/*
* Exynos4210 I2C Bus Serial Interface Emulation
*
* Copyright (C) 2012 Samsung Electronics Co Ltd.
* Maksim Kozlov, <m.kozlov@samsung.com>
* Igor Mitsyanko, <i.mitsyanko@samsung.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/timer.h"
#include "hw/sysbus.h"
#include "hw/i2c/i2c.h"
#ifndef EXYNOS4_I2C_DEBUG
#define EXYNOS4_I2C_DEBUG 0
#endif
#define TYPE_EXYNOS4_I2C "exynos4210.i2c"
#define EXYNOS4_I2C(obj) \
OBJECT_CHECK(Exynos4210I2CState, (obj), TYPE_EXYNOS4_I2C)
/* Exynos4210 I2C memory map */
#define EXYNOS4_I2C_MEM_SIZE 0x14
#define I2CCON_ADDR 0x00 /* control register */
#define I2CSTAT_ADDR 0x04 /* control/status register */
#define I2CADD_ADDR 0x08 /* address register */
#define I2CDS_ADDR 0x0c /* data shift register */
#define I2CLC_ADDR 0x10 /* line control register */
#define I2CCON_ACK_GEN (1 << 7)
#define I2CCON_INTRS_EN (1 << 5)
#define I2CCON_INT_PEND (1 << 4)
#define EXYNOS4_I2C_MODE(reg) (((reg) >> 6) & 3)
#define I2C_IN_MASTER_MODE(reg) (((reg) >> 6) & 2)
#define I2CMODE_MASTER_Rx 0x2
#define I2CMODE_MASTER_Tx 0x3
#define I2CSTAT_LAST_BIT (1 << 0)
#define I2CSTAT_OUTPUT_EN (1 << 4)
#define I2CSTAT_START_BUSY (1 << 5)
#if EXYNOS4_I2C_DEBUG
#define DPRINT(fmt, args...) \
do { fprintf(stderr, "QEMU I2C: "fmt, ## args); } while (0)
static const char *exynos4_i2c_get_regname(unsigned offset)
{
switch (offset) {
case I2CCON_ADDR:
return "I2CCON";
case I2CSTAT_ADDR:
return "I2CSTAT";
case I2CADD_ADDR:
return "I2CADD";
case I2CDS_ADDR:
return "I2CDS";
case I2CLC_ADDR:
return "I2CLC";
default:
return "[?]";
}
}
#else
#define DPRINT(fmt, args...) do { } while (0)
#endif
typedef struct Exynos4210I2CState {
SysBusDevice parent_obj;
MemoryRegion iomem;
I2CBus *bus;
qemu_irq irq;
uint8_t i2ccon;
uint8_t i2cstat;
uint8_t i2cadd;
uint8_t i2cds;
uint8_t i2clc;
bool scl_free;
} Exynos4210I2CState;
static inline void exynos4210_i2c_raise_interrupt(Exynos4210I2CState *s)
{
if (s->i2ccon & I2CCON_INTRS_EN) {
s->i2ccon |= I2CCON_INT_PEND;
qemu_irq_raise(s->irq);
}
}
static void exynos4210_i2c_data_receive(void *opaque)
{
Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
int ret;
s->i2cstat &= ~I2CSTAT_LAST_BIT;
s->scl_free = false;
ret = i2c_recv(s->bus);
if (ret < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
s->i2cstat |= I2CSTAT_LAST_BIT; /* Data is not acknowledged */
} else {
s->i2cds = ret;
}
exynos4210_i2c_raise_interrupt(s);
}
static void exynos4210_i2c_data_send(void *opaque)
{
Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
s->i2cstat &= ~I2CSTAT_LAST_BIT;
s->scl_free = false;
if (i2c_send(s->bus, s->i2cds) < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
s->i2cstat |= I2CSTAT_LAST_BIT;
}
exynos4210_i2c_raise_interrupt(s);
}
static uint64_t exynos4210_i2c_read(void *opaque, hwaddr offset,
unsigned size)
{
Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
uint8_t value;
switch (offset) {
case I2CCON_ADDR:
value = s->i2ccon;
break;
case I2CSTAT_ADDR:
value = s->i2cstat;
break;
case I2CADD_ADDR:
value = s->i2cadd;
break;
case I2CDS_ADDR:
value = s->i2cds;
s->scl_free = true;
if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx &&
(s->i2cstat & I2CSTAT_START_BUSY) &&
!(s->i2ccon & I2CCON_INT_PEND)) {
exynos4210_i2c_data_receive(s);
}
break;
case I2CLC_ADDR:
value = s->i2clc;
break;
default:
value = 0;
DPRINT("ERROR: Bad read offset 0x%x\n", (unsigned int)offset);
break;
}
DPRINT("read %s [0x%02x] -> 0x%02x\n", exynos4_i2c_get_regname(offset),
(unsigned int)offset, value);
return value;
}
static void exynos4210_i2c_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
uint8_t v = value & 0xff;
DPRINT("write %s [0x%02x] <- 0x%02x\n", exynos4_i2c_get_regname(offset),
