]>
Commit | Line | Data |
---|---|---|
233fdd50 KG |
1 | /* |
2 | * Copyright 2008 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * Version 2 as published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <common.h> | |
10 | #include <asm/fsl_ddr_sdram.h> | |
11 | ||
12 | #include "ddr.h" | |
13 | /* | |
14 | * Calculate the Density of each Physical Rank. | |
15 | * Returned size is in bytes. | |
16 | * | |
17 | * Study these table from Byte 31 of JEDEC SPD Spec. | |
18 | * | |
19 | * DDR I DDR II | |
20 | * Bit Size Size | |
21 | * --- ----- ------ | |
22 | * 7 high 512MB 512MB | |
23 | * 6 256MB 256MB | |
24 | * 5 128MB 128MB | |
25 | * 4 64MB 16GB | |
26 | * 3 32MB 8GB | |
27 | * 2 16MB 4GB | |
28 | * 1 2GB 2GB | |
29 | * 0 low 1GB 1GB | |
30 | * | |
31 | * Reorder Table to be linear by stripping the bottom | |
32 | * 2 or 5 bits off and shifting them up to the top. | |
33 | * | |
34 | */ | |
35 | static phys_size_t | |
36 | compute_ranksize(unsigned int mem_type, unsigned char row_dens) | |
37 | { | |
38 | phys_size_t bsize; | |
39 | ||
40 | /* Bottom 5 bits up to the top. */ | |
41 | bsize = ((row_dens >> 5) | ((row_dens & 31) << 3)); | |
42 | bsize <<= 27ULL; | |
43 | debug("DDR: DDR II rank density = 0x%08x\n", bsize); | |
44 | ||
45 | return bsize; | |
46 | } | |
47 | ||
48 | /* | |
49 | * Convert a two-nibble BCD value into a cycle time. | |
50 | * While the spec calls for nano-seconds, picos are returned. | |
51 | * | |
52 | * This implements the tables for bytes 9, 23 and 25 for both | |
53 | * DDR I and II. No allowance for distinguishing the invalid | |
54 | * fields absent for DDR I yet present in DDR II is made. | |
55 | * (That is, cycle times of .25, .33, .66 and .75 ns are | |
56 | * allowed for both DDR II and I.) | |
57 | */ | |
58 | static unsigned int | |
59 | convert_bcd_tenths_to_cycle_time_ps(unsigned int spd_val) | |
60 | { | |
61 | /* Table look up the lower nibble, allow DDR I & II. */ | |
62 | unsigned int tenths_ps[16] = { | |
63 | 0, | |
64 | 100, | |
65 | 200, | |
66 | 300, | |
67 | 400, | |
68 | 500, | |
69 | 600, | |
70 | 700, | |
71 | 800, | |
72 | 900, | |
73 | 250, /* This and the next 3 entries valid ... */ | |
74 | 330, /* ... only for tCK calculations. */ | |
75 | 660, | |
76 | 750, | |
77 | 0, /* undefined */ | |
78 | 0 /* undefined */ | |
79 | }; | |
80 | ||
81 | unsigned int whole_ns = (spd_val & 0xF0) >> 4; | |
82 | unsigned int tenth_ns = spd_val & 0x0F; | |
83 | unsigned int ps = whole_ns * 1000 + tenths_ps[tenth_ns]; | |
84 | ||
85 | return ps; | |
86 | } | |
87 | ||
88 | static unsigned int | |
89 | convert_bcd_hundredths_to_cycle_time_ps(unsigned int spd_val) | |
90 | { | |
91 | unsigned int tenth_ns = (spd_val & 0xF0) >> 4; | |
92 | unsigned int hundredth_ns = spd_val & 0x0F; | |
93 | unsigned int ps = tenth_ns * 100 + hundredth_ns * 10; | |
94 | ||
95 | return ps; | |
96 | } | |
97 | ||
98 | static unsigned int byte40_table_ps[8] = { | |
99 | 0, | |
100 | 250, | |
101 | 330, | |
102 | 500, | |
103 | 660, | |
104 | 750, | |
