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// SPDX-License-Identifier: GPL-2.0
/*
* Mips Jazz DMA controller support
* Copyright (C) 1995, 1996 by Andreas Busse
*
* NOTE: Some of the argument checking could be removed when
* things have settled down. Also, instead of returning 0xffffffff
* on failure of vdma_alloc() one could leave page #0 unused
* and return the more usual NULL pointer as logical address.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/spinlock.h>
#include <linux/gfp.h>
#include <asm/mipsregs.h>
#include <asm/jazz.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/dma.h>
#include <asm/jazzdma.h>
#include <asm/pgtable.h>
/*
* Set this to one to enable additional vdma debug code.
*/
#define CONF_DEBUG_VDMA 0
static VDMA_PGTBL_ENTRY *pgtbl;
static DEFINE_SPINLOCK(vdma_lock);
/*
* Debug stuff
*/
#define vdma_debug ((CONF_DEBUG_VDMA) ? debuglvl : 0)
static int debuglvl = 3;
/*
* Initialize the pagetable with a one-to-one mapping of
* the first 16 Mbytes of main memory and declare all
* entries to be unused. Using this method will at least
* allow some early device driver operations to work.
*/
static inline void vdma_pgtbl_init(void)
{
unsigned long paddr = 0;
int i;
for (i = 0; i < VDMA_PGTBL_ENTRIES; i++) {
pgtbl[i].frame = paddr;
pgtbl[i].owner = VDMA_PAGE_EMPTY;
paddr += VDMA_PAGESIZE;
}
}
/*
* Initialize the Jazz R4030 dma controller
*/
static int __init vdma_init(void)
{
/*
* Allocate 32k of memory for DMA page tables. This needs to be page
* aligned and should be uncached to avoid cache flushing after every
* update.
*/
pgtbl = (VDMA_PGTBL_ENTRY *)__get_free_pages(GFP_KERNEL | GFP_DMA,
get_order(VDMA_PGTBL_SIZE));
BUG_ON(!pgtbl);
dma_cache_wback_inv((unsigned long)pgtbl, VDMA_PGTBL_SIZE);
pgtbl = (VDMA_PGTBL_ENTRY *)KSEG1ADDR(pgtbl);
/*
* Clear the R4030 translation table
*/
vdma_pgtbl_init();
r4030_write_reg32(JAZZ_R4030_TRSTBL_BASE, CPHYSADDR(pgtbl));
r4030_write_reg32(JAZZ_R4030_TRSTBL_LIM, VDMA_PGTBL_SIZE);
r4030_write_reg32(JAZZ_R4030_TRSTBL_INV, 0);
printk(KERN_INFO "VDMA: R4030 DMA pagetables initialized.\n");
return 0;
}
/*
* Allocate DMA pagetables using a simple first-fit algorithm
*/
unsigned long vdma_alloc(unsigned long paddr, unsigned long size)
{
int first, last, pages, frame, i;
unsigned long laddr, flags;
/* check arguments */
if (paddr > 0x1fffffff) {
if (vdma_debug)
printk("vdma_alloc: Invalid physical address: %08lx\n",
paddr);
return VDMA_ERROR; /* invalid physical address */
}
if (size > 0x400000 || size == 0) {
if (vdma_debug)
printk("vdma_alloc: Invalid size: %08lx\n", size);
return VDMA_ERROR; /* invalid physical address */
}
spin_lock_irqsave(&vdma_lock, flags);
/*
* Find free chunk
*/
pages = VDMA_PAGE(paddr + size) - VDMA_PAGE(paddr) + 1;
first = 0;
while (1) {
while (pgtbl[first].owner != VDMA_PAGE_EMPTY &&
first < VDMA_PGTBL_ENTRIES) first++;
if (first + pages > VDMA_PGTBL_ENTRIES) { /* nothing free */
spin_unlock_irqrestore(&vdma_lock, flags);
return VDMA_ERROR;
}
last = first + 1;
while (pgtbl[last].owner == VDMA_PAGE_EMPTY
&& last - first < pages)
last++;
if (last - first == pages)
break; /* found */
first = last + 1;
}
/*
* Mark pages as allocated
*/
laddr = (first << 12) + (paddr & (VDMA_PAGESIZE - 1));
frame = paddr & ~(VDMA_PAGESIZE - 1);
for (i = first; i < last; i++) {
pgtbl[i].frame = frame;
pgtbl[i].owner = laddr;
frame += VDMA_PAGESIZE;
}
/*
* Update translation table and return logical start address
*/
r4030_write_reg32(JAZZ_R4030_TRSTBL_INV, 0);
if (vdma_debug > 1)
printk("vdma_alloc: Allocated %d pages starting from %08lx\n",
pages, laddr);
if (vdma_debug > 2) {
printk("LADDR: ");
for (i = first; i < last; i++)
printk("%08x ", i << 12);
printk("\nPADDR: ");
for (i = first; i < last; i++)
printk("%08x ", pgtbl[i].frame);
printk("\nOWNER: ");
for (i = first; i < last; i++)
printk("%08x ", pgtbl[i].owner);
printk("\n");
}
spin_unlock_irqrestore(&vdma_lock, flags);
return laddr;
}
EXPORT_SYMBOL(vdma_alloc);
/*
* Free previously allocated dma translation pages
* Note that this does NOT change the translation table,
* it just marks the free'd pages as unused!
*/
int vdma_free(unsigned long laddr)
{
int i;
i = laddr >> 12;
if (pgtbl[i].owner != laddr) {
printk
("vdma_free: trying to free other's dma pages, laddr=%8lx\n",
laddr);
return -1;
}
while (i < VDMA_PGTBL_ENTRIES && pgtbl[i].owner == laddr) {
pgtbl[i].owner = VDMA_PAGE_EMPTY;
i++;
}
if (vdma_debug > 1)
printk("vdma_free: freed %ld pages starting from %08lx\n",
i - (laddr >> 12), laddr);
return 0;
}
EXPORT_SYMBOL(vdma_free);
/*
* Map certain page(s) to another physical address.
* Caller must have allocated the page(s) before.
*/
int vdma_remap(unsigned long laddr, unsigned long paddr, unsigned long size)
{
int first, pages;
if (laddr > 0xffffff) {
if (vdma_debug)
printk
("vdma_map: Invalid logical address: %08lx\n",
laddr);
return -EINVAL; /* invalid logical address */
}
if (paddr > 0x1fffffff) {
if (vdma_debug)
printk
("vdma_map: Invalid physical address: %08lx\n",
paddr);
return -EINVAL; /* invalid physical address */
}
pages = (((paddr & (VDMA_PAGESIZE - 1)) + size) >> 12) + 1;
first = laddr >> 12;
if (vdma_debug)
printk("vdma_remap: first=%x, pages=%x\n", first, pages);
if (first + pages > VDMA_PGTBL_ENTRIES) {
if (vdma_debug)
printk("vdma_alloc: Invalid size: %08lx\n", size);
return -EINVAL;
}
paddr &= ~(VDMA_PAGESIZE - 1);
while (pages > 0 && first < VDMA_PGTBL_ENTRIES) {
if (pgtbl[first].owner != laddr) {
if (vdma_debug)
printk("Trying to remap other's pages.\n");
return -EPERM; /* not owner */
}
pgtbl[first].frame = paddr;
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