Add pre and post configuration callbacks for Spartan FPGAs

This patch adds a post configuration callback for Spartan2/3 FPGAs.
pre and post configuration callback are now optional and
not called when the function pointer is set to NULL.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd-electronics.com>
diff --git a/common/spartan2.c b/common/spartan2.c
index 457009f..ef107bc 100644
--- a/common/spartan2.c
+++ b/common/spartan2.c
@@ -561,6 +561,13 @@
 		}
 		putc ('\n');			/* terminate the dotted line */
 
+		/*
+		 * Run the post configuration function if there is one.
+		 */
+		if (*fn->post) {
+			(*fn->post) (cookie);
+		}
+
 #ifdef CFG_FPGA_PROG_FEEDBACK
 		if (ret_val == FPGA_SUCCESS) {
 			puts ("Done.\n");
@@ -615,8 +622,10 @@
 			PRINTF ("%s: Relocating descriptor at 0x%p\n", __FUNCTION__,
 					desc);
 
-			addr = (ulong) (fn->pre) + reloc_offset;
-			fn_r->pre = (Xilinx_pre_fn) addr;
+			if (fn->pre) {
+				addr = (ulong) (fn->pre) + reloc_offset;
+				fn_r->pre = (Xilinx_pre_fn) addr;
+			}
 
 			addr = (ulong) (fn->pgm) + reloc_offset;
 			fn_r->pgm = (Xilinx_pgm_fn) addr;
@@ -633,6 +642,11 @@
 			addr = (ulong) (fn->wr) + reloc_offset;
 			fn_r->wr = (Xilinx_wr_fn) addr;
 
+			if (fn->post) {
+				addr = (ulong) (fn->post) + reloc_offset;
+				fn_r->post = (Xilinx_post_fn) addr;
+			}
+
 			fn_r->relocated = TRUE;
 
 		} else {
diff --git a/common/spartan3.c b/common/spartan3.c
index 17379eb..56a172e 100644
--- a/common/spartan3.c
+++ b/common/spartan3.c
@@ -566,6 +566,13 @@
 		}
 		putc ('\n');			/* terminate the dotted line */
 
+		/*
+		 * Run the post configuration function if there is one.
+		 */
+		if (*fn->post) {
+			(*fn->post) (cookie);
+		}
+
 #ifdef CFG_FPGA_PROG_FEEDBACK
 		if (ret_val == FPGA_SUCCESS) {
 			puts ("Done.\n");
@@ -620,8 +627,10 @@
 			PRINTF ("%s: Relocating descriptor at 0x%p\n", __FUNCTION__,
 					desc);
 
-			addr = (ulong) (fn->pre) + reloc_offset;
-			fn_r->pre = (Xilinx_pre_fn) addr;
+			if (fn->pre) {
+				addr = (ulong) (fn->pre) + reloc_offset;
+				fn_r->pre = (Xilinx_pre_fn) addr;
+			}
 
 			addr = (ulong) (fn->pgm) + reloc_offset;
 			fn_r->pgm = (Xilinx_pgm_fn) addr;
@@ -638,6 +647,11 @@
 			addr = (ulong) (fn->wr) + reloc_offset;
 			fn_r->wr = (Xilinx_wr_fn) addr;
 
+			if (fn->post) {
+				addr = (ulong) (fn->post) + reloc_offset;
+				fn_r->post = (Xilinx_post_fn) addr;
+			}
+
 			fn_r->relocated = TRUE;
 
 		} else {
diff --git a/include/spartan2.h b/include/spartan2.h
index d2e81e3..f3cde68 100644
--- a/include/spartan2.h
+++ b/include/spartan2.h
@@ -58,6 +58,7 @@
 	Xilinx_init_fn	init;
 	Xilinx_done_fn	done;
 	Xilinx_wr_fn	wr;
+	Xilinx_post_fn	post;
 	int           	relocated;
 } Xilinx_Spartan2_Slave_Serial_fns;
 
diff --git a/include/spartan3.h b/include/spartan3.h
index 65a3f5a..529aade 100644
--- a/include/spartan3.h
+++ b/include/spartan3.h
@@ -58,6 +58,7 @@
 	Xilinx_init_fn	init;
 	Xilinx_done_fn	done;
 	Xilinx_wr_fn	wr;
+	Xilinx_post_fn	post;
 	int           	relocated;
 } Xilinx_Spartan3_Slave_Serial_fns;