1 #ifndef QEMU_I2C_H 2 #define QEMU_I2C_H 3 4 #include "hw/qdev-core.h" 5 #include "qom/object.h" 6 7 /* The QEMU I2C implementation only supports simple transfers that complete 8 immediately. It does not support slave devices that need to be able to 9 defer their response (eg. CPU slave interfaces where the data is supplied 10 by the device driver in response to an interrupt). */ 11 12 enum i2c_event { 13 I2C_START_RECV, 14 I2C_START_SEND, 15 I2C_START_SEND_ASYNC, 16 I2C_FINISH, 17 I2C_NACK /* Masker NACKed a receive byte. */ 18 }; 19 20 typedef struct I2CNodeList I2CNodeList; 21 22 #define TYPE_I2C_SLAVE "i2c-slave" 23 OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass, 24 I2C_SLAVE) 25 26 struct I2CSlaveClass { 27 DeviceClass parent_class; 28 29 /* Master to slave. Returns non-zero for a NAK, 0 for success. */ 30 int (*send)(I2CSlave *s, uint8_t data); 31 32 /* Master to slave (asynchronous). Receiving slave must call i2c_ack(). */ 33 void (*send_async)(I2CSlave *s, uint8_t data); 34 35 /* 36 * Slave to master. This cannot fail, the device should always 37 * return something here. 38 */ 39 uint8_t (*recv)(I2CSlave *s); 40 41 /* 42 * Notify the slave of a bus state change. For start event, 43 * returns non-zero to NAK an operation. For other events the 44 * return code is not used and should be zero. 45 */ 46 int (*event)(I2CSlave *s, enum i2c_event event); 47 48 /* 49 * Check if this device matches the address provided. Returns bool of 50 * true if it matches (or broadcast), and updates the device list, false 51 * otherwise. 52 * 53 * If broadcast is true, match should add the device and return true. 54 */ 55 bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast, 56 I2CNodeList *current_devs); 57 }; 58 59 struct I2CSlave { 60 DeviceState qdev; 61 62 /* Remaining fields for internal use by the I2C code. */ 63 uint8_t address; 64 }; 65 66 #define TYPE_I2C_BUS "i2c-bus" 67 OBJECT_DECLARE_SIMPLE_TYPE(I2CBus, I2C_BUS) 68 69 typedef struct I2CNode I2CNode; 70 71 struct I2CNode { 72 I2CSlave *elt; 73 QLIST_ENTRY(I2CNode) next; 74 }; 75 76 typedef struct I2CPendingMaster I2CPendingMaster; 77 78 struct I2CPendingMaster { 79 QEMUBH *bh; 80 QSIMPLEQ_ENTRY(I2CPendingMaster) entry; 81 }; 82 83 typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList; 84 typedef QSIMPLEQ_HEAD(I2CPendingMasters, I2CPendingMaster) I2CPendingMasters; 85 86 struct I2CBus { 87 BusState qbus; 88 I2CNodeList current_devs; 89 I2CPendingMasters pending_masters; 90 uint8_t saved_address; 91 bool broadcast; 92 93 /* Set from slave currently mastering the bus. */ 94 QEMUBH *bh; 95 }; 96 97 I2CBus *i2c_init_bus(DeviceState *parent, const char *name); 98 int i2c_bus_busy(I2CBus *bus); 99 100 /** 101 * i2c_start_transfer: start a transfer on an I2C bus. 102 * 103 * @bus: #I2CBus to be used 104 * @address: address of the slave 105 * @is_recv: indicates the transfer direction 106 * 107 * When @is_recv is a known boolean constant, use the 108 * i2c_start_recv() or i2c_start_send() helper instead. 109 * 110 * Returns: 0 on success, -1 on error 111 */ 112 int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv); 113 114 /** 115 * i2c_start_recv: start a 'receive' transfer on an I2C bus. 116 * 117 * @bus: #I2CBus to be used 118 * @address: address of the slave 119 * 120 * Returns: 0 on success, -1 on error 121 */ 122 int i2c_start_recv(I2CBus *bus, uint8_t address); 123 124 /** 125 * i2c_start_send: start a 'send' transfer on an I2C bus. 126 * 127 * @bus: #I2CBus to be used 128 * @address: address of the slave 129 * 130 * Returns: 0 on success, -1 on error 131 */ 