* Patch by Travis Sawyer, 26 Feb 2004:

[karo-tx-uboot.git] / common / cmd_ace.c

diff --git a/common/cmd_ace.c b/common/cmd_ace.c
index 555fbe398821b833e4d33c56f02f8e536b213bdf..b6f8604780139106f14867843702780639d8c184 100644 (file)
--- a/common/cmd_ace.c
+++ b/common/cmd_ace.c
@@ -121,6 +121,7 @@ static unsigned long systemace_read(int dev,
 {
       unsigned val;
       int retry;
+      unsigned blk_countdown;
       unsigned char*dp = (unsigned char*)buffer;
 
       if (get_cf_lock() < 0) {
@@ -136,6 +137,10 @@ static unsigned long systemace_read(int dev,
            return 0;
       }
 
+#ifdef DEBUG_SYSTEMACE
+      printf("... systemace read %lu sectors at %lu\n", blkcnt, start);
+#endif
+
       retry = 2000;
       for (;;) {
            unsigned val = ace_readw(0x04);
@@ -161,34 +166,55 @@ static unsigned long systemace_read(int dev,
            retry -= 1;
       }
 
-       /* Write LBA block address */
-      ace_writew(start & 0xffff, 0x10);
-      start >>= 16;
-      ace_writew(start & 0xff, 0x12);
+       /* The SystemACE can only transfer 256 sectors at a time, so
+          limit the current chunk of sectors. The blk_countdown
+          variable is the number of sectors left to transfer. */
 
-       /* Write sector count | ReadMemCardData. */
-      ace_writew(blkcnt | 0x0300, 0x14);
+      blk_countdown = blkcnt;
+      while (blk_countdown > 0) {
+           unsigned trans = blk_countdown;
 
-       /* CONTROLREG = CFGRESET|LOCKREQ */
-      ace_writew(0x0082, 0x18);
+           if (trans > 256) trans = 256;
 
-      retry = blkcnt * 16;
-      while (retry > 0) {
-           int idx;
+#ifdef DEBUG_SYSTEMACE
+           printf("... transfer %lu sector in a chunk\n", trans);
+#endif
+             /* Write LBA block address */
+           ace_writew((start>> 0) & 0xffff, 0x10);
+           ace_writew((start>>16) & 0x00ff, 0x12);
 
-             /* Wait for buffer to become ready. */
-           while (! (ace_readw(0x04) & 0x0020)) {
-                 udelay(1000);
-           }
+             /* NOTE: in the Write Sector count below, a count of 0
+                causes a transfer of 256, so &0xff gives the right
+                value for whatever transfer count we want. */
+
+             /* Write sector count | ReadMemCardData. */
+           ace_writew((trans&0xff) | 0x0300, 0x14);
 
-             /* Read 16 words of 2bytes from the sector buffer. */
-           for (idx = 0 ;  idx < 16 ;  idx += 1) {
-                 unsigned short val = ace_readw(0x40);
-                 *dp++ = val & 0xff;
-                 *dp++ = (val>>8) & 0xff;
+             /* CONTROLREG = CFGRESET|LOCKREQ */
+           ace_writew(0x0082, 0x18);
+
+           retry = trans * 16;
+           while (retry > 0) {
+                 int idx;
+
+                   /* Wait for buffer to become ready. */
+                 while (! (ace_readw(0x04) & 0x0020)) {
+                       udelay(1000);
+                 }
+
+                   /* Read 16 words of 2bytes from the sector buffer. */
+                 for (idx = 0 ;  idx < 16 ;  idx += 1) {
+                       unsigned short val = ace_readw(0x40);
+                       *dp++ = val & 0xff;
+                       *dp++ = (val>>8) & 0xff;
+                 }
+
+                 retry -= 1;
            }
 
-           retry -= 1;
+             /* Count the blocks we transfer this time. */
+           start += trans;
+           blk_countdown -= trans;
       }
 
       release_cf_lock();