make sure i2c rxbuf does not overrun

[rsbs2] / bmc / i2c.c

diff --git a/bmc/i2c.c b/bmc/i2c.c
index 6550c92fc62b084bc6d572cc8ae90b046e3d9045..c5f587babaf1535549200513d9953a4fda53ac21 100644 (file)
--- a/bmc/i2c.c
+++ b/bmc/i2c.c
@@ -2,22 +2,25 @@
 #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);  
 
-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);
        PORTC = 0x03;
 }
 
@@ -52,9 +55,11 @@ void i2c_send(unsigned char *buf, int len)
        }
 
        TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
+       while(TWCR & (1<<TWSTO)) {}
 
-       printf("I2C Data sent 0x%02x\n", TW_STATUS);
-
+#ifdef DEBUG
+       printf("I2C Data sent\n");
+#endif
 
 out:   
        TWDR = 0x00;
@@ -64,14 +69,17 @@ out:
 
 ISR (TWI_vect, ISR_BLOCK)
 {
+       if (i2c_done)
+               TWCR_RESET;
+
        switch (TW_STATUS) {
                case TW_SR_SLA_ACK:
 #ifdef DEBUG
                        printf("I2C: Slave 0x%02x adressed\n", TWDR);
 #endif
-                       pos = 0x00;
-                       databuf[pos] = TWDR;
-                       pos++;
+                       i2c_pos = 0x00;
+                       i2c_databuf[i2c_pos] = TWDR;
+                       i2c_pos++;
                        TWCR_ACK;
                        break;
 
@@ -79,8 +87,13 @@ 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;
 
@@ -88,13 +101,16 @@ ISR (TWI_vect, ISR_BLOCK)
 #ifdef DEBUG
                        printf("I2C: STOP received\n");
 #endif
-                       decode_ipmb_pkt((unsigned char*)databuf, pos);
-                       pos = 0x00;
+                       i2c_len = i2c_pos;
+                       i2c_pos = 0x00;
+                       i2c_done = 0x01;
                        TWCR_RESET;
                        break;
 
                default:
+#ifdef DEBUG
                        printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
+#endif
                        TWCR_RESET;
                        break;
        }