Improve "reset" command's interaction with watchdog.

"reset altbank" will reset another bank WITHOUT watch dog timer enabled
    "reset altbank wd" will reset another bank WITH watch dog enabled
    "diswd" will disable watch dog after u-boot boots up successfully

Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>

cpu/mpc86xx/cpu.c

@@ -169,7 +169,7 @@ soft_restart(unsigned long addr)
 
 int set_px_sysclk(ulong sysclk)
 {
-         u8 sysclk_s, sysclk_r, sysclk_v, vclkh, vclkl, sysclk_aux,tmp;
+         u8 sysclk_s, sysclk_r, sysclk_v, vclkh, vclkl, sysclk_aux;
 
          /* Per table 27, page 58 of MPC8641HPCN spec*/
          switch(sysclk)
@@ -354,6 +354,24 @@ void set_px_go_with_watchdog(void)
          out8(PIXIS_BASE+PIXIS_VCTL,tmp);
 }
 
+int disable_watchdog(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	u8 tmp;
+	tmp = in8(PIXIS_BASE+PIXIS_VCTL);
+	tmp = tmp & 0x1E;
+	out8(PIXIS_BASE+PIXIS_VCTL,tmp);
+	tmp = in8(PIXIS_BASE + PIXIS_VCTL);
+	tmp &= ~ 0x08; /* setting VCTL[WDEN] to 0 to disable watch dog */
+	out8(PIXIS_BASE + PIXIS_VCTL, tmp);
+	return 0;
+}
+
+U_BOOT_CMD(
+	diswd, 1, 0, disable_watchdog,
+	"diswd	- Disable watchdog timer \n",
+	NULL
+);
+
 /* This function takes the non-integral cpu:mpx pll ratio
  * and converts it to an integer that can be used to assign
  * FPGA register values.
@@ -509,18 +527,27 @@ do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 					goto my_usage;
 
 				while(1); /* Not reached */
-			} else {
-				/* Reset from next bank without changing frequencies */
+			} else if(argv[2][1] == 'd'){
+				/* Reset from next bank without changing frequencies but with watchdog timer enabled */
 				read_from_px_regs(0);
 				read_from_px_regs_altbank(0);
-				if(argc > 2)
-					goto my_usage;
 				printf("Setting registers VCFGEN1, VBOOT, and VCTL\n");
 				set_altbank();
 				read_from_px_regs_altbank(1);
 				printf("Enabling watchdog timer on the FPGA and resetting board to boot from the other bank....\n");
 				set_px_go_with_watchdog();
 				while(1); /* Not reached */
+			} else {
+				/* Reset from next bank without changing frequency and without watchdog timer enabled */
+				read_from_px_regs(0);
+				read_from_px_regs_altbank(0);
+				if(argc > 2)
+					goto my_usage;
+				printf("Setting registers VCFGNE1, VBOOT, and VCTL\n");
+				set_altbank();
+				read_from_px_regs_altbank(1);
+				printf("Resetting board to boot from the other bank....\n");
+				set_px_go();
 			}
 
 		default: