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qemu/hw/i2c/allwinner-i2c.c
Strahinja Jankovic 9be8a82c0e {hw/i2c,docs/system/arm}: Allwinner TWI/I2C Emulation 
This patch implements Allwinner TWI/I2C controller emulation. Only
master-mode functionality is implemented.

The SPL boot for Cubieboard expects AXP209 PMIC on TWI0/I2C0 bus, so this is
first part enabling the TWI/I2C bus operation.

Since both Allwinner A10 and H3 use the same module, it is added for
both boards.

Docs are also updated for Cubieboard and Orangepi-PC board to indicate
I2C availability.

Signed-off-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20221226220303.14420-4-strahinja.p.jankovic@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2023-01-12 16:50:19 +00:00

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/*
* Allwinner I2C Bus Serial Interface Emulation
*
* Copyright (C) 2022 Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
*
* This file is derived from IMX I2C controller,
* by Jean-Christophe DUBOIS .
*
* 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/>.
*
* SPDX-License-Identifier: MIT
*/
#include "qemu/osdep.h"
#include "hw/i2c/allwinner-i2c.h"
#include "hw/irq.h"
#include "migration/vmstate.h"
#include "hw/i2c/i2c.h"
#include "qemu/log.h"
#include "trace.h"
#include "qemu/module.h"
/* Allwinner I2C memory map */
#define TWI_ADDR_REG 0x00 /* slave address register */
#define TWI_XADDR_REG 0x04 /* extended slave address register */
#define TWI_DATA_REG 0x08 /* data register */
#define TWI_CNTR_REG 0x0c /* control register */
#define TWI_STAT_REG 0x10 /* status register */
#define TWI_CCR_REG 0x14 /* clock control register */
#define TWI_SRST_REG 0x18 /* software reset register */
#define TWI_EFR_REG 0x1c /* enhance feature register */
#define TWI_LCR_REG 0x20 /* line control register */
/* Used only in slave mode, do not set */
#define TWI_ADDR_RESET 0
#define TWI_XADDR_RESET 0
/* Data register */
#define TWI_DATA_MASK 0xFF
#define TWI_DATA_RESET 0
/* Control register */
#define TWI_CNTR_INT_EN (1 << 7)
#define TWI_CNTR_BUS_EN (1 << 6)
#define TWI_CNTR_M_STA (1 << 5)
#define TWI_CNTR_M_STP (1 << 4)
#define TWI_CNTR_INT_FLAG (1 << 3)
#define TWI_CNTR_A_ACK (1 << 2)
#define TWI_CNTR_MASK 0xFC
#define TWI_CNTR_RESET 0
/* Status register */
#define TWI_STAT_MASK 0xF8
#define TWI_STAT_RESET 0xF8
/* Clock register */
#define TWI_CCR_CLK_M_MASK 0x78
#define TWI_CCR_CLK_N_MASK 0x07
#define TWI_CCR_MASK 0x7F
#define TWI_CCR_RESET 0
/* Soft reset */
#define TWI_SRST_MASK 0x01
#define TWI_SRST_RESET 0
/* Enhance feature */
#define TWI_EFR_MASK 0x03
#define TWI_EFR_RESET 0
/* Line control */
#define TWI_LCR_SCL_STATE (1 << 5)
#define TWI_LCR_SDA_STATE (1 << 4)
#define TWI_LCR_SCL_CTL (1 << 3)
#define TWI_LCR_SCL_CTL_EN (1 << 2)
#define TWI_LCR_SDA_CTL (1 << 1)
#define TWI_LCR_SDA_CTL_EN (1 << 0)
#define TWI_LCR_MASK 0x3F
#define TWI_LCR_RESET 0x3A
/* Status value in STAT register is shifted by 3 bits */
#define TWI_STAT_SHIFT 3
#define STAT_FROM_STA(x) ((x) << TWI_STAT_SHIFT)
#define STAT_TO_STA(x) ((x) >> TWI_STAT_SHIFT)
enum {
STAT_BUS_ERROR = 0,
/* Master mode */
STAT_M_STA_TX,
STAT_M_RSTA_TX,
STAT_M_ADDR_WR_ACK,
STAT_M_ADDR_WR_NACK,
STAT_M_DATA_TX_ACK,
STAT_M_DATA_TX_NACK,
STAT_M_ARB_LOST,
STAT_M_ADDR_RD_ACK,
STAT_M_ADDR_RD_NACK,
STAT_M_DATA_RX_ACK,
STAT_M_DATA_RX_NACK,
/* Slave mode */
STAT_S_ADDR_WR_ACK,
STAT_S_ARB_LOST_AW_ACK,
STAT_S_GCA_ACK,
STAT_S_ARB_LOST_GCA_ACK,
STAT_S_DATA_RX_SA_ACK,
STAT_S_DATA_RX_SA_NACK,
STAT_S_DATA_RX_GCA_ACK,
STAT_S_DATA_RX_GCA_NACK,
STAT_S_STP_RSTA,
STAT_S_ADDR_RD_ACK,
STAT_S_ARB_LOST_AR_ACK,
STAT_S_DATA_TX_ACK,
STAT_S_DATA_TX_NACK,
STAT_S_LB_TX_ACK,
/* Master mode, 10-bit */
STAT_M_2ND_ADDR_WR_ACK,
