/* * Exynos4210 I2C Bus Serial Interface Emulation * * Copyright (C) 2012 Samsung Electronics Co Ltd. * Maksim Kozlov, <m.kozlov@samsung.com> * Igor Mitsyanko, <i.mitsyanko@samsung.com> * * 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/timer.h" #include "sysbus.h" #include "i2c.h" #ifndef EXYNOS4_I2C_DEBUG #define EXYNOS4_I2C_DEBUG 0 #endif #define TYPE_EXYNOS4_I2C "exynos4210.i2c" #define EXYNOS4_I2C(obj) \ OBJECT_CHECK(Exynos4210I2CState, (obj), TYPE_EXYNOS4_I2C) /* Exynos4210 I2C memory map */ #define EXYNOS4_I2C_MEM_SIZE 0x14 #define I2CCON_ADDR 0x00 /* control register */ #define I2CSTAT_ADDR 0x04 /* control/status register */ #define I2CADD_ADDR 0x08 /* address register */ #define I2CDS_ADDR 0x0c /* data shift register */ #define I2CLC_ADDR 0x10 /* line control register */ #define I2CCON_ACK_GEN (1 << 7) #define I2CCON_INTRS_EN (1 << 5) #define I2CCON_INT_PEND (1 << 4) #define EXYNOS4_I2C_MODE(reg) (((reg) >> 6) & 3) #define I2C_IN_MASTER_MODE(reg) (((reg) >> 6) & 2) #define I2CMODE_MASTER_Rx 0x2 #define I2CMODE_MASTER_Tx 0x3 #define I2CSTAT_LAST_BIT (1 << 0) #define I2CSTAT_OUTPUT_EN (1 << 4) #define I2CSTAT_START_BUSY (1 << 5) #if EXYNOS4_I2C_DEBUG #define DPRINT(fmt, args...) \ do { fprintf(stderr, "QEMU I2C: "fmt, ## args); } while (0) static const char *exynos4_i2c_get_regname(unsigned offset) { switch (offset) { case I2CCON_ADDR: return "I2CCON"; case I2CSTAT_ADDR: return "I2CSTAT"; case I2CADD_ADDR: return "I2CADD"; case I2CDS_ADDR: return "I2CDS"; case I2CLC_ADDR: return "I2CLC"; default: return "[?]"; } } #else #define DPRINT(fmt, args...) do { } while (0) #endif typedef struct Exynos4210I2CState { SysBusDevice busdev; MemoryRegion iomem; i2c_bus *bus; qemu_irq irq; uint8_t i2ccon; uint8_t i2cstat; uint8_t i2cadd; uint8_t i2cds; uint8_t i2clc; bool scl_free; } Exynos4210I2CState; static inline void exynos4210_i2c_raise_interrupt(Exynos4210I2CState *s) { if (s->i2ccon & I2CCON_INTRS_EN) { s->i2ccon |= I2CCON_INT_PEND; qemu_irq_raise(s->irq); } } static void exynos4210_i2c_data_receive(void *opaque) { Exynos4210I2CState *s = (Exynos4210I2CState *)opaque; int ret; s->i2cstat &= ~I2CSTAT_LAST_BIT; s->scl_free = false; ret = i2c_recv(s->bus); if (ret < 0 && (s->i2ccon & I2CCON_ACK_GEN)) { s->i2cstat |= I2CSTAT_LAST_BIT; /* Data is not acknowledged */ } else { s->i2cds = ret; } exynos4210_i2c_raise_interrupt(s); } static void exynos4210_i2c_data_send(void *opaque) { Exynos4210I2CState *s = (Exynos4210I2CState *)opaque; s->i2cstat &= ~I2CSTAT_LAST_BIT; s->scl_free = false; if (i2c_send(s->bus, s->i2cds) < 0 && (s->i2ccon & I2CCON_ACK_GEN)) { s->i2cstat |= I2CSTAT_LAST_BIT; } exynos4210_i2c_raise_interrupt(s); } static uint64_t exynos4210_i2c_read(void *opaque, hwaddr offset, unsigned size) { Exynos4210I2CState *s = (Exynos4210I2CState *)opaque; uint8_t value; switch (offset) { case I2CCON_ADDR: value = s->i2ccon; break; case I2CSTAT_ADDR: value = s->i2cstat; break; case I2CADD_ADDR: value = s->i2cadd; break; case I2CDS_ADDR: value = s->i2cds; s->scl_free = true; if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx && (s->i2cstat & I2CSTAT_START_BUSY) && !(s->i2ccon & I2CCON_INT_PEND)) { exynos4210_i2c_data_receive(s); } break; case I2CLC_ADDR: value = s->i2clc; break; default: value = 0; DPRINT("ERROR: Bad read offset 0x%x\n", (unsigned int)offset); break; } DPRINT("read %s [0x%02x] -> 0x%02x\n", exynos4_i2c_get_regname(offset), (unsigned int)offset, value); return value; } static void exynos4210_i2c_write(void *opaque, hwaddr offset, uint64_t value, unsigned size) { Exynos4210I2CState *s = (Exynos4210I2CState *)opaque; uint8_t v = value & 0xff; DPRINT("write %s [0x%02x] <- 0x%02x\n", exynos4_i2c_get_regname(offset), (unsigned int)offset, v); switch (offset) { case I2CCON_ADDR: s->i2ccon = (v & ~I2CCON_INT_PEND) | (s->i2ccon & I2CCON_INT_PEND); if ((s->i2ccon & I2CCON_INT_PEND) && !