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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/kernel/dma-isa.c
*
* Copyright (C) 1999-2000 Russell King
*
* ISA DMA primitives
* Taken from various sources, including:
* linux/include/asm/dma.h: Defines for using and allocating dma channels.
* Written by Hennus Bergman, 1992.
* High DMA channel support & info by Hannu Savolainen and John Boyd,
* Nov. 1992.
* arch/arm/kernel/dma-ebsa285.c
* Copyright (C) 1998 Phil Blundell
*/
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <asm/dma.h>
#include <asm/mach/dma.h>
#define ISA_DMA_MASK 0
#define ISA_DMA_MODE 1
#define ISA_DMA_CLRFF 2
#define ISA_DMA_PGHI 3
#define ISA_DMA_PGLO 4
#define ISA_DMA_ADDR 5
#define ISA_DMA_COUNT 6
static unsigned int isa_dma_port[8][7] = {
/* MASK MODE CLRFF PAGE_HI PAGE_LO ADDR COUNT */
{ 0x0a, 0x0b, 0x0c, 0x487, 0x087, 0x00, 0x01 },
{ 0x0a, 0x0b, 0x0c, 0x483, 0x083, 0x02, 0x03 },
{ 0x0a, 0x0b, 0x0c, 0x481, 0x081, 0x04, 0x05 },
{ 0x0a, 0x0b, 0x0c, 0x482, 0x082, 0x06, 0x07 },
{ 0xd4, 0xd6, 0xd8, 0x000, 0x000, 0xc0, 0xc2 },
{ 0xd4, 0xd6, 0xd8, 0x48b, 0x08b, 0xc4, 0xc6 },
{ 0xd4, 0xd6, 0xd8, 0x489, 0x089, 0xc8, 0xca },
{ 0xd4, 0xd6, 0xd8, 0x48a, 0x08a, 0xcc, 0xce }
};
static int isa_get_dma_residue(unsigned int chan, dma_t *dma)
{
unsigned int io_port = isa_dma_port[chan][ISA_DMA_COUNT];
int count;
count = 1 + inb(io_port);
count |= inb(io_port) << 8;
return chan < 4 ? count : (count << 1);
}
static struct device isa_dma_dev = {
.init_name = "fallback device",
.coherent_dma_mask = ~(dma_addr_t)0,
.dma_mask = &isa_dma_dev.coherent_dma_mask,
};
static void isa_enable_dma(unsigned int chan, dma_t *dma)
{
if (dma->invalid) {
unsigned long address, length;
unsigned int mode;
enum dma_data_direction direction;
mode = (chan & 3) | dma->dma_mode;
switch (dma->dma_mode & DMA_MODE_MASK) {
case DMA_MODE_READ:
direction = DMA_FROM_DEVICE;
break;
case DMA_MODE_WRITE:
direction = DMA_TO_DEVICE;
break;
case DMA_MODE_CASCADE:
direction = DMA_BIDIRECTIONAL;
break;
default:
direction = DMA_NONE;
break;
}
if (!dma->sg) {
/*
* Cope with ISA-style drivers which expect cache
* coherence.
*/
dma->sg = &dma->buf;
dma->sgcount = 1;
dma->buf.length = dma->count;
dma->buf.dma_address = dma_map_single(&isa_dma_dev,
dma->addr, dma->count,
direction);
}
address = dma->buf.dma_address;
length = dma->buf.length - 1;
outb(address >> 16, isa_dma_port[chan][ISA_DMA_PGLO]);
outb(address >> 24, isa_dma_port[chan][ISA_DMA_PGHI]);
if (chan >= 4) {
address >>= 1;
length >>= 1;
}
outb(0, isa_dma_port[chan][ISA_DMA_CLRFF]);
outb(address, isa_dma_port[chan][ISA_DMA_ADDR]);
outb(address >> 8, isa_dma_port[chan][ISA_DMA_ADDR]);
outb(length, isa_dma_port[chan][ISA_DMA_COUNT]);
outb(length >> 8, isa_dma_port[chan][ISA_DMA_COUNT]);
outb(mode, isa_dma_port[chan][ISA_DMA_MODE]);
dma->invalid = 0;
}
outb(chan & 3, isa_dma_port[chan][ISA_DMA_MASK]);
}
static void isa_disable_dma(unsigned int chan, dma_t *dma)
{
outb(chan | 4, isa_dma_port[chan][ISA_DMA_MASK]);
}
static struct dma_ops isa_dma_ops = {
.type = "ISA",
.enable = isa_enable_dma,
.disable = isa_disable_dma,
.residue = isa_get_dma_residue,
};
static struct resource dma_resources[] = { {
.name = "dma1",
.start = 0x0000,
.end = 0x000f
}, {
.name = "dma low page",
.start = 0x0080,
.end = 0x008f
}, {
.name = "dma2",
.start = 0x00c0,
.end = 0x00df
}, {
.name = "dma high page",
.start = 0x0480,
.end = 0x048f
} };
static dma_t isa_dma[8];
/*
* ISA DMA always starts at channel 0
*/
void __init isa_init_dma(void)
{
/*
* Try to autodetect presence of an ISA DMA controller.
* We do some minimal initialisation, and check that
* channel 0's DMA address registers are writeable.
*/
outb(0xff, 0x0d);
outb(0xff, 0xda);
/*
* Write high and low address, and then read them back
* in the same order.
*/
outb(0x55, 0x00);
outb(0xaa, 0x00);
if (inb(0) == 0x55 && inb(0) == 0xaa) {
unsigned int chan, i;
for (chan = 0; chan < 8; chan++) {
isa_dma[chan].d_ops = &isa_dma_ops;
isa_disable_dma(chan, NULL);
}
outb(0x40, 0x0b);
outb(0x41, 0x0b);
outb(0x42, 0x0b);
outb(0x43, 0x0b);
outb(0xc0, 0xd6);
outb(0x41, 0xd6);
outb(0x42, 0xd6);
outb(0x43, 0xd6);
outb(0, 0xd4);
outb(0x10, 0x08);
outb(0x10, 0xd0);
/*
* Is this correct? According to my documentation, it
* doesn't appear to be. It should be:
* outb(0x3f, 0x40b); outb(0x3f, 0x4d6);
*/
outb(0x30, 0x40b);
outb(0x31, 0x40b);
outb(0x32, 0x40b);
outb(0x33, 0x40b);
outb(0x31, 0x4d6);
outb(0x32, 0x4d6);
outb(0x33, 0x4d6);
for (i = 0; i < ARRAY_SIZE(dma_resources); i++)
request_resource(&ioport_resource, dma_resources + i);
for (chan = 0; chan < 8; chan++) {
int ret = isa_dma_add(chan, &isa_dma[chan]);
if (ret)
pr_err("ISADMA%u: unable to register: %d\n",
chan, ret);
}
request_dma(DMA_ISA_CASCADE, "cascade");
}
}
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