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/*
* MCF5206e MBUS module (I2C bus) driver
*
* Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include "mcf5206/mcfmbus.h"
#include "mcf5206/mcf5206e.h"
#include "i2c.h"
/* Events of I2C machine */
typedef enum i2c_event {
EVENT_NONE, /* Spurious event */
EVENT_TRANSFER, /* Start new transfer */
EVENT_NEXTMSG, /* Start processing of next message in transfer */
EVENT_ACK, /* Sending finished with ACK */
EVENT_NACK, /* Sending finished with NACK */
EVENT_TIMEOUT, /* Timeout occured */
EVENT_DATA_RECV, /* Data received */
EVENT_ARB_LOST, /* Arbitration lost */
EVENT_SLAVE /* Addressed as a slave */
} i2c_event;
static mcfmbus *mbus;
/*** Auxillary primitives ***/
/* Change state of finite state machine */
#define next_state(bus,new_state) \
do { \
(bus)->state = (new_state); \
} while (0)
/* Initiate start condition on the I2C bus */
#define mcfmbus_start(bus) \
do { \
*MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_MSTA; \
} while (0)
/* Initiate stop condition on the I2C bus */
#define mcfmbus_stop(bus) \
do { \
*MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_MSTA; \
} while (0)
/* Initiate repeat start condition on the I2C bus */
#define mcfmbus_rstart(bus) \
do { \
*MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_RSTA; \
} while (0)
/* Send byte to the bus */
#define mcfmbus_send(bus,byte) \
do { \
*MCF5206E_MBDR((bus)->base) = (byte); \
} while (0)
/* Set transmit mode */
#define mcfmbus_tx_mode(bus) \
do { \
*MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_MTX; \
} while (0)
/* Set receive mode */
#define mcfmbus_rx_mode(bus) \
do { \
*MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_MTX; \
(void)*MCF5206E_MBDR((bus)->base); \
} while (0)
/* Transmit acknowledge when byte received */
#define mcfmbus_send_ack(bus) \
do { \
*MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_TXAK; \
} while (0)
/* DO NOT transmit acknowledge when byte received */
#define mcfmbus_send_nack(bus) \
do { \
*MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_TXAK; \
} while (0)
#define mcfmbus_error(bus,err_status) \
do { \
do { \
(bus)->cmsg->status = (err_status); \
(bus)->cmsg++; \
} while (((bus)->cmsg - (bus)->msg < (bus)->nmsg) && \
((bus)->cmsg->flags & I2C_MSG_ERRSKIP)); \
bus->cmsg--; \
} while (0)
/* mcfmbus_get_event --
* Read MBUS module status register, determine interrupt reason and
* return appropriate event.
*
* PARAMETERS:
* bus - pointer to MBUS module descriptor structure
*
* RETURNS:
* event code
*/
static i2c_event
mcfmbus_get_event(mcfmbus *bus)
{
i2c_event event;
uint8_t status, control;
rtems_interrupt_level level;
rtems_interrupt_disable(level);
status = *MCF5206E_MBSR(bus->base);
control = *MCF5206E_MBCR(bus->base);
if (status & MCF5206E_MBSR_MIF) /* Interrupt occured */
{
if (status & MCF5206E_MBSR_MAAS)
{
event = EVENT_SLAVE;
*MCF5206E_MBCR(bus->base) = control; /* To clear Addressed As Slave
condition */
}
else if (status & MCF5206E_MBSR_MAL) /* Arbitration lost */
{
*MCF5206E_MBSR(bus->base) = status & ~MCF5206E_MBSR_MAL;
event = EVENT_ARB_LOST;
}
else if (control & MCF5206E_MBCR_MTX) /* Trasmit mode */
{
if (status & MCF5206E_MBSR_RXAK)
event = EVENT_NACK;
