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drivers/ddr/fsl: Dual-license DDR driver
[people/ms/u-boot.git] / drivers / ddr / fsl / ddr1_dimm_params.c
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1/*
2 * Copyright 2008 Freescale Semiconductor, Inc.
3 *
ee3556bc 4 * SPDX-License-Identifier: GPL-2.0 BSD-3-Clause
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5 */
6
7#include <common.h>
5614e71b 8#include <fsl_ddr_sdram.h>
05c05a23 9
5614e71b 10#include <fsl_ddr.h>
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11
12/*
13 * Calculate the Density of each Physical Rank.
14 * Returned size is in bytes.
15 *
16 * Study these table from Byte 31 of JEDEC SPD Spec.
17 *
18 * DDR I DDR II
19 * Bit Size Size
20 * --- ----- ------
21 * 7 high 512MB 512MB
22 * 6 256MB 256MB
23 * 5 128MB 128MB
24 * 4 64MB 16GB
25 * 3 32MB 8GB
26 * 2 16MB 4GB
27 * 1 2GB 2GB
28 * 0 low 1GB 1GB
29 *
30 * Reorder Table to be linear by stripping the bottom
31 * 2 or 5 bits off and shifting them up to the top.
32 */
33
e7563aff 34static unsigned long long
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35compute_ranksize(unsigned int mem_type, unsigned char row_dens)
36{
e7563aff 37 unsigned long long bsize;
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38
39 /* Bottom 2 bits up to the top. */
40 bsize = ((row_dens >> 2) | ((row_dens & 3) << 6));
41 bsize <<= 24ULL;
cd84b1fa 42 debug("DDR: DDR I rank density = 0x%16llx\n", bsize);
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43
44 return bsize;
45}
46
47/*
48 * Convert a two-nibble BCD value into a cycle time.
49 * While the spec calls for nano-seconds, picos are returned.
50 *
51 * This implements the tables for bytes 9, 23 and 25 for both
52 * DDR I and II. No allowance for distinguishing the invalid
53 * fields absent for DDR I yet present in DDR II is made.
54 * (That is, cycle times of .25, .33, .66 and .75 ns are
55 * allowed for both DDR II and I.)
56 */
57static unsigned int
58convert_bcd_tenths_to_cycle_time_ps(unsigned int spd_val)
59{
60 /* Table look up the lower nibble, allow DDR I & II. */
61 unsigned int tenths_ps[16] = {
62 0,
63 100,
64 200,
65 300,
66 400,
67 500,
68 600,
69 700,
70 800,
71 900,
72 250, /* This and the next 3 entries valid ... */
73 330, /* ... only for tCK calculations. */
74 660,
75 750,
76 0, /* undefined */
77 0 /* undefined */
78 };
79
80 unsigned int whole_ns = (spd_val & 0xF0) >> 4;
81 unsigned int tenth_ns = spd_val & 0x0F;
82 unsigned int ps = whole_ns * 1000 + tenths_ps[tenth_ns];
83
84 return ps;
85}
86
87static unsigned int
88convert_bcd_hundredths_to_cycle_time_ps(unsigned int spd_val)
89{
90 unsigned int tenth_ns = (spd_val & 0xF0) >> 4;
91 unsigned int hundredth_ns = spd_val & 0x0F;
92 unsigned int ps = tenth_ns * 100 + hundredth_ns * 10;
93
94 return ps;
95}
96
97static unsigned int byte40_table_ps[8] = {
98 0,
99 250,
100 330,
101 500,
102 660,
103 750,
104 0, /* supposed to be RFC, but not sure what that means */
105 0 /* Undefined */
106};
107
108static unsigned int
109compute_trfc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trfc)
110{
a4ca3799 111 return ((trctrfc_ext & 0x1) * 256 + trfc) * 1000
05c05a23 112 + byte40_table_ps[(trctrfc_ext >> 1) & 0x7];
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113}
114
115static unsigned int
116compute_trc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trc)
117{
a4ca3799 118 return trc * 1000 + byte40_table_ps[(trctrfc_ext >> 4) & 0x7];
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119}
120
121/*
122 * tCKmax from DDR I SPD Byte 43
123 *
124 * Bits 7:2 == whole ns
125 * Bits 1:0 == quarter ns
126 * 00 == 0.00 ns
127 * 01 == 0.25 ns
128 * 10 == 0.50 ns
129 * 11 == 0.75 ns
130 *
131 * Returns picoseconds.
