[kernel] Split XMS/DMA buffer from track cache for BIOS and DF drivers

elks/arch/i86/drivers/block/bioshd.c

@@ -106,7 +106,7 @@ static struct gendisk bioshd_gendisk = {
 
 static void BFPROC set_cache_invalid(void)
 {
-    if (cache_drive) debug_cache2("INV%d ", cache_drive - drive_info);
+    if (cache_drive) debug_cache("INV%d ", bios_drive_map[cache_drive - drive_info]);
     cache_drive = NULL;
 }
 
@@ -525,11 +525,11 @@ static void BFPROC get_chst(struct drive_infot *drivep, sector_t *start_sec,
 #if FULL_TRACK
     if (fulltrack) {
         int save = *s;
-        int max_sectors = DMASEGSZ / drivep->sector_size;
+        int max_sectors = TRACKSEGSZ / drivep->sector_size;
         if (*s - 1 < max_sectors) { /* adjust start sector backwards for full track read*/
             *s = 1;
             *t = max_sectors;
-        } else {                    /* likely 2880k: limit to size of DMASEG buffer */
+        } else {                    /* likely 2880k: limit to size of TRACKSEG buffer */
             *s = max_sectors + 1;
             *t = drivep->sectors - *s + 1;
         }
@@ -559,8 +559,6 @@ static int BFPROC do_readwrite(struct drive_infot *drivep, sector_t start, char
     if (cmd == READ) debug_bios("bioshd(%x): read lba %ld count %d\n",
                         drive, start, this_pass);
 
-    errs = MAX_ERRS;        /* BIOS disk reads should be retried at least five times */
-    do {
 #pragma GCC diagnostic ignored "-Wshift-count-overflow"
         usedmaseg = seg >> 16; /* will be nonzero only if XMS configured and XMS buffer */
         if (!usedmaseg) {
@@ -576,13 +574,16 @@ static int BFPROC do_readwrite(struct drive_infot *drivep, sector_t start, char
             offset = 0;
             if (cmd == WRITE)           /* copy xms buffer down before write*/
                 xms_fmemcpyw(0, DMASEG, buf, seg, this_pass*(drivep->sector_size >> 1));
-            set_cache_invalid();
+            //set_cache_invalid();      /* don't invalidate cache - not shared */
         } else {
             segment = (seg_t)seg;
             offset = (unsigned) buf;
         }
-        debug_cache("%s%d CHS %d/%d/%d count %d\n",
-            cmd==WRITE? "WR": "RD", drive, cylinder, head, sector, this_pass);
+    errs = MAX_ERRS;        /* BIOS disk reads should be retried at least five times */
+    do {
+        debug_cache("%s%s%d CHS %d/%d/%d count %d\n",
+            cmd==WRITE? "WR": "RD", usedmaseg? "X": "", drive, cylinder, head, sector,
+                this_pass);
         debug_bios("bioshd(%x): cmd %d CHS %d/%d/%d count %d\n",
             drive, cmd, cylinder, head, sector, this_pass);
 
@@ -602,16 +603,18 @@ static int BFPROC do_readwrite(struct drive_infot *drivep, sector_t start, char
     if (usedmaseg) {
         if (cmd == READ)            /* copy DMASEG up to xms*/
             xms_fmemcpyw(buf, seg, 0, DMASEG, this_pass*(drivep->sector_size >> 1));
-        set_cache_invalid();
+        //set_cache_invalid();      /* don't invalidate cache - not shared */
     }
+    if (cmd == WRITE && drivep == cache_drive)
+        set_cache_invalid();        /* cache isn't updated on writes */
     return this_pass;
 }
 
 #ifdef CONFIG_TRACK_CACHE               /* use track-sized sector cache*/
 static sector_t cache_startsector;
 static sector_t cache_endsector;
 
