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q800: implement mac rom reset function for BIOS-less mode 

On Linux, calling `reboot(RB_AUTOBOOT);` will result in
arch/m68k/mac/misc.c's mac_reset function being called. That in turn
looks at the rombase (or uses 0x40800000 is there's no rombase), adds
0xa, and jumps to that address. At the moment, there's nothing there, so
the kernel just crashes when trying to reboot. So, this commit adds a
very simple implementation at that location, which just writes to via2
to power down. We also correct the value of ROMBASE while we're at it.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200102120150.281082-1-Jason@zx2c4.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Jason A. Donenfeld 2020-01-02 13:01:50 +01:00 committed by Laurent Vivier
parent eb064db94c
commit e24e58e8ac
1 changed files with 28 additions and 1 deletions
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29
hw/m68k/q800.c
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@ -47,7 +47,7 @@
#include "sysemu/runstate.h"
#include "sysemu/reset.h"
#define MACROM_ADDR 0x40000000
#define MACROM_ADDR 0x40800000
#define MACROM_SIZE 0x00100000
#define MACROM_FILENAME "MacROM.bin"
@ -128,6 +128,27 @@ static void main_cpu_reset(void *opaque)
cpu->env.pc = ldl_phys(cs->as, 4);
}
static uint8_t fake_mac_rom[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* offset: 0xa - mac_reset */
/* via2[vDirB] |= VIA2B_vPower */
0x20, 0x7C, 0x50, 0xF0, 0x24, 0x00, /* moveal VIA2_BASE+vDirB,%a0 */
0x10, 0x10, /* moveb %a0@,%d0 */
0x00, 0x00, 0x00, 0x04, /* orib #4,%d0 */
0x10, 0x80, /* moveb %d0,%a0@ */
/* via2[vBufB] &= ~VIA2B_vPower */
0x20, 0x7C, 0x50, 0xF0, 0x20, 0x00, /* moveal VIA2_BASE+vBufB,%a0 */
0x10, 0x10, /* moveb %a0@,%d0 */
0x02, 0x00, 0xFF, 0xFB, /* andib #-5,%d0 */
0x10, 0x80, /* moveb %d0,%a0@ */
/* while (true) ; */
0x60, 0xFE /* bras [self] */
};
static void q800_init(MachineState *machine)
{
M68kCPU *cpu = NULL;
@ -346,6 +367,12 @@ static void q800_init(MachineState *machine)
(graphic_width * graphic_depth + 7) / 8);
BOOTINFO1(cs->as, parameters_base, BI_MAC_SCCBASE, SCC_BASE);
rom = g_malloc(sizeof(*rom));
memory_region_init_ram_ptr(rom, NULL, "m68k_fake_mac.rom",
sizeof(fake_mac_rom), fake_mac_rom);
memory_region_set_readonly(rom, true);
memory_region_add_subregion(get_system_memory(), MACROM_ADDR, rom);
if (kernel_cmdline) {
BOOTINFOSTR(cs->as, parameters_base, BI_COMMAND_LINE,
kernel_cmdline);