diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/arm/kernel/dma-isa.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/arch/arm/kernel/dma-isa.c b/arch/arm/kernel/dma-isa.c new file mode 100644 index 000000000..2d90ecce5 --- /dev/null +++ b/arch/arm/kernel/dma-isa.c @@ -0,0 +1,225 @@ +// 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"); + } +} |