diff options
Diffstat (limited to 'hw/i2c/allwinner-i2c.c')
| -rw-r--r-- | hw/i2c/allwinner-i2c.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/hw/i2c/allwinner-i2c.c b/hw/i2c/allwinner-i2c.c new file mode 100644 index 0000000..a435965 --- /dev/null +++ b/hw/i2c/allwinner-i2c.c @@ -0,0 +1,459 @@ +/* + * 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) |