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Add configurable bounce and cache buffers to DF driver
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Remove heap allocated bounce buffer
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@ghaerr
ghaerr committed Oct 18, 2024
1 parent 8376ef7 commit 22c7556
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Showing 3 changed files with 48 additions and 47 deletions.
87 changes: 44 additions & 43 deletions elks/arch/i86/drivers/block/directfd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,9 @@
#error Direct FD driver requires CONFIG_ASYNCIO
#endif

//#define DEBUG printk
#define DEBUG(...)

/*
* The original 8272A doesn't have FD_DOR, FD_DIR or FD_CCR registers,
* but the 82077 found on modern clones can be configured in hardware
Expand All @@ -132,10 +135,13 @@ char USE_IMPLIED_SEEK = 0; /* =1 for QEMU with 360k/AT stretch floppies (not rea
#define TIMEOUT_MOTOR_OFF (3 * HZ) /* 3 secs wait for floppy motor off after I/O */
#define TIMEOUT_CMD_COMPL (6 * HZ) /* 6 secs wait for FDC command complete */

#define FLOPPY_DMA 2 /* hardwired on old PCs */
/* locations for cache and bounce buffers */
#define CACHE_SEG DMASEG /* track cache at DMASEG:0 (shared with BIOS driver) */
#define CACHE_OFF 0
#define BOUNCE_SEG DMASEG /* share bounce buffer with track cache at DMASEG:0 */
#define BOUNCE_OFF 0

//#define DEBUG printk
#define DEBUG(...)
#define FLOPPY_DMA 2 /* hardwired on old PCs */

#define abs(v) (((int)(v) >= 0)? (v): -(v))

Expand Down Expand Up @@ -163,7 +169,14 @@ static unsigned char running; /* keep track of motors already running */
* max X times - some types of errors increase the errorcount by 2 or
* even 3, so we might actually retry only X/2 times before giving up.
*/
#define MAX_ERRORS 6
#define MAX_ERRORS 6

/*
* Threshold for reporting FDC errors to the console.
* Setting this to zero may flood your screen when using
* ultra cheap floppies ;-)
*/
#define MIN_ERRORS 0

/*
* Maximum number of sectors in a track buffer. Track buffering is disabled
Expand Down Expand Up @@ -270,27 +283,13 @@ static int access_count;
static unsigned int changed_floppies;

/*
* Threshold for reporting FDC errors to the console.
* Setting this to zero may flood your screen when using
* ultra cheap floppies ;-)
*/
#define MIN_ERRORS 0

/*
* The block buffer is used for all writes and for reads
* in case track buffering doesn't work or has been turned off.
*/
static char *floppy_buffer;

/*
* These are global variables, as that's the easiest way to give
* information to interrupts. They are the data used for the current
* request.
* These are global variables, as that's the easiest way to pass info
* to interrupts. They are the data used for the current request.
*/
#define NO_TRACK 255

static bool use_cache; /* read entire track when set*/
static int use_bounce; /* XMS or 64k address wrap when set */
static bool use_cache; /* expand read request to fill cache when set */
static int use_bounce; /* XMS I/O or 64k address wrap or not caching when set */
static unsigned char cache_drive = 255;
static int cache_track;
static int cur_spec1 = -1;
Expand Down Expand Up @@ -480,21 +479,26 @@ static void DFPROC setup_DMA(void)
unsigned long dma_addr;

DEBUG("setupDMA ");
#pragma GCC diagnostic ignored "-Wshift-count-overflow"
dma_addr = LINADDR(CACHE_SEG, CACHE_OFF);
count = req->rq_nr_sectors << 9;
physaddr = (req->rq_seg << 4) + (unsigned int)req->rq_buffer;
#pragma GCC diagnostic ignored "-Wshift-count-overflow"
use_bounce = (req->rq_seg >> 16) || (physaddr + count) < physaddr;
if (use_bounce)
dma_addr = LINADDR(kernel_ds, floppy_buffer);
else
dma_addr = LINADDR(req->rq_seg, req->rq_buffer);
if (!use_cache) { /* use_cache overrides use_bounce */
if (use_bounce) {
dma_addr = LINADDR(BOUNCE_SEG, BOUNCE_OFF);
#if (BOUNCE_SEG == CACHE_SEG) && (BOUNCE_OFF == CACHE_OFF)
invalidate_cache();
#endif
} else
dma_addr = LINADDR(req->rq_seg, req->rq_buffer);
}

if (use_cache) {
dma_addr = LINADDR(DMASEG, 0);
/* read sectors/track (one side) + split block */
count = (floppy->sect + (floppy->sect & 1 && !head)) << 9;
} else if (use_bounce && command == FD_WRITE) {
xms_fmemcpyw(floppy_buffer, kernel_ds, req->rq_buffer, req->rq_seg, BLOCK_SIZE/2);
xms_fmemcpyw(BOUNCE_OFF, BOUNCE_SEG, req->rq_buffer, req->rq_seg, BLOCK_SIZE/2);
}
DEBUG("%d/%lx;", count, dma_addr);