STAT_M_2ND_ADDR_WR_NACK,
/* Idle */
STAT_IDLE = 0x1f
} TWI_STAT_STA;
static const char *allwinner_i2c_get_regname(unsigned offset)
{
switch (offset) {
case TWI_ADDR_REG:
return "ADDR";
case TWI_XADDR_REG:
return "XADDR";
case TWI_DATA_REG:
return "DATA";
case TWI_CNTR_REG:
return "CNTR";
case TWI_STAT_REG:
return "STAT";
case TWI_CCR_REG:
return "CCR";
case TWI_SRST_REG:
return "SRST";
case TWI_EFR_REG:
return "EFR";
case TWI_LCR_REG:
return "LCR";
default:
return "[?]";
}
}
static inline bool allwinner_i2c_is_reset(AWI2CState *s)
{
return s->srst & TWI_SRST_MASK;
}
static inline bool allwinner_i2c_bus_is_enabled(AWI2CState *s)
{
return s->cntr & TWI_CNTR_BUS_EN;
}
static inline bool allwinner_i2c_interrupt_is_enabled(AWI2CState *s)
{
return s->cntr & TWI_CNTR_INT_EN;
}
static void allwinner_i2c_reset_hold(Object *obj)
{
AWI2CState *s = AW_I2C(obj);
if (STAT_TO_STA(s->stat) != STAT_IDLE) {
i2c_end_transfer(s->bus);
}
s->addr = TWI_ADDR_RESET;
s->xaddr = TWI_XADDR_RESET;
s->data = TWI_DATA_RESET;
s->cntr = TWI_CNTR_RESET;
s->stat = TWI_STAT_RESET;
s->ccr = TWI_CCR_RESET;
s->srst = TWI_SRST_RESET;
s->efr = TWI_EFR_RESET;
s->lcr = TWI_LCR_RESET;
}
static inline void allwinner_i2c_raise_interrupt(AWI2CState *s)
{
/*
* Raise an interrupt if the device is not reset and it is configured
* to generate some interrupts.
*/
if (!allwinner_i2c_is_reset(s) && allwinner_i2c_bus_is_enabled(s)) {
if (STAT_TO_STA(s->stat) != STAT_IDLE) {
s->cntr |= TWI_CNTR_INT_FLAG;
if (allwinner_i2c_interrupt_is_enabled(s)) {
qemu_irq_raise(s->irq);
}
}
}
}
static uint64_t allwinner_i2c_read(void *opaque, hwaddr offset,
unsigned size)
{
uint16_t value;
AWI2CState *s = AW_I2C(opaque);
switch (offset) {
case TWI_ADDR_REG:
value = s->addr;
break;
case TWI_XADDR_REG:
value = s->xaddr;
break;
case TWI_DATA_REG:
if ((STAT_TO_STA(s->stat) == STAT_M_ADDR_RD_ACK) ||
(STAT_TO_STA(s->stat) == STAT_M_DATA_RX_ACK) ||
(STAT_TO_STA(s->stat) == STAT_M_DATA_RX_NACK)) {
/* Get the next byte */
s->data = i2c_recv(s->bus);
if (s->cntr & TWI_CNTR_A_ACK) {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_ACK);
} else {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_NACK);
}
allwinner_i2c_raise_interrupt(s);
}
value = s->data;
break;
case TWI_CNTR_REG:
value = s->cntr;
break;
case TWI_STAT_REG:
value = s->stat;
/*
* If polling when reading then change state to indicate data
* is available
*/
if (STAT_TO_STA(s->stat) == STAT_M_ADDR_RD_ACK) {
if (s->cntr & TWI_CNTR_A_ACK) {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_ACK);
} else {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_NACK);
}
allwinner_i2c_raise_interrupt(s);
}
break;
case TWI_CCR_REG:
value = s->ccr;
break;
case TWI_SRST_REG:
value = s->srst;
break;
case TWI_EFR_REG:
value = s->efr;
break;
case TWI_LCR_REG:
value = s->lcr;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
HWADDR_PRIx "\n", TYPE_AW_I2C, __func__, offset);
value = 0;
break;
}
trace_allwinner_i2c_read(allwinner_i2c_get_regname(offset), offset, value);
return (uint64_t)value;
}
static void allwinner_i2c_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
AWI2CState *s = AW_I2C(opaque);
value &= 0xff;
trace_allwinner_i2c_write(allwinner_i2c_get_regname(offset), offset, value);
switch (offset) {
case TWI_ADDR_REG:
s->addr = (uint8_t)value;
break;
case TWI_XADDR_REG:
s->xaddr = (uint8_t)value;
break;
case TWI_DATA_REG:
/* If the device is in reset or not enabled, nothing to do */
if (allwinner_i2c_is_reset(s) || (!allwinner_i2c_bus_is_enabled(s))) {
break;
}
s->data = value & TWI_DATA_MASK;
switch (STAT_TO_STA(s->stat)) {
case STAT_M_STA_TX:
case STAT_M_RSTA_TX:
/* Send address */
if (i2c_start_transfer(s->bus, extract32(s->data, 1, 7),