else
event = EVENT_ACK;
}
else /* Received */
{
event = EVENT_DATA_RECV;
}
/* Clear interrupt condition */
*MCF5206E_MBSR(bus->base) &= ~MCF5206E_MBSR_MIF;
}
else
{
event = EVENT_NONE;
}
rtems_interrupt_enable(level);
return event;
}
static void
mcfmbus_machine_error(mcfmbus *bus, i2c_event event)
{
return;
}
/* mcfmbus_machine --
* finite state machine for I2C bus protocol
*
* PARAMETERS:
* bus - pointer to ColdFire MBUS descriptor structure
* event - I2C event
*
* RETURNS:
* none
*/
static void
mcfmbus_machine(mcfmbus *bus, i2c_event event)
{
uint8_t b;
switch (bus->state)
{
case STATE_IDLE:
switch (event)
{
case EVENT_NEXTMSG: /* Start new message processing */
bus->cmsg++;
/* FALLTHRU */
case EVENT_TRANSFER: /* Initiate new transfer */
if (bus->cmsg - bus->msg >= bus->nmsg)
{
mcfmbus_stop(bus);
next_state(bus, STATE_IDLE);
bus->msg = bus->cmsg = NULL;
bus->nmsg = bus->byte = 0;
bus->done(bus->done_arg_ptr);
break;
}
/* Initiate START or REPEATED START condition on the bus */
if (event == EVENT_TRANSFER)
{
mcfmbus_start(bus);
}
else /* (event == EVENT_NEXTMSG) */
{
mcfmbus_rstart(bus);
}
bus->byte = 0;
mcfmbus_tx_mode(bus);
/* Initiate slave address sending */
if (bus->cmsg->flags & I2C_MSG_ADDR_10)
{
i2c_address a = bus->cmsg->addr;
b = 0xf0 | (((a >> 8) & 0x03) << 1);
if (bus->cmsg->flags & I2C_MSG_WR)
{
mcfmbus_send(bus, b);
next_state(bus, STATE_ADDR_1_W);
}
else
{
mcfmbus_send(bus, b | 1);
next_state(bus, STATE_ADDR_1_R);
}
}
else
{
b = (bus->cmsg->addr & ~0x01);
if (bus->cmsg->flags & I2C_MSG_WR)
{
next_state(bus, STATE_SENDING);
}
else
{
next_state(bus, STATE_ADDR_7);
b |= 1;
}
mcfmbus_send(bus, b);
}
break;
default:
mcfmbus_machine_error(bus, event);
break;
}
break;
case STATE_ADDR_7:
switch (event)
{
case EVENT_ACK:
mcfmbus_rx_mode(bus);
if (bus->cmsg->len <= 1)
mcfmbus_send_nack(bus);
else
mcfmbus_send_ack(bus);
next_state(bus, STATE_RECEIVING);
break;
case EVENT_NACK:
mcfmbus_error(bus, I2C_NO_DEVICE);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
case EVENT_ARB_LOST:
mcfmbus_error(bus, I2C_ARBITRATION_LOST);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
default:
mcfmbus_machine_error(bus, event);
break;
}
break;
case STATE_ADDR_1_R:
case STATE_ADDR_1_W:
switch (event)
{
case EVENT_ACK:
{
uint8_t b = (bus->cmsg->addr & 0xff);
mcfmbus_send(bus, b);
if (bus->state == STATE_ADDR_1_W)
{
next_state(bus, STATE_SENDING);
}
else
{
i2c_address a;
mcfmbus_rstart(bus);
mcfmbus_tx_mode(bus);
a = bus->cmsg->addr;
b = 0xf0 | (((a >> 8) & 0x03) << 1) | 1;
mcfmbus_send(bus, b);
next_state(bus, STATE_ADDR_7);
}
break;
}
case EVENT_NACK:
mcfmbus_error(bus, I2C_NO_DEVICE);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
case EVENT_ARB_LOST:
mcfmbus_error(bus, I2C_ARBITRATION_LOST);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
default:
mcfmbus_machine_error(bus, event);
break;
}
break;
case STATE_SENDING:
switch (event)
{
case EVENT_ACK:
if (bus->byte == bus->cmsg->len)
{
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
}
else
{
mcfmbus_send(bus, bus->cmsg->buf[bus->byte++]);
next_state(bus, STATE_SENDING);
}
break;
case EVENT_NACK:
if (bus->byte == 0)
{
mcfmbus_error(bus, I2C_NO_DEVICE);
}
else
{
mcfmbus_error(bus, I2C_NO_ACKNOWLEDGE);
