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qemu/hw/i2c/aspeed_i2c.c
Cédric Le Goater 4960f084cf aspeed/i2c: introduce a state machine 
The Aspeed I2C controller maintains a state machine in the command
register, which is mostly used for debug.

Let's start adding a few states to handle abnormal STOP
commands. Today, the model uses the busy status of the bus as a
condition to do so but it is not precise enough.

Also remove the ABNORMAL bit for failing TX commands. This is
incorrect with respect to the specs.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1494827476-1487-4-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-06-02 11:51:49 +01:00

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/*
* ARM Aspeed I2C controller
*
* Copyright (C) 2016 IBM Corp.
*
* 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/sysbus.h"
#include "qemu/log.h"
#include "hw/i2c/aspeed_i2c.h"
/* I2C Global Register */
#define I2C_CTRL_STATUS 0x00 /* Device Interrupt Status */
#define I2C_CTRL_ASSIGN 0x08 /* Device Interrupt Target
Assignment */
/* I2C Device (Bus) Register */
#define I2CD_FUN_CTRL_REG 0x00 /* I2CD Function Control */
#define I2CD_BUFF_SEL_MASK (0x7 << 20)
#define I2CD_BUFF_SEL(x) (x << 20)
#define I2CD_M_SDA_LOCK_EN (0x1 << 16)
#define I2CD_MULTI_MASTER_DIS (0x1 << 15)
#define I2CD_M_SCL_DRIVE_EN (0x1 << 14)
#define I2CD_MSB_STS (0x1 << 9)
#define I2CD_SDA_DRIVE_1T_EN (0x1 << 8)
#define I2CD_M_SDA_DRIVE_1T_EN (0x1 << 7)
#define I2CD_M_HIGH_SPEED_EN (0x1 << 6)
#define I2CD_DEF_ADDR_EN (0x1 << 5)
#define I2CD_DEF_ALERT_EN (0x1 << 4)
#define I2CD_DEF_ARP_EN (0x1 << 3)
#define I2CD_DEF_GCALL_EN (0x1 << 2)
#define I2CD_SLAVE_EN (0x1 << 1)
#define I2CD_MASTER_EN (0x1)
#define I2CD_AC_TIMING_REG1 0x04 /* Clock and AC Timing Control #1 */
#define I2CD_AC_TIMING_REG2 0x08 /* Clock and AC Timing Control #1 */
#define I2CD_INTR_CTRL_REG 0x0c /* I2CD Interrupt Control */
#define I2CD_INTR_STS_REG 0x10 /* I2CD Interrupt Status */
#define I2CD_INTR_SDA_DL_TIMEOUT (0x1 << 14)
#define I2CD_INTR_BUS_RECOVER_DONE (0x1 << 13)
#define I2CD_INTR_SMBUS_ALERT (0x1 << 12) /* Bus [0-3] only */
#define I2CD_INTR_SMBUS_ARP_ADDR (0x1 << 11) /* Removed */
#define I2CD_INTR_SMBUS_DEV_ALERT_ADDR (0x1 << 10) /* Removed */
#define I2CD_INTR_SMBUS_DEF_ADDR (0x1 << 9) /* Removed */
#define I2CD_INTR_GCALL_ADDR (0x1 << 8) /* Removed */
#define I2CD_INTR_SLAVE_MATCH (0x1 << 7) /* use RX_DONE */
#define I2CD_INTR_SCL_TIMEOUT (0x1 << 6)
#define I2CD_INTR_ABNORMAL (0x1 << 5)
#define I2CD_INTR_NORMAL_STOP (0x1 << 4)
#define I2CD_INTR_ARBIT_LOSS (0x1 << 3)
#define I2CD_INTR_RX_DONE (0x1 << 2)
#define I2CD_INTR_TX_NAK (0x1 << 1)
#define I2CD_INTR_TX_ACK (0x1 << 0)
#define I2CD_CMD_REG 0x14 /* I2CD Command/Status */
#define I2CD_SDA_OE (0x1 << 28)
#define I2CD_SDA_O (0x1 << 27)
#define I2CD_SCL_OE (0x1 << 26)
#define I2CD_SCL_O (0x1 << 25)
#define I2CD_TX_TIMING (0x1 << 24)
