X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/blobdiff_plain/99e4226b74acd4286b735b5da275853701dcacf0..5bece6bf8c66ade0960290b6fe75623da7968e09:/bmc/i2c.c

diff --git a/bmc/i2c.c b/bmc/i2c.c
index 992d6ce..07d2e79 100644
--- a/bmc/i2c.c
+++ b/bmc/i2c.c
@@ -2,24 +2,145 @@
 #include <avr/interrupt.h>
 #include <stdio.h>
 #include "i2c.h"
+#include "bmc.h"
+#include "config.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;
+
+#define I2C_FREQ 20000UL
+
 void i2c_init()
 {
-	TWAR = BMC_ADDR;
-	TWCR &= ~(1<<TWSTA)|(1<<TWSTO);
-	TWCR|= (1<<TWEA) | (1<<TWEN)|(1<<TWIE); 
+	/* SCLf = F_CPU / (16 + 2 * TWBR * 4^TWPS)
+	 * TWPS is 0 =>
+	 * TWBR = (F_CPU/(2 * SCL)) - 8
+	 */
+	TWBR = (F_CPU/(2*I2C_FREQ))-8;
+	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
+}
+
+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 != TW_START) {
+#ifdef DEBUG
+		printf("I2C: error sending START\n");
+#endif
+		goto out;
+	}
+
+	TWDR = buf[0]; /* SLA_W */
+	TWCR = ((1<<TWINT) | (1<<TWEN));
+
+	while(!(TWCR & (1<<TWINT))) {}
+	if (TW_STATUS != TW_MT_SLA_ACK) {
+#ifdef DEBUG
+		printf("I2C: error sending SLA_W\n");
+#endif
+		goto out2;
+	}
+	
+	for(i = 1; i < len; i++) {
+		TWDR = buf[i]; /* Send Data */
+		TWCR = ((1<<TWINT) | (1<<TWEN));
+
+		while(!(TWCR & (1<<TWINT))) {}
+		if (TW_STATUS != TW_MT_DATA_ACK) {
+#ifdef DEBUG
+			printf("I2C: error sending DATA byte %d\n", i);
+#endif
+			goto out2;
+		}
+	}
+
+#ifdef DEBUG
+	printf("I2C Data sent\n");
+#endif
+
+out2:
+	TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
+	while(TWCR & (1<<TWSTO)) {}
+
+out:	
+	SREG = old_SREG;
+	TWCR = old_TWCR | (1<<TWINT);
 }
 
-ISR (TWI_vect)
+ISR (TWI_vect, ISR_BLOCK)
 {
-	printf("Interrupt, Status: %02x!\n", TW_STATUS);
+	if (i2c_done)
+		TWCR_RESET;
 
 	switch (TW_STATUS) {
+		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;
+
+		case TW_NO_INFO:
+#ifdef DEBUG
+			printf("I2C: TW_NO_INFO received status 0x%2x\n", TW_STATUS);
+#endif
+			TWCR |= (1<<TWINT);
+			break;
+
 		default:
+#ifdef DEBUG
+			printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
+#endif
 			TWCR_RESET;
 			break;
 	}