}
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
case EVENT_ARB_LOST:
mcfmbus_error(bus, I2C_ARBITRATION_LOST);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
default:
mcfmbus_machine_error(bus, event);
break;
}
break;
case STATE_RECEIVING:
switch (event)
{
case EVENT_DATA_RECV:
if (bus->cmsg->len - bus->byte <= 2)
{
mcfmbus_send_nack(bus);
if (bus->cmsg->len - bus->byte <= 1)
{
if (bus->cmsg - bus->msg + 1 == bus->nmsg)
mcfmbus_stop(bus);
else
mcfmbus_rstart(bus);
}
}
else
{
mcfmbus_send_ack(bus);
}
bus->cmsg->buf[bus->byte++] = *MCF5206E_MBDR(bus->base);
if (bus->cmsg->len == bus->byte)
{
next_state(bus,STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
}
else
{
next_state(bus,STATE_RECEIVING);
}
break;
case EVENT_ARB_LOST:
mcfmbus_error(bus, I2C_ARBITRATION_LOST);
next_state(bus, STATE_IDLE);
mcfmbus_machine(bus, EVENT_NEXTMSG);
break;
default:
mcfmbus_machine_error(bus, event);
break;
}
break;
}
}
/* mcfmbus_interrupt_handler --
* MBUS module interrupt handler routine
*
* PARAMETERS:
* vector - interrupt vector number (not used)
*
* RETURNS:
* none
*/
rtems_isr
mcfmbus_interrupt_handler(rtems_vector_number vector)
{
i2c_event event;
event = mcfmbus_get_event(mbus);
mcfmbus_machine(mbus, event);
}
/* mcfmbus_poll --
* MBUS module poll routine; used to poll events when I2C driver
* operates in poll-driven mode.
*
* PARAMETERS:
* none
*
* RETURNS:
* none
*/
void
mcfmbus_poll(mcfmbus *bus)
{
i2c_event event;
event = mcfmbus_get_event(bus);
if (event != EVENT_NONE)
mcfmbus_machine(bus, event);
}
/* mcfmbus_select_clock_divider --
* Select divider for system clock which is used for I2C bus clock
* generation. Not each divider can be selected for I2C bus; this
* function select nearest larger or equal divider.
*
* PARAMETERS:
* i2c_bus - pointer to the bus descriptor structure
* divider - system frequency divider for I2C serial clock.
* RETURNS:
* RTEMS_SUCCESSFUL, if operation performed successfully, or
* RTEMS error code when failed.
*/
rtems_status_code
mcfmbus_select_clock_divider(mcfmbus *i2c_bus, int divider)
{
int i;
int mbc;
struct {
int divider;
int mbc;
} dividers[] ={
{ 20, 0x20 }, { 22, 0x21 }, { 24, 0x22 }, { 26, 0x23 },
{ 28, 0x00 }, { 30, 0x01 }, { 32, 0x25 }, { 34, 0x02 },
{ 36, 0x26 }, { 40, 0x03 }, { 44, 0x04 }, { 48, 0x05 },
{ 56, 0x06 }, { 64, 0x2a }, { 68, 0x07 }, { 72, 0x2B },
{ 80, 0x08 }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
{ 112, 0x2E }, { 128, 0x0B }, { 144, 0x0C }, { 160, 0x0D },
{ 192, 0x0E }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
{ 288, 0x10 }, { 320, 0x11 }, { 384, 0x12 }, { 448, 0x36 },
{ 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x15 },
{ 768, 0x16 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
{ 1152, 0x18 }, { 1280, 0x19 }, { 1536, 0x1A }, { 1792, 0x3E },
{ 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
{ 3072, 0x1E }, { 3840, 0x1F }
};
if (i2c_bus == NULL)
return RTEMS_INVALID_ADDRESS;
for (i = 0, mbc = -1; i < sizeof(dividers)/sizeof(dividers[0]); i++)
{
mbc = dividers[i].mbc;
if (dividers[i].divider >= divider)
{
break;
}
}
*MCF5206E_MFDR(i2c_bus->base) = mbc;
return RTEMS_SUCCESSFUL;
}
/* mcfmbus_initialize --
* Initialize ColdFire MBUS I2C bus controller.
