Add pico2 arm flashless target board (#604)

Grazfather · Felix "xq" Queißner · tact1m4n3 · web-flow · commit 72f71c1b1645 · 2025-06-24T22:46:27.000-07:00
Co-authored-by: Felix "xq" Queißner &lt;git@random-projects.net&gt;
Co-authored-by: tact1m4n3 &lt;tudor@dicu.org&gt;
diff --git a/build.zig b/build.zig
@@ -569,6 +569,7 @@ pub fn MicroBuild(port_select: PortSelect) type {
                     .chip_name = target.chip.name,
                     .memory_regions = target.chip.memory_regions,
                     .generate = linker_script_options.generate,
+                    .ram_image = target.ram_image,
                 };
 
                 const args_str = std.json.stringifyAlloc(
diff --git a/core/src/cpus/cortex_m.zig b/core/src/cpus/cortex_m.zig
@@ -591,7 +591,7 @@ pub const startup_logic = struct {
     extern var microzig_bss_end: u8;
     extern const microzig_data_load_start: u8;
 
-    pub fn ram_image_entrypoint() linksection(".entry") callconv(.naked) void {
+    pub fn ram_image_entry_point() linksection("microzig_ram_start") callconv(.naked) void {
         asm volatile (
             \\
             // Set VTOR to point to ram table
@@ -684,20 +684,20 @@ fn is_ramimage() bool {
 
 pub fn export_startup_logic() void {
     if (is_ramimage())
-        @export(&startup_logic.ram_image_entrypoint, .{
+        @export(&startup_logic.ram_image_entry_point, .{
             .name = "_entry_point",
             .linkage = .strong,
+        })
+    else
+        @export(&startup_logic._vector_table, .{
+            .name = "_vector_table",
+            .section = "microzig_flash_start",
+            .linkage = .strong,
         });
 
     @export(&startup_logic._start, .{
         .name = "_start",
     });
-
-    @export(&startup_logic._vector_table, .{
-        .name = "_vector_table",
-        .section = "microzig_flash_start",
-        .linkage = .strong,
-    });
 }
 
 const scs_base = 0xE000E000;
diff --git a/examples/raspberrypi/rp2xxx/build.zig b/examples/raspberrypi/rp2xxx/build.zig
@@ -26,6 +26,8 @@ pub fn build(b: *std.Build) void {
         .{ .target = raspberrypi.pico, .name = "pico_pcf8574", .file = "src/rp2040_only/pcf8574.zig" },
         .{ .target = raspberrypi.pico, .name = "pico_i2c_slave", .file = "src/rp2040_only/i2c_slave.zig" },
         .{ .target = raspberrypi.pico_flashless, .name = "pico_flashless_blinky", .file = "src/blinky.zig" },
+        .{ .target = raspberrypi.pico2_arm_flashless, .name = "pico2_arm_flashless_blinky", .file = "src/blinky.zig" },
+        .{ .target = raspberrypi.pico2_riscv_flashless, .name = "pico2_riscv_flashless_blinky", .file = "src/blinky.zig" },
 