Expand Down Expand Up @@ -658,6 +662,7 @@ static void rw_interrupt(void)
{
struct request *req = CURRENT;
int nr, bad;
char *cache_offset;

nr = result();
/* NOTE: If use_cache is active and sector count is uneven, ST0 will
Expand Down Expand Up @@ -726,15 +731,14 @@ static void rw_interrupt(void)
probing = 0;
}
if (use_cache) {
/* This encoding is ugly, should use block-start, block-end instead */
cache_drive = current_drive;
cache_drive = current_drive; /* cache now valid */
cache_track = (seek_track << 1) + head;
DEBUG("rd %04x:%04x->%08lx:%04x;", DMASEG, sector << 9,
cache_offset = (char *)((sector << 9) + CACHE_OFF);
DEBUG("rd %04x:%04x->%08lx:%04x;", CACHE_SEG, cache_offset,
(unsigned long)req->rq_seg, req->rq_buffer);
xms_fmemcpyw(req->rq_buffer, req->rq_seg, (char *)(sector << 9), DMASEG,
BLOCK_SIZE/2);
xms_fmemcpyw(req->rq_buffer, req->rq_seg, cache_offset, CACHE_SEG, BLOCK_SIZE/2);
} else if (use_bounce && command == FD_READ) {
xms_fmemcpyw(req->rq_buffer, req->rq_seg, floppy_buffer, kernel_ds, BLOCK_SIZE/2);
xms_fmemcpyw(req->rq_buffer, req->rq_seg, BOUNCE_OFF, BOUNCE_SEG, BLOCK_SIZE/2);
}
request_done(1);
DEBUG("RQOK;");
Expand Down Expand Up @@ -1208,13 +1212,15 @@ static void DFPROC redo_fd_request(void)
*/
DEBUG("cache CHS %d/%d/%d\n", seek_track, head, sector);
debug_cache2("CH %d ", start >> 1);
cache_offset = (char *)(sector << 9);
cache_offset = (char *)((sector << 9) + CACHE_OFF);
if (command == FD_READ) { /* cache hit, no I/O necessary */
xms_fmemcpyw(req->rq_buffer, req->rq_seg, cache_offset, DMASEG, BLOCK_SIZE/2);
xms_fmemcpyw(req->rq_buffer, req->rq_seg, cache_offset, CACHE_SEG,
BLOCK_SIZE/2);
request_done(1);
goto repeat;
} else if (command == FD_WRITE) /* update track buffer, then write */
xms_fmemcpyw(cache_offset, DMASEG, req->rq_buffer, req->rq_seg, BLOCK_SIZE/2);
xms_fmemcpyw(cache_offset, CACHE_SEG, req->rq_buffer, req->rq_seg,
BLOCK_SIZE/2);
}

/* restart timer for hung operations, 6 secs probably too long ... */
Expand Down Expand Up @@ -1404,7 +1410,6 @@ static void DFPROC floppy_deregister(void)
*(__u32 __far *)FLOPPY_VEC = old_floppy_vec;
enable_irq(FLOPPY_IRQ);
set_irq();
heap_free(floppy_buffer);
}

/* Try to determine the floppy controller type */
Expand Down Expand Up @@ -1455,14 +1460,10 @@ static int DFPROC floppy_register(void)
current_DOR = 0x0c;
outb(0x0c, FD_DOR); /* all motors off, enable IRQ and DMA */

floppy_buffer = heap_alloc(BLOCK_SIZE, HEAP_TAG_DRVR);
if (!floppy_buffer)
return -ENOMEM;
old_floppy_vec = *((__u32 __far *)FLOPPY_VEC);
err = request_irq(FLOPPY_IRQ, floppy_interrupt, INT_GENERIC);
if (err) {
printk("df: IRQ %d busy\n", FLOPPY_IRQ);
heap_free(floppy_buffer);
return err;
}

Expand Down
2 changes: 1 addition & 1 deletion elks/include/linuxmt/debug.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
#define DEBUG_LEVEL 0 /* default startup debug level*/
#define DEBUG_BIOS 0 /* BIOS driver*/
#define DEBUG_BLK 0 /* block i/o*/
#define DEBUG_CACHE 1 /* floppy track cache*/
#define DEBUG_CACHE 0 /* floppy track cache*/
#define DEBUG_ETH 0 /* ethernet*/
#define DEBUG_FAT 0 /* FAT filesystem*/
#define DEBUG_FILE 0 /* sys open and file i/o*/
Expand Down
6 changes: 3 additions & 3 deletions elkscmd/rootfs_template/bootopts
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Original file line number Diff line number Diff line change
Expand Up @@ -13,11 +13,11 @@
#sync=30
#init=/bin/init 3 n # muser serial no rc.sys
#init=/bin/sash
root=df0
#root=df0
#root=hda1 ro
#kstack
#strace
#FTRACE=1
#net=ne0
debug=1
console=ttyS0,19200 3
#debug=1
#console=ttyS0,19200 3

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