Nios II - Add EPCS Controller bootrom work-around

  -When booting from an epcs controller, the epcs bootrom may leave the
  slave select in an asserted state causing soft reset hang. This
  patch ensures slave select is negated at reset.
  Patch by Scott McNutt, 08 Jun 2006

4 files changed, 36 insertions, 0 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 5480a69d8f..547f90c65e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,12 @@
 Changes since U-Boot 1.1.4:
 ======================================================================
 
+* Nios II - Add EPCS Controller bootrom work-around
+  -When booting from an epcs controller, the epcs bootrom may leave the
+  slave select in an asserted state causing soft reset hang. This
+  patch ensures slave select is negated at reset.
+  Patch by Scott McNutt, 08 Jun 2006
+
 * Update PK1C20 board
   -Update base addresses for standard configuration
   -Eliminate use of CACHE_BYPASS in board code
diff --git a/cpu/nios2/epcs.c b/cpu/nios2/epcs.c
index fd9fd8498a..414c38c2b1 100644
--- a/cpu/nios2/epcs.c
+++ b/cpu/nios2/epcs.c
@@ -210,6 +210,21 @@ static struct epcs_devinfo_t devinfo[] = {
 	{ 0, 0, 0, 0, 0, 0 }
 };
 
+int epcs_reset (void)
+{
+	/* When booting from an epcs controller, the epcs bootrom
+	 * code may leave the slave select in an asserted state.
+	 * This causes two problems: (1) The initial epcs access
+	 * will fail -- not a big deal, and (2) a software reset
+	 * will cause the bootrom code to hang since it does not
+	 * ensure the select is negated prior to first access -- a
+	 * big deal. Here we just negate chip select and everything
+	 * gets better :-)
+	 */
+	epcs_cs (0); /* Negate chip select */
+	return (0);
+}
+
 epcs_devinfo_t *epcs_dev_find (void)
 {
 	unsigned char buf[4];
diff --git a/include/nios2-epcs.h b/include/nios2-epcs.h
index 2c9522cfd8..20e0c87c89 100644
--- a/include/nios2-epcs.h
+++ b/include/nios2-epcs.h
@@ -38,6 +38,11 @@ typedef struct epcs_devinfo_t {
 	unsigned char   prot_mask;	/* Protection mask */
 }epcs_devinfo_t;
 
+/* Resets the epcs controller -- to prevent (potential) soft-reset
+ * problems when booting from the epcs controller
+ */
+extern int epcs_reset (void);
+
 /* Returns the devinfo struct if EPCS device is found;
  * NULL otherwise.
  */
diff --git a/lib_nios2/board.c b/lib_nios2/board.c
index cd23037771..7ffb3f019b 100644
--- a/lib_nios2/board.c
+++ b/lib_nios2/board.c
@@ -31,6 +31,9 @@
 #ifdef CONFIG_STATUS_LED
 #include <status_led.h>
 #endif
+#if defined(CFG_NIOS_EPCSBASE)
+#include <nios2-epcs.h>
+#endif
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -93,6 +96,9 @@ init_fnc_t *init_sequence[] = {
 #if defined(CONFIG_BOARD_EARLY_INIT_F)
 	board_early_init_f,	/* Call board-specific init code early.*/
 #endif
+#if defined(CFG_NIOS_EPCSBASE)
+	epcs_reset,
+#endif
 
 	env_init,
 	serial_init,
@@ -165,6 +171,10 @@ void board_init (void)
 	WATCHDOG_RESET ();
 	interrupt_init ();
 
+#if defined(CONFIG_BOARD_LATE_INIT)
+	board_late_init ();
+#endif
+
 	/* main_loop */
 	for (;;) {
 		WATCHDOG_RESET ();