105 | 0, /* supposed to be RFC, but not sure what that means */ | |
106 | 0 /* Undefined */ | |
107 | }; | |
108 | ||
109 | static unsigned int | |
110 | compute_trfc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trfc) | |
111 | { | |
112 | unsigned int trfc_ps; | |
113 | ||
114 | trfc_ps = (((trctrfc_ext & 0x1) * 256) + trfc) * 1000 | |
115 | + byte40_table_ps[(trctrfc_ext >> 1) & 0x7]; | |
116 | ||
117 | return trfc_ps; | |
118 | } | |
119 | ||
120 | static unsigned int | |
121 | compute_trc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trc) | |
122 | { | |
123 | unsigned int trc_ps; | |
124 | ||
125 | trc_ps = trc * 1000 + byte40_table_ps[(trctrfc_ext >> 4) & 0x7]; | |
126 | ||
127 | return trc_ps; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Determine Refresh Rate. Ignore self refresh bit on DDR I. | |
132 | * Table from SPD Spec, Byte 12, converted to picoseconds and | |
133 | * filled in with "default" normal values. | |
134 | */ | |
135 | static unsigned int | |
136 | determine_refresh_rate_ps(const unsigned int spd_refresh) | |
137 | { | |
138 | unsigned int refresh_time_ps[8] = { | |
139 | 15625000, /* 0 Normal 1.00x */ | |
140 | 3900000, /* 1 Reduced .25x */ | |
141 | 7800000, /* 2 Extended .50x */ | |
142 | 31300000, /* 3 Extended 2.00x */ | |
143 | 62500000, /* 4 Extended 4.00x */ | |
144 | 125000000, /* 5 Extended 8.00x */ | |
145 | 15625000, /* 6 Normal 1.00x filler */ | |
146 | 15625000, /* 7 Normal 1.00x filler */ | |
147 | }; | |
148 | ||
149 | return refresh_time_ps[spd_refresh & 0x7]; | |
150 | } | |
151 | ||
152 | /* | |
153 | * The purpose of this function is to compute a suitable | |
154 | * CAS latency given the DRAM clock period. The SPD only | |
155 | * defines at most 3 CAS latencies. Typically the slower in | |
156 | * frequency the DIMM runs at, the shorter its CAS latency can. | |
157 | * be. If the DIMM is operating at a sufficiently low frequency, | |
158 | * it may be able to run at a CAS latency shorter than the | |
159 | * shortest SPD-defined CAS latency. | |
160 | * | |
161 | * If a CAS latency is not found, 0 is returned. | |
162 | * | |
163 | * Do this by finding in the standard speed bin table the longest | |
164 | * tCKmin that doesn't exceed the value of mclk_ps (tCK). | |
165 | * | |
166 | * An assumption made is that the SDRAM device allows the | |
167 | * CL to be programmed for a value that is lower than those | |
168 | * advertised by the SPD. This is not always the case, | |
169 | * as those modes not defined in the SPD are optional. | |
170 | * | |
171 | * CAS latency de-rating based upon values JEDEC Standard No. 79-2C | |
172 | * Table 40, "DDR2 SDRAM stanadard speed bins and tCK, tRCD, tRP, tRAS, | |
173 | * and tRC for corresponding bin" | |
174 | * | |
175 | * ordinal 2, ddr2_speed_bins[1] contains tCK for CL=3 | |
176 | * Not certain if any good value exists for CL=2 | |
177 | */ | |
178 | /* CL2 CL3 CL4 CL5 CL6 */ | |
179 | unsigned short ddr2_speed_bins[] = { 0, 5000, 3750, 3000, 2500 }; | |
180 | ||
