hw/i2c/imx_i2c.c - qemu - Git at Google

 /*
  *  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 "qemu/osdep.h"
 #include "hw/i2c/imx_i2c.h"
 #include "hw/irq.h"
 #include "migration/vmstate.h"
 #include "hw/i2c/i2c.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "trace.h"

 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)
 {
     if (imx_i2c_is_enabled(s)) {
         s->i2sr |= I2SR_IIF;

         if (imx_i2c_interrupt_is_enabled(s)) {
             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)) {
             uint8_t 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);
                 imx_i2c_raise_interrupt(s);
             }

             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;
     }

     trace_imx_i2c_read(DEVICE(s)->canonical_path, 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);

     trace_imx_i2c_read(DEVICE(s)->canonical_path, imx_i2c_get_regname(offset),
                        offset, value);

     value &= 0xff;

     switch (offset) {
     case IADR_ADDR:
         s->iadr = value & IADR_MASK;
         /* i2c_slave_set_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 address 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 = (const 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(dev, NULL);
 }

 static void imx_i2c_class_init(ObjectClass *klass, const void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->vmsd = &imx_i2c_vmstate;
     device_class_set_legacy_reset(dc, imx_i2c_reset);
     dc->realize = imx_i2c_realize;
     dc->desc = "i.MX I2C Controller";
 }

 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)
	/*
	* 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 "qemu/osdep.h"
	#include "hw/i2c/imx_i2c.h"
	#include "hw/irq.h"
	#include "migration/vmstate.h"
	#include "hw/i2c/i2c.h"
	#include "qemu/log.h"
	#include "qemu/module.h"
	#include "trace.h"

	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)
	{
	if (imx_i2c_is_enabled(s)) {
	s->i2sr \|= I2SR_IIF;

	if (imx_i2c_interrupt_is_enabled(s)) {
	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)) {
	uint8_t 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);
	imx_i2c_raise_interrupt(s);
	}

	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;
	}

	trace_imx_i2c_read(DEVICE(s)->canonical_path, 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);

	trace_imx_i2c_read(DEVICE(s)->canonical_path, imx_i2c_get_regname(offset),
	offset, value);

	value &= 0xff;

	switch (offset) {
	case IADR_ADDR:
	s->iadr = value & IADR_MASK;
	/* i2c_slave_set_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 address 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 = (const 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(dev, NULL);
	}

	static void imx_i2c_class_init(ObjectClass klass, const void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->vmsd = &imx_i2c_vmstate;
	device_class_set_legacy_reset(dc, imx_i2c_reset);
	dc->realize = imx_i2c_realize;
	dc->desc = "i.MX I2C Controller";
	}

	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)