132 */
133static unsigned int
134compute_tckmax_from_spd_ps(unsigned int byte43)
135{
136 return (byte43 >> 2) * 1000 + (byte43 & 0x3) * 250;
137}
138
139/*
140 * Determine Refresh Rate. Ignore self refresh bit on DDR I.
141 * Table from SPD Spec, Byte 12, converted to picoseconds and
142 * filled in with "default" normal values.
143 */
144static unsigned int
145determine_refresh_rate_ps(const unsigned int spd_refresh)
146{
147 unsigned int refresh_time_ps[8] = {
148 15625000, /* 0 Normal 1.00x */
149 3900000, /* 1 Reduced .25x */
150 7800000, /* 2 Extended .50x */
151 31300000, /* 3 Extended 2.00x */
152 62500000, /* 4 Extended 4.00x */
153 125000000, /* 5 Extended 8.00x */
154 15625000, /* 6 Normal 1.00x filler */
155 15625000, /* 7 Normal 1.00x filler */
156 };
157
158 return refresh_time_ps[spd_refresh & 0x7];
159}
160
161/*
162 * The purpose of this function is to compute a suitable
163 * CAS latency given the DRAM clock period. The SPD only
164 * defines at most 3 CAS latencies. Typically the slower in
165 * frequency the DIMM runs at, the shorter its CAS latency can be.
166 * If the DIMM is operating at a sufficiently low frequency,
167 * it may be able to run at a CAS latency shorter than the
168 * shortest SPD-defined CAS latency.
169 *
170 * If a CAS latency is not found, 0 is returned.
171 *
172 * Do this by finding in the standard speed bin table the longest
173 * tCKmin that doesn't exceed the value of mclk_ps (tCK).
174 *
175 * An assumption made is that the SDRAM device allows the
176 * CL to be programmed for a value that is lower than those
177 * advertised by the SPD. This is not always the case,
178 * as those modes not defined in the SPD are optional.
179 *
180 * CAS latency de-rating based upon values JEDEC Standard No. 79-E
181 * Table 11.
182 *
183 * ordinal 2, ddr1_speed_bins[1] contains tCK for CL=2
184 */
185 /* CL2.0 CL2.5 CL3.0 */
186unsigned short ddr1_speed_bins[] = {0, 7500, 6000, 5000 };
187
188unsigned int
189compute_derated_DDR1_CAS_latency(unsigned int mclk_ps)
190{
191 const unsigned int num_speed_bins = ARRAY_SIZE(ddr1_speed_bins);
192 unsigned int lowest_tCKmin_found = 0;
193 unsigned int lowest_tCKmin_CL = 0;
194 unsigned int i;
195
196 debug("mclk_ps = %u\n", mclk_ps);
197
198 for (i = 0; i < num_speed_bins; i++) {
199 unsigned int x = ddr1_speed_bins[i];
200 debug("i=%u, x = %u, lowest_tCKmin_found = %u\n",
201 i, x, lowest_tCKmin_found);
202 if (x && lowest_tCKmin_found <= x && x <= mclk_ps) {
203 lowest_tCKmin_found = x;
204 lowest_tCKmin_CL = i + 1;
205 }
206 }
207
208 debug("lowest_tCKmin_CL = %u\n", lowest_tCKmin_CL);
209
210 return lowest_tCKmin_CL;
211}
212
213/*
214 * ddr_compute_dimm_parameters for DDR1 SPD
215 *
216 * Compute DIMM parameters based upon the SPD information in spd.
217 * Writes the results to the dimm_params_t structure pointed by pdimm.
218 *
219 * FIXME: use #define for the retvals
220 */
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221unsigned int ddr_compute_dimm_parameters(const unsigned int ctrl_num,
222 const ddr1_spd_eeprom_t *spd,
223 dimm_params_t *pdimm,
224 unsigned int dimm_number)
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225{
226 unsigned int retval;
227
228 if (spd->mem_type) {
229 if (spd->mem_type != SPD_MEMTYPE_DDR) {
230 printf("DIMM %u: is not a DDR1 SPD.\n", dimm_number);
231 return 1;
232 }
233 } else {
234 memset(pdimm, 0, sizeof(dimm_params_t));
235 return 1;
236 }
237
238 retval = ddr1_spd_check(spd);
239 if (retval) {
240 printf("DIMM %u: failed checksum\n", dimm_number);
241 return 2;
242 }
243
244 /*
245 * The part name in ASCII in the SPD EEPROM is not null terminated.