(unsigned int)offset, v);
switch (offset) {
case I2CCON_ADDR:
s->i2ccon = (v & ~I2CCON_INT_PEND) | (s->i2ccon & I2CCON_INT_PEND);
if ((s->i2ccon & I2CCON_INT_PEND) && !(v & I2CCON_INT_PEND)) {
s->i2ccon &= ~I2CCON_INT_PEND;
qemu_irq_lower(s->irq);
if (!(s->i2ccon & I2CCON_INTRS_EN)) {
s->i2cstat &= ~I2CSTAT_START_BUSY;
}
if (s->i2cstat & I2CSTAT_START_BUSY) {
if (s->scl_free) {
if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx) {
exynos4210_i2c_data_send(s);
} else if (EXYNOS4_I2C_MODE(s->i2cstat) ==
I2CMODE_MASTER_Rx) {
exynos4210_i2c_data_receive(s);
}
} else {
s->i2ccon |= I2CCON_INT_PEND;
qemu_irq_raise(s->irq);
}
}
}
break;
case I2CSTAT_ADDR:
s->i2cstat =
(s->i2cstat & I2CSTAT_START_BUSY) | (v & ~I2CSTAT_START_BUSY);
if (!(s->i2cstat & I2CSTAT_OUTPUT_EN)) {
s->i2cstat &= ~I2CSTAT_START_BUSY;
s->scl_free = true;
qemu_irq_lower(s->irq);
break;
}
/* Nothing to do if in i2c slave mode */
if (!I2C_IN_MASTER_MODE(s->i2cstat)) {
break;
}
if (v & I2CSTAT_START_BUSY) {
s->i2cstat &= ~I2CSTAT_LAST_BIT;
s->i2cstat |= I2CSTAT_START_BUSY; /* Line is busy */
s->scl_free = false;
/* Generate start bit and send slave address */
if (i2c_start_transfer(s->bus, s->i2cds >> 1, s->i2cds & 0x1) &&
(s->i2ccon & I2CCON_ACK_GEN)) {
s->i2cstat |= I2CSTAT_LAST_BIT;
} else if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx) {
exynos4210_i2c_data_receive(s);
}
exynos4210_i2c_raise_interrupt(s);
} else {
i2c_end_transfer(s->bus);
if (!(s->i2ccon & I2CCON_INT_PEND)) {
s->i2cstat &= ~I2CSTAT_START_BUSY;
}
s->scl_free = true;
}
break;
case I2CADD_ADDR:
if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) {
s->i2cadd = v;
}
break;
case I2CDS_ADDR:
if (s->i2cstat & I2CSTAT_OUTPUT_EN) {
s->i2cds = v;
s->scl_free = true;
if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx &&
(s->i2cstat & I2CSTAT_START_BUSY) &&
!(s->i2ccon & I2CCON_INT_PEND)) {
exynos4210_i2c_data_send(s);
}
}
break;
case I2CLC_ADDR:
s->i2clc = v;
break;
default:
DPRINT("ERROR: Bad write offset 0x%x\n", (unsigned int)offset);
break;
}
}
static const MemoryRegionOps exynos4210_i2c_ops = {
.read = exynos4210_i2c_read,
.write = exynos4210_i2c_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static const VMStateDescription exynos4210_i2c_vmstate = {
.name = "exynos4210.i2c",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(i2ccon, Exynos4210I2CState),
VMSTATE_UINT8(i2cstat, Exynos4210I2CState),
VMSTATE_UINT8(i2cds, Exynos4210I2CState),
VMSTATE_UINT8(i2cadd, Exynos4210I2CState),
VMSTATE_UINT8(i2clc, Exynos4210I2CState),
VMSTATE_BOOL(scl_free, Exynos4210I2CState),
VMSTATE_END_OF_LIST()
}
};
static void exynos4210_i2c_reset(DeviceState *d)
{
Exynos4210I2CState *s = EXYNOS4_I2C(d);
s->i2ccon = 0x00;
s->i2cstat = 0x00;
s->i2cds = 0xFF;
s->i2clc = 0x00;
s->i2cadd = 0xFF;
s->scl_free = true;
}
static int exynos4210_i2c_realize(SysBusDevice *sbd)
{
DeviceState *dev = DEVICE(sbd);
Exynos4210I2CState *s = EXYNOS4_I2C(dev);
memory_region_init_io(&s->iomem, OBJECT(s), &exynos4210_i2c_ops, s,
TYPE_EXYNOS4_I2C, EXYNOS4_I2C_MEM_SIZE);
sysbus_init_mmio(sbd, &s->iomem);
sysbus_init_irq(sbd, &s->irq);
s->bus = i2c_init_bus(dev, "i2c");
return 0;
}
static void exynos4210_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass);
dc->vmsd = &exynos4210_i2c_vmstate;
dc->reset = exynos4210_i2c_reset;
sbdc->init = exynos4210_i2c_realize;
}
static const TypeInfo exynos4210_i2c_type_info = {
.name = TYPE_EXYNOS4_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(Exynos4210I2CState),
.class_init = exynos4210_i2c_class_init,
};
static void exynos4210_i2c_register_types(void)
{
type_register_static(&exynos4210_i2c_type_info);
}
type_init(exynos4210_i2c_register_types)