#define I2CD_TX_STATUS (0x1 << 23)
#define I2CD_TX_STATE_SHIFT 19 /* Tx State Machine */
#define I2CD_TX_STATE_MASK 0xf
#define I2CD_IDLE 0x0
#define I2CD_MACTIVE 0x8
#define I2CD_MSTART 0x9
#define I2CD_MSTARTR 0xa
#define I2CD_MSTOP 0xb
#define I2CD_MTXD 0xc
#define I2CD_MRXACK 0xd
#define I2CD_MRXD 0xe
#define I2CD_MTXACK 0xf
#define I2CD_SWAIT 0x1
#define I2CD_SRXD 0x4
#define I2CD_STXACK 0x5
#define I2CD_STXD 0x6
#define I2CD_SRXACK 0x7
#define I2CD_RECOVER 0x3
#define I2CD_SCL_LINE_STS (0x1 << 18)
#define I2CD_SDA_LINE_STS (0x1 << 17)
#define I2CD_BUS_BUSY_STS (0x1 << 16)
#define I2CD_SDA_OE_OUT_DIR (0x1 << 15)
#define I2CD_SDA_O_OUT_DIR (0x1 << 14)
#define I2CD_SCL_OE_OUT_DIR (0x1 << 13)
#define I2CD_SCL_O_OUT_DIR (0x1 << 12)
#define I2CD_BUS_RECOVER_CMD_EN (0x1 << 11)
#define I2CD_S_ALT_EN (0x1 << 10)
#define I2CD_RX_DMA_ENABLE (0x1 << 9)
#define I2CD_TX_DMA_ENABLE (0x1 << 8)
/* Command Bit */
#define I2CD_M_STOP_CMD (0x1 << 5)
#define I2CD_M_S_RX_CMD_LAST (0x1 << 4)
#define I2CD_M_RX_CMD (0x1 << 3)
#define I2CD_S_TX_CMD (0x1 << 2)
#define I2CD_M_TX_CMD (0x1 << 1)
#define I2CD_M_START_CMD (0x1)
#define I2CD_DEV_ADDR_REG 0x18 /* Slave Device Address */
#define I2CD_BUF_CTRL_REG 0x1c /* Pool Buffer Control */
#define I2CD_BYTE_BUF_REG 0x20 /* Transmit/Receive Byte Buffer */
#define I2CD_BYTE_BUF_TX_SHIFT 0
#define I2CD_BYTE_BUF_TX_MASK 0xff
#define I2CD_BYTE_BUF_RX_SHIFT 8
#define I2CD_BYTE_BUF_RX_MASK 0xff
static inline bool aspeed_i2c_bus_is_master(AspeedI2CBus *bus)
{
return bus->ctrl & I2CD_MASTER_EN;
}
static inline bool aspeed_i2c_bus_is_enabled(AspeedI2CBus *bus)
{
return bus->ctrl & (I2CD_MASTER_EN | I2CD_SLAVE_EN);
}
static inline void aspeed_i2c_bus_raise_interrupt(AspeedI2CBus *bus)
{
bus->intr_status &= bus->intr_ctrl;
if (bus->intr_status) {
bus->controller->intr_status |= 1 << bus->id;
qemu_irq_raise(bus->controller->irq);
}
}
static uint64_t aspeed_i2c_bus_read(void *opaque, hwaddr offset,
unsigned size)
{
AspeedI2CBus *bus = opaque;
switch (offset) {
case I2CD_FUN_CTRL_REG:
return bus->ctrl;
case I2CD_AC_TIMING_REG1:
return bus->timing[0];
case I2CD_AC_TIMING_REG2:
return bus->timing[1];
case I2CD_INTR_CTRL_REG:
return bus->intr_ctrl;
case I2CD_INTR_STS_REG:
return bus->intr_status;
case I2CD_BYTE_BUF_REG:
return bus->buf;
case I2CD_CMD_REG:
return bus->cmd | (i2c_bus_busy(bus->bus) << 16);
default:
qemu_log_mask(LOG_GUEST_ERROR,
"%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, offset);
return -1;
}
}
static void aspeed_i2c_set_state(AspeedI2CBus *bus, uint8_t state)
{
bus->cmd &= ~(I2CD_TX_STATE_MASK << I2CD_TX_STATE_SHIFT);
bus->cmd |= (state & I2CD_TX_STATE_MASK) << I2CD_TX_STATE_SHIFT;
}
static uint8_t aspeed_i2c_get_state(AspeedI2CBus *bus)
{
return (bus->cmd >> I2CD_TX_STATE_SHIFT) & I2CD_TX_STATE_MASK;
}
/*
* The state machine needs some refinement. It is only used to track
* invalid STOP commands for the moment.
