diff options
Diffstat (limited to 'c/src/lib/libcpu/bfin/serial/twi.c')
| -rw-r--r-- | c/src/lib/libcpu/bfin/serial/twi.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/bfin/serial/twi.c b/c/src/lib/libcpu/bfin/serial/twi.c new file mode 100644 index 0000000000..5bdb9ef742 --- /dev/null +++ b/c/src/lib/libcpu/bfin/serial/twi.c @@ -0,0 +1,256 @@ +/* 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. + * + * $Id$ + */ + + +#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; + boolean volatile masterActive; + rtems_status_code volatile masterResult; + boolean 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; + uint8_t data; + + 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; +} + |