/* * Raspberry Pi emulation (c) 2012 Gregory Estrade * This code is licensed under the GNU GPLv2 and later. * * This file models the system mailboxes, which are used for * communication with low-bandwidth GPU peripherals. Refs: * https://github.com/raspberrypi/firmware/wiki/Mailboxes * https://github.com/raspberrypi/firmware/wiki/Accessing-mailboxes */ #include "qemu/osdep.h" #include "qapi/error.h" #include "hw/misc/bcm2835_mbox.h" #include "qemu/log.h" #include "qemu/module.h" #define MAIL0_PEEK 0x90 #define MAIL0_SENDER 0x94 #define MAIL1_STATUS 0xb8 /* Mailbox status register */ #define MAIL0_STATUS 0x98 #define ARM_MS_FULL 0x80000000 #define ARM_MS_EMPTY 0x40000000 #define ARM_MS_LEVEL 0x400000FF /* Max. value depends on mailbox depth */ /* MAILBOX config/status register */ #define MAIL0_CONFIG 0x9c /* ANY write to this register clears the error bits! */ #define ARM_MC_IHAVEDATAIRQEN 0x00000001 /* mbox irq enable: has data */ #define ARM_MC_IHAVESPACEIRQEN 0x00000002 /* mbox irq enable: has space */ #define ARM_MC_OPPISEMPTYIRQEN 0x00000004 /* mbox irq enable: Opp is empty */ #define ARM_MC_MAIL_CLEAR 0x00000008 /* mbox clear write 1, then 0 */ #define ARM_MC_IHAVEDATAIRQPEND 0x00000010 /* mbox irq pending: has space */ #define ARM_MC_IHAVESPACEIRQPEND 0x00000020 /* mbox irq pending: Opp is empty */ #define ARM_MC_OPPISEMPTYIRQPEND 0x00000040 /* mbox irq pending */ /* Bit 7 is unused */ #define ARM_MC_ERRNOOWN 0x00000100 /* error : none owner read from mailbox */ #define ARM_MC_ERROVERFLW 0x00000200 /* error : write to fill mailbox */ #define ARM_MC_ERRUNDRFLW 0x00000400 /* error : read from empty mailbox */ static void mbox_update_status(BCM2835Mbox *mb) { mb->status &= ~(ARM_MS_EMPTY | ARM_MS_FULL); if (mb->count == 0) { mb->status |= ARM_MS_EMPTY; } else if (mb->count == MBOX_SIZE) { mb->status |= ARM_MS_FULL; } } static void mbox_reset(BCM2835Mbox *mb) { int n; mb->count = 0; mb->config = 0; for (n = 0; n < MBOX_SIZE; n++) { mb->reg[n] = MBOX_INVALID_DATA; } mbox_update_status(mb); } static uint32_t mbox_pull(BCM2835Mbox *mb, int index) { int n; uint32_t val; assert(mb->count > 0); assert(index < mb->count); val = mb->reg[index]; for (n = index + 1; n < mb->count; n++) { mb->reg[n - 1] = mb->reg[n]; } mb->count--; mb->reg[mb->count] = MBOX_INVALID_DATA; mbox_update_status(mb); return val; } static void mbox_push(BCM2835Mbox *mb, uint32_t val) { assert(mb->count < MBOX_SIZE); mb->reg[mb->count++] = val; mbox_update_status(mb); } static void bcm2835_mbox_update(BCM2835MboxState *s) { uint32_t value; bool set; int n; s->mbox_irq_disabled = true; /* Get pending responses and put them in the vc->arm mbox, * as long as it's not full */ for (n = 0; n < MBOX_CHAN_COUNT; n++) { while (s->available[n] && !(s->mbox[0].status & ARM_MS_FULL)) { value = ldl_le_phys(&s->mbox_as, n << MBOX_AS_CHAN_SHIFT); assert(value != MBOX_INVALID_DATA); /* Pending interrupt but no data */ mbox_push(&s->mbox[0], value); } } /* TODO (?): Try to push pending requests from the arm->vc mbox */ /* Re-enable calls from the IRQ routine */ s->mbox_irq_disabled = false; /* Update ARM IRQ status */ set = false; s->mbox[0].config &= ~ARM_MC_IHAVEDATAIRQPEND; if (!(s->mbox[0].status & ARM_MS_EMPTY)) { s->mbox[0].config |= ARM_MC_IHAVEDATAIRQPEND; if (s->mbox[0].config & ARM_MC_IHAVEDATAIRQEN) { set = true; } } qemu_set_irq(s->arm_irq, set); } static void bcm2835_mbox_set_irq(void *opaque, int irq, int level) { BCM2835MboxState *s = opaque; s->available[irq] = level; /* avoid recursively calling bcm2835_mbox_update when the interrupt * status changes due to the ldl_phys call within that function */ if (!s->mbox_irq_disabled) { bcm2835_mbox_update(s); } } static uint64_t bcm2835_mbox_read(void *opaque, hwaddr offset, unsigned size) { BCM2835MboxState *s = opaque; uint32_t res = 0; offset &= 0xff; switch (offset) { case 0x80 ... 