/* this is not much more than a shell; it does not do anything useful yet */
/* TWI (I2C) driver for Blackfin
*
* Copyright (c) 2008 Kallisti Labs, Los Gatos, CA, USA
* written by Allan Hessenflow <allanh@kallisti.com>
*
* 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 <stdlib.h>
#include <rtems.h>
#include <libcpu/twiRegs.h>
#include "twi.h"
#ifndef N_BFIN_TWI
#define N_BFIN_TWI 1
#endif
#define BFIN_REG16(base, offset) \
(*((uint16_t volatile *) ((char *)(base) + (offset))))
static struct {
void *base;
rtems_id irqSem;
rtems_id mutex;
bfin_twi_callback_t callback;
void *callbackArg;
bfin_twi_request_t volatile *req;
uint8_t volatile *dataPtr;
int volatile count;
bool volatile masterActive;
rtems_status_code volatile masterResult;
bool volatile slaveActive;
} twi[N_BFIN_TWI];
rtems_status_code bfin_twi_init(int channel, bfin_twi_config_t *config) {
rtems_status_code result;
void *base;
if (channel < 0 || channel >= N_BFIN_TWI)
return RTEMS_INVALID_NUMBER;
base = config->base;
twi[channel].base = base;
result = rtems_semaphore_create(rtems_build_name('t','w','i','s'),
0,
RTEMS_FIFO |
RTEMS_SIMPLE_BINARY_SEMAPHORE |
RTEMS_NO_INHERIT_PRIORITY |
RTEMS_NO_PRIORITY_CEILING |
RTEMS_LOCAL,
0,
&twi[channel].irqSem);
result = rtems_semaphore_create(rtems_build_name('t','w','i','m'),
1,
RTEMS_PRIORITY |
RTEMS_SIMPLE_BINARY_SEMAPHORE |
RTEMS_INHERIT_PRIORITY |
RTEMS_NO_PRIORITY_CEILING |
RTEMS_LOCAL,
0,
&twi[channel].mutex);
BFIN_REG16(base, TWI_CONTROL_OFFSET) =
(uint16_t) (((config->sclk +9999999) / 10000000) <<
TWI_CONTROL_PRESCALE_SHIFT) |
TWI_CONTROL_TWI_ENA;
BFIN_REG16(base, TWI_CLKDIV_OFFSET) = config->fast ?
((8 << TWI_CLKDIV_CLKHI_SHIFT) |
(17 << TWI_CLKDIV_CLKLOW_SHIFT)) :
((33 << TWI_CLKDIV_CLKHI_SHIFT) |
(67 << TWI_CLKDIV_CLKLOW_SHIFT));
BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET) = 0;
BFIN_REG16(base, TWI_MASTER_CTL_OFFSET) = config->fast ?
TWI_MASTER_CTL_FAST :
0;
BFIN_REG16(base, TWI_SLAVE_ADDR_OFFSET) = (uint16_t) config->slave_address <<
TWI_SLAVE_ADDR_SADDR_SHIFT;
BFIN_REG16(base, TWI_MASTER_STAT_OFFSET) = TWI_MASTER_STAT_BUFWRERR |
TWI_MASTER_STAT_BUFRDERR |
TWI_MASTER_STAT_DNAK |
TWI_MASTER_STAT_ANAK |
TWI_MASTER_STAT_LOSTARB;
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = TWI_FIFO_CTL_XMTFLUSH |
TWI_FIFO_CTL_RCVFLUSH;
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = 0;
BFIN_REG16(base, TWI_INT_STAT_OFFSET) = TWI_INT_STAT_RCVSERV |
TWI_INT_STAT_XMTSERV |
TWI_INT_STAT_MERR |
TWI_INT_STAT_MCOMP |
TWI_INT_STAT_SOVF |
TWI_INT_STAT_SERR |
TWI_INT_STAT_SCOMP |
TWI_INT_STAT_SINIT;
BFIN_REG16(base, TWI_INT_MASK_OFFSET) = TWI_INT_MASK_RCVSERVM |
TWI_INT_MASK_XMTSERVM;
return result;
}
rtems_status_code bfin_twi_register_callback(int channel,
bfin_twi_callback_t callback,
void *arg) {
void *base;
int level;
if (channel < 0 || channel >= N_BFIN_TWI)
return RTEMS_INVALID_NUMBER;
base = twi[channel].base;
if (callback == NULL)
BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET) = 0;
rtems_interrupt_disable(level);
twi[channel].callback = callback;
twi[channel].callbackArg = arg;
rtems_interrupt_enable(level);
if (callback != NULL)
BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET) = TWI_SLAVE_CTL_GEN |
