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qemu/hw/misc/bcm2835_mbox.c
Andrew Baumann 99494e696e bcm2835_mbox: add BCM2835 mailboxes 
This adds the system mailboxes which are used to communicate with a
number of GPU peripherals on Pi/Pi2.

Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-02-03 14:56:32 +00:00

334 lines
9.2 KiB
C
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/*
* 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 "hw/misc/bcm2835_mbox.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_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_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_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)
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