181 | unsigned int | |
182 | compute_derated_DDR2_CAS_latency(unsigned int mclk_ps) | |
183 | { | |
184 | const unsigned int num_speed_bins = ARRAY_SIZE(ddr2_speed_bins); | |
185 | unsigned int lowest_tCKmin_found = 0; | |
186 | unsigned int lowest_tCKmin_CL = 0; | |
187 | unsigned int i; | |
188 | ||
189 | debug("mclk_ps = %u\n", mclk_ps); | |
190 | ||
191 | for (i = 0; i < num_speed_bins; i++) { | |
192 | unsigned int x = ddr2_speed_bins[i]; | |
193 | debug("i=%u, x = %u, lowest_tCKmin_found = %u\n", | |
194 | i, x, lowest_tCKmin_found); | |
195 | if (x && x <= mclk_ps && x >= lowest_tCKmin_found ) { | |
196 | lowest_tCKmin_found = x; | |
197 | lowest_tCKmin_CL = i + 2; | |
198 | } | |
199 | } | |
200 | ||
201 | debug("lowest_tCKmin_CL = %u\n", lowest_tCKmin_CL); | |
202 | ||
203 | return lowest_tCKmin_CL; | |
204 | } | |
205 | ||
206 | /* | |
207 | * ddr_compute_dimm_parameters for DDR2 SPD | |
208 | * | |
209 | * Compute DIMM parameters based upon the SPD information in spd. | |
210 | * Writes the results to the dimm_params_t structure pointed by pdimm. | |
211 | * | |
212 | * FIXME: use #define for the retvals | |
213 | */ | |
214 | unsigned int | |
215 | ddr_compute_dimm_parameters(const ddr2_spd_eeprom_t *spd, | |
216 | dimm_params_t *pdimm, | |
217 | unsigned int dimm_number) | |
218 | { | |
219 | unsigned int retval; | |
220 | ||
221 | if (spd->mem_type) { | |
222 | if (spd->mem_type != SPD_MEMTYPE_DDR2) { | |
223 | printf("DIMM %u: is not a DDR2 SPD.\n", dimm_number); | |
224 | return 1; | |
225 | } | |
226 | } else { | |
227 | memset(pdimm, 0, sizeof(dimm_params_t)); | |
228 | return 1; | |
229 | } | |
230 | ||
231 | retval = ddr2_spd_check(spd); | |
232 | if (retval) { | |
233 | printf("DIMM %u: failed checksum\n", dimm_number); | |
234 | return 2; | |
235 | } | |
236 | ||
237 | /* | |
238 | * The part name in ASCII in the SPD EEPROM is not null terminated. | |
239 | * Guarantee null termination here by presetting all bytes to 0 | |
240 | * and copying the part name in ASCII from the SPD onto it | |
241 | */ | |
242 | memset(pdimm->mpart, 0, sizeof(pdimm->mpart)); | |
243 | memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1); | |
244 | ||
245 | /* DIMM organization parameters */ | |
246 | pdimm->n_ranks = (spd->mod_ranks & 0x7) + 1; | |
247 | pdimm->rank_density = compute_ranksize(spd->mem_type, spd->rank_dens); | |
248 | pdimm->capacity = pdimm->n_ranks * pdimm->rank_density; | |
249 | pdimm->data_width = spd->dataw; | |
250 | pdimm->primary_sdram_width = spd->primw; | |
251 | pdimm->ec_sdram_width = spd->ecw; | |
252 | ||
253 | /* FIXME: what about registered SO-DIMM? */ | |
254 | switch (spd->dimm_type) { | |
255 | case 0x01: /* RDIMM */ | |
256 | case 0x10: /* Mini-RDIMM */ | |
257 | pdimm->registered_dimm = 1; /* register buffered */ | |
258 | break; | |
259 | ||
260 | case 0x02: /* UDIMM */ | |
261 | case 0x04: /* SO-DIMM */ | |
262 | case 0x08: /* Micro-DIMM */ | |
263 | case 0x20: /* Mini-UDIMM */ | |
264 | pdimm->registered_dimm = 0; /* unbuffered */ | |
