fix: fix alignment of mbox (#10, #11)

fixes #10, #11
kkebo · Mar 22, 2024 · 6c46eaf · 6c46eaf
1 parent a2df3df
commit 6c46eaf
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Showing 5 changed files with 24 additions and 42 deletions.
diff --git a/Package.swift b/Package.swift
@@ -11,7 +11,8 @@ let package = Package(
         .target(
             name: "Kernel",
             dependencies: [
-                "Volatile"
+                "Volatile",
+                "MailboxMessage",
             ],
             swiftSettings: [
                 .enableExperimentalFeature("Embedded"),
@@ -22,6 +23,7 @@ let package = Package(
             ]
         ),
         .systemLibrary(name: "Volatile"),
+        .target(name: "MailboxMessage"),
     ],
     swiftLanguageVersions: [.version("6")]
 )
diff --git a/Sources/Kernel/mbox.swift b/Sources/Kernel/mbox.swift
@@ -1,3 +1,5 @@
+@preconcurrency import var MailboxMessage.mbox
+
 let videocoreMbox = mmioBase + 0xB880
 let mboxRead = videocoreMbox
 let mboxPoll = videocoreMbox + 0x10
@@ -19,55 +21,16 @@ private func receiveMboxEmpty() -> Bool {
     mmioLoad(mboxStatus) & mboxEmpty > 0
 }
 
-@_alignment(16)
-struct Mbox {
-    var v1: UInt32
-    var v2: UInt32
-    var v3: UInt32
-    var v4: UInt32
-    var v5: UInt32
-    var v6: UInt32
-    var v7: UInt32
-    var v8: UInt32
-    var v9: UInt32
-
-    init(_ v1: UInt32, _ v2: UInt32, _ v3: UInt32, _ v4: UInt32, _ v5: UInt32, _ v6: UInt32, _ v7: UInt32, _ v8: UInt32, _ v9: UInt32) {
-        self.v1 = v1
-        self.v2 = v2
-        self.v3 = v3
-        self.v4 = v4
-        self.v5 = v5
-        self.v6 = v6
-        self.v7 = v7
-        self.v8 = v8
-        self.v9 = v9
-    }
-}
-
-#if RASPI4 || RASPI3
-    let mbox = Mbox(
-        9 * 4,
-        0,  // request
-        0x38002,  // set clock rate
-        12,
-        8,
-        2,  // UART clock
-        3_000_000,  // 3 Mhz
-        0,  // clear turbo
-        0  // mbox tag last
-    )
-#endif
-
 func mboxCall(ch: UInt8) -> Bool {
-    withUnsafePointer(to: mbox) { ptr in
+    withUnsafePointer(to: &mbox) { ptr in
         let addr = UInt32(UInt(bitPattern: ptr))
         let r = addr & ~0xF | UInt32(ch & 0xF)
         while transmitMboxFull() {}
         mmioStore(r, to: mboxWrite)
         while true {
             while receiveMboxEmpty() {}
             if mmioLoad(mboxRead) == r {
-                return ptr.pointee.v2 == mboxResponse
+                return mbox.1 == mboxResponse
             }
         }
     }

diff --git a/Sources/Kernel/uart.swift b/Sources/Kernel/uart.swift
@@ -1,3 +1,7 @@
+#if RASPI4 || RASPI3
+    @preconcurrency import var MailboxMessage.mbox
+#endif
+
 #if RASPI4
     let mmioBase: UInt = 0xFE00_0000
 #elseif RASPI3 || RASPI2
@@ -49,6 +53,15 @@ func initUART() {
 
     #if RASPI4 || RASPI3
         // set up clock to 3 MHz
+        mbox.0 = 9 * 4
+        mbox.1 = 0  // request
+        mbox.2 = 0x38002  // set clock rate
+        mbox.3 = 12
+        mbox.4 = 8
+        mbox.5 = 2  // UART clock
+        mbox.6 = 3_000_000  // 3 Mhz
+        mbox.7 = 0  // clear turbo
+        mbox.8 = 0  // mbox tag last
         guard mboxCall(ch: 8) else { while true {} }
     #endif
 

diff --git a/Sources/MailboxMessage/dummy.c b/Sources/MailboxMessage/dummy.c
@@ -0,0 +1 @@
+#include "mbox.h"
diff --git a/Sources/MailboxMessage/include/mbox.h b/Sources/MailboxMessage/include/mbox.h
@@ -0,0 +1,3 @@
+#pragma once
+
+volatile unsigned int  __attribute__((aligned(16))) mbox[9];
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		#pragma once

		volatile unsigned int __attribute__((aligned(16))) mbox[9];