0x8c: /* MAIL0_READ */ if (s->mbox[0].status & ARM_MS_EMPTY) { res = MBOX_INVALID_DATA; } else { res = mbox_pull(&s->mbox[0], 0); } break; case MAIL0_PEEK: res = s->mbox[0].reg[0]; break; case MAIL0_SENDER: break; case MAIL0_STATUS: res = s->mbox[0].status; break; case MAIL0_CONFIG: res = s->mbox[0].config; break; case MAIL1_STATUS: res = s->mbox[1].status; break; default: qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n", __func__, offset); return 0; } bcm2835_mbox_update(s); return res; } static void bcm2835_mbox_write(void *opaque, hwaddr offset, uint64_t value, unsigned size) { BCM2835MboxState *s = opaque; hwaddr childaddr; uint8_t ch; offset &= 0xff; switch (offset) { case MAIL0_SENDER: break; case MAIL0_CONFIG: s->mbox[0].config &= ~ARM_MC_IHAVEDATAIRQEN; s->mbox[0].config |= value & ARM_MC_IHAVEDATAIRQEN; break; case 0xa0 ... 0xac: /* MAIL1_WRITE */ if (s->mbox[1].status & ARM_MS_FULL) { /* Mailbox full */ qemu_log_mask(LOG_GUEST_ERROR, "%s: mailbox full\n", __func__); } else { ch = value & 0xf; if (ch < MBOX_CHAN_COUNT) { childaddr = ch << MBOX_AS_CHAN_SHIFT; if (ldl_le_phys(&s->mbox_as, childaddr + MBOX_AS_PENDING)) { /* Child busy, push delayed. Push it in the arm->vc mbox */ mbox_push(&s->mbox[1], value); } else { /* Push it directly to the child device */ stl_le_phys(&s->mbox_as, childaddr, value); } } else { /* Invalid channel number */ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid channel %u\n", __func__, ch); } } break; default: qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n", __func__, offset); return; } bcm2835_mbox_update(s); } static const MemoryRegionOps bcm2835_mbox_ops = { .read = bcm2835_mbox_read, .write = bcm2835_mbox_write, .endianness = DEVICE_NATIVE_ENDIAN, .valid.min_access_size = 4, .valid.max_access_size = 4, }; /* vmstate of a single mailbox */ static const VMStateDescription vmstate_bcm2835_mbox_box = { .name = TYPE_BCM2835_MBOX "_box", .version_id = 1, .minimum_version_id = 1, .fields = (VMStateField[]) { VMSTATE_UINT32_ARRAY(reg, BCM2835Mbox, MBOX_SIZE), VMSTATE_UINT32(count, BCM2835Mbox), VMSTATE_UINT32(status, BCM2835Mbox), VMSTATE_UINT32(config, BCM2835Mbox), VMSTATE_END_OF_LIST() } }; /* vmstate of the entire device */ static const VMStateDescription vmstate_bcm2835_mbox = { .name = TYPE_BCM2835_MBOX, .version_id = 1, .minimum_version_id = 1, .minimum_version_id_old = 1, .fields = (VMStateField[]) { VMSTATE_BOOL_ARRAY(available, BCM2835MboxState, MBOX_CHAN_COUNT), VMSTATE_STRUCT_ARRAY(mbox, BCM2835MboxState, 2, 1, vmstate_bcm2835_mbox_box, BCM2835Mbox), VMSTATE_END_OF_LIST() } }; static void bcm2835_mbox_init(Object *obj) { BCM2835MboxState *s = BCM2835_MBOX(obj); memory_region_init_io(&s->iomem, obj, &bcm2835_mbox_ops, s, TYPE_BCM2835_MBOX, 0x400); sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem); sysbus_init_irq(SYS_BUS_DEVICE(s), &s->arm_irq); qdev_init_gpio_in(DEVICE(s), bcm2835_mbox_set_irq, MBOX_CHAN_COUNT); } static void bcm2835_mbox_reset(DeviceState *dev) { BCM2835MboxState *s = BCM2835_MBOX(dev); int n; mbox_reset(&s->mbox[0]); mbox_reset(&s->mbox[1]); s->mbox_irq_disabled = false; for (n = 0; n < MBOX_CHAN_COUNT; n++) { s->available[n] = false; } } static void bcm2835_mbox_realize(DeviceState *dev, Error **errp) { BCM2835MboxState *s = BCM2835_MBOX(dev); Object *obj; Error *err = NULL; obj = object_property_get_link(OBJECT(dev), "mbox-mr", &err); if (obj == NULL) { error_setg(errp, "%s: required mbox-mr link not found: %s", __func__, error_get_pretty(err)); return; } s->mbox_mr = MEMORY_REGION(obj); address_space_init(&s->mbox_as, s->mbox_mr, NULL); bcm2835_mbox_reset(dev); } static void bcm2835_mbox_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); dc->realize = bcm2835_mbox_realize; dc->reset = bcm2835_mbox_reset; dc->vmsd = &vmstate_bcm2835_mbox; } static TypeInfo bcm2835_mbox_info = { .name = TYPE_BCM2835_MBOX, .parent = TYPE_SYS_BUS_DEVICE, .instance_size = sizeof(BCM2835MboxState), .class_init = bcm2835_mbox_class_init, .instance_init = bcm2835_mbox_init, }; static void bcm2835_mbox_register_types(void) { type_register_static(&bcm2835_mbox_info); } type_init(bcm2835_mbox_register_types)