*
* PARAMETERS:
* i2c_bus - pointer to the bus descriptor structure
* base - ColdFire internal peripherial base address
*
* RETURNS:
* RTEMS_SUCCESSFUL, or RTEMS error code when initialization failed.
*/
rtems_status_code
mcfmbus_initialize(mcfmbus *i2c_bus, uint32_t base)
{
rtems_interrupt_level level;
rtems_status_code sc;
if (mbus != NULL) /* Check if already initialized */
return RTEMS_RESOURCE_IN_USE;
if (i2c_bus == NULL)
return RTEMS_INVALID_ADDRESS;
i2c_bus->base = base;
i2c_bus->state = STATE_IDLE;
i2c_bus->msg = NULL;
i2c_bus->cmsg = NULL;
i2c_bus->nmsg = 0;
i2c_bus->byte = 0;
sc = rtems_interrupt_catch(
mcfmbus_interrupt_handler,
24 + ((*MCF5206E_ICR(base, MCF5206E_INTR_MBUS) & MCF5206E_ICR_IL) >>
MCF5206E_ICR_IL_S),
&i2c_bus->oldisr
);
if (sc != RTEMS_SUCCESSFUL)
return sc;
mbus = i2c_bus;
rtems_interrupt_disable(level);
*MCF5206E_IMR(base) &= ~MCF5206E_INTR_BIT(MCF5206E_INTR_MBUS);
*MCF5206E_MBCR(base) = 0;
*MCF5206E_MBSR(base) = 0;
*MCF5206E_MBDR(base) = 0x1F; /* Maximum possible divider is 3840 */
*MCF5206E_MBCR(base) = MCF5206E_MBCR_MEN | MCF5206E_MBCR_MIEN;
rtems_interrupt_enable(level);
return RTEMS_SUCCESSFUL;
}
/* mcfmbus_i2c_transfer --
* Initiate multiple-messages transfer over I2C bus via ColdFire MBUS
* controller.
*
* PARAMETERS:
* bus - pointer to MBUS controller descriptor
* nmsg - number of messages
* msg - pointer to messages array
* done - function which is called when transfer is finished
* done_arg_ptr - arbitrary argument ptr passed to done funciton
*
* RETURNS:
* RTEMS_SUCCESSFUL if transfer initiated successfully, or error
* code when failed.
*/
rtems_status_code
mcfmbus_i2c_transfer(mcfmbus *bus, int nmsg, i2c_message *msg,
i2c_transfer_done done, void *done_arg_ptr)
{
if (bus != mbus)
return RTEMS_NOT_CONFIGURED;
bus->done = done;
bus->done_arg_ptr = done_arg_ptr;
bus->cmsg = bus->msg = msg;
bus->nmsg = nmsg;
bus->byte = 0;
bus->state = STATE_IDLE;
mcfmbus_machine(bus, EVENT_TRANSFER);
return RTEMS_SUCCESSFUL;
}
/* mcfmbus_i2c_done --
* Close ColdFire MBUS I2C bus controller and release all resources.
*
* PARAMETERS:
* bus - pointer to MBUS controller descriptor
*
* RETURNS:
* RTEMS_SUCCESSFUL, if transfer initiated successfully, or error
* code when failed.
*/
rtems_status_code
mcfmbus_i2c_done(mcfmbus *i2c_bus)
{
rtems_status_code sc;
uint32_t base;
if (mbus == NULL)
return RTEMS_NOT_CONFIGURED;
if (mbus != i2c_bus)
return RTEMS_INVALID_ADDRESS;
base = i2c_bus->base;
*MCF5206E_IMR(base) |= MCF5206E_INTR_BIT(MCF5206E_INTR_MBUS);
*MCF5206E_MBCR(base) = 0;
sc = rtems_interrupt_catch(
i2c_bus->oldisr,
24 + ((*MCF5206E_ICR(base, MCF5206E_INTR_MBUS) & MCF5206E_ICR_IL) >>
MCF5206E_ICR_IL_S),
NULL
);
return sc;
}
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