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 7104758551a25b280296ea999091638557a56f00..92c00cc2ea5d71a6995f509a09bfa376a9b662c8 100644 (file)
--- a/bmc/i2c.c
+++ b/bmc/i2c.c
@@ -3,32 +3,87 @@
 #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);  
 
-static volatile unsigned char databuf[12];
-static volatile uint8_t pos = 0x00;
+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()
 {
+       TWBR = 0xff;
        TWAR = BMC_ADDR & 0xfe;
        TWDR = 0x00;
        TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
        TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE)); 
-       printf("Status: 0x%02x\n", TW_STATUS);
+#ifdef __AVR_ATmega16__
        PORTC = 0x03;
+#else
+#error "Don't know how to set pullups for this chip, please add support"
+#endif
+}
+
+void i2c_send(unsigned char *buf, int len)
+{
+       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)
 {
-       switch (TW_STATUS) {
+       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
-                       pos = 0x00;
+                       i2c_pos = 0x00;
+                       i2c_databuf[i2c_pos] = TWDR;
+                       i2c_pos++;
                        TWCR_ACK;
                        break;
 
@@ -36,8 +91,13 @@ ISR (TWI_vect, ISR_BLOCK)
 #ifdef DEBUG
                        printf("I2C: Data received: 0x%02x\n", TWDR);
 #endif
-                       databuf[pos] = TWDR;
-                       pos++;
+                       if (i2c_pos >= sizeof(i2c_databuf)) {
+                               TWCR_RESET;
+                               i2c_pos = 0x00;
+                               break;
+                       }
+                       i2c_databuf[i2c_pos] = TWDR;
+                       i2c_pos++;
                        TWCR_ACK;
                        break;
 
@@ -45,20 +105,16 @@ ISR (TWI_vect, ISR_BLOCK)
 #ifdef DEBUG
                        printf("I2C: STOP received\n");
 #endif
-                       decode_bmc_cmd((unsigned char*)databuf, pos);
-                       pos = 0x00;
+                       i2c_len = i2c_pos;
+                       i2c_pos = 0x00;
+                       i2c_done = 0x01;
                        TWCR_RESET;
                        break;
 
-               case TW_ST_SLA_ACK:
-               case TW_ST_DATA_ACK:
-                       printf("I2C: Data requested\n");
-                       TWDR = 0x00;
-                       TWCR_ACK;
-                       break;
-
                default:
-                       printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
+#ifdef DEBUG
+                       printf("I2C: Unimplemented status 0x%02x\n", (TW_STATUS & 0xf8));
+#endif
                        TWCR_RESET;
                        break;
        }