rockchip: mkimage: pad the header to 8-bytes (using a 'nop') for RK3399

The RK3399 boot code (running as AArch64) poses a bit of a challenge
for SPL image generation:
 * The BootROM will start execution right after the 4-byte header (at
   the odd instruction word loaded into SRAM at 0xff8c2004, with the
   'RK33' boot magic residing at 0xff8c2000).
 * The default padding (during ELF generation) for AArch64 is 0x0,
   which is an illegal instruction and the .text section needs to be
   naturally aligned (someone might locate a 64bit constant relative
   to the section start and unaligned loads trigger a fault for all
   privileged modes of an ARMv8)... so we can't simply define the
   CONFIG_SPL_TEXT_BASE option to the odd address (0xff8c2004).
 * Finally, we don't want to change the values used for padding of
   the SPL .text section for all ARMv8 targets to the instruction
   word encoding 'nop', as this would affect all padding in this
   section and might hide errors that would otherwise quickly trigger
   an illegal insn exception.

To deal with this situation, we modify the rkimage generation to
 - understand the fact that the RK3399 needs to pad the header to an
   8 byte boundary using an AArch64 'nop'
 - the necessary logic to adjust the header_size (which controls the
   location where the payload is copied into the image) and to insert
   this padding (AArch64 insn words are always little-endian) into
   the image following the 4-byte header magic.

X-AffectedPlatforms: RK3399-Q7
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>

1 files changed, 85 insertions, 12 deletions

diff --git a/tools/rkcommon.c b/tools/rkcommon.c
index 6595e02..1ea072b 100644
--- a/tools/rkcommon.c
+++ b/tools/rkcommon.c
@@ -41,25 +41,36 @@ struct header0_info {
 };
 
 /**
+ * struct header1_info
+ */
+struct header1_info {
+	uint32_t magic;
+	uint32_t first_insn;
+};
+
+/**
  * struct spl_info - spl info for each chip
  *
  * @imagename:		Image name(passed by "mkimage -n")
  * @spl_hdr:		Boot ROM requires a 4-bytes spl header
  * @spl_size:		Spl size(include extra 4-bytes spl header)
  * @spl_rc4:		RC4 encode the SPL binary (same key as header)
+ * @spl_aarch64:        Pad the header with an AArch64 'nop's to 8-bytes
  */
+
 struct spl_info {
 	const char *imagename;
 	const char *spl_hdr;
 	const uint32_t spl_size;
 	const bool spl_rc4;
+	const bool spl_aarch64;
 };
 
 static struct spl_info spl_infos[] = {
-	{ "rk3036", "RK30", 0x1000, false },
-	{ "rk3188", "RK31", 0x8000 - 0x800, true },
-	{ "rk3288", "RK32", 0x8000, false },
-	{ "rk3399", "RK33", 0x20000, false },
+	{ "rk3036", "RK30", 0x1000, false, false },
+	{ "rk3188", "RK31", 0x8000 - 0x800, true, false },
+	{ "rk3288", "RK32", 0x8000, false, false },
+	{ "rk3399", "RK33", 0x20000, false, true },
 };
 
 static unsigned char rc4_key[16] = {
@@ -106,6 +117,16 @@ const char *rkcommon_get_spl_hdr(struct image_tool_params *params)
 	return info->spl_hdr;
 }
 
+const bool rkcommon_get_spl_hdr_padto8(struct image_tool_params *params)
+{
+	struct spl_info *info = rkcommon_get_spl_info(params->imagename);
+
+	/*
+	 * info would not be NULL, because of we checked params before.
+	 */
+	return info->spl_aarch64;
+}
+
 int rkcommon_get_spl_size(struct image_tool_params *params)
 {
 	struct spl_info *info = rkcommon_get_spl_info(params->imagename);
@@ -126,16 +147,12 @@ bool rkcommon_need_rc4_spl(struct image_tool_params *params)
 	return info->spl_rc4;
 }
 
-int rkcommon_set_header(void *buf, uint file_size,
-			struct image_tool_params *params)
+static void rkcommon_set_header0(void *buf, uint file_size,
+				 struct image_tool_params *params)
 {
-	struct header0_info *hdr;
+	struct header0_info *hdr = buf;
 
-	if (file_size > rkcommon_get_spl_size(params))
-		return -ENOSPC;
-
-	memset(buf,  '\0', RK_INIT_OFFSET * RK_BLK_SIZE);
-	hdr = (struct header0_info *)buf;
+	memset(buf, '\0', RK_INIT_OFFSET * RK_BLK_SIZE);
 	hdr->signature = RK_SIGNATURE;
 	hdr->disable_rc4 = !rkcommon_need_rc4_spl(params);
 	hdr->init_offset = RK_INIT_OFFSET;
@@ -145,6 +162,31 @@ int rkcommon_set_header(void *buf, uint file_size,
 	hdr->init_boot_size = hdr->init_size + RK_MAX_BOOT_SIZE / RK_BLK_SIZE;
 
 	rc4_encode(buf, RK_BLK_SIZE, rc4_key);
+}
+
+int rkcommon_set_header(void *buf, uint file_size,
+			struct image_tool_params *params)
+{
+	struct header1_info *hdr = buf + RK_SPL_HDR_START;
+
+	if (file_size > rkcommon_get_spl_size(params))
+		return -ENOSPC;
+
+	rkcommon_set_header0(buf, file_size, params);
+
+	/* Set up the SPL name and add the AArch64 'nop' padding, if needed */
+	memcpy(&hdr->magic, rkcommon_get_spl_hdr(params), RK_SPL_HDR_SIZE);
+
+	/*
+	 * Pad the 4-byte header to 8-bytes using an AArch64 'nop'.
+	 * Note that AArch64 insns are always encoded as little-endian.
+	 */
+	if (rkcommon_get_spl_hdr_padto8(params))
+		hdr->first_insn = cpu_to_le32(0xd503201f);
+
+	if (rkcommon_need_rc4_spl(params))
+		rkcommon_rc4_encode_spl(buf, RK_SPL_HDR_START,
+					params->file_size - RK_SPL_HDR_START);
 
 	return 0;
 }
@@ -161,3 +203,34 @@ void rkcommon_rc4_encode_spl(void *buf, unsigned int offset, unsigned int size)
 		remaining -= step;
 	}
 }
+
+void rkcommon_vrec_header(struct image_tool_params *params,
+			  struct image_type_params *tparams)
+{
+	/*
+	 * The SPL image looks as follows:
+	 *
+	 * 0x0    header0 (see rkcommon.c)
+	 * 0x800  spl_name ('RK30', ..., 'RK33')
+	 * 0x804  first instruction to be executed
+	 *        (image start for AArch32, 'nop' for AArch64))
+	 * 0x808  second instruction to be executed
+	 *        (image start for AArch64)
+	 *
+	 * For AArch64 (ARMv8) payloads, we receive an input file that
+	 * needs to start on an 8-byte boundary (natural alignment), so
+	 * we need to put a NOP at 0x804.
+	 *
+	 * Depending on this, the header is either 0x804 or 0x808 bytes
+	 * in length.
+	 */
+	if (rkcommon_get_spl_hdr_padto8(params))
+		tparams->header_size = RK_SPL_HDR_START + 8;
+	else
+		tparams->header_size = RK_SPL_HDR_START + 4;
+
+	/* Allocate, clear and install the header */
+	tparams->hdr = malloc(tparams->header_size);
+	memset(tparams->hdr, 0, tparams->header_size);
+	tparams->header_size = tparams->header_size;
+}