132 int i2c_start_send(I2CBus *bus, uint8_t address); 133 134 /** 135 * i2c_start_send_async: start an asynchronous 'send' transfer on an I2C bus. 136 * 137 * @bus: #I2CBus to be used 138 * @address: address of the slave 139 * 140 * Return: 0 on success, -1 on error 141 */ 142 int i2c_start_send_async(I2CBus *bus, uint8_t address); 143 144 void i2c_schedule_pending_master(I2CBus *bus); 145 146 void i2c_end_transfer(I2CBus *bus); 147 void i2c_nack(I2CBus *bus); 148 void i2c_ack(I2CBus *bus); 149 void i2c_bus_master(I2CBus *bus, QEMUBH *bh); 150 void i2c_bus_release(I2CBus *bus); 151 int i2c_send(I2CBus *bus, uint8_t data); 152 int i2c_send_async(I2CBus *bus, uint8_t data); 153 uint8_t i2c_recv(I2CBus *bus); 154 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, 155 I2CNodeList *current_devs); 156 157 /** 158 * Create an I2C slave device on the heap. 159 * @name: a device type name 160 * @addr: I2C address of the slave when put on a bus 161 * 162 * This only initializes the device state structure and allows 163 * properties to be set. Type @name must exist. The device still 164 * needs to be realized. See qdev-core.h. 165 */ 166 I2CSlave *i2c_slave_new(const char *name, uint8_t addr); 167 168 /** 169 * Create and realize an I2C slave device on the heap. 170 * @bus: I2C bus to put it on 171 * @name: I2C slave device type name 172 * @addr: I2C address of the slave when put on a bus 173 * 174 * Create the device state structure, initialize it, put it on the 175 * specified @bus, and drop the reference to it (the device is realized). 176 */ 177 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr); 178 179 /** 180 * Realize and drop a reference an I2C slave device 181 * @dev: I2C slave device to realize 182 * @bus: I2C bus to put it on 183 * @addr: I2C address of the slave on the bus 184 * @errp: pointer to NULL initialized error object 185 * 186 * Returns: %true on success, %false on failure. 187 * 188 * Call 'realize' on @dev, put it on the specified @bus, and drop the 189 * reference to it. 190 * 191 * This function is useful if you have created @dev via qdev_new(), 192 * i2c_slave_new() or i2c_slave_try_new() (which take a reference to 193 * the device it returns to you), so that you can set properties on it 194 * before realizing it. If you don't need to set properties then 195 * i2c_slave_create_simple() is probably better (as it does the create, 196 * init and realize in one step). 197 * 198 * If you are embedding the I2C slave into another QOM device and 199 * initialized it via some variant on object_initialize_child() then 200 * do not use this function, because that family of functions arrange 201 * for the only reference to the child device to be held by the parent 202 * via the child<> property, and so the reference-count-drop done here 203 * would be incorrect. (Instead you would want i2c_slave_realize(), 204 * which doesn't currently exist but would be trivial to create if we 205 * had any code that wanted it.) 206 */ 207 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp); 208 209 /** 210 * Set the I2C bus address of a slave device 211 * @dev: I2C slave device 212 * @address: I2C address of the slave when put on a bus 213 */ 214 void i2c_slave_set_address(I2CSlave *dev, uint8_t address); 215 216 extern const VMStateDescription vmstate_i2c_slave; 217 218 #define VMSTATE_I2C_SLAVE(_field, _state) { \ 219 .name = (stringify(_field)), \ 220 .size = sizeof(I2CSlave), \ 221 .vmsd = &vmstate_i2c_slave, \ 222 .flags = VMS_STRUCT, \ 223 .offset = vmstate_offset_value(_state, _field, I2CSlave), \ 224 } 225 226 #endif 227