Add app to read raw /dev/mem for debugging

This allows for direct access by the host to the same memory region as the AXIS
ports are accessing. Should be useful for debugging.

app/Makefile

@@ -4,6 +4,7 @@ CFLAGS := -c -Wall -Werror
 INCLUDES := -I.
 
 EXECUTABLE = \
+	read-memory \
 	test-cfg
 
 
@@ -15,6 +16,10 @@ all : $(EXECUTABLE)
 	$(CC) $(INCLUDES) $(CFLAGS) $< -o $@
 
 
+read-memory : read-memory.o
+	$(CC) $< -o $@ $(LDFLAGS)
+
+
 test-cfg : test-cfg.o
 	$(CC) $< -o $@ $(LDFLAGS)
 

app/read-memory.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+int main(int argc, char *argv[])
+{
+	int i = 0;
+	int total = 0;
+
+	if (argc < 3) {
+		printf("Usage: %s <phys_addr> <length>\n", argv[0]);
+		return 0;
+	}
+
+	//off_t offset = 462422016;
+	off_t offset = atoi(argv[1]);
+	size_t len = atoi(argv[2]);
+	printf("phys_addr: %ld, %02x, length: %ld\n", (long int)offset, (unsigned int)offset,
+	       (long int)len);
+
+	int fd = open("/dev/mem", O_SYNC);
+	unsigned short *mem =
+	    (unsigned short *)mmap(NULL, len, PROT_READ | PROT_WRITE,
+				   MAP_PRIVATE, fd, offset);
+
+	if (mem == NULL) {
+		printf("Can't map memory\n");
+		return -2;
+	}
+
+//      for (i = 0; i < len; ++i) {
+//              mem[i] = 0xDEAD;
+//      }
+
+	for (i = 0; i < len; ++i) {
+		if (0xDEAD == mem[i]) {
+			total++;
+			printf("%6d, %10ld, %02x, %02x\n", total, (offset + i),
+			       (unsigned int)(offset + i), (int)mem[i]);
+		}
+	}
+	printf("\n");
+
+	return 0;
+}