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qemu/hw/i2c/imx_i2c.c

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/*
* i.MX I2C Bus Serial Interface Emulation
*
* Copyright (C) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net>
*
* 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/osdep.h"
#include "hw/i2c/imx_i2c.h"
#include "hw/i2c/i2c.h"
#include "qemu/log.h"
#ifndef DEBUG_IMX_I2C
#define DEBUG_IMX_I2C 0
#endif
#define DPRINTF(fmt, args...) \
do { \
if (DEBUG_IMX_I2C) { \
fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_I2C, \
__func__, ##args); \
} \
} while (0)
static const char *imx_i2c_get_regname(unsigned offset)
{
switch (offset) {
case IADR_ADDR:
return "IADR";
case IFDR_ADDR:
return "IFDR";
case I2CR_ADDR:
return "I2CR";
case I2SR_ADDR:
return "I2SR";
case I2DR_ADDR:
return "I2DR";
default:
return "[?]";
}
}
static inline bool imx_i2c_is_enabled(IMXI2CState *s)
{
return s->i2cr & I2CR_IEN;
}
static inline bool imx_i2c_interrupt_is_enabled(IMXI2CState *s)
{
return s->i2cr & I2CR_IIEN;
}
static inline bool imx_i2c_is_master(IMXI2CState *s)
{
return s->i2cr & I2CR_MSTA;
}
static void imx_i2c_reset(DeviceState *dev)
{
IMXI2CState *s = IMX_I2C(dev);
if (s->address != ADDR_RESET) {
i2c_end_transfer(s->bus);
}
s->address = ADDR_RESET;
s->iadr = IADR_RESET;
s->ifdr = IFDR_RESET;
s->i2cr = I2CR_RESET;
s->i2sr = I2SR_RESET;
s->i2dr_read = I2DR_RESET;
s->i2dr_write = I2DR_RESET;
}
static inline void imx_i2c_raise_interrupt(IMXI2CState *s)
{
/*
* raise an interrupt if the device is enabled and it is configured
* to generate some interrupts.
*/
if (imx_i2c_is_enabled(s) && imx_i2c_interrupt_is_enabled(s)) {
s->i2sr |= I2SR_IIF;
qemu_irq_raise(s->irq);
}
}
static uint64_t imx_i2c_read(void *opaque, hwaddr offset,
unsigned size)
{
uint16_t value;
IMXI2CState *s = IMX_I2C(opaque);
switch (offset) {
case IADR_ADDR:
value = s->iadr;
break;
case IFDR_ADDR:
value = s->ifdr;
break;
case I2CR_ADDR:
value = s->i2cr;
break;
case I2SR_ADDR:
value = s->i2sr;
break;
case I2DR_ADDR:
value = s->i2dr_read;
if (imx_i2c_is_master(s)) {
uint8_t ret = 0xff;
if (s->address == ADDR_RESET) {
/* something is wrong as the address is not set */
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read "
"without specifying the slave address\n",
TYPE_IMX_I2C, __func__);
} else if (s->i2cr & I2CR_MTX) {
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read "
"but MTX is set\n", TYPE_IMX_I2C, __func__);
} else {
/* get the next byte */
ret = i2c_recv(s->bus);
imx_i2c_raise_interrupt(s);
}
s->i2dr_read = ret;
} else {
qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n",
TYPE_IMX_I2C, __func__);
}
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset);
value = 0;
break;
}
DPRINTF("read %s [0x%" HWADDR_PRIx "] -> 0x%02x\n",
imx_i2c_get_regname(offset), offset, value);
return (uint64_t)value;
}
static void imx_i2c_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
IMXI2CState *s = IMX_I2C(opaque);
DPRINTF("write %s [0x%" HWADDR_PRIx "] <- 0x%02x\n",
imx_i2c_get_regname(offset), offset, (int)value);
value &= 0xff;
switch (offset) {
case IADR_ADDR:
s->iadr = value & IADR_MASK;
/* i2c_set_slave_address(s->bus, (uint8_t)s->iadr); */
break;
case IFDR_ADDR:
s->ifdr = value & IFDR_MASK;
break;
case I2CR_ADDR:
if (imx_i2c_is_enabled(s) && ((value & I2CR_IEN) == 0)) {
/* This is a soft reset. IADR is preserved during soft resets */
