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qemu-e2k/hw/i2c/allwinner-i2c.c
Peter Maydell 6c50845a91 hw/i2c/allwinner-i2c: Fix subclassing of TYPE_AW_I2C_SUN6I 
In commit 8461bfdca9 we added the TYPE_AW_I2C_SUN6I, which is a
minor variant of the TYPE_AW_I2C device.  However, we didn't quite
get the class hierarchy right.  We made the new TYPE_AW_I2C_SUN6I a
subclass of TYPE_SYS_BUS_DEVICE, which means that you can't validly
use a pointer to this object via the AW_I2C() cast macro, which
insists on having something that is an instance of TYPE_AW_I2C or
some subclass of that type.

This only causes a problem if QOM cast macro debugging is enabled;
that is supposed to be on by default, but a mistake in the meson
conversion in commit c55cf6ab03 meant that it ended up disabled by
default, and we didn't catch this bug.

Fix the problem by arranging the classes in the same way we do for
TYPE_PL011 and TYPE_PL011_LUMINARY in hw/char/pl011.c -- make the
variant class be a subclass of the "normal" version of the device.

This was reported in
https://gitlab.com/qemu-project/qemu/-/issues/1586 but this fix alone
isn't sufficient, as there is a separate cast-related issue in the
CXL code in pci_expander_bridge.c.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
2023-04-11 14:13:29 +01:00

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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->irq_clear_inverted && !(s->cntr & TWI_CNTR_INT_FLAG)) {
/* Write 0 to clear this flag */
qemu_irq_lower(s->irq);
} else if (s->irq_clear_inverted && (s->cntr & TWI_CNTR_INT_FLAG)) {
/* Write 1 to clear this flag */
s->cntr &= ~TWI_CNTR_INT_FLAG;
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_sun6i_init(Object *obj)
{
AWI2CState *s = AW_I2C(obj);
s->irq_clear_inverted = true;
}
static const TypeInfo allwinner_i2c_sun6i_type_info = {
.name = TYPE_AW_I2C_SUN6I,
.parent = TYPE_AW_I2C,
.instance_init = allwinner_i2c_sun6i_init,
};
static void allwinner_i2c_register_types(void)
{
type_register_static(&allwinner_i2c_type_info);
type_register_static(&allwinner_i2c_sun6i_type_info);
}
type_init(allwinner_i2c_register_types)
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