include/hw/i2c/smbus_slave.h

   1 /*
   2  * QEMU SMBus device (slave) API
   3  *
   4  * Copyright (c) 2007 Arastra, Inc.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #ifndef HW_SMBUS_SLAVE_H
  26 #define HW_SMBUS_SLAVE_H
  27
  28 #include "hw/i2c/i2c.h"
  29 #include "qom/object.h"
  30
  31 #define TYPE_SMBUS_DEVICE "smbus-device"
  32 OBJECT_DECLARE_TYPE(SMBusDevice, SMBusDeviceClass,
  33                     SMBUS_DEVICE)
  34
  35
  36 struct SMBusDeviceClass {
  37     I2CSlaveClass parent_class;
  38
  39     /*
  40      * An operation with no data, special in SMBus.
  41      * This may be NULL, quick commands are ignore in that case.
  42      */
  43     void (*quick_cmd)(SMBusDevice *dev, uint8_t read);
  44
  45     /*
  46      * We can't distinguish between a word write and a block write with
  47      * length 1, so pass the whole data block including the length byte
  48      * (if present).  The device is responsible figuring out what type of
  49      * command this is.
  50      * This may be NULL if no data is written to the device.  Writes
  51      * will be ignore in that case.
  52      */
  53     int (*write_data)(SMBusDevice *dev, uint8_t *buf, uint8_t len);
  54
  55     /*
  56      * Likewise we can't distinguish between different reads, or even know
  57      * the length of the read until the read is complete, so read data a
  58      * byte at a time.  The device is responsible for adding the length
  59      * byte on block reads.  This call cannot fail, it should return
  60      * something, preferably 0xff if nothing is available.
  61      * This may be NULL if no data is read from the device.  Reads will
  62      * return 0xff in that case.
  63      */
  64     uint8_t (*receive_byte)(SMBusDevice *dev);
  65 };
  66
  67 #define SMBUS_DATA_MAX_LEN 34  /* command + len + 32 bytes of data.  */
  68
  69 struct SMBusDevice {
  70     /* The SMBus protocol is implemented on top of I2C.  */
  71     I2CSlave i2c;
  72
  73     /* Remaining fields for internal use only.  */
  74     int32_t mode;
  75     int32_t data_len;
  76     uint8_t data_buf[SMBUS_DATA_MAX_LEN];
  77 };
  78
  79 extern const VMStateDescription vmstate_smbus_device;
  80
  81 #define VMSTATE_SMBUS_DEVICE(_field, _state) {                       \
  82     .name       = (stringify(_field)),                               \
  83     .size       = sizeof(SMBusDevice),                               \
  84     .vmsd       = &vmstate_smbus_device,                             \
  85     .flags      = VMS_STRUCT,                                        \
  86     .offset     = vmstate_offset_value(_state, _field, SMBusDevice), \
  87 }
  88
  89 /*
  90  * Users should call this in their .needed functions to know if the
  91  * SMBus slave data needs to be transferred.
  92  */
  93 bool smbus_vmstate_needed(SMBusDevice *dev);
  94
  95 #endif