diff options
Diffstat (limited to 'src/hw/i2c/imx_i2c.c')
| -rw-r--r-- | src/hw/i2c/imx_i2c.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/src/hw/i2c/imx_i2c.c b/src/hw/i2c/imx_i2c.c new file mode 100644 index 0000000..cb62c7a --- /dev/null +++ b/src/hw/i2c/imx_i2c.c @@ -0,0 +1,335 @@ +/* + * i.MX I2C Bus Serial Interface Emulation + * + * Copyright (C) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net> + * + * 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 "hw/i2c/imx_i2c.h" +#include "hw/i2c/i2c.h" + +#ifndef DEBUG_IMX_I2C +#define DEBUG_IMX_I2C 0 +#endif + +#define DPRINTF(fmt, args...) \ + do { \ + if (DEBUG_IMX_I2C) { \ + fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_I2C, \ + __func__, ##args); \ + } \ + } while (0) + +static const char *imx_i2c_get_regname(unsigned offset) +{ + switch (offset) { + case IADR_ADDR: + return "IADR"; + case IFDR_ADDR: + return "IFDR"; + case I2CR_ADDR: + return "I2CR"; + case I2SR_ADDR: + return "I2SR"; + case I2DR_ADDR: + return "I2DR"; + default: + return "[?]"; + } +} + +static inline bool imx_i2c_is_enabled(IMXI2CState *s) +{ + return s->i2cr & I2CR_IEN; +} + +static inline bool imx_i2c_interrupt_is_enabled(IMXI2CState *s) +{ + return s->i2cr & I2CR_IIEN; +} + +static inline bool imx_i2c_is_master(IMXI2CState *s) +{ + return s->i2cr & I2CR_MSTA; +} + +static void imx_i2c_reset(DeviceState *dev) +{ + IMXI2CState *s = IMX_I2C(dev); + + if (s->address != ADDR_RESET) { + i2c_end_transfer(s->bus); + } + + s->address = ADDR_RESET; + s->iadr = IADR_RESET; + s->ifdr = IFDR_RESET; + s->i2cr = I2CR_RESET; + s->i2sr = I2SR_RESET; + s->i2dr_read = I2DR_RESET; + s->i2dr_write = I2DR_RESET; +} + +static inline void imx_i2c_raise_interrupt(IMXI2CState *s) +{ + /* + * raise an interrupt if the device is enabled and it is configured + * to generate some interrupts. + */ + if (imx_i2c_is_enabled(s) && imx_i2c_interrupt_is_enabled(s)) { + s->i2sr |= I2SR_IIF; + qemu_irq_raise(s->irq); + } +} + +static uint64_t imx_i2c_read(void *opaque, hwaddr offset, + unsigned size) +{ + uint16_t value; + IMXI2CState *s = IMX_I2C(opaque); + + switch (offset) { + case IADR_ADDR: + value = s->iadr; + break; + case IFDR_ADDR: + value = s->ifdr; + break; + case I2CR_ADDR: + value = s->i2cr; + break; + case I2SR_ADDR: + value = s->i2sr; + break; + case I2DR_ADDR: + value = s->i2dr_read; + + if (imx_i2c_is_master(s)) { + int ret = 0xff; + + if (s->address == ADDR_RESET) { + /* something is wrong as the address is not set */ + qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read " + "without specifying the slave address\n", + TYPE_IMX_I2C, __func__); + } else if (s->i2cr & I2CR_MTX) { + qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read " + "but MTX is set\n", TYPE_IMX_I2C, __func__); + } else { + /* get the next byte */ + ret = i2c_recv(s->bus); + + if (ret >= 0) { + imx_i2c_raise_interrupt(s); + } else { + qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: read failed " + "for device 0x%02x\n", TYPE_IMX_I2C, + __func__, s->address); + ret = 0xff; + } + } + + s->i2dr_read = ret; + } else { + qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n", + TYPE_IMX_I2C, __func__); + } + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%" + HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset); + value = 0; + break; + } + + DPRINTF("read %s [0x%" HWADDR_PRIx "] -> 0x%02x\n", + imx_i2c_get_regname(offset), offset, value); + + return (uint64_t)value; +} + +static void imx_i2c_write(void *opaque, hwaddr offset, + uint64_t value, unsigned size) +{ + IMXI2CState *s = IMX_I2C(opaque); + + DPRINTF("write %s [0x%" HWADDR_PRIx "] <- 0x%02x\n", + imx_i2c_get_regname(offset), offset, (int)value); + + value &= 0xff; + + switch (offset) { + case IADR_ADDR: + s->iadr = value & IADR_MASK; + /* i2c_set_slave_address(s->bus, (uint8_t)s->iadr); */ + break; + case IFDR_ADDR: + s->ifdr = value & IFDR_MASK; + break; + case I2CR_ADDR: + if (imx_i2c_is_enabled(s) && ((value & I2CR_IEN) == 0)) { + /* This is a soft reset. IADR is preserved during soft resets */ + uint16_t iadr = s->iadr; + imx_i2c_reset(DEVICE(s)); + s->iadr = iadr; + } else { /* normal write */ + s->i2cr = value & I2CR_MASK; + + if (imx_i2c_is_master(s)) { + /* set the bus to busy */ + s->i2sr |= I2SR_IBB; + } else { /* slave mode */ + /* bus is not busy anymore */ + s->i2sr &= ~I2SR_IBB; + + /* + * if we unset the master mode then it ends the ongoing + * transfer if any + */ + if (s->address != ADDR_RESET) { + i2c_end_transfer(s->bus); + s->address = ADDR_RESET; + } + } + + if (s->i2cr & I2CR_RSTA) { /* Restart */ + /* if this is a restart then it ends the ongoing transfer */ + if (s->address != ADDR_RESET) { + i2c_end_transfer(s->bus); + s->address = ADDR_RESET; + s->i2cr &= ~I2CR_RSTA; + } + } + } + break; + case I2SR_ADDR: + /* + * if the user writes 0 to IIF then lower the interrupt and + * reset the bit + */ + if ((s->i2sr & I2SR_IIF) && !(value & I2SR_IIF)) { + s->i2sr &= ~I2SR_IIF; + qemu_irq_lower(s->irq); + } + + /* + * if the user writes 0 to IAL, reset the bit + */ + if ((s->i2sr & I2SR_IAL) && !(value & I2SR_IAL)) { + s->i2sr &= ~I2SR_IAL; + } + + break; + case I2DR_ADDR: + /* if the device is not enabled, nothing to do */ + if (!imx_i2c_is_enabled(s)) { + break; + } + + s->i2dr_write = value & I2DR_MASK; + + if (imx_i2c_is_master(s)) { + /* If this is the first write cycle then it is the slave addr */ + if (s->address == ADDR_RESET) { + if (i2c_start_transfer(s->bus, extract32(s->i2dr_write, 1, 7), + extract32(s->i2dr_write, 0, 1))) { + /* if non zero is returned, the adress is not valid */ + s->i2sr |= I2SR_RXAK; + } else { + s->address = s->i2dr_write; + s->i2sr &= ~I2SR_RXAK; + imx_i2c_raise_interrupt(s); + } + } else { /* This is a normal data write */ + if (i2c_send(s->bus, s->i2dr_write)) { + /* if the target return non zero then end the transfer */ + s->i2sr |= I2SR_RXAK; + s->address = ADDR_RESET; + i2c_end_transfer(s->bus); + } else { + s->i2sr &= ~I2SR_RXAK; + imx_i2c_raise_interrupt(s); + } + } + } else { + qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n", + TYPE_IMX_I2C, __func__); + } + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%" + HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset); + break; + } +} + +static const MemoryRegionOps imx_i2c_ops = { + .read = imx_i2c_read, + .write = imx_i2c_write, + .valid.min_access_size = 1, + .valid.max_access_size = 2, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static const VMStateDescription imx_i2c_vmstate = { + .name = TYPE_IMX_I2C, + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT16(address, IMXI2CState), + VMSTATE_UINT16(iadr, IMXI2CState), + VMSTATE_UINT16(ifdr, IMXI2CState), + VMSTATE_UINT16(i2cr, IMXI2CState), + VMSTATE_UINT16(i2sr, IMXI2CState), + VMSTATE_UINT16(i2dr_read, IMXI2CState), + VMSTATE_UINT16(i2dr_write, IMXI2CState), + VMSTATE_END_OF_LIST() + } +}; + +static void imx_i2c_realize(DeviceState *dev, Error **errp) +{ + IMXI2CState *s = IMX_I2C(dev); + + memory_region_init_io(&s->iomem, OBJECT(s), &imx_i2c_ops, s, TYPE_IMX_I2C, + IMX_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(DEVICE(dev), "i2c"); +} + +static void imx_i2c_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->vmsd = &imx_i2c_vmstate; + dc->reset = imx_i2c_reset; + dc->realize = imx_i2c_realize; +} + +static const TypeInfo imx_i2c_type_info = { + .name = TYPE_IMX_I2C, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(IMXI2CState), + .class_init = imx_i2c_class_init, +}; + +static void imx_i2c_register_types(void) +{ + type_register_static(&imx_i2c_type_info); +} + +type_init(imx_i2c_register_types) |
