libsa/sdcd: correct blocksize

[Tetsuya Isaki <isaki%pastel-flower.jp@localhost>]

Hello,

These two patches improve libsa/sdcd.c.  sdcd has a few problems
but it is working, so that we didn't notice it easily.

The first one corrects a condition expression.
- start is LBA but dblk is relative from this partition.
- Numerical comparison makes it easy.
There would have been no impact.

The second one clarifies confusing definitions of sector size.
There are three kind of sector size in this code.  DEV_BSIZE
from xxstrategy, media's sector size, and Human68k's sector size.
By this patch,
- For 512 bytes/sector HDD, no changes are intended.
- For CD, corrects the blocksize (%d5) passes to SCSIIOCS.
  It has worked previously though the blocksize was incorrect.
  Now it works with correct blocksize.
- As a secondary effect, 256 or 1024 bytes/sector media may work but
  not well tested.

May I commit it, or any comments?
---
Tetsuya Isaki <isaki%pastel-flower.jp@localhost / isaki%NetBSD.org@localhost>


(First patch)
--- sys/arch/x68k/stand/libsa/sdcd.c
+++ sys/arch/x68k/stand/libsa/sdcd.c
@@ -289,7 +289,7 @@ sdstrategy(void *arg, int rw, daddr_t dblk, size_t size,
 	}
 	nblks = howmany(size, 256 << current_blklen);
 
-	if ((dblk & 0x1fffff) == 0x1fffff && (nblks & 0xff) == nblks) {
+	if (start < 0x200000 && nblks < 256) {
 		if (rw & F_WRITE)
 			error = IOCS_S_WRITE(start, nblks, current_id,
 			                     current_blklen, buf);


(Second patch)
--- sys/arch/x68k/stand/libsa/sdcd.c
+++ sys/arch/x68k/stand/libsa/sdcd.c
@@ -26,6 +26,7 @@
  */
 
 #include <sys/param.h>
+#include <sys/bitops.h>
 #include <sys/disklabel.h>
 #include <lib/libkern/libkern.h>
 #include <lib/libsa/stand.h>
@@ -36,7 +37,9 @@
 
 
 static int current_id = -1;
-static int current_blklen, current_devsize, current_npart;
+static int current_blkbytes;
+static int current_blkshift;
+static int current_devsize, current_npart;
 static struct boot_partinfo partitions[MAXPARTITIONS];
 
 static int readdisklabel(int);
@@ -48,6 +51,44 @@ static int check_unit(int);
 #define DPRINTF(x)	
 #endif
 
+/*
+ * Convert the number of sectors on Human68k
+ * into the number of blocks on the current device.
+ */
+static int
+human2blk(int n)
+{
+	int blk_per_sect;
+
+	/* Human68k uses 1024 byte/sector. */
+	blk_per_sect = 4 >> current_blkshift;
+	if (blk_per_sect == 0)
+		blk_per_sect = 1;
+	return blk_per_sect * n;
+}
+
+/*
+ * Convert the number of sectors on Human68k
+ * into the number of DEV_BSIZE sectors.
+ */
+static int
+human2bsd(int n)
+{
+
+	return n * (1024 / DEV_BSIZE);
+}
+
+/*
+ * Convert the number of DEV_BSIZE sectors
+ * into the number of blocks on the current device.
+ */
+static int
+bsd2blk(int n)
+{
+
+	return ((DEV_BSIZE / 256) * n) >> current_blkshift;
+}
+
 static int
 check_unit(int id)
 {
@@ -90,12 +131,13 @@ check_unit(int id)
 			error = EUNIT;
 			goto out;
 		}
-		current_blklen = rcdata->size >> 9;
+		current_blkbytes = rcdata->size;
+		current_blkshift = fls32(current_blkbytes) - 9;
 		current_devsize = rcdata->block;
 	}
 
 	{
-		error = IOCS_S_READ(0, 1, id, current_blklen, buffer);
+		error = IOCS_S_READ(0, 1, id, current_blkshift, buffer);
 		if (error < 0) {
 			error =  EIO;
 			goto out;
@@ -125,15 +167,15 @@ readdisklabel(int id)
 	error = check_unit(id);
 	if (error)
 		return error;
-	if (current_blklen > 4) {
+	if (current_blkbytes > 2048) {
 		printf("FATAL: Unsupported block size %d.\n",
-		    256 << current_blklen);
+		    current_blkbytes);
 		return ERDLAB;
 	}
 
 	/* Try BSD disklabel first */
 	buffer = alloca(2048);
-	error = IOCS_S_READ(LABELSECTOR, 1, id, current_blklen, buffer);
+	error = IOCS_S_READ(LABELSECTOR, 1, id, current_blkshift, buffer);
 	if (error < 0)
 		return EIO;
 	label = (void *)(buffer + LABELOFFSET);
@@ -149,13 +191,7 @@ readdisklabel(int id)
 	}
 