uint16_t iadr = s->iadr;
imx_i2c_reset(DEVICE(s));
s->iadr = iadr;
} else { /* normal write */
s->i2cr = value & I2CR_MASK;
if (imx_i2c_is_master(s)) {
/* set the bus to busy */
s->i2sr |= I2SR_IBB;
} else { /* slave mode */
/* bus is not busy anymore */
s->i2sr &= ~I2SR_IBB;
/*
* if we unset the master mode then it ends the ongoing
* transfer if any
*/
if (s->address != ADDR_RESET) {
i2c_end_transfer(s->bus);
s->address = ADDR_RESET;
}
}
if (s->i2cr & I2CR_RSTA) { /* Restart */
/* if this is a restart then it ends the ongoing transfer */
if (s->address != ADDR_RESET) {
i2c_end_transfer(s->bus);
s->address = ADDR_RESET;
s->i2cr &= ~I2CR_RSTA;
}
}
}
break;
case I2SR_ADDR:
/*
* if the user writes 0 to IIF then lower the interrupt and
* reset the bit
*/
if ((s->i2sr & I2SR_IIF) && !(value & I2SR_IIF)) {
s->i2sr &= ~I2SR_IIF;
qemu_irq_lower(s->irq);
}
/*
* if the user writes 0 to IAL, reset the bit
*/
if ((s->i2sr & I2SR_IAL) && !(value & I2SR_IAL)) {
s->i2sr &= ~I2SR_IAL;
}
break;
case I2DR_ADDR:
/* if the device is not enabled, nothing to do */
if (!imx_i2c_is_enabled(s)) {
break;
}
s->i2dr_write = value & I2DR_MASK;
if (imx_i2c_is_master(s)) {
/* If this is the first write cycle then it is the slave addr */
if (s->address == ADDR_RESET) {
if (i2c_start_transfer(s->bus, extract32(s->i2dr_write, 1, 7),
extract32(s->i2dr_write, 0, 1))) {
/* if non zero is returned, the address is not valid */
s->i2sr |= I2SR_RXAK;
} else {
s->address = s->i2dr_write;
s->i2sr &= ~I2SR_RXAK;
imx_i2c_raise_interrupt(s);
}
} else { /* This is a normal data write */
if (i2c_send(s->bus, s->i2dr_write)) {
/* if the target return non zero then end the transfer */
s->i2sr |= I2SR_RXAK;
s->address = ADDR_RESET;
i2c_end_transfer(s->bus);
} else {
s->i2sr &= ~I2SR_RXAK;
imx_i2c_raise_interrupt(s);
}
}
} else {
qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n",
TYPE_IMX_I2C, __func__);
}
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset);
break;
}
}
static const MemoryRegionOps imx_i2c_ops = {
.read = imx_i2c_read,
.write = imx_i2c_write,
.valid.min_access_size = 1,
.valid.max_access_size = 2,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static const VMStateDescription imx_i2c_vmstate = {
.name = TYPE_IMX_I2C,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT16(address, IMXI2CState),
VMSTATE_UINT16(iadr, IMXI2CState),
VMSTATE_UINT16(ifdr, IMXI2CState),
VMSTATE_UINT16(i2cr, IMXI2CState),
VMSTATE_UINT16(i2sr, IMXI2CState),
VMSTATE_UINT16(i2dr_read, IMXI2CState),
VMSTATE_UINT16(i2dr_write, IMXI2CState),
VMSTATE_END_OF_LIST()
}
};
static void imx_i2c_realize(DeviceState *dev, Error **errp)
{
IMXI2CState *s = IMX_I2C(dev);
memory_region_init_io(&s->iomem, OBJECT(s), &imx_i2c_ops, s, TYPE_IMX_I2C,
IMX_I2C_MEM_SIZE);
sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
s->bus = i2c_init_bus(DEVICE(dev), NULL);
}
static void imx_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &imx_i2c_vmstate;
dc->reset = imx_i2c_reset;
dc->realize = imx_i2c_realize;
dc->desc = "i.MX I2C Controller";
}
static const TypeInfo imx_i2c_type_info = {
.name = TYPE_IMX_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMXI2CState),
.class_init = imx_i2c_class_init,
};
static void imx_i2c_register_types(void)
{
type_register_static(&imx_i2c_type_info);
}
type_init(imx_i2c_register_types)
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