add block write function to spartan3 slave serial load

Using seperate function calls for each bit-bang of slave serial
load can be painfully slow. This patch adds the possibility to
supply a block write function that loads the complete block of
data in one call (like it can already be done with Altera FPGAs).
On an MCF5373L (240 MHz) loading an XC3S4000 this reduces the load
time from around 15 seconds to around 3 seconds

Signed-off-by: Wolfgang Wegner <w.wegner at astro-kom.de>

drivers/fpga/spartan3.c

@@ -385,34 +385,38 @@ static int Spartan3_ss_load (Xilinx_desc * desc, void *buf, size_t bsize)
 		} while ((*fn->init) (cookie));
 
 		/* Load the data */
-		while (bytecount < bsize) {
-
-			/* Xilinx detects an error if INIT goes low (active)
-			   while DONE is low (inactive) */
-			if ((*fn->done) (cookie) == 0 && (*fn->init) (cookie)) {
-				puts ("** CRC error during FPGA load.\n");
-				return (FPGA_FAIL);
-			}
-			val = data [bytecount ++];
-			i = 8;
-			do {
-				/* Deassert the clock */
-				(*fn->clk) (FALSE, TRUE, cookie);
-				CONFIG_FPGA_DELAY ();
-				/* Write data */
-				(*fn->wr) ((val & 0x80), TRUE, cookie);
-				CONFIG_FPGA_DELAY ();
-				/* Assert the clock */
-				(*fn->clk) (TRUE, TRUE, cookie);
-				CONFIG_FPGA_DELAY ();
-				val <<= 1;
-				i --;
-			} while (i > 0);
+		if(*fn->bwr)
+			(*fn->bwr) (data, bsize, TRUE, cookie);
+		else {
+			while (bytecount < bsize) {
+
+				/* Xilinx detects an error if INIT goes low (active)
+				   while DONE is low (inactive) */
+				if ((*fn->done) (cookie) == 0 && (*fn->init) (cookie)) {
+					puts ("** CRC error during FPGA load.\n");
+					return (FPGA_FAIL);
+				}
+				val = data [bytecount ++];
+				i = 8;
+				do {
+					/* Deassert the clock */
+					(*fn->clk) (FALSE, TRUE, cookie);
+					CONFIG_FPGA_DELAY ();
+					/* Write data */
+					(*fn->wr) ((val & 0x80), TRUE, cookie);
+					CONFIG_FPGA_DELAY ();
+					/* Assert the clock */
+					(*fn->clk) (TRUE, TRUE, cookie);
+					CONFIG_FPGA_DELAY ();
+					val <<= 1;
+					i --;
+				} while (i > 0);
 
 #ifdef CONFIG_SYS_FPGA_PROG_FEEDBACK
-			if (bytecount % (bsize / 40) == 0)
-				putc ('.');		/* let them know we are alive */
+				if (bytecount % (bsize / 40) == 0)
+					putc ('.');		/* let them know we are alive */
 #endif
+			}
 		}
 
 		CONFIG_FPGA_DELAY ();

include/spartan3.h

@@ -57,6 +57,7 @@ typedef struct {
 	Xilinx_done_fn	done;
 	Xilinx_wr_fn	wr;
 	Xilinx_post_fn	post;
+	Xilinx_bwr_fn	bwr; /* block write function */
 } Xilinx_Spartan3_Slave_Serial_fns;
 
 /* Device Image Sizes

include/xilinx.h

@@ -100,5 +100,6 @@ typedef int (*Xilinx_busy_fn)( int cookie );
 typedef int (*Xilinx_abort_fn)( int cookie );
 typedef int (*Xilinx_pre_fn)( int cookie );
 typedef int (*Xilinx_post_fn)( int cookie );
+typedef int (*Xilinx_bwr_fn)( void *buf, size_t len, int flush, int cookie );
 
 #endif  /* _XILINX_H_ */