NetBSD/sys/arch/atari/dev/dma.c

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/* $NetBSD: dma.c,v 1.11 1996/10/13 04:10:52 christos Exp $ */
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/*
* Copyright (c) 1995 Leo Weppelman.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Leo Weppelman.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This file contains special code dealing with the DMA interface
* on the Atari ST.
*
* The DMA circuitry requires some special treatment for the peripheral
* devices which make use of the ST's DMA feature (the hard disk and the
* floppy drive).
* All devices using DMA need mutually exclusive access and can follow some
* standard pattern which will be provided in this file.
*
* The file contains the following entry points:
*
* st_dmagrab: ensure exclusive access to the DMA circuitry
* st_dmafree: free exclusive access to the DMA circuitry
* st_dmawanted: somebody is queued waiting for DMA-access
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* dmaint: DMA interrupt routine, switches to the current driver
* st_dmaaddr_set: specify 24 bit RAM address
* st_dmaaddr_get: get address of last DMA-op
* st_dmacomm: program DMA, flush FIFO first
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*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/queue.h>
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#include <machine/cpu.h>
#include <machine/iomap.h>
#include <machine/dma.h>
#define NDMA_DEV 10 /* Max 2 floppy's, 8 hard-disks */
typedef struct dma_entry {
TAILQ_ENTRY(dma_entry) entries; /* List pointers */
void (*call_func)(void *); /* Call when lock granted */
void (*int_func)(void *); /* Call on DMA interrupt */
void *softc; /* Arg. to int_func */
int *lock_stat; /* status of DMA lock */
} DMA_ENTRY;
/*
* Preallocated entries. An allocator seem an overkill here.
*/
static DMA_ENTRY dmatable[NDMA_DEV]; /* preallocated entries */
/*
* Heads of free and active lists:
*/
static TAILQ_HEAD(freehead, dma_entry) dma_free;
static TAILQ_HEAD(acthead, dma_entry) dma_active;
static int must_init = 1; /* Must initialize */
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void cdmaint __P((int));
long sr; /* sr at time of interrupt */
static void init_queues __P((void));
static void
init_queues()
{
int i;
TAILQ_INIT(&dma_free);
TAILQ_INIT(&dma_active);
for(i = 0; i < NDMA_DEV; i++)
TAILQ_INSERT_HEAD(&dma_free, &dmatable[i], entries);
}
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int
st_dmagrab(int_func, call_func, softc, lock_stat, rcaller)
dma_farg int_func;
dma_farg call_func;
void *softc;
int *lock_stat;
int rcaller;
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{
int sps;
DMA_ENTRY *req;
if(must_init) {
init_queues();
must_init = 0;
}
*lock_stat = DMA_LOCK_REQ;
sps = splhigh();
/*
* Create a request...
*/
if(dma_free.tqh_first == NULL)
panic("st_dmagrab: Too many outstanding requests\n");
req = dma_free.tqh_first;
TAILQ_REMOVE(&dma_free, dma_free.tqh_first, entries);
req->call_func = call_func;
req->int_func = int_func;
req->softc = softc;
req->lock_stat = lock_stat;
TAILQ_INSERT_TAIL(&dma_active, req, entries);
if(dma_active.tqh_first != req) {
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splx(sps);
return(0);
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}
splx(sps);
/*
* We're at the head of the queue, ergo: we got the lock.
*/
*lock_stat = DMA_LOCK_GRANT;
if(rcaller) {
/*
* Just return to caller immediately without going
* through 'call_func' first.
*/
return(1);
}
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(*call_func)(softc); /* Call followup function */
return(0);
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}
void
st_dmafree(softc, lock_stat)
void *softc;
int *lock_stat;
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{
int sps;
DMA_ENTRY *req;
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sps = splhigh();
/*
* Some validity checks first.
*/
if((req = dma_active.tqh_first) == NULL)
panic("st_dmafree: empty active queue\n");
if(req->softc != softc)
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printf("Caller of st_dmafree is not lock-owner!\n");
/*
* Clear lock status, move request from active to free queue.
*/
*lock_stat = 0;
TAILQ_REMOVE(&dma_active, req, entries);
TAILQ_INSERT_HEAD(&dma_free, req, entries);
if((req = dma_active.tqh_first) != NULL) {
/*
* Call next request through softint handler. This avoids
* spl-conflicts.
*/
*req->lock_stat = DMA_LOCK_GRANT;
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add_sicallback((si_farg)req->call_func, req->softc, 0);
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}
splx(sps);
return;
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}
int
st_dmawanted()
{
return(dma_active.tqh_first->entries.tqe_next != NULL);
}
void
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cdmaint(sr)
int sr; /* sr at time of interrupt */
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{
dma_farg int_func;
void *softc;
if(dma_active.tqh_first != NULL) {
int_func = dma_active.tqh_first->int_func;
softc = dma_active.tqh_first->softc;
if(!BASEPRI(sr))
add_sicallback((si_farg)int_func, softc, 0);
else {
spl1();
(*int_func)(softc);
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spl0();
}
}
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else printf("DMA interrupt discarded\n");
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}
/*
* Setup address for DMA-transfer.
* Note: The order _is_ important!
*/
void
st_dmaaddr_set(address)
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caddr_t address;
{
register u_long ad = (u_long)address;
DMA->dma_addr[AD_LOW ] = (ad ) & 0xff;
DMA->dma_addr[AD_MID ] = (ad >> 8) & 0xff;
DMA->dma_addr[AD_HIGH] = (ad >>16) & 0xff;
}
/*
* Get address from DMA unit.
*/
u_long
st_dmaaddr_get()
{
register u_long ad = 0;
ad = (DMA->dma_addr[AD_LOW ] & 0xff);
ad |= (DMA->dma_addr[AD_MID ] & 0xff) << 8;
ad |= (DMA->dma_addr[AD_HIGH] & 0xff) <<16;
return(ad);
}
/*
* Program the DMA-controller to transfer 'nblk' blocks of 512 bytes.
* The DMA_WRBIT trick flushes the FIFO before doing DMA.
*/
void
st_dmacomm(mode, nblk)
int mode, nblk;
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{
DMA->dma_mode = mode;
DMA->dma_mode = mode ^ DMA_WRBIT;
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DMA->dma_mode = mode;
DMA->dma_data = nblk;
delay(2); /* Needed for Falcon */
DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT);
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}