use CTC unit to generate correct timings for power/reset

[rsbs2] / bmc / i2c.c

diff --git a/bmc/i2c.c b/bmc/i2c.c
index 992d6ce4c840f2cb6324c2067396352f631e1578..92c00cc2ea5d71a6995f509a09bfa376a9b662c8 100644 (file)
--- a/bmc/i2c.c
+++ b/bmc/i2c.c
@@ -2,24 +2,119 @@
 #include <avr/interrupt.h>
 #include <stdio.h>
 #include "i2c.h"
+#include "bmc.h"
+#include "ipmb.h"
 
 #define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);  
 #define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
 #define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);  
 
+volatile unsigned char i2c_databuf[24];
+volatile uint8_t i2c_len = 0x00;
+static volatile uint8_t i2c_pos = 0x00;
+volatile uint8_t i2c_done = 0x00;
+
 void i2c_init()
 {
-       TWAR = BMC_ADDR;
-       TWCR &= ~(1<<TWSTA)|(1<<TWSTO);
-       TWCR|= (1<<TWEA) | (1<<TWEN)|(1<<TWIE); 
+       TWBR = 0xff;
+       TWAR = BMC_ADDR & 0xfe;
+       TWDR = 0x00;
+       TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
+       TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE)); 
+#ifdef __AVR_ATmega16__
+       PORTC = 0x03;
+#else
+#error "Don't know how to set pullups for this chip, please add support"
+#endif
 }
 
-ISR (TWI_vect)
+void i2c_send(unsigned char *buf, int len)
 {
-       printf("Interrupt, Status: %02x!\n", TW_STATUS);
+       uint8_t old_TWCR = TWCR;
+       uint8_t old_SREG = SREG;
+       int i;
+
+       cli();
+
+       TWCR = ((1<<TWINT) | (1<<TWSTA) | (1<<TWEN)); /* Send start */
+
+       while(!(TWCR & (1<<TWINT))) {}
+       if ((TW_STATUS & 0xf8) != TW_START)
+               goto out;
+
+       TWDR = buf[0]; /* SLA_W */
+       TWCR = ((1<<TWINT) | (1<<TWEN));
+
+       while(!(TWCR & (1<<TWINT))) {}
+       if ((TW_STATUS & 0xf8) != TW_MT_SLA_ACK)
+               goto out;
+       
+       for(i = 1; i < len; i++) {
+               TWDR = buf[i]; /* Send Data */
+               TWCR = ((1<<TWINT) | (1<<TWEN));
+
+               while(!(TWCR & (1<<TWINT))) {}
+               if ((TW_STATUS & 0xf8) != TW_MT_DATA_ACK)
+                       goto out;
+       }
+
+       TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
+       while(TWCR & (1<<TWSTO)) {}
+
+#ifdef DEBUG
+       printf("I2C Data sent\n");
+#endif
+
+out:   
+       TWDR = 0x00;
+       TWCR = old_TWCR;
+       SREG = old_SREG;
+}
+
+ISR (TWI_vect, ISR_BLOCK)
+{
+       if (i2c_done)
+               TWCR_RESET;
+
+       switch (TW_STATUS & 0xf8) {
+               case TW_SR_SLA_ACK:
+#ifdef DEBUG
+                       printf("I2C: Slave 0x%02x adressed\n", TWDR);
+#endif
+                       i2c_pos = 0x00;
+                       i2c_databuf[i2c_pos] = TWDR;
+                       i2c_pos++;
+                       TWCR_ACK;
+                       break;
+
+               case TW_SR_DATA_ACK:
+#ifdef DEBUG
+                       printf("I2C: Data received: 0x%02x\n", TWDR);
+#endif
+                       if (i2c_pos >= sizeof(i2c_databuf)) {
+                               TWCR_RESET;
+                               i2c_pos = 0x00;
+                               break;
+                       }
+                       i2c_databuf[i2c_pos] = TWDR;
+                       i2c_pos++;
+                       TWCR_ACK;
+                       break;
+
+               case TW_SR_STOP:
+#ifdef DEBUG
+                       printf("I2C: STOP received\n");
+#endif
+                       i2c_len = i2c_pos;
+                       i2c_pos = 0x00;
+                       i2c_done = 0x01;
+                       TWCR_RESET;
+                       break;
 
-       switch (TW_STATUS) {
                default:
+#ifdef DEBUG
+                       printf("I2C: Unimplemented status 0x%02x\n", (TW_STATUS & 0xf8));
+#endif
                        TWCR_RESET;
                        break;
        }