*/
static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
{
bus->cmd &= ~0xFFFF;
bus->cmd |= value & 0xFFFF;
bus->intr_status = 0;
if (bus->cmd & I2CD_M_START_CMD) {
uint8_t state = aspeed_i2c_get_state(bus) & I2CD_MACTIVE ?
I2CD_MSTARTR : I2CD_MSTART;
aspeed_i2c_set_state(bus, state);
if (i2c_start_transfer(bus->bus, extract32(bus->buf, 1, 7),
extract32(bus->buf, 0, 1))) {
bus->intr_status |= I2CD_INTR_TX_NAK;
} else {
bus->intr_status |= I2CD_INTR_TX_ACK;
}
/* START command is also a TX command, as the slave address is
* sent on the bus */
bus->cmd &= ~(I2CD_M_START_CMD | I2CD_M_TX_CMD);
/* No slave found */
if (!i2c_bus_busy(bus->bus)) {
return;
}
aspeed_i2c_set_state(bus, I2CD_MACTIVE);
}
if (bus->cmd & I2CD_M_TX_CMD) {
aspeed_i2c_set_state(bus, I2CD_MTXD);
if (i2c_send(bus->bus, bus->buf)) {
bus->intr_status |= (I2CD_INTR_TX_NAK);
i2c_end_transfer(bus->bus);
} else {
bus->intr_status |= I2CD_INTR_TX_ACK;
}
bus->cmd &= ~I2CD_M_TX_CMD;
aspeed_i2c_set_state(bus, I2CD_MACTIVE);
}
if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) {
int ret;
aspeed_i2c_set_state(bus, I2CD_MRXD);
ret = i2c_recv(bus->bus);
if (ret < 0) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
ret = 0xff;
} else {
bus->intr_status |= I2CD_INTR_RX_DONE;
}
bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
i2c_nack(bus->bus);
}
bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST);
aspeed_i2c_set_state(bus, I2CD_MACTIVE);
}
if (bus->cmd & I2CD_M_STOP_CMD) {
if (!(aspeed_i2c_get_state(bus) & I2CD_MACTIVE)) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: abnormal stop\n", __func__);
bus->intr_status |= I2CD_INTR_ABNORMAL;
} else {
aspeed_i2c_set_state(bus, I2CD_MSTOP);
i2c_end_transfer(bus->bus);
bus->intr_status |= I2CD_INTR_NORMAL_STOP;
}
bus->cmd &= ~I2CD_M_STOP_CMD;
aspeed_i2c_set_state(bus, I2CD_IDLE);
}
}
static void aspeed_i2c_bus_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
AspeedI2CBus *bus = opaque;
switch (offset) {
case I2CD_FUN_CTRL_REG:
if (value & I2CD_SLAVE_EN) {
qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
__func__);
break;
}
bus->ctrl = value & 0x0071C3FF;
break;
case I2CD_AC_TIMING_REG1:
bus->timing[0] = value & 0xFFFFF0F;
break;
case I2CD_AC_TIMING_REG2:
bus->timing[1] = value & 0x7;
break;
case I2CD_INTR_CTRL_REG:
bus->intr_ctrl = value & 0x7FFF;
break;
case I2CD_INTR_STS_REG:
bus->intr_status &= ~(value & 0x7FFF);
bus->controller->intr_status &= ~(1 << bus->id);
qemu_irq_lower(bus->controller->irq);
break;
case I2CD_DEV_ADDR_REG:
qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
__func__);
break;
case I2CD_BYTE_BUF_REG:
bus->buf = (value & I2CD_BYTE_BUF_TX_MASK) << I2CD_BYTE_BUF_TX_SHIFT;
break;
case I2CD_CMD_REG:
if (!aspeed_i2c_bus_is_enabled(bus)) {
break;
}
if (!aspeed_i2c_bus_is_master(bus)) {
qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
__func__);
break;
}
aspeed_i2c_bus_handle_cmd(bus, value);
aspeed_i2c_bus_raise_interrupt(bus);
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
}
}
static uint64_t aspeed_i2c_ctrl_read(void *opaque, hwaddr offset,
unsigned size)
{
AspeedI2CState *s = opaque;
switch (offset) {
case I2C_CTRL_STATUS:
return s->intr_status;
default:
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
break;
}
return -1;
}
static void aspeed_i2c_ctrl_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
switch (offset) {
case I2C_CTRL_STATUS:
default:
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
