add pimoroni2w support

kernel/rp2350.x

@@ -0,0 +1,60 @@
+MEMORY {
+    FLASH : ORIGIN = 0x10000000, LENGTH = 4096K
+
+    RAM : ORIGIN = 0x20000000, LENGTH = 512K
+    SRAM4 : ORIGIN = 0x20080000, LENGTH = 4K
+    SRAM5 : ORIGIN = 0x20081000, LENGTH = 4K
+}
+
+SECTIONS {
+    /* ### Boot ROM info
+     *
+     * Goes after .vector_table, to keep it in the first 4K of flash
+     * where the Boot ROM (and picotool) can find it
+     */
+    .start_block : ALIGN(4)
+    {
+        __start_block_addr = .;
+        KEEP(*(.start_block));
+        KEEP(*(.boot_info));
+    } > FLASH
+
+} INSERT AFTER .vector_table;
+
+/* move .text to start /after/ the boot info */
+_stext = ADDR(.start_block) + SIZEOF(.start_block);
+
+SECTIONS {
+    /* ### Picotool 'Binary Info' Entries
+     *
+     * Picotool looks through this block (as we have pointers to it in our
+     * header) to find interesting information.
+     */
+    .bi_entries : ALIGN(4)
+    {
+        /* We put this in the header */
+        __bi_entries_start = .;
+        /* Here are the entries */
+        KEEP(*(.bi_entries));
+        /* Keep this block a nice round size */
+        . = ALIGN(4);
+        /* We put this in the header */
+        __bi_entries_end = .;
+    } > FLASH
+} INSERT AFTER .text;
+
+SECTIONS {
+    /* ### Boot ROM extra info
+     *
+     * Goes after everything in our program, so it can contain a signature.
+     */
+    .end_block : ALIGN(4)
+    {
+        __end_block_addr = .;
+        KEEP(*(.end_block));
+    } > FLASH
+
+} INSERT AFTER .uninit;
+
+PROVIDE(start_to_end = __end_block_addr - __start_block_addr);
+PROVIDE(end_to_start = __start_block_addr - __end_block_addr);