extract32(s->data, 0, 1))) {
/* If non zero is returned, the address is not valid */
s->stat = STAT_FROM_STA(STAT_M_ADDR_WR_NACK);
} else {
/* Determine if read of write */
if (extract32(s->data, 0, 1)) {
s->stat = STAT_FROM_STA(STAT_M_ADDR_RD_ACK);
} else {
s->stat = STAT_FROM_STA(STAT_M_ADDR_WR_ACK);
}
allwinner_i2c_raise_interrupt(s);
}
break;
case STAT_M_ADDR_WR_ACK:
case STAT_M_DATA_TX_ACK:
if (i2c_send(s->bus, s->data)) {
/* If the target return non zero then end the transfer */
s->stat = STAT_FROM_STA(STAT_M_DATA_TX_NACK);
i2c_end_transfer(s->bus);
} else {
s->stat = STAT_FROM_STA(STAT_M_DATA_TX_ACK);
allwinner_i2c_raise_interrupt(s);
}
break;
default:
break;
}
break;
case TWI_CNTR_REG:
if (!allwinner_i2c_is_reset(s)) {
/* Do something only if not in software reset */
s->cntr = value & TWI_CNTR_MASK;
/* Check if start condition should be sent */
if (s->cntr & TWI_CNTR_M_STA) {
/* Update status */
if (STAT_TO_STA(s->stat) == STAT_IDLE) {
/* Send start condition */
s->stat = STAT_FROM_STA(STAT_M_STA_TX);
} else {
/* Send repeated start condition */
s->stat = STAT_FROM_STA(STAT_M_RSTA_TX);
}
/* Clear start condition */
s->cntr &= ~TWI_CNTR_M_STA;
}
if (s->cntr & TWI_CNTR_M_STP) {
/* Update status */
i2c_end_transfer(s->bus);
s->stat = STAT_FROM_STA(STAT_IDLE);
s->cntr &= ~TWI_CNTR_M_STP;
}
if ((s->cntr & TWI_CNTR_INT_FLAG) == 0) {
/* Interrupt flag cleared */
qemu_irq_lower(s->irq);
}
if ((s->cntr & TWI_CNTR_A_ACK) == 0) {
if (STAT_TO_STA(s->stat) == STAT_M_DATA_RX_ACK) {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_NACK);
}
} else {
if (STAT_TO_STA(s->stat) == STAT_M_DATA_RX_NACK) {
s->stat = STAT_FROM_STA(STAT_M_DATA_RX_ACK);
}
}
allwinner_i2c_raise_interrupt(s);
}
break;
case TWI_CCR_REG:
s->ccr = value & TWI_CCR_MASK;
break;
case TWI_SRST_REG:
if (((value & TWI_SRST_MASK) == 0) && (s->srst & TWI_SRST_MASK)) {
/* Perform reset */
allwinner_i2c_reset_hold(OBJECT(s));
}
s->srst = value & TWI_SRST_MASK;
break;
case TWI_EFR_REG:
s->efr = value & TWI_EFR_MASK;
break;
case TWI_LCR_REG:
s->lcr = value & TWI_LCR_MASK;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
HWADDR_PRIx "\n", TYPE_AW_I2C, __func__, offset);
break;
}
}
static const MemoryRegionOps allwinner_i2c_ops = {
.read = allwinner_i2c_read,
.write = allwinner_i2c_write,
.valid.min_access_size = 1,
.valid.max_access_size = 4,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static const VMStateDescription allwinner_i2c_vmstate = {
.name = TYPE_AW_I2C,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(addr, AWI2CState),
VMSTATE_UINT8(xaddr, AWI2CState),
VMSTATE_UINT8(data, AWI2CState),
VMSTATE_UINT8(cntr, AWI2CState),
VMSTATE_UINT8(ccr, AWI2CState),
VMSTATE_UINT8(srst, AWI2CState),
VMSTATE_UINT8(efr, AWI2CState),
VMSTATE_UINT8(lcr, AWI2CState),
VMSTATE_END_OF_LIST()
}
};
static void allwinner_i2c_realize(DeviceState *dev, Error **errp)
{
AWI2CState *s = AW_I2C(dev);
memory_region_init_io(&s->iomem, OBJECT(s), &allwinner_i2c_ops, s,
TYPE_AW_I2C, AW_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(dev, "i2c");
}
static void allwinner_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
ResettableClass *rc = RESETTABLE_CLASS(klass);
rc->phases.hold = allwinner_i2c_reset_hold;
dc->vmsd = &allwinner_i2c_vmstate;
dc->realize = allwinner_i2c_realize;
dc->desc = "Allwinner I2C Controller";
}
static const TypeInfo allwinner_i2c_type_info = {
.name = TYPE_AW_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(AWI2CState),
.class_init = allwinner_i2c_class_init,
};
static void allwinner_i2c_register_types(void)
{
type_register_static(&allwinner_i2c_type_info);
}
type_init(allwinner_i2c_register_types)
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