d496ca1902
A block of data left behind by the firmware to tell the system important things such as the size of memory.
92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/*
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* Copyright (c) 2018 Travis Geiselbrecht
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <lk/err.h>
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#include <lk/reg.h>
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#include <lk/trace.h>
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#include <kernel/thread.h>
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#include <platform.h>
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#include <platform/interrupts.h>
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#include <platform/debug.h>
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#include <platform/timer.h>
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#include <platform/rosco-m68k.h>
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#include <string.h>
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#include <sys/types.h>
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#include <kernel/novm.h>
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#include "platform_p.h"
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#define LOCAL_TRACE 0
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extern uint8_t __bss_end;
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// firmware structure left behind by boot rom
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// described at
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// https://github.com/rosco-m68k/rosco_m68k/blob/develop/code/firmware/rosco_m68k_firmware/InterfaceReference.md
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#define ROSCO_SDB_MAGIC (0xb105d47a)
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struct rosco_system_data_block {
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uint32_t magic;
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uint32_t status;
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uint16_t timer_tick_counter;
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uint16_t system_flags;
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uint32_t upticks_counter;
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uint8_t easy68k_flag_echo_on;
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uint8_t easy68k_flag_prompt_on;
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uint8_t easy68k_flag_lf_display;
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uint8_t timer_tick_internal;
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uint32_t mem_size;
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uint32_t default_uart_base;
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uint32_t cpu_info;
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};
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STATIC_ASSERT(sizeof(struct rosco_system_data_block) == 0x20);
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const volatile struct rosco_system_data_block *sdb = (void *)0x400;
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void platform_early_init(void) {
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duart_early_init();
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// default to 1MB memory at 0
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uint32_t membase = 0x0;
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uint32_t memsize = 0x100000; // 1MB
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if (sdb->magic != ROSCO_SDB_MAGIC) {
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dprintf(INFO, "ROSCO-M68K: firmware failed magic check\n");
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} else {
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dprintf(INFO, "ROSCO-M68K: firmware structure at 0x400 - 0x41f:\n");
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hexdump((void *)sdb, sizeof(*sdb));
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printf("cpu family %u speed %u\n", sdb->cpu_info >> 29, sdb->cpu_info & 0x1fffffff);
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memsize = sdb->mem_size;
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}
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dprintf(INFO, "ROSCO-M68K: memory base %#x size %#x\n", membase, memsize);
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novm_add_arena("mem", membase, memsize);
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// build a table of illegal instructions around 0 to try to catch bad branches
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uint16_t ins = 0x4afa;
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for (uintptr_t i = 0; i < 256; i++) {
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memcpy((void *)i, &ins, 2);
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}
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}
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void platform_init(void) {
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duart_init();
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}
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enum handler_return m68k_platform_irq(uint8_t irq) {
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LTRACEF("irq %u\n", irq);
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switch (irq) {
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case 0x45: // DUART irq
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return duart_irq();
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default:
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panic("unhandled platform irq %u\n", irq);
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}
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return INT_NO_RESCHEDULE;
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}
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