265 | break; | |
266 | ||
267 | default: | |
268 | printf("unknown dimm_type 0x%02X\n", spd->dimm_type); | |
269 | return 1; | |
270 | break; | |
271 | } | |
272 | ||
273 | /* SDRAM device parameters */ | |
274 | pdimm->n_row_addr = spd->nrow_addr; | |
275 | pdimm->n_col_addr = spd->ncol_addr; | |
276 | pdimm->n_banks_per_sdram_device = spd->nbanks; | |
277 | pdimm->edc_config = spd->config; | |
278 | pdimm->burst_lengths_bitmask = spd->burstl; | |
279 | pdimm->row_density = spd->rank_dens; | |
280 | ||
281 | /* | |
282 | * Calculate the Maximum Data Rate based on the Minimum Cycle time. | |
283 | * The SPD clk_cycle field (tCKmin) is measured in tenths of | |
284 | * nanoseconds and represented as BCD. | |
285 | */ | |
286 | pdimm->tCKmin_X_ps | |
287 | = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle); | |
288 | pdimm->tCKmin_X_minus_1_ps | |
289 | = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle2); | |
290 | pdimm->tCKmin_X_minus_2_ps | |
291 | = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle3); | |
292 | ||
293 | pdimm->tCKmax_ps = convert_bcd_tenths_to_cycle_time_ps(spd->tckmax); | |
294 | ||
295 | /* | |
296 | * Compute CAS latencies defined by SPD | |
297 | * The SPD caslat_X should have at least 1 and at most 3 bits set. | |
298 | * | |
299 | * If cas_lat after masking is 0, the __ilog2 function returns | |
300 | * 255 into the variable. This behavior is abused once. | |
301 | */ | |
302 | pdimm->caslat_X = __ilog2(spd->cas_lat); | |
303 | pdimm->caslat_X_minus_1 = __ilog2(spd->cas_lat | |
304 | & ~(1 << pdimm->caslat_X)); | |
305 | pdimm->caslat_X_minus_2 = __ilog2(spd->cas_lat | |
306 | & ~(1 << pdimm->caslat_X) | |
307 | & ~(1 << pdimm->caslat_X_minus_1)); | |
308 | ||
309 | /* Compute CAS latencies below that defined by SPD */ | |
310 | pdimm->caslat_lowest_derated | |
311 | = compute_derated_DDR2_CAS_latency(get_memory_clk_period_ps()); | |
312 | ||
313 | /* Compute timing parameters */ | |
314 | pdimm->tRCD_ps = spd->trcd * 250; | |
315 | pdimm->tRP_ps = spd->trp * 250; | |
316 | pdimm->tRAS_ps = spd->tras * 1000; | |
317 | ||
318 | pdimm->tWR_ps = spd->twr * 250; | |
319 | pdimm->tWTR_ps = spd->twtr * 250; | |
320 | pdimm->tRFC_ps = compute_trfc_ps_from_spd(spd->trctrfc_ext, spd->trfc); | |
321 | ||
322 | pdimm->tRRD_ps = spd->trrd * 250; | |
323 | pdimm->tRC_ps = compute_trc_ps_from_spd(spd->trctrfc_ext, spd->trc); | |
324 | ||
325 | pdimm->refresh_rate_ps = determine_refresh_rate_ps(spd->refresh); | |
326 | ||
327 | pdimm->tIS_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_setup); | |
328 | pdimm->tIH_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_hold); | |
329 | pdimm->tDS_ps | |
330 | = convert_bcd_hundredths_to_cycle_time_ps(spd->data_setup); | |
331 | pdimm->tDH_ps | |
332 | = convert_bcd_hundredths_to_cycle_time_ps(spd->data_hold); | |
333 | ||
334 | pdimm->tRTP_ps = spd->trtp * 250; | |
335 | pdimm->tDQSQ_max_ps = spd->tdqsq * 10; | |
336 | pdimm->tQHS_ps = spd->tqhs * 10; | |
337 | ||
338 | return 0; | |
339 | } |