break;
}
}
static const MemoryRegionOps aspeed_i2c_bus_ops = {
.read = aspeed_i2c_bus_read,
.write = aspeed_i2c_bus_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
static const MemoryRegionOps aspeed_i2c_ctrl_ops = {
.read = aspeed_i2c_ctrl_read,
.write = aspeed_i2c_ctrl_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
static const VMStateDescription aspeed_i2c_bus_vmstate = {
.name = TYPE_ASPEED_I2C,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(id, AspeedI2CBus),
VMSTATE_UINT32(ctrl, AspeedI2CBus),
VMSTATE_UINT32_ARRAY(timing, AspeedI2CBus, 2),
VMSTATE_UINT32(intr_ctrl, AspeedI2CBus),
VMSTATE_UINT32(intr_status, AspeedI2CBus),
VMSTATE_UINT32(cmd, AspeedI2CBus),
VMSTATE_UINT32(buf, AspeedI2CBus),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription aspeed_i2c_vmstate = {
.name = TYPE_ASPEED_I2C,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT32(intr_status, AspeedI2CState),
VMSTATE_STRUCT_ARRAY(busses, AspeedI2CState,
ASPEED_I2C_NR_BUSSES, 1, aspeed_i2c_bus_vmstate,
AspeedI2CBus),
VMSTATE_END_OF_LIST()
}
};
static void aspeed_i2c_reset(DeviceState *dev)
{
int i;
AspeedI2CState *s = ASPEED_I2C(dev);
s->intr_status = 0;
for (i = 0; i < ASPEED_I2C_NR_BUSSES; i++) {
s->busses[i].intr_ctrl = 0;
s->busses[i].intr_status = 0;
s->busses[i].cmd = 0;
s->busses[i].buf = 0;
i2c_end_transfer(s->busses[i].bus);
}
}
/*
* Address Definitions
*
* 0x000 ... 0x03F: Global Register
* 0x040 ... 0x07F: Device 1
* 0x080 ... 0x0BF: Device 2
* 0x0C0 ... 0x0FF: Device 3
* 0x100 ... 0x13F: Device 4
* 0x140 ... 0x17F: Device 5
* 0x180 ... 0x1BF: Device 6
* 0x1C0 ... 0x1FF: Device 7
* 0x200 ... 0x2FF: Buffer Pool (unused in linux driver)
* 0x300 ... 0x33F: Device 8
* 0x340 ... 0x37F: Device 9
* 0x380 ... 0x3BF: Device 10
* 0x3C0 ... 0x3FF: Device 11
* 0x400 ... 0x43F: Device 12
* 0x440 ... 0x47F: Device 13
* 0x480 ... 0x4BF: Device 14
* 0x800 ... 0xFFF: Buffer Pool (unused in linux driver)
*/
static void aspeed_i2c_realize(DeviceState *dev, Error **errp)
{
int i;
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
AspeedI2CState *s = ASPEED_I2C(dev);
sysbus_init_irq(sbd, &s->irq);
memory_region_init_io(&s->iomem, OBJECT(s), &aspeed_i2c_ctrl_ops, s,
"aspeed.i2c", 0x1000);
sysbus_init_mmio(sbd, &s->iomem);
for (i = 0; i < ASPEED_I2C_NR_BUSSES; i++) {
char name[16];
int offset = i < 7 ? 1 : 5;
snprintf(name, sizeof(name), "aspeed.i2c.%d", i);
s->busses[i].controller = s;
s->busses[i].id = i;
s->busses[i].bus = i2c_init_bus(dev, name);
memory_region_init_io(&s->busses[i].mr, OBJECT(dev),
&aspeed_i2c_bus_ops, &s->busses[i], name, 0x40);
memory_region_add_subregion(&s->iomem, 0x40 * (i + offset),
&s->busses[i].mr);
}
}
static void aspeed_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &aspeed_i2c_vmstate;
dc->reset = aspeed_i2c_reset;
dc->realize = aspeed_i2c_realize;
dc->desc = "Aspeed I2C Controller";
}
static const TypeInfo aspeed_i2c_info = {
.name = TYPE_ASPEED_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(AspeedI2CState),
.class_init = aspeed_i2c_class_init,
};
static void aspeed_i2c_register_types(void)
{
type_register_static(&aspeed_i2c_info);
}
type_init(aspeed_i2c_register_types)
I2CBus *aspeed_i2c_get_bus(DeviceState *dev, int busnr)
{
AspeedI2CState *s = ASPEED_I2C(dev);
I2CBus *bus = NULL;
if (busnr >= 0 && busnr < ASPEED_I2C_NR_BUSSES) {
bus = s->busses[busnr].bus;
}
return bus;
}
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