-/* read from start sector to end of track into DMASEG track buffer, no retries*/
+/* read from start sector to end of track into TRACKSEG track buffer, no retries*/
 static void BFPROC do_readtrack(struct drive_infot *drivep, sector_t start)
 {
     unsigned int cylinder, head, sector, num_sectors;
@@ -621,8 +624,8 @@ static void BFPROC do_readtrack(struct drive_infot *drivep, sector_t start)
     drive = bios_drive_map[drive];
     get_chst(drivep, &start, &cylinder, &head, &sector, &num_sectors, 1);
 
-    if (num_sectors > (DMASEGSZ / drivep->sector_size))
-        num_sectors = DMASEGSZ / drivep->sector_size;
+    if (num_sectors > (TRACKSEGSZ / drivep->sector_size))
+        num_sectors = TRACKSEGSZ / drivep->sector_size;
 
     do {
         debug_cache("\nTR%d %lu(CHS %u,%u,%u-%u) ", drive, start>>1, cylinder, head,
@@ -632,7 +635,7 @@ static void BFPROC do_readtrack(struct drive_infot *drivep, sector_t start)
 
         bios_set_ddpt(drivep->sectors);
         error = bios_disk_rw(BIOSHD_READ, num_sectors, drive,
-                                 cylinder, head, sector, DMASEG, 0);
+                                 cylinder, head, sector, TRACKSEG, 0);
         if (error) {
             printk("bioshd(%x): track read retry #%d CHS %d/%d/%d count %d\n",
                 drive, errs + 1, cylinder, head, sector, num_sectors);
@@ -665,7 +668,7 @@ static int BFPROC cache_valid(struct drive_infot *drivep, sector_t start, char *
     offset = (int)(start - cache_startsector) * drivep->sector_size;
     debug_bios("bioshd(%x): cache hit lba %ld\n",
         bios_drive_map[drivep-drive_info], start);
-    xms_fmemcpyw(buf, seg, (void *)offset, DMASEG, drivep->sector_size >> 1);
+    xms_fmemcpyw(buf, seg, (void *)offset, TRACKSEG, drivep->sector_size >> 1);
     return 1;
 }
 

elks/arch/i86/drivers/block/directfd.c

@@ -137,10 +137,10 @@ char USE_IMPLIED_SEEK = 0; /* =1 for QEMU with 360k/AT stretch floppies (not rea
 #define TIMEOUT_CMD_COMPL  (6 * HZ)    /* 6 secs wait for FDC command complete */
 
 /* 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_SEG      TRACKSEG /* share bounce buffer with track cache at TRACKSEG:0 */
 #define BOUNCE_OFF      0
+#define CACHE_SEG       TRACKSEG /* track cache at TRACKSEG:0 (same as BIOS FD driver) */
+#define CACHE_OFF       0
 
 #define FLOPPY_DMA      2       /* hardwired on old PCs */
 

elks/include/linuxmt/config.h

@@ -103,27 +103,39 @@
 #define DEF_SETUPSEG    DEF_INITSEG + 0x20
 #define DEF_SYSMAX      0x2F00  /* maximum system size (=.text+.fartext+.data) */
 
-/* Segment DMASEG up to DMASEGEND is used as a bounce buffer of at least 1K (=BLOCKSIZE)
- * below the first 64K boundary (=0x1000:0) for use with the old 8237 DMA controller.
- * If floppy track caching is enabled, this area is also used for the track buffer
- * for direct DMA access using multisector I/O.
- * Following DMASEGEND is the kernel code and data at REL_SYSSEG.
+/* Segment DMASEG up to DMASEGEND is used for the XMS/DMA bounce buffer and track cache.
+ * Following DMASEGEND is the kernel code at REL_SYSSEG (or kernel data for ROM configs).
+ *
+ * A "bounce buffer" is configured below the first 64K boundary for use with
+ * old 8237 DMA controller which wraps addresses wider than 16-bits on PC/XT systems.
+ * If floppy track caching is enabled, the track buffer is also configured in
+ * low memory for direct DMA access usig multisector I/O.
+ * The DF driver uses the first sector of its track cache for the XMS/DMA buffer.
+ * In contrast, the BIOS FD/HD driver is configured to use an XMS/DMA buffer
+ * outside its track cache; thus the complicated defines below.
  */
 
