diff options
Diffstat (limited to 'hw/avr/atmega.c')
| -rw-r--r-- | hw/avr/atmega.c | 39 |
1 files changed, 32 insertions, 7 deletions
diff --git a/hw/avr/atmega.c b/hw/avr/atmega.c index f6844bf..11fab184 100644 --- a/hw/avr/atmega.c +++ b/hw/avr/atmega.c @@ -19,6 +19,7 @@ #include "hw/sysbus.h" #include "qom/object.h" #include "hw/misc/unimp.h" +#include "migration/vmstate.h" #include "atmega.h" enum AtmegaPeripheral { @@ -224,8 +225,6 @@ static void atmega_realize(DeviceState *dev, Error **errp) char *devname; size_t i; - assert(mc->io_size <= 0x200); - if (!s->xtal_freq_hz) { error_setg(errp, "\"xtal-frequency-hz\" property must be provided."); return; @@ -240,11 +239,37 @@ static void atmega_realize(DeviceState *dev, Error **errp) qdev_realize(DEVICE(&s->cpu), NULL, &error_abort); cpudev = DEVICE(&s->cpu); - /* SRAM */ - memory_region_init_ram(&s->sram, OBJECT(dev), "sram", mc->sram_size, - &error_abort); - memory_region_add_subregion(get_system_memory(), - OFFSET_DATA + mc->io_size, &s->sram); + /* + * SRAM + * + * Softmmu is not able mix i/o and ram on the same page. + * Therefore in all cases, the first page exclusively contains i/o. + * + * If the MCU's i/o region matches the page size, then we can simply + * allocate all ram starting at the second page. Otherwise, we must + * allocate some ram as i/o to complete the first page. + */ + assert(mc->io_size == 0x100 || mc->io_size == 0x200); + if (mc->io_size >= TARGET_PAGE_SIZE) { + memory_region_init_ram(&s->sram, OBJECT(dev), "sram", mc->sram_size, + &error_abort); + memory_region_add_subregion(get_system_memory(), + OFFSET_DATA + mc->io_size, &s->sram); + } else { + int sram_io_size = TARGET_PAGE_SIZE - mc->io_size; + void *sram_io_mem = g_malloc0(sram_io_size); + + memory_region_init_ram_device_ptr(&s->sram_io, OBJECT(dev), "sram-as-io", + sram_io_size, sram_io_mem); + memory_region_add_subregion(get_system_memory(), + OFFSET_DATA + mc->io_size, &s->sram_io); + vmstate_register_ram(&s->sram_io, dev); + + memory_region_init_ram(&s->sram, OBJECT(dev), "sram", + mc->sram_size - sram_io_size, &error_abort); + memory_region_add_subregion(get_system_memory(), + OFFSET_DATA + TARGET_PAGE_SIZE, &s->sram); + } /* Flash */ memory_region_init_rom(&s->flash, OBJECT(dev), |