         .{ .target = raspberrypi.pico2_arm, .name = "pico2_arm_random_data", .file = "src/rp2350_only/random_data.zig" },
         .{ .target = raspberrypi.pico2_riscv, .name = "pico2_riscv_random_data", .file = "src/rp2350_only/random_data.zig" },
diff --git a/port/raspberrypi/rp2xxx/build.zig b/port/raspberrypi/rp2xxx/build.zig
@@ -17,7 +17,9 @@ boards: struct {
         pico: *const microzig.Target,
         pico_flashless: *const microzig.Target,
         pico2_arm: *const microzig.Target,
+        pico2_arm_flashless: *const microzig.Target,
         pico2_riscv: *const microzig.Target,
+        pico2_riscv_flashless: *const microzig.Target,
     },
     waveshare: struct {
         rp2040_plus_4m: *const microzig.Target,
@@ -175,13 +177,13 @@ pub fn init(dep: *std.Build.Dependency) Self {
                     },
                 }),
                 .pico_flashless = chip_rp2040.derive(.{
-                    .entry = .{ .symbol_name = "_entry_point" },
-                    .linker_script = .{ .generate = .none, .file = b.path("ld/rp2040/ram_image_linker.ld") },
                     .ram_image = true,
+                    // we can use the default generated linker script
+                    .linker_script = .{},
                     .board = .{
                         .name = "RaspberryPi Pico (ram image)",
                         .url = "https://www.raspberrypi.com/products/raspberry-pi-pico/",
-                        .root_source_file = b.path("src/boards/raspberry_pi_pico2.zig"),
+                        .root_source_file = b.path("src/boards/raspberry_pi_pico_flashless.zig"),
                     },
                 }),
                 .pico2_arm = chip_rp2350_arm.derive(.{
@@ -191,13 +193,35 @@ pub fn init(dep: *std.Build.Dependency) Self {
                         .root_source_file = b.path("src/boards/raspberry_pi_pico2.zig"),
                     },
                 }),
+                .pico2_arm_flashless = chip_rp2350_arm.derive(.{
+                    .ram_image = true,
+                    .linker_script = .{
+                        .file = b.path("ld/rp2350/arm_ram_image_sections.ld"),
+                    },
+                    .board = .{
+                        .name = "RaspberryPi Pico 2 (ram image)",
+                        .url = "https://www.raspberrypi.com/products/raspberry-pi-pico2/",
+                        .root_source_file = b.path("src/boards/raspberry_pi_pico2.zig"),
+                    },
+                }),
                 .pico2_riscv = chip_rp2350_riscv.derive(.{
                     .board = .{
                         .name = "RaspberryPi Pico 2",
                         .url = "https://www.raspberrypi.com/products/raspberry-pi-pico2/",
                         .root_source_file = b.path("src/boards/raspberry_pi_pico2.zig"),
                     },
                 }),
+                .pico2_riscv_flashless = chip_rp2350_riscv.derive(.{
+                    .ram_image = true,
+                    .linker_script = .{
+                        .file = b.path("ld/rp2350/riscv_ram_image_sections.ld"),
+                    },
+                    .board = .{
+                        .name = "RaspberryPi Pico 2 (ram image)",
+                        .url = "https://www.raspberrypi.com/products/raspberry-pi-pico2/",
+                        .root_source_file = b.path("src/boards/raspberry_pi_pico2.zig"),
+                    },
+                }),
             },
             .waveshare = .{
                 .rp2040_plus_4m = chip_rp2040.derive(.{
diff --git a/port/raspberrypi/rp2xxx/ld/rp2040/ram_image_linker.ld b/port/raspberrypi/rp2xxx/ld/rp2040/ram_image_linker.ld
diff --git a/port/raspberrypi/rp2xxx/ld/rp2350/arm_ram_image_sections.ld b/port/raspberrypi/rp2xxx/ld/rp2350/arm_ram_image_sections.ld
@@ -0,0 +1,18 @@
+SECTIONS {
+  .bootmeta :
+  {
+    __bootmeta_start__ = .;
+    KEEP(*(.bootmeta))
+    __bootmeta_end__ = .;
+  } > ram0
+}
+INSERT AFTER .ram_start;
+
+SECTIONS {
+  .ram_vectors (NOLOAD) :
+  {
+    KEEP(*(ram_vectors))
+  } > ram0
+}
+INSERT AFTER .bss;
+
diff --git a/port/raspberrypi/rp2xxx/ld/rp2350/riscv_ram_image_sections.ld b/port/raspberrypi/rp2xxx/ld/rp2350/riscv_ram_image_sections.ld
@@ -0,0 +1,23 @@
+SECTIONS {
+  .bootmeta :
+  {
+    __bootmeta_start__ = .;
+    KEEP(*(.bootmeta))
+    __bootmeta_end__ = .;
+  } > ram0
+
+  .vectors :
+  {
+    KEEP(*(core_vectors))
+  } > ram0
+}
+INSERT AFTER .ram_start;
+
+SECTIONS {
+  .ram_vectors (NOLOAD) :
+  {
+    KEEP(*(ram_vectors))
+  } > ram0
+}
+INSERT AFTER .bss;
+
diff --git a/port/raspberrypi/rp2xxx/ld/rp2350/riscv_sections.ld b/port/raspberrypi/rp2xxx/ld/rp2350/riscv_sections.ld
@@ -15,7 +15,7 @@ SECTIONS {
 INSERT AFTER .flash_start;
 