TWI_SLAVE_CTL_SEN;
return RTEMS_SUCCESSFUL;
}
void bfin_twi_isr(int source) {
void *base;
int i;
uint16_t r;
uint16_t stat;
for (i = 0; i < N_BFIN_TWI; i++) {
base = twi[i].base;
if (base) {
stat = BFIN_REG16(base, TWI_INT_STAT_OFFSET);
if (stat) {
BFIN_REG16(base, TWI_INT_STAT_OFFSET) = stat;
if ((stat & TWI_INT_STAT_SINIT) && !twi[i].slaveActive) {
twi[i].slaveActive = true;
r = BFIN_REG16(base, TWI_FIFO_CTL_OFFSET);
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = r | TWI_FIFO_CTL_XMTFLUSH;
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = r;
r = BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET);
BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET) = r | TWI_SLAVE_CTL_STDVAL;
}
if (twi[i].slaveActive) {
if (stat & (TWI_INT_STAT_SCOMP | TWI_INT_STAT_SERR)) {
r = BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET);
BFIN_REG16(base, TWI_SLAVE_CTL_OFFSET) = r & ~TWI_SLAVE_CTL_STDVAL;
twi[i].slaveActive = false;
}
}
if (twi[i].masterActive && !twi[i].slaveActive) {
if (stat & (TWI_INT_STAT_MCOMP | TWI_INT_STAT_MERR)) {
if (!(stat & TWI_INT_STAT_MERR)) {
rtems_semaphore_release(twi[i].irqSem);
} else
rtems_semaphore_release(twi[i].irqSem);
}
}
}
}
}
}
rtems_status_code bfin_twi_request(int channel, uint8_t address,
bfin_twi_request_t *request,
rtems_interval timeout) {
rtems_status_code result;
void *base;
rtems_interrupt_level level;
uint16_t r;
uint16_t masterMode;
if (channel < 0 || channel >= N_BFIN_TWI)
return RTEMS_INVALID_NUMBER;
result = rtems_semaphore_obtain(twi[channel].mutex,
RTEMS_WAIT, RTEMS_NO_TIMEOUT);
if (result == RTEMS_SUCCESSFUL) {
base = twi[channel].base;
twi[channel].req = request;
if (request->write) {
twi[channel].dataPtr = request->data;
twi[channel].count = request->count;
} else
twi[channel].count = 0;
BFIN_REG16(base, TWI_MASTER_ADDR_OFFSET) = (uint16_t) address <<
TWI_MASTER_ADDR_MADDR_SHIFT;
masterMode = BFIN_REG16(base, TWI_MASTER_CTL_OFFSET);
masterMode |= (request->count << TWI_MASTER_CTL_DCNT_SHIFT);
if (request->next)
masterMode |= TWI_MASTER_CTL_RSTART;
if (!request->write)
masterMode |= TWI_MASTER_CTL_MDIR;
masterMode |= TWI_MASTER_CTL_MEN;
rtems_interrupt_disable(level);
if (!twi[channel].slaveActive) {
r = BFIN_REG16(base, TWI_FIFO_CTL_OFFSET);
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = r | TWI_FIFO_CTL_XMTFLUSH;
BFIN_REG16(base, TWI_FIFO_CTL_OFFSET) = r;
if (request->write) {
while (twi[channel].count &&
(BFIN_REG16(base, TWI_FIFO_STAT_OFFSET) &
TWI_FIFO_STAT_XMTSTAT_MASK) !=
TWI_FIFO_STAT_XMTSTAT_FULL) {
BFIN_REG16(base, TWI_XMT_DATA8_OFFSET) =
(uint16_t) *twi[channel].dataPtr++;
twi[channel].count--;
}
}
twi[channel].masterActive = true;
BFIN_REG16(base, TWI_MASTER_CTL_OFFSET) = masterMode;
} else {
twi[channel].masterActive = false;
twi[channel].masterResult = -1; /* BISON (code should be equiv to lost arbitration) */
}
rtems_interrupt_enable(level);
while (result == RTEMS_SUCCESSFUL && twi[channel].masterActive)
result = rtems_semaphore_obtain(twi[channel].irqSem,
RTEMS_WAIT, timeout);
if (result == RTEMS_SUCCESSFUL)
result = twi[channel].masterResult;
else {
/* BISON abort */
}
rtems_semaphore_release(twi[channel].mutex);
}
return result;
}
