Support RT1180 family

The 1180 family uses a different boot header than previous families. The
header is generated to support the default configuration where hash and
signature errors are ignored.

The XIP `__pre_init` strategy is still used, more for ease of getting
something running than because of any known problems with the boot ROM's
implementation of loading images to different memories.

The boot ROM for the 1180 does not appear to allow the entry point to
lie outside the (loaded or execute-in-place) image, so a new `.xip`
section is added after the vector table to put the address inside the
image while keeping VMA=LMA. This could cause problems for tools that
manipulate binaries based on section names.

3 files changed, 117 insertions, 4 deletions

diff --git a/src/host/imxrt-boot-header-1180.x b/src/host/imxrt-boot-header-1180.x
new file mode 100644
index 0000000..101725a
--- /dev/null
+++ b/src/host/imxrt-boot-header-1180.x
@@ -0,0 +1,104 @@
+/* ===--- Begin imxrt-boot-header-1180.x ---===
+ * This extra content is injected into the linker script depending on the
+ * runtime configuration.
+ */
+
+__image_size = SIZEOF(.vector_table) + SIZEOF(.text) + SIZEOF(.xip) + SIZEOF(.rodata) + SIZEOF(.data);
+
+EXTERN(FLEXSPI_CONFIGURATION_BLOCK);
+
+/* # Sections */
+SECTIONS
+{
+  /* Boot header for serial NOR FlexSPI XIP.
+   *
+   * It's 'XIP' in that it starts executing instructions
+   * from flash immediately out of reset. The runtime then
+   * manually copies instructions (data, etc.), and we jump
+   * to that. After that jump, we're no longer XIP.
+   *
+   * The i.MX RT boot ROM also supports a way to copy the
+   * application image by changing the boot data configuration.
+   * Specifically, point the 'Image offset' to somewhere other
+   * than the start of flash, and specify how many bytes to copy.
+   * The boot ROM copies the image, then jumps to the entry point.
+   * It is currently not tested or used, mainly  for consistency
+   * with the other iMXRT families.
+   */
+  .boot1 ORIGIN(FLASH):
+  {
+    FILL(0x00);
+    /* ------------------
+     * Memory configuration block
+     * ------------------
+     *
+     * The size and layout is different for different boot devices. Currently,
+     * only NOR flash is supported.
+     */
+    . += __fcb_offset;          /* Can change based on boot source */
+    KEEP(*(.fcb));
+    . = ORIGIN(FLASH) + 0x1000;
+
+    /* ------------------
+     * Container 1
+     * ------------------
+     */
+    __container1_start = .;
+    LONG(0x87000000 | (__container1_len << 8)); /* Tag, length, version */
+    LONG(0); /* Flags */
+    LONG(0x01000000); /* 1 image, fuse version 0, SW version 0 */
+    LONG(__signature_block_start - __container1_start); /* Signature block offset */
+
+    /* Image array, image 0 */
+    LONG(0xa000); /* Image offset */
+    LONG(__image_size); /* Image size */
+    QUAD(LOADADDR(.vector_table)); /* Load address (execute in place) */
+    QUAD(Reset); /* Entry point */
+    LONG(0x213); /* Flags: Unencrypted, SHA512 hashed, executable image for Cortex-M33 */
+    LONG(0); /* Reserved (image meta data) */
+  } > FLASH
+
+  /* Put the hash in a separate section for easier replacement in a post-build step */
+  .image_hash :
+  {
+    QUAD(0); /* Hash 512 bytes */
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+  } > FLASH
+
+  .boot2 :
+  {
+    FILL(0x00);
+    QUAD(0); /* IV 256 bytes, zero for unencrypted image */
+    QUAD(0);
+    QUAD(0);
+    QUAD(0);
+
+    /* ------------------
+     * Signature block
+     * ------------------
+     */
+    __signature_block_start = .;
+    LONG(0x90000000 | (__signature_block_len << 8)); /* Tag, length, version */
+    LONG(0); /* SRK Table offset, Certificate Offset */
+    LONG(0); /* Signature offset, Blob offset */
+    LONG(0); /* Reserved */
+    __signature_block_end = .;
+    __signature_block_len = __signature_block_end - __signature_block_start;
+    __container1_end = .;
+    __container1_len = __container1_end - __container1_start;
+
+    /* DCD is replaced by XMCD. Satisfy assertions intended for other families. */
+    __dcd_start = .;
+    __dcd_end = .;
+
+    . = ORIGIN(FLASH) + 0x2000;   /* Pad to 8k alignment for the container/images boundary */
+  } > FLASH
+}
+
+/* ===--- End imxrt-boot-header-1180.x ---=== */
diff --git a/src/host/imxrt-boot-header.x b/src/host/imxrt-boot-header.x
index 615fc65..3f33603 100644
--- a/src/host/imxrt-boot-header.x
+++ b/src/host/imxrt-boot-header.x
@@ -8,7 +8,7 @@
  * Note that it depends on the section layout! Need to represent contiguous
  * sections starting from the boot header.
  */
-__image_size = SIZEOF(.boot) + SIZEOF(.vector_table) + SIZEOF(.text) + SIZEOF(.rodata);
+__image_size = SIZEOF(.boot) + SIZEOF(.vector_table) + SIZEOF(.xip) + SIZEOF(.text) + SIZEOF(.rodata);
 
 /* END TODO */
 EXTERN(FLEXSPI_CONFIGURATION_BLOCK);
diff --git a/src/host/imxrt-link.x b/src/host/imxrt-link.x
index 6c28f99..a389325 100644
--- a/src/host/imxrt-link.x
+++ b/src/host/imxrt-link.x
@@ -48,6 +48,7 @@ SECTIONS
 
   .vector_table : ALIGN(1024)
   {
+    FILL(0xff);
     __vector_table = .;
     __svector_table = .;
 
@@ -68,13 +69,19 @@ SECTIONS
   } > REGION_VTABLE AT> REGION_LOAD_VTABLE
   __sivector_table = LOADADDR(.vector_table);
 
+  /* This section guarantees VMA = LMA to allow the execute-in-place entry point to be inside the image. */
+  .xip :
+  {
+    /* Included here if not otherwise included in the boot header. */
+    *(.Reset);
+    *(.__pre_init);
+  } > REGION_LOAD_TEXT
+
   .text :
   {
+    FILL(0xff);
     __stext = .;
     *(.text .text.*);
-    /* Included in .text if not otherwise included in the boot header. */
-    *(.Reset);
-    *(.__pre_init);
     /* The HardFaultTrampoline uses the `b` instruction to enter `HardFault`,
        so must be placed close to it. */
     *(.HardFaultTrampoline);
@@ -86,6 +93,7 @@ SECTIONS
 
   .rodata : ALIGN(4)
   {
+    FILL(0xff);
     . = ALIGN(4);
     __srodata = .;
     *(.rodata .rodata.*);
@@ -100,6 +108,7 @@ SECTIONS
 
   .data : ALIGN(4)
   {
+    FILL(0xff);
     . = ALIGN(4);
     __sdata = .;
     *(.data .data.*);