246 * Guarantee null termination here by presetting all bytes to 0
247 * and copying the part name in ASCII from the SPD onto it
248 */
249 memset(pdimm->mpart, 0, sizeof(pdimm->mpart));
250 memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1);
251
252 /* DIMM organization parameters */
253 pdimm->n_ranks = spd->nrows;
254 pdimm->rank_density = compute_ranksize(spd->mem_type, spd->bank_dens);
255 pdimm->capacity = pdimm->n_ranks * pdimm->rank_density;
256 pdimm->data_width = spd->dataw_lsb;
257 pdimm->primary_sdram_width = spd->primw;
258 pdimm->ec_sdram_width = spd->ecw;
259
260 /*
261 * FIXME: Need to determine registered_dimm status.
262 * 1 == register buffered
263 * 0 == unbuffered
264 */
265 pdimm->registered_dimm = 0; /* unbuffered */
266
267 /* SDRAM device parameters */
268 pdimm->n_row_addr = spd->nrow_addr;
269 pdimm->n_col_addr = spd->ncol_addr;
270 pdimm->n_banks_per_sdram_device = spd->nbanks;
271 pdimm->edc_config = spd->config;
272 pdimm->burst_lengths_bitmask = spd->burstl;
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273
274 /*
275 * Calculate the Maximum Data Rate based on the Minimum Cycle time.
276 * The SPD clk_cycle field (tCKmin) is measured in tenths of
277 * nanoseconds and represented as BCD.
278 */
0dd38a35 279 pdimm->tckmin_x_ps
05c05a23 280 = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle);
0dd38a35 281 pdimm->tckmin_x_minus_1_ps
05c05a23 282 = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle2);
0dd38a35 283 pdimm->tckmin_x_minus_2_ps
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284 = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle3);
285
0dd38a35 286 pdimm->tckmax_ps = compute_tckmax_from_spd_ps(spd->tckmax);
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287
288 /*
289 * Compute CAS latencies defined by SPD
0dd38a35 290 * The SPD caslat_x should have at least 1 and at most 3 bits set.
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291 *
292 * If cas_lat after masking is 0, the __ilog2 function returns
293 * 255 into the variable. This behavior is abused once.
294 */
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295 pdimm->caslat_x = __ilog2(spd->cas_lat);
296 pdimm->caslat_x_minus_1 = __ilog2(spd->cas_lat
297 & ~(1 << pdimm->caslat_x));
298 pdimm->caslat_x_minus_2 = __ilog2(spd->cas_lat
299 & ~(1 << pdimm->caslat_x)
300 & ~(1 << pdimm->caslat_x_minus_1));
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301
302 /* Compute CAS latencies below that defined by SPD */
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303 pdimm->caslat_lowest_derated = compute_derated_DDR1_CAS_latency(
304 get_memory_clk_period_ps(ctrl_num));
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305
306 /* Compute timing parameters */
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307 pdimm->trcd_ps = spd->trcd * 250;
308 pdimm->trp_ps = spd->trp * 250;
309 pdimm->tras_ps = spd->tras * 1000;
05c05a23 310
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311 pdimm->twr_ps = mclk_to_picos(ctrl_num, 3);
312 pdimm->twtr_ps = mclk_to_picos(ctrl_num, 1);
0dd38a35 313 pdimm->trfc_ps = compute_trfc_ps_from_spd(0, spd->trfc);
05c05a23 314
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315 pdimm->trrd_ps = spd->trrd * 250;
316 pdimm->trc_ps = compute_trc_ps_from_spd(0, spd->trc);
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317
318 pdimm->refresh_rate_ps = determine_refresh_rate_ps(spd->refresh);
319
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320 pdimm->tis_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_setup);
321 pdimm->tih_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_hold);
322 pdimm->tds_ps
05c05a23 323 = convert_bcd_hundredths_to_cycle_time_ps(spd->data_setup);
0dd38a35 324 pdimm->tdh_ps
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325 = convert_bcd_hundredths_to_cycle_time_ps(spd->data_hold);
326
03e664d8 327 pdimm->trtp_ps = mclk_to_picos(ctrl_num, 2); /* By the book. */
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328 pdimm->tdqsq_max_ps = spd->tdqsq * 10;
329 pdimm->tqhs_ps = spd->tqhs * 10;
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330
331 return 0;
332}