From: Alan Cox <alan@linux.intel.com>
Date: Wed, 10 Dec 2014 23:19:50 +0000 (+0000)
Subject: trs80: further work on the hd driver
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=7e6e530833516209453f30d976e6cf3b83f7751e;p=FUZIX.git

trs80: further work on the hd driver

Still needs a floppy boot block to begin testing
---

diff --git a/Kernel/platform-trs80/devhd.c b/Kernel/platform-trs80/devhd.c
index cba79c55..ca43c88f 100644
--- a/Kernel/platform-trs80/devhd.c
+++ b/Kernel/platform-trs80/devhd.c
@@ -23,9 +23,9 @@ __sfr __at 0xCF hd_cmd;
 #define HDCMD_RESTORE	0x10
 #define HDCMD_READ	0x20
 #define HDCMD_WRITE	0x30
-#define HDCMD_VERIFY	0x40
+#define HDCMD_VERIFY	0x40	/* Not on the 1010 later only */
 #define HDCMD_FORMAT	0x50
-#define HDCMD_INIT	0x60
+#define HDCMD_INIT	0x60	/* Ditto */
 #define HDCMD_SEEK	0x70
 
 /* Seek and restore low 4 bits are the step rate, read/write support
@@ -33,13 +33,25 @@ __sfr __at 0xCF hd_cmd;
 
 #define MAX_HD	4
 
-
+/* Wait for DRQ or an error */
 static uint8_t hd_waitready(void)
 {
 	uint8_t st;
 	do {
 		st = hd_status;
-	} while (st & 0x80);
+	} while (!(st & 0x40));
+	return st;
+}
+
+
+
+/* Wait for DRQ or an error */
+static uint8_t hd_waitdrq(void)
+{
+	uint8_t st;
+	do {
+		st = hd_status;
+	} while (!(st & 0x09));
 	return st;
 }
 
@@ -49,20 +61,21 @@ static uint8_t hd_xfer(bool is_read, uint16_t addr)
 	int ct = 256;
 	uint8_t *ptr = (uint8_t *)addr;
 
-	if (!(hd_status & 0x08))
+	/* Error ? */
+	if (hd_status & 0x01)
 		return hd_status;
 	if (is_read) {
 		/* Ought to check DRQ per byte ? */
 		while (ct--) {
 			*ptr++ = hd_data;
 		}
-		return 0;
 	} else {
 		while (ct--) {
 			hd_data = *ptr++;
 		}
-		return 0;
 	}
+	/* Should be returning READY, and maybe SEEKDONE */
+	return hd_status;
 }
 
 /*
@@ -93,26 +106,36 @@ static int hd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
 	/* We assume 32 sectors per track for now. From our 512 byte
 	   PoV that's 16 */
 
-	/* For our test purposes we use a disk with 32 sectors, 8 heads so
-	   our blocks map out as   ccccccccCCCCCCCCHHHSSSS */
+	/* For our test purposes we use a disk with 32 sectors, 4 heads so
+	   our blocks map out as   00cccccc ccCCCCCC CCHHSSSS
+
+	   This matches a real ST506 which is 153 cyls, 4 heads, 32 sector */
+
+	hd_precomp = 0x20;	/* For now, matches an ST506 */
 	hd_seccnt = 1;
 	sector = ((block & 15) << 1) + 1;
-	hd_secnum = sector;
-	hd_cyllo = (block >> 7) & 0xFF;
-	hd_cylhi = (block >> 15) & 0xFF;
-	head = (block >> 4) & 7;
+ 	hd_secnum = sector;
+	hd_cyllo = (block >> 6) & 0xFF;
+	hd_cylhi = (block >> 14) & 0xFF;
+	head = (block >> 4) & 3;
 
 	hd_precomp = 0;		/* FIXME */
 	hd_sdh = 0x80 | head | (minor << 3);
 
 	while (ct < 2) {
 		for (tries = 0; tries < 4; tries++) {
+			/* issue the command */
 			hd_cmd = cmd;
-			err = hd_waitready();
-			if (err == 0) {
+			/* DRQ will go high once the controller is ready
+			   for us */
+			err = hd_waitdrq();
+			if (!(err & 1)) {
 				err = hd_xfer(is_read, dptr);
-				break;
+				/* Ready, no error ? */
+				if ((err & 0x41) == 0x40)
+					break;
 			}
+
 			if (tries > 1) {
 				hd_cmd = HDCMD_RESTORE;
 				hd_waitready();
@@ -139,10 +162,11 @@ bad2:
 int hd_open(uint8_t minor, uint16_t flag)
 {
 	flag;
-	if (minor > MAX_HD) {
+	if (minor >= MAX_HD) {
 		udata.u_error = ENODEV;
 		return -1;
 	}
+
 	return 0;
 }