]> cvs.zerfleddert.de Git - rsbs2/blob - bmc/i2c.c
implement all remaining IPMB queries seen on the wire
[rsbs2] / bmc / i2c.c
1 #include <util/twi.h>
2 #include <avr/interrupt.h>
3 #include <stdio.h>
4 #include "i2c.h"
5 #include "bmc.h"
6 #include "config.h"
7 #include "ipmb.h"
8
9 #define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
10 #define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
11 #define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);
12
13 volatile unsigned char i2c_databuf[24];
14 volatile uint8_t i2c_len = 0x00;
15 static volatile uint8_t i2c_pos = 0x00;
16 volatile uint8_t i2c_done = 0x00;
17
18 #define I2C_FREQ 20000UL
19
20 void i2c_init()
21 {
22 /* SCLf = F_CPU / (16 + 2 * TWBR * 4^TWPS)
23 * TWPS is 0 =>
24 * TWBR = (F_CPU/(2 * SCL)) - 8
25 */
26 TWBR = (F_CPU/(2*I2C_FREQ))-8;
27 TWAR = BMC_ADDR & 0xfe;
28 TWDR = 0x00;
29 TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
30 TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE));
31 #ifdef __AVR_ATmega16__
32 PORTC = 0x03;
33 #else
34 #error "Don't know how to set pullups for this chip, please add support"
35 #endif
36 }
37
38 void i2c_send(unsigned char *buf, int len)
39 {
40 uint8_t old_TWCR = TWCR;
41 uint8_t old_SREG = SREG;
42 int i;
43
44 cli();
45
46 TWCR = ((1<<TWINT) | (1<<TWSTA) | (1<<TWEN)); /* Send start */
47
48 while(!(TWCR & (1<<TWINT))) {}
49 if (TW_STATUS != TW_START) {
50 #ifdef DEBUG
51 printf("I2C: error sending START\n");
52 #endif
53 goto out;
54 }
55
56 TWDR = buf[0]; /* SLA_W */
57 TWCR = ((1<<TWINT) | (1<<TWEN));
58
59 while(!(TWCR & (1<<TWINT))) {}
60 if (TW_STATUS != TW_MT_SLA_ACK) {
61 #ifdef DEBUG
62 printf("I2C: error sending SLA_W\n");
63 #endif
64 goto out2;
65 }
66
67 for(i = 1; i < len; i++) {
68 TWDR = buf[i]; /* Send Data */
69 TWCR = ((1<<TWINT) | (1<<TWEN));
70
71 while(!(TWCR & (1<<TWINT))) {}
72 if (TW_STATUS != TW_MT_DATA_ACK) {
73 #ifdef DEBUG
74 printf("I2C: error sending DATA byte %d\n", i);
75 #endif
76 goto out2;
77 }
78 }
79
80 #ifdef DEBUG
81 printf("I2C Data sent\n");
82 #endif
83
84 out2:
85 TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
86 while(TWCR & (1<<TWSTO)) {}
87
88 out:
89 SREG = old_SREG;
90 TWCR = old_TWCR | (1<<TWINT);
91 }
92
93 ISR (TWI_vect, ISR_BLOCK)
94 {
95 if (i2c_done)
96 TWCR_RESET;
97
98 switch (TW_STATUS) {
99 case TW_SR_SLA_ACK:
100 #ifdef DEBUG
101 printf("I2C: Slave 0x%02x adressed\n", TWDR);
102 #endif
103 i2c_pos = 0x00;
104 i2c_databuf[i2c_pos] = TWDR;
105 i2c_pos++;
106 TWCR_ACK;
107 break;
108
109 case TW_SR_DATA_ACK:
110 #ifdef DEBUG
111 printf("I2C: Data received: 0x%02x\n", TWDR);
112 #endif
113 if (i2c_pos >= sizeof(i2c_databuf)) {
114 TWCR_RESET;
115 i2c_pos = 0x00;
116 break;
117 }
118 i2c_databuf[i2c_pos] = TWDR;
119 i2c_pos++;
120 TWCR_ACK;
121 break;
122
123 case TW_SR_STOP:
124 #ifdef DEBUG
125 printf("I2C: STOP received\n");
126 #endif
127 i2c_len = i2c_pos;
128 i2c_pos = 0x00;
129 i2c_done = 0x01;
130 TWCR_RESET;
131 break;
132
133 case TW_NO_INFO:
134 #ifdef DEBUG
135 printf("I2C: TW_NO_INFO received status 0x%2x\n", TW_STATUS);
136 #endif
137 TWCR |= (1<<TWINT);
138 break;
139
140 default:
141 #ifdef DEBUG
142 printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
143 #endif
144 TWCR_RESET;
145 break;
146 }
147 }
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