Eric Biederman | 5ade04a | 2003-10-22 04:03:46 +0000 | [diff] [blame^] | 1 | static const char *addr_of_char(unsigned char ch) |
| 2 | { |
| 3 | static const char byte[] = { |
| 4 | 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
| 5 | 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, |
| 6 | 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, |
| 7 | 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, |
| 8 | 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, |
| 9 | 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, |
| 10 | 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, |
| 11 | 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, |
| 12 | 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, |
| 13 | 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, |
| 14 | 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, |
| 15 | 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, |
| 16 | 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, |
| 17 | 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, |
| 18 | 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, |
| 19 | 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, |
| 20 | 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, |
| 21 | 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, |
| 22 | 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, |
| 23 | 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, |
| 24 | 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, |
| 25 | 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, |
| 26 | 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, |
| 27 | 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, |
| 28 | 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, |
| 29 | 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, |
| 30 | 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, |
| 31 | 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, |
| 32 | 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, |
| 33 | 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, |
| 34 | 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, |
| 35 | 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, |
| 36 | }; |
| 37 | return byte + ch; |
| 38 | } |
| 39 | |
| 40 | static void console_tx_byte(unsigned char ch) |
| 41 | { |
| 42 | asm volatile( |
| 43 | "int $0x80" |
| 44 | : |
| 45 | : "a" (4), "b" (1), "c" (addr_of_char(ch)), "d" (1)); |
| 46 | } |
| 47 | |
| 48 | static void console_tx_string(const char *str) |
| 49 | { |
| 50 | unsigned char ch; |
| 51 | while((ch = *str++) != '\0') { |
| 52 | console_tx_byte(ch); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | |
| 57 | |
| 58 | static int smbus_read_byte(unsigned device, unsigned address) |
| 59 | { |
| 60 | static const unsigned char dimm[] = { |
| 61 | 0x80, 0x08, 0x07, 0x0d, 0x0a, 0x02, 0x48, 0x00, 0x04, 0x60, 0x70, 0x02, 0x82, 0x08, 0x08, 0x01, |
| 62 | 0x0e, 0x04, 0x0c, 0x01, 0x02, 0x20, 0x00, 0x75, 0x70, 0x00, 0x00, 0x48, 0x30, 0x48, 0x2a, 0x40, |
| 63 | 0x80, 0x80, 0x45, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 64 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x33, |
| 65 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 66 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 67 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 68 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 69 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 70 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 71 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 72 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 73 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 74 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 75 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 76 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 77 | |
| 78 | 0x80, 0x08, 0x07, 0x0d, 0x0a, 0x02, 0x48, 0x00, 0x04, 0x60, 0x70, 0x02, 0x82, 0x08, 0x08, 0x01, |
| 79 | 0x0e, 0x04, 0x0c, 0x01, 0x02, 0x20, 0x00, 0x75, 0x70, 0x00, 0x00, 0x48, 0x30, 0x48, 0x2a, 0x40, |
| 80 | 0x80, 0x80, 0x45, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 81 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x33, |
| 82 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 83 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 84 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 85 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 86 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 87 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 88 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 89 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 90 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 91 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 92 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 93 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
| 94 | }; |
| 95 | return dimm[(device << 8) + address]; |
| 96 | } |
| 97 | |
| 98 | #define SMBUS_MEM_DEVICE_START 0x00 |
| 99 | #define SMBUS_MEM_DEVICE_END 0x00 |
| 100 | #define SMBUS_MEM_DEVICE_INC 1 |
| 101 | |
| 102 | |
| 103 | static void spd_set_memclk(void) |
| 104 | { |
| 105 | /* Compute the minimum cycle time for these dimms */ |
| 106 | unsigned min_cycle_time, min_latency; |
| 107 | unsigned device; |
| 108 | unsigned value; |
| 109 | |
| 110 | value = 0x50; |
| 111 | min_cycle_time = 0x75; |
| 112 | min_latency = 2; |
| 113 | device = 0; |
| 114 | |
| 115 | /* Compute the least latency with the fastest clock supported |
| 116 | * by both the memory controller and the dimms. |
| 117 | */ |
| 118 | for(device = SMBUS_MEM_DEVICE_START; |
| 119 | device <= SMBUS_MEM_DEVICE_END; |
| 120 | device += SMBUS_MEM_DEVICE_INC) |
| 121 | { |
| 122 | int new_cycle_time, new_latency; |
| 123 | int index; |
| 124 | int latencies; |
| 125 | int latency; |
| 126 | |
| 127 | /* First find the supported CAS latencies |
| 128 | * Byte 18 for DDR SDRAM is interpreted: |
| 129 | * bit 0 == CAS Latency = 1.0 |
| 130 | * bit 1 == CAS Latency = 1.5 |
| 131 | * bit 2 == CAS Latency = 2.0 |
| 132 | * bit 3 == CAS Latency = 2.5 |
| 133 | * bit 4 == CAS Latency = 3.0 |
| 134 | * bit 5 == CAS Latency = 3.5 |
| 135 | * bit 6 == TBD |
| 136 | * bit 7 == TBD |
| 137 | */ |
| 138 | new_cycle_time = 0xa0; |
| 139 | new_latency = 5; |
| 140 | |
| 141 | latencies = smbus_read_byte(device, 18); |
| 142 | |
| 143 | /* Compute the lowest cas latency supported */ |
| 144 | latency = __builtin_bsr(latencies) -2; |
| 145 | |
| 146 | /* Loop through and find a fast clock with a low latency */ |
| 147 | for(index = 0; index < 3; index++, latency++) { |
| 148 | int value; |
| 149 | if ((latency < 2) || (latency > 4) || |
| 150 | (!(latencies & (1 << latency)))) { |
| 151 | continue; |
| 152 | } |
| 153 | value = smbus_read_byte(device, index); |
| 154 | if (value < 0) continue; |
| 155 | |
| 156 | /* Only increase the latency if we decreas the clock */ |
| 157 | if ((value >= min_cycle_time) && (value < new_cycle_time)) { |
| 158 | new_cycle_time = value; |
| 159 | new_latency = latency; |
| 160 | console_tx_byte(device); |
| 161 | |
| 162 | } |
| 163 | } |
| 164 | console_tx_string("Transmitting this string causes problems\n"); |
| 165 | /* Does min_latency need to be increased? */ |
| 166 | if (new_cycle_time > min_cycle_time) { |
| 167 | min_cycle_time = new_cycle_time; |
| 168 | } |
| 169 | /* Does min_cycle_time need to be increased? */ |
| 170 | if (new_latency > min_latency) { |
| 171 | min_latency = new_latency; |
| 172 | } |
| 173 | } |
| 174 | } |