+#if defined(CONFIG_BLK_DEV_BFD) || defined(CONFIG_BLK_DEV_BHD)
+#define DMASEGSZ        0x0400      /* BLOCK_SIZE (1024) for external XMS/DMA buffer */
+#else
+#define DMASEGSZ        0           /* no external XMS/DMA buffer */
+#endif
+
+#if defined(CONFIG_BLK_DEV_BFD) || defined(CONFIG_BLK_DEV_BHD) || defined(CONFIG_BLK_FD)
 #ifdef CONFIG_TRACK_CACHE           /* floppy track buffer in low mem */
-#define DMASEGSZ        0x2400      /* SECTOR_SIZE * 18 (9216) */
+#define TRACKSEGSZ      0x2400      /* SECTOR_SIZE * 18 (9216) */
 #else
-#define DMASEGSZ        0x0400      /* BLOCK_SIZE (1024) */
+#define TRACKSEGSZ      0x0400      /* BLOCK_SIZE (1024) */
+#endif
+#define TRACKSEG        (DMASEG+(DMASEGSZ>>4))
+#define DMASEGEND       (DMASEG+(DMASEGSZ>>4)+(TRACKSEGSZ>>4))
+#else
+#define DMASEGEND       DMASEG      /* no DMASEG buffer */
 #endif
-#define DMASEGEND       (DMASEG+(DMASEGSZ>>4))
 
 #ifdef CONFIG_ROMCODE
-#if defined(CONFIG_BLK_DEV_BFD) || defined(CONFIG_BLK_DEV_BHD)  /* BIOS disk driver*/
-#define DMASEG          0x80        /* 0x400 bytes floppy sector buffer */
+#define DMASEG          0x80        /* start of floppy sector buffer */
 #define KERNEL_DATA     DMASEGEND   /* kernel data segment */
-#else
-#define KERNEL_DATA     0x080       /* kernel data segment */
-#endif
 #define SETUP_DATA      CONFIG_ROM_SETUP_DATA
 #endif
 

emu86.sh

@@ -12,20 +12,18 @@
 # Kernel image @ segment 0xE000 (as 64K BIOS extension)
 # Root filesystem @ segment 0x8000 (assumes 512K RAM & 512K ROM)
 
-# 8088 version using emu-rom-full.config from './buildimages.sh fast'
+# 8088 ROM version using emu-rom-full.config from './buildimages.sh fast'
 exec emu86 -w 0xe0000 -f image/rom-8088.bin -w 0x80000 -f image/romfs-8088.bin ${1+"$@"}
 
-# just built rom version using 'make'
-exec emu86 -w 0xe0000 -f elks/arch/i86/boot/Image -w 0x80000 -f image/romfs.bin ${1+"$@"}
+# just built ROM version using 'make'
+#exec emu86 -w 0xe0000 -f elks/arch/i86/boot/Image -w 0x80000 -f image/romfs.bin ${1+"$@"}
 
 # For ELKS Full ROM Configuration:
 # ELKS must be configured minimally with 'cp emu86-rom-full.config .config'
 # This adds MINIX/FAT filesytems with BIOS driver
-
-exec emu86 -w 0xe0000 -f elks/arch/i86/boot/Image -w 0x80000 -f image/romfs.bin -I image/fd1440.bin ${1+"$@"}
+#exec emu86 -w 0xe0000 -f rom-8088.bin -w 0x80000 -f image/romfs.bin -I image/fd1440.img ${1+"$@"}
 
 # For ELKS disk image Configuration:
 # ELKS must be configured with 'cp emu86-disk.config .config'
 # This uses headless console, HLT on idle, no CONFIG_IDE_PROBE
-
-exec emu86 -I image/fd1440.bin ${1+"$@"}
+#exec emu86 -I image/fd1440.img ${1+"$@"}