(v & I2CCON_INT_PEND)) { s->i2ccon &= ~I2CCON_INT_PEND; qemu_irq_lower(s->irq); if (!(s->i2ccon & I2CCON_INTRS_EN)) { s->i2cstat &= ~I2CSTAT_START_BUSY; } if (s->i2cstat & I2CSTAT_START_BUSY) { if (s->scl_free) { if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx) { exynos4210_i2c_data_send(s); } else if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx) { exynos4210_i2c_data_receive(s); } } else { s->i2ccon |= I2CCON_INT_PEND; qemu_irq_raise(s->irq); } } } break; case I2CSTAT_ADDR: s->i2cstat = (s->i2cstat & I2CSTAT_START_BUSY) | (v & ~I2CSTAT_START_BUSY); if (!(s->i2cstat & I2CSTAT_OUTPUT_EN)) { s->i2cstat &= ~I2CSTAT_START_BUSY; s->scl_free = true; qemu_irq_lower(s->irq); break; } /* Nothing to do if in i2c slave mode */ if (!I2C_IN_MASTER_MODE(s->i2cstat)) { break; } if (v & I2CSTAT_START_BUSY) { s->i2cstat &= ~I2CSTAT_LAST_BIT; s->i2cstat |= I2CSTAT_START_BUSY; /* Line is busy */ s->scl_free = false; /* Generate start bit and send slave address */ if (i2c_start_transfer(s->bus, s->i2cds >> 1, s->i2cds & 0x1) && (s->i2ccon & I2CCON_ACK_GEN)) { s->i2cstat |= I2CSTAT_LAST_BIT; } else if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx) { exynos4210_i2c_data_receive(s); } exynos4210_i2c_raise_interrupt(s); } else { i2c_end_transfer(s->bus); if (!(s->i2ccon & I2CCON_INT_PEND)) { s->i2cstat &= ~I2CSTAT_START_BUSY; } s->scl_free = true; } break; case I2CADD_ADDR: if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) { s->i2cadd = v; } break; case I2CDS_ADDR: if (s->i2cstat & I2CSTAT_OUTPUT_EN) { s->i2cds = v; s->scl_free = true; if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx && (s->i2cstat & I2CSTAT_START_BUSY) && !(s->i2ccon & I2CCON_INT_PEND)) { exynos4210_i2c_data_send(s); } } break; case I2CLC_ADDR: s->i2clc = v; break; default: DPRINT("ERROR: Bad write offset 0x%x\n", (unsigned int)offset); break; } } static const MemoryRegionOps exynos4210_i2c_ops = { .read = exynos4210_i2c_read, .write = exynos4210_i2c_write, .endianness = DEVICE_NATIVE_ENDIAN, }; static const VMStateDescription exynos4210_i2c_vmstate = { .name = TYPE_EXYNOS4_I2C, .version_id = 1, .minimum_version_id = 1, .fields = (VMStateField[]) { VMSTATE_UINT8(i2ccon, Exynos4210I2CState), VMSTATE_UINT8(i2cstat, Exynos4210I2CState), VMSTATE_UINT8(i2cds, Exynos4210I2CState), VMSTATE_UINT8(i2cadd, Exynos4210I2CState), VMSTATE_UINT8(i2clc, Exynos4210I2CState), VMSTATE_BOOL(scl_free, Exynos4210I2CState), VMSTATE_END_OF_LIST() } }; static void exynos4210_i2c_reset(DeviceState *d) { Exynos4210I2CState *s = EXYNOS4_I2C(d); s->i2ccon = 0x00; s->i2cstat = 0x00; s->i2cds = 0xFF; s->i2clc = 0x00; s->i2cadd = 0xFF; s->scl_free = true; } static int exynos4210_i2c_realize(SysBusDevice *dev) { Exynos4210I2CState *s = EXYNOS4_I2C(dev); memory_region_init_io(&s->iomem, &exynos4210_i2c_ops, s, TYPE_EXYNOS4_I2C, EXYNOS4_I2C_MEM_SIZE); sysbus_init_mmio(dev, &s->iomem); sysbus_init_irq(dev, &s->irq); s->bus = i2c_init_bus(&dev->qdev, "i2c"); return 0; } static void exynos4210_i2c_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass); dc->vmsd = &exynos4210_i2c_vmstate; dc->reset = exynos4210_i2c_reset; sbdc->init = exynos4210_i2c_realize; } static const TypeInfo exynos4210_i2c_type_info = { .name = TYPE_EXYNOS4_I2C, .parent = TYPE_SYS_BUS_DEVICE, .instance_size = sizeof(Exynos4210I2CState), .class_init = exynos4210_i2c_class_init, }; static void exynos4210_i2c_register_types(void) { type_register_static(&exynos4210_i2c_type_info); } type_init(exynos4210_i2c_register_types)