rp2xxx: Enable fpu and dcp in core 1 entrypoint

core/src/cpus/cortex_m/m33.zig

@@ -238,7 +238,30 @@ pub const SystemControlBlock = extern struct {
     _AFSR: u32,
     reserved1: [18]u32,
     /// Coprocessor Access Control Register.
-    CPACR: u32,
+    CPACR: mmio.Mmio(packed struct(u32) {
+        CP0: Privilege,
+        CP1: Privilege,
+        CP2: Privilege,
+        CP3: Privilege,
+        CP4: Privilege,
+        CP5: Privilege,
+        CP6: Privilege,
+        CP7: Privilege,
+        reserved16: u4,
+        CP10: Privilege,
+        CP11: Privilege,
+        reserved24: u8,
+
+        pub const Privilege = enum(u2) {
+            /// Access denied. Any attempted access generates a NOCP UsageFault.
+            access_denied = 0b00,
+            /// Privileged access only. An unprivileged access generates a NOCP UsageFault.
+            priviledged_access_only = 0b01,
+            reserved = 0b10,
+            /// Full access.
+            full_access = 0b11,
+        };
+    }),
     /// Non-secure Access Control Register.
     NSACR: u32,
 };

port/raspberrypi/rp2xxx/src/hal.zig

@@ -99,33 +99,7 @@ const is_fpu_used: bool = builtin.abi.float() == .hard;
 /// Allows user to easily swap in their own clock config while still
 /// using the recommended initialization sequence
 pub fn init_sequence(comptime clock_cfg: clocks.config.Global) void {
-    if (compatibility.chip == .RP2350 and
-        compatibility.arch == .arm)
-    {
-        var cpacr: u32 = microzig.cpu.peripherals.scb.CPACR;
-
-        if (microzig.options.hal.enable_fpu) {
-            if (is_fpu_used) {
-                // enable lazy state preservation
-                microzig.cpu.peripherals.fpu.FPCCR.modify(.{
-                    .ASPEN = 1,
-                    .LSPEN = 1,
-                });
-
-                // enable the FPU
-                cpacr |= 0xF << 20;
-            } else {
-                @compileError("target doesn't have FPU features enabled");
-            }
-        }
-
-        if (microzig.options.hal.use_dcp) {
-            // enable the DCP
-            cpacr |= 0b11 << 8;
-        }
-
-        microzig.cpu.peripherals.scb.CPACR = cpacr;
-    }
+    maybe_enable_fpu_and_dcp();
 
     // Disable the watchdog as a soft reset doesn't disable the WD automatically!
     watchdog.disable();
@@ -155,6 +129,40 @@ pub fn init_sequence(comptime clock_cfg: clocks.config.Global) void {
     resets.unreset_block_wait(resets.masks.all);
 }
 
+/// Enables fpu and/or dcp on RP2350 arm if requested in HAL options. On RP2350
+/// riscv and RP2040 this is a noop. Called in init_sequence and on core1
+/// startup.
+pub fn maybe_enable_fpu_and_dcp() void {
+    if (compatibility.chip == .RP2350 and
+        compatibility.arch == .arm)
+    {
+        if (microzig.options.hal.enable_fpu) {
+            if (is_fpu_used) {
+                // enable lazy state preservation
+                microzig.cpu.peripherals.fpu.FPCCR.modify(.{
+                    .ASPEN = 1,
+                    .LSPEN = 1,
+                });
+
+                // enable the FPU for the current core
+                microzig.cpu.peripherals.scb.CPACR.modify(.{
+                    .CP10 = .full_access,
+                    .CP11 = .full_access,
+                });
+            } else {
+                @compileError("target doesn't have FPU features enabled");
+            }
+        }
+
+        if (microzig.options.hal.use_dcp) {
+            // enable the DCP for the current core
+            microzig.cpu.peripherals.scb.CPACR.modify(.{
+                .CP4 = .full_access,
+            });
+        }
+    }
+}
+
 pub fn get_cpu_id() u32 {
     return SIO.CPUID.read().CPUID;
 }

port/raspberrypi/rp2xxx/src/hal/multicore.zig

@@ -77,6 +77,7 @@ pub fn launch_core1_with_stack(entrypoint: *const fn () void, stack: []u32) void
         fn _wrapper(_: u32, _: u32, _: u32, _: u32, entry: u32, stack_base: [*]u32) callconv(.c) void {
             // TODO: protect stack using MPU
             _ = stack_base;
+            microzig.hal.maybe_enable_fpu_and_dcp();
             @as(*const fn () void, @ptrFromInt(entry))();
         }
     }._wrapper;