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/* $NetBSD: dma.c,v 1.5 1995/11/06 21:13:38 leo Exp $ */
/*
* 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
* 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
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/queue.h>
#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)(); /* Call when lock granted */
void (*int_func)(); /* 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 */
static int sched_soft = 0; /* callback scheduled */
/*
* 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 */
static void cdmasoft __P((void));
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);
}
int st_dmagrab(int_func, call_func, softc, lock_stat, rcaller)
void (*int_func)();
void (*call_func)();
void *softc;
int *lock_stat;
int rcaller;
{
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");
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) {
splx(sps);
return(0);
}
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);
}
(*call_func)(softc); /* Call followup function */
return(0);
}
void
st_dmafree(softc, lock_stat)
void *softc;
int *lock_stat;
{
int sps;
DMA_ENTRY *req;
sps = splhigh();
/*
* Some validity checks first.
*/
if((req = dma_active.tqh_first) == NULL)
panic("st_dmafree: empty active queue");
if(req->softc != softc)
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;
add_sicallback(req->call_func, req->softc, 0);
}
splx(sps);
return;
}
int
st_dmawanted()
{
return(dma_active.tqh_first->entries.tqe_next != NULL);
}
cdmaint(sr)
long sr; /* sr at time of interrupt */
{
if(dma_active.tqh_first != NULL) {
if(!BASEPRI(sr)) {
if(!sched_soft++)
add_sicallback(cdmasoft, 0, 0);
}
else {
spl1();
cdmasoft();
}
}
else printf("DMA interrupt discarded\n");
}
static void cdmasoft()
{
int s;
void (*int_func)();
void *softc;
/*
* Prevent a race condition here. DMA might be freed while
* the callback was pending!
*/
s = splhigh();
sched_soft = 0;
if(dma_active.tqh_first != NULL) {
int_func = dma_active.tqh_first->int_func;
softc = dma_active.tqh_first->softc;
}
else int_func = NULL;
splx(s);
if(int_func != NULL)
(*int_func)(softc);
}
/*
* Setup address for DMA-transfer.
* Note: The order _is_ important!
*/
void
st_dmaaddr_set(address)
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;
{
DMA->dma_mode = mode;
DMA->dma_mode = mode ^ DMA_WRBIT;
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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