 	/* Try Human68K-style partition table */
-#if 0
-	/* assumes 512byte/sec */
-	error = IOCS_S_READ(DOSPARTOFF, 2, id, current_blklen, buffer);
-#else
-	error = IOCS_S_READ(8 >> current_blklen, 8 >> current_blklen,
-			    id, current_blklen, buffer);
-#endif
+	error = IOCS_S_READ(human2blk(2), 1, id, current_blkshift, buffer);
 	if (error < 0)
 		return EIO;
 	parttbl = (void *)(buffer + DOSBBSECTOR);
@@ -166,9 +202,9 @@ readdisklabel(int id)
 	     current_npart < MAXPARTITIONS && i < 15 && parttbl[i].dp_size;
 	     i++) {
 		partitions[current_npart].start
-			= parttbl[i].dp_start * 2;
+			= human2bsd(parttbl[i].dp_start);
 		partitions[current_npart].size
-			= parttbl[i].dp_size  * 2;
+			= human2bsd(parttbl[i].dp_size);
 		if (++current_npart == RAW_PART) {
 			partitions[current_npart].start = 0;
 			partitions[current_npart].size = -1; /* XXX */
@@ -205,8 +241,7 @@ sd_getbsdpartition(int id, int humanpart)
 		return -1;
 	}
 	buffer = alloca(2048);
-	error = IOCS_S_READ(8 >> current_blklen, 8 >> current_blklen,
-			    id, current_blklen, buffer);
+	error = IOCS_S_READ(human2blk(2), 1, id, current_blkshift, buffer);
 	if (error < 0) {
 		printf("Reading partition table: %s\n", strerror(error));
 		return -1;
@@ -214,8 +249,7 @@ sd_getbsdpartition(int id, int humanpart)
 	parttbl = (void *)(buffer + DOSBBSECTOR);
 	if (strncmp(buffer, "X68K", 4) != 0)
 		return 0;
-	parttop = parttbl[humanpart].dp_start;
-	parttop = parttop << (2 - current_blklen);
+	parttop = human2bsd(parttbl[humanpart].dp_start);
 
 	for (i = 0; i < current_npart; i++) {
 		if (partitions[i].start == parttop)
@@ -230,7 +264,6 @@ sd_getbsdpartition(int id, int humanpart)
 struct sdcd_softc {
 	int			sc_part;
 	struct boot_partinfo	sc_partinfo;
-	int			sc_blocksize;
 };
 
 /* sdopen(struct open_file *f, int id, int part) */
@@ -260,7 +293,6 @@ sdopen(struct open_file *f, ...)
 	sc = alloc(sizeof(struct sdcd_softc));
 	sc->sc_part = part;
 	sc->sc_partinfo = partitions[part];
-	sc->sc_blocksize = current_blklen << 9;
 	f->f_devdata = sc;
 	return 0;
 }
@@ -287,22 +319,23 @@ sdstrategy(void *arg, int rw, daddr_t dblk, size_t size,
 			*rsize = 0;
 		return 0;
 	}
-	nblks = howmany(size, 256 << current_blklen);
+	start = bsd2blk(start);
+	nblks = howmany(size, current_blkbytes);
 
 	if (start < 0x200000 && nblks < 256) {
 		if (rw & F_WRITE)
 			error = IOCS_S_WRITE(start, nblks, current_id,
-			                     current_blklen, buf);
+			                     current_blkshift, buf);
 		else
 			error = IOCS_S_READ(start, nblks, current_id,
-			                    current_blklen, buf);
+			                    current_blkshift, buf);
 	} else {
 		if (rw & F_WRITE)
 			error = IOCS_S_WRITEEXT(start, nblks, current_id,
-			                        current_blklen, buf);
+			                        current_blkshift, buf);
 		else
 			error = IOCS_S_READEXT(start, nblks, current_id,
-			                       current_blklen, buf);
+			                       current_blkshift, buf);
 	}
 	if (error < 0)
 		return EIO;
@@ -341,7 +374,6 @@ cdopen(struct open_file *f, ...)
 	sc->sc_part = 0;
 	sc->sc_partinfo.start = 0;
 	sc->sc_partinfo.size = current_devsize;
-	sc->sc_blocksize = current_blklen << 9;
 	f->f_devdata = sc;
 	current_id = id;
 
@@ -360,10 +392,5 @@ int
 cdstrategy(void *arg, int rw, daddr_t dblk, size_t size,
            void *buf, size_t *rsize)
 {
-	struct sdcd_softc *sc = arg;
-
-	/* cast dblk to avoid divdi3; 32bit is enough even for BD-ROMs.  */
-	return sdstrategy(arg, rw,
-			  (unsigned int) dblk / (sc->sc_blocksize/DEV_BSIZE),
-	                  size, buf, rsize);
+	return sdstrategy(arg, rw, dblk, size, buf, rsize);
 }