 SECTIONS {
-  .ram_vectors (NOLOAD)  :
+  .ram_vectors (NOLOAD) :
   {
     KEEP(*(ram_vectors))
   } > ram0
diff --git a/port/raspberrypi/rp2xxx/src/boards/raspberry_pi_pico_flashless.zig b/port/raspberrypi/rp2xxx/src/boards/raspberry_pi_pico_flashless.zig
@@ -0,0 +1 @@
+pub const xosc_freq = 12_000_000;
diff --git a/port/raspberrypi/rp2xxx/src/cpus/hazard3.zig b/port/raspberrypi/rp2xxx/src/cpus/hazard3.zig
@@ -169,7 +169,10 @@ var ram_vectors: [vector_count]Handler = undefined;
 pub const startup_logic = struct {
     extern fn microzig_main() noreturn;
 
-    pub export fn _start() linksection("microzig_flash_start") callconv(.naked) noreturn {
+    pub export fn _start() linksection(if (microzig.config.ram_image)
+        "microzig_ram_start"
+    else
+        "microzig_flash_start") callconv(.naked) noreturn {
         asm volatile (
             \\.option push
             \\.option norelax
@@ -199,7 +202,9 @@ pub const startup_logic = struct {
     }
 
     pub export fn _start_c() callconv(.c) noreturn {
-        root.initialize_system_memories();
+        if (!microzig.config.ram_image) {
+            root.initialize_system_memories();
+        }
 
         // Move vector table to RAM if requested
         if (interrupt.has_ram_vectors()) {
@@ -316,7 +321,7 @@ pub fn export_startup_logic() void {
 
     @export(&startup_logic.external_interrupt_table, .{
         .name = "_external_interrupt_table",
-        .section = "flash_vectors",
+        .section = if (!microzig.config.ram_image) "flash_vectors" else null,
         .linkage = .strong,
     });
 }
diff --git a/port/raspberrypi/rp2xxx/src/hal.zig b/port/raspberrypi/rp2xxx/src/hal.zig
@@ -30,12 +30,12 @@ pub const watchdog = @import("hal/watchdog.zig");
 pub const cyw49_pio_spi = @import("hal/cyw43_pio_spi.zig");
 pub const drivers = @import("hal/drivers.zig");
 pub const compatibility = @import("hal/compatibility.zig");
-pub const image_def = @import("hal/image_def.zig");
+pub const bootmeta = @import("hal/bootmeta.zig");
 
 comptime {
     // HACK: tests can't access microzig. maybe there's a better way to do this.
     if (!builtin.is_test and compatibility.chip == .RP2350) {
-        _ = image_def;
+        _ = bootmeta;
     }
 
     // On the RP2040, we need to import the `atomic.zig` file to export some global
@@ -46,8 +46,18 @@ comptime {
     }
 }
 
-pub const HAL_Options = struct {
-    image_def_security: image_def.Security = .secure,
+pub const HAL_Options = switch (compatibility.chip) {
+    .RP2040 => struct {},
+    .RP2350 => struct {
+        bootmeta: struct {
+            image_def_exe_security: bootmeta.ImageDef.ImageTypeFlags.ExeSecurity = .secure,
+
+            /// Next metadata block to link after image_def. **Last block in the
+            /// chain must link back to the first one** (to
+            /// `bootmeta.image_def_block`).
+            next_block: ?*const anyopaque = null,
+        } = .{},
+    },
 };
 
 /// A default clock configuration with sensible defaults that will work
diff --git a/port/raspberrypi/rp2xxx/src/hal/bootmeta.zig b/port/raspberrypi/rp2xxx/src/hal/bootmeta.zig
diff --git a/port/raspberrypi/rp2xxx/src/hal/image_def.zig b/port/raspberrypi/rp2xxx/src/hal/image_def.zig
diff --git a/tools/generate_linker_script.zig b/tools/generate_linker_script.zig

Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,7 @@ SECTIONS {`
`15`	`15`	`INSERT AFTER .flash_start;`
`16`	`16`
`17`	`17`	`SECTIONS {`
`18`		`- .ram_vectors (NOLOAD) :`
	`18`	`+ .ram_vectors (NOLOAD) :`
`19`	`19`	`{`
`20`	`20`	`KEEP(*(ram_vectors))`
`21`	`21`	`} > ram0`