outs++;
DBG(" can't merge, new segment.\n");
} else {
outs->dma_length += s->length;
DBG(" merged, new len: %lx\n", outs->dma_length);
}
}
if (segstart == s) {
/* This is a new segment, fill entries */
DBG(" - filling new segment.\n");
outs->dma_address = dma_addr;
outs->dma_length = slen;
}
/* Calculate next page pointer for contiguous check */
dma_next = dma_addr + slen;
DBG(" - dma next is: %lx\n", dma_next);
}
/* Flush/invalidate TLB caches if necessary */
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
spin_unlock_irqrestore(&(tbl->it_lock), flags);
DBG("mapped %d elements:\n", outcount);
/* For the sake of iommu_unmap_sg, we clear out the length in the
* next entry of the sglist if we didn't fill the list completely
*/
if (outcount < incount) {
outs++;
outs->dma_address = DMA_ERROR_CODE;
outs->dma_length = 0;
}
/* Make sure updates are seen by hardware */
mb();
return outcount;
failure:
for (s = &sglist[0]; s <= outs; s++) {
if (s->dma_length != 0) {
unsigned long vaddr, npages;
vaddr = s->dma_address & PAGE_MASK;
npages = (PAGE_ALIGN(s->dma_address + s->dma_length) - vaddr)
>> PAGE_SHIFT;
__iommu_free(tbl, vaddr, npages);
s->dma_address = DMA_ERROR_CODE;
s->dma_length = 0;
}
}
spin_unlock_irqrestore(&(tbl->it_lock), flags);
return 0;
}
void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction)
{
unsigned long flags;
BUG_ON(direction == DMA_NONE);
if (!tbl)
return;
spin_lock_irqsave(&(tbl->it_lock), flags);
while (nelems--) {
unsigned int npages;
dma_addr_t dma_handle = sglist->dma_address;
if (sglist->dma_length == 0)
break;
npages = (PAGE_ALIGN(dma_handle + sglist->dma_length)
- (dma_handle & PAGE_MASK)) >> PAGE_SHIFT;
__iommu_free(tbl, dma_handle, npages);
sglist++;
}
/* Flush/invalidate TLBs if necessary. As for iommu_free(), we
* do not do an mb() here, the affected platforms do not need it
* when freeing.
*/
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
spin_unlock_irqrestore(&(tbl->it_lock), flags);
}
/*
* Build a iommu_table structure. This contains a bit map which
* is used to manage allocation of the tce space.
*/
struct iommu_table *iommu_init_table(struct iommu_table *tbl)
{
unsigned long sz;
static int welcomed = 0;
/* Set aside 1/4 of the table for large allocations. */
tbl->it_halfpoint = tbl->it_size * 3 / 4;
/* number of bytes needed for the bitmap */
sz = (tbl->it_size + 7) >> 3;
tbl->it_map = (unsigned long *)__get_free_pages(GFP_ATOMIC, get_order(sz));
if (!tbl->it_map)
panic("iommu_init_table: Can't allocate %ld bytes\n", sz);
memset(tbl->it_map, 0, sz);
tbl->it_hint = 0;
tbl->it_largehint = tbl->it_halfpoint;
spin_lock_init(&tbl->it_lock);
/* Clear the hardware table in case firmware left allocations in it */
ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
if (!welcomed) {
printk(KERN_INFO "IOMMU table initialized, virtual merging %s\n",
novmerge ? "disabled" : "enabled");
welcomed = 1;
}
return tbl;
}
void iommu_free_table(struct device_node *dn)
{
struct pci_dn *pdn = dn->data;
struct iommu_table *tbl = pdn->iommu_table;
unsigned long bitmap_sz, i;
unsigned int order;
if (!tbl || !tbl->it_map) {
printk(KERN_ERR "%s: expected TCE map for %s\n", __FUNCTION__,
dn->full_name);
return;
}
/* verify that table contains no entries */
/* it_size is in entries, and we're examining 64 at a time */
for (i = 0; i < (tbl->it_size/64); i++) {
if (tbl->it_map[i] != 0) {
printk(KERN_WARNING "%s: Unexpected TCEs for %s\n",
__FUNCTION__, dn->full_name);
break;
}
}
/* calculate bitmap size in bytes */
bitmap_sz = (tbl->it_size + 7) / 8;
/* free bitmap */
order = get_order(bitmap_sz);
free_pages((unsigned long) tbl->it_map, order);
/* free table */
kfree(tbl);
}
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address of the buffer
* passed here is the kernel (virtual) address of the buffer. The buffer
* need not be page aligned, the dma_addr_t returned will point to the same
* byte within the page as vaddr.
*/
dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr,
size_t size, enum dma_data_direction direction)
{
dma_addr_t dma_handle = DMA_ERROR_CODE;
unsigned long uaddr;
unsigned int npages;
BUG_ON(direction == DMA_NONE);
uaddr = (unsigned long)vaddr;
npages = PAGE_ALIGN(uaddr + size) - (uaddr & PAGE_MASK);
npages >>= PAGE_SHIFT;
if (tbl) {
dma_handle = iommu_alloc(tbl, vaddr, npages, direction, 0);
if (dma_handle == DMA_ERROR_CODE) {
if (printk_ratelimit()) {
printk(KERN_INFO "iommu_alloc failed, "
"tbl %p vaddr %p npages %d\n",
tbl, vaddr, npages);
}
} else
dma_handle |= (uaddr & ~PAGE_MASK);
}
return dma_handle;
}
void iommu_unmap_single(struct iommu_table *tbl, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction)
{
BUG_ON(direction == DMA_NONE);
if (tbl)
iommu_free(tbl, dma_handle, (PAGE_ALIGN(dma_handle + size) -
(dma_handle & PAGE_MASK)) >> PAGE_SHIFT);
}
/* Allocates a contiguous real buffer and creates mappings over it.
* Returns the virtual address of the buffer and sets dma_handle
* to the dma address (mapping) of the first page.
*/
void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size,
dma_addr_t *dma_handle, gfp_t flag)
{
void *ret = NULL;
dma_addr_t mapping;
unsigned int npages, order;
size = PAGE_ALIGN(size);
npages = size >> PAGE_SHIFT;
order = get_order(size);
/*
* Client asked for way too much space. This is checked later
* anyway. It is easier to debug here for the drivers than in
* the tce tables.
*/
if (order >= IOMAP_MAX_ORDER) {
printk("iommu_alloc_consistent size too large: 0x%lx\n", size);
return NULL;
}
if (!tbl)
return NULL;
/* Alloc enough pages (and possibly more) */
ret = (void *)__get_free_pages(flag, order);
if (!ret)
return NULL;
memset(ret, 0, size);
/* Set up tces to cover the allocated range */
mapping = iommu_alloc(tbl, ret, npages, DMA_BIDIRECTIONAL, order);
if (mapping == DMA_ERROR_CODE) {
free_pages((unsigned long)ret, order);
ret = NULL;
} else
*dma_handle = mapping;
return ret;
}
void iommu_free_coherent(struct iommu_table *tbl, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
unsigned int npages;
if (tbl) {
size = PAGE_ALIGN(size);
npages = size >> PAGE_SHIFT;
iommu_free(tbl, dma_handle, npages);
free_pages((unsigned long)vaddr, get_order(size));
}
}
