[platform][vax] add some code to try to sniff the board type

This lets us select the console routines to use.

arch/vax/arch.c

@@ -14,6 +14,8 @@
 
 #define LOCAL_TRACE 0
 
+extern uint8_t irq_stack[1024];
+
 void arch_early_init(void) {
     // set the top level exception handler
     //riscv_csr_write(mtvec, (uintptr_t)&riscv_exception_entry);
@@ -38,8 +40,6 @@ void arch_init(void) {
 }
 
 void arch_idle(void) {
-    // disabled for now, QEMU seems to have some trouble emulating wfi properly
-    // also have trouble breaking into sifive-e board with openocd when wfi
 //    __asm__ volatile("wfi");
 }
 

arch/vax/include/arch/vax.h

@@ -5,4 +5,6 @@
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT
  */
+#pragma once
+
 #include <arch/vax/mtpr.h>

arch/vax/start.S

@@ -37,18 +37,21 @@ _start:
     sobgtr  %r2,1b
 
     // branch to our new spot
+    // TODO: use a REI to make sure the cpu dumps the pipeline
     movl    $relocated, %r0
     jmp     (%r0)
 
 relocated:
     // set the stack to the end of us
-    moval    stack_end,%sp
+    moval    irq_stack_end,%sp
 
     // branch into main and we're done
     calls   $0, lk_main
     halt
 
 .section .data
+// declare bootargs here to make sure it goes in the data segment, since it's
+// saved before the bss is zeroed out.
 .align 4
 .globl bootargs
 bootargs:
@@ -57,6 +60,6 @@ bootargs_end:
 
 .section .bss
 .align 4
-stack:
+irq_stack:
     .skip 1024
-stack_end:
+irq_stack_end:

platform/vax/console.c

@@ -9,12 +9,24 @@
 #include <platform.h>
 #include <platform/debug.h>
 
-// todo: move to .S file
-unsigned int rom_putchar_addr = 0x20040068;
-extern int rom_putchar(int c);
+#include "platform_p.h"
+
+// Console io via rom routine
+unsigned int rom_putchar_addr;
+extern void rom_putchar(int c);
+
+// PR version
+void putchar_mtfr(int c) {
+    // wait until ready
+    while ((mfpr(PR_TXCS) & 0x80) == 0)
+        ;
+
+    // output char
+    mtpr((char)c, PR_TXDB);
+}
 
 // select the above routine
-int (*putchar_func)(int c) = &rom_putchar;
+void (*putchar_func)(int c);
 
 void platform_dputc(char c) {
     if (c == '\n')
@@ -35,5 +47,19 @@ int platform_pgetc(char *c, bool wait) {
     return platform_dgetc(c, wait);
 }
 
+void platform_early_console_init(void) {
+    // TODO: decide what type of console to use based on vax machine
+
+    // Only understand a few at the moment
+    switch (vax_boardtype) {
+        case 0x14000004: // Microvax 3100/40
+            rom_putchar_addr = 0x20040068;
+            putchar_func = &rom_putchar;
+            break;
+        default:
+            // default is to use the pr routines
+            putchar_func = &putchar_mtfr;
+    }
+}
 
 

platform/vax/init.c

@@ -8,6 +8,39 @@
 #include <lk/debug.h>
 #include <platform.h>
 #include <platform/timer.h>
+#include <arch/vax.h>
+
+#include "platform_p.h"
+
+uint32_t vax_cputype;
+uint32_t vax_boardtype;
+
+void platform_early_init(void) {
+    // decode what kind of vax we are so we can make a few platform decisions
+    // generally follows logic in netbsd sys/arch/vax/...
+    uint32_t sid = mfpr(PR_SID);
+    vax_cputype = sid >> 24;
+    vax_boardtype = vax_cputype << 24;
+
+    switch (vax_cputype) {
+        case 10: // CVAX
+        case 11: // RIGEL
+        case 18: // MARIAH
+        case 19: // NVAX
+        case 20: { // SOC
+            uint32_t sie = *(uint32_t *)(0x20040004);
+            vax_boardtype |= sie >> 24;
+            break;
+        }
+    }
+
+    platform_early_console_init();
+
+    printf("\n");
+    printf("VAX: sid %#x\n", sid);
+    printf("VAX: cputype %#x\n", vax_cputype);
+    printf("VAX: boardtype %#x\n", vax_boardtype);
+}
 
 // stubbed out time
 static lk_time_t t = 0;

platform/vax/platform_p.h

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2019 Travis Geiselbrecht
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+#pragma once
+
+#include <lib/cbuf.h>
+
+// super simple cheesy system detection mechanism
+// mostly cribbed from netbsd
+extern uint32_t vax_cputype;
+extern uint32_t vax_boardtype;
+
+void platform_early_console_init(void);