Blackfin: bootldr: implement BF53x/BF56x LDR loader

The BF53x/BF56x parts do not have an on-chip ROM to boot LDRs out of
arbitrary memory locations, so implement a basic one in software.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

common/cmd_bootldr.c

@@ -16,6 +16,127 @@
 #include <asm/blackfin.h>
 #include <asm/mach-common/bits/bootrom.h>
 
+/* Simple sanity check on the specified address to make sure it contains
+ * an LDR image of some sort.
+ */
+static bool ldr_valid_signature(uint8_t *data)
+{
+#if defined(__ADSPBF561__)
+
+	/* BF56x has a 4 byte global header */
+	if (data[3] == 0xA0)
+		return true;
+
+#elif defined(__ADSPBF531__) || defined(__ADSPBF532__) || defined(__ADSPBF533__) || \
+      defined(__ADSPBF534__) || defined(__ADSPBF536__) || defined(__ADSPBF537__) || \
+      defined(__ADSPBF538__) || defined(__ADSPBF539__)
+
+	/* all the BF53x should start at this address mask */
+	uint32_t addr;
+	memmove(&addr, data, sizeof(addr));
+	if ((addr & 0xFF0FFF0F) == 0xFF000000)
+		return true;
+#else
+
+	/* everything newer has a magic byte */
+	uint32_t count;
+	memmove(&count, data + 8, sizeof(count));
+	if (data[3] == 0xAD && count == 0)
+		return true;
+
+#endif
+
+	return false;
+}
+
+/* If the Blackfin is new enough, the Blackfin on-chip ROM supports loading
+ * LDRs from random memory addresses.  So whenever possible, use that.  In
+ * the older cases (BF53x/BF561), parse the LDR format ourselves.
+ */
+#define ZEROFILL  0x0001
+#define RESVECT   0x0002
+#define INIT      0x0008
+#define IGNORE    0x0010
+#define FINAL     0x8000
+static void ldr_load(uint8_t *base_addr)
+{
+#if defined(__ADSPBF531__) || defined(__ADSPBF532__) || defined(__ADSPBF533__) || \
+  /*defined(__ADSPBF534__) || defined(__ADSPBF536__) || defined(__ADSPBF537__) ||*/\
+    defined(__ADSPBF538__) || defined(__ADSPBF539__) || defined(__ADSPBF561__)
+
+	void *ret;
+
+	uint32_t addr;
+	uint32_t count;
+	uint16_t flags;
+
+	/* the bf56x has a 4 byte global header ... but it is useless to
+	 * us when booting an LDR from a memory address, so skip it
+	 */
+# ifdef __ADSPBF561__
+	base_addr += 4;
+# endif
+
+	memmove(&flags, base_addr + 8, sizeof(flags));
+	bfin_write_EVT1(flags & RESVECT ? 0xFFA00000 : 0xFFA08000);
+
+	do {
+		/* block header may not be aligned */
+		memmove(&addr, base_addr, sizeof(addr));
+		memmove(&count, base_addr+4, sizeof(count));
+		memmove(&flags, base_addr+8, sizeof(flags));
+		base_addr += sizeof(addr) + sizeof(count) + sizeof(flags);
+
+		printf("loading to 0x%08x (0x%x bytes) flags: 0x%04x\n",
+			addr, count, flags);
+
+		if (!(flags & IGNORE)) {
+			if (flags & ZEROFILL)
+				memset((void *)addr, 0x00, count);
+			else
+				memcpy((void *)addr, base_addr, count);
+
+			if (flags & INIT) {
+				void (*init)(void) = (void *)addr;
+				init();
+			}
+		}
+
+		if (!(flags & ZEROFILL))
+			base_addr += count;
+	} while (!(flags & FINAL));
+
+#endif
+}
+
+/* For BF537, we use the _BOOTROM_BOOT_DXE_FLASH funky ROM function.
+ * For all other BF53x/BF56x, we just call the entry point.
+ * For everything else (newer), we use _BOOTROM_MEMBOOT ROM function.
+ */
+static void ldr_exec(void *addr)
+{
+#if defined(__ADSPBF534__) || defined(__ADSPBF536__) || defined(__ADSPBF537__)
+
+	/* restore EVT1 to reset value as this is what the bootrom uses as
+	 * the default entry point when booting the final block of LDRs
+	 */
+	bfin_write_EVT1(L1_INST_SRAM);
+	__asm__("call (%0);" : : "a"(_BOOTROM_MEMBOOT), "q7"(addr) : "RETS", "memory");
+
+#elif defined(__ADSPBF531__) || defined(__ADSPBF532__) || defined(__ADSPBF533__) || \
+      defined(__ADSPBF538__) || defined(__ADSPBF539__) || defined(__ADSPBF561__)
+
+	void (*ldr_entry)(void) = bfin_read_EVT1();
+	ldr_entry();
+
+#else
+
+	int32_t (*BOOTROM_MEM)(void *, int32_t, int32_t, void *) = (void *)_BOOTROM_MEMBOOT;
+	BOOTROM_MEM(addr, 0, 0, NULL);
+
+#endif
+}
+
 /*
  * the bootldr command loads an address, checks to see if there
  *   is a Boot stream that the on-chip BOOTROM can understand,
@@ -23,11 +144,9 @@
  *   to also add booting from SPI, or TWI, but this function does
  *   not currently support that.
  */
-
 int do_bootldr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 {
 	void *addr;
-	uint32_t *data;
 
 	/* Get the address */
 	if (argc < 2)
@@ -36,22 +155,14 @@ int do_bootldr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 		addr = (void *)simple_strtoul(argv[1], NULL, 16);
 
 	/* Check if it is a LDR file */
-	data = addr;
-#if defined(__ADSPBF54x__) || defined(__ADSPBF52x__)
-	if ((*data & 0xFF000000) == 0xAD000000 && data[2] == 0x00000000) {
-#else
-	if (*data == 0xFF800060 || *data == 0xFF800040 || *data == 0xFF800020) {
-#endif
-		/* We want to boot from FLASH or SDRAM */
+	if (ldr_valid_signature(addr)) {
 		printf("## Booting ldr image at 0x%p ...\n", addr);
+		ldr_load(addr);
 
 		icache_disable();
 		dcache_disable();
 
-		__asm__(
-			"jump (%1);"
-			:
-			: "q7" (addr), "a" (_BOOTROM_MEMBOOT));
+		ldr_exec(addr);
 	} else
 		printf("## No ldr image at address 0x%p\n", addr);