1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/mach-sa1100/cpu-sa1110.c 4 * 5 * Copyright (C) 2001 Russell King 6 * 7 * Note: there are two erratas that apply to the SA1110 here: 8 * 7 - SDRAM auto-power-up failure (rev A0) 9 * 13 - Corruption of internal register reads/writes following 10 * SDRAM reads (rev A0, B0, B1) 11 * 12 * We ignore rev. A0 and B0 devices; I don't think they're worth supporting. 13 * 14 * The SDRAM type can be passed on the command line as cpu_sa1110.sdram=type 15 */ 16 #include <linux/cpufreq.h> 17 #include <linux/delay.h> 18 #include <linux/init.h> 19 #include <linux/io.h> 20 #include <linux/kernel.h> 21 #include <linux/moduleparam.h> 22 #include <linux/types.h> 23 24 #include <asm/cputype.h> 25 #include <asm/mach-types.h> 26 27 #include <mach/generic.h> 28 #include <mach/hardware.h> 29 30 #undef DEBUG 31 32 struct sdram_params { 33 const char name[20]; 34 u_char rows; /* bits */ 35 u_char cas_latency; /* cycles */ 36 u_char tck; /* clock cycle time (ns) */ 37 u_char trcd; /* activate to r/w (ns) */ 38 u_char trp; /* precharge to activate (ns) */ 39 u_char twr; /* write recovery time (ns) */ 40 u_short refresh; /* refresh time for array (us) */ 41 }; 42 43 struct sdram_info { 44 u_int mdcnfg; 45 u_int mdrefr; 46 u_int mdcas[3]; 47 }; 48 49 static struct sdram_params sdram_tbl[] __initdata = { 50 { /* Toshiba TC59SM716 CL2 */ 51 .name = "TC59SM716-CL2", 52 .rows = 12, 53 .tck = 10, 54 .trcd = 20, 55 .trp = 20, 56 .twr = 10, 57 .refresh = 64000, 58 .cas_latency = 2, 59 }, { /* Toshiba TC59SM716 CL3 */ 60 .name = "TC59SM716-CL3", 61 .rows = 12, 62 .tck = 8, 63 .trcd = 20, 64 .trp = 20, 65 .twr = 8, 66 .refresh = 64000, 67 .cas_latency = 3, 68 }, { /* Samsung K4S641632D TC75 */ 69 .name = "K4S641632D", 70 .rows = 14, 71 .tck = 9, 72 .trcd = 27, 73 .trp = 20, 74 .twr = 9, 75 .refresh = 64000, 76 .cas_latency = 3, 77 }, { /* Samsung K4S281632B-1H */ 78 .name = "K4S281632B-1H", 79 .rows = 12, 80 .tck = 10, 81 .trp = 20, 82 .twr = 10, 83 .refresh = 64000, 84 .cas_latency = 3, 85 }, { /* Samsung KM416S4030CT */ 86 .name = "KM416S4030CT", 87 .rows = 13, 88 .tck = 8, 89 .trcd = 24, /* 3 CLKs */ 90 .trp = 24, /* 3 CLKs */ 91 .twr = 16, /* Trdl: 2 CLKs */ 92 .refresh = 64000, 93 .cas_latency = 3, 94 }, { /* Winbond W982516AH75L CL3 */ 95 .name = "W982516AH75L", 96 .rows = 16, 97 .tck = 8, 98 .trcd = 20, 99 .trp = 20, 100 .twr = 8, 101 .refresh = 64000, 102 .cas_latency = 3, 103 }, { /* Micron MT48LC8M16A2TG-75 */ 104 .name = "MT48LC8M16A2TG-75", 105 .rows = 12, 106 .tck = 8, 107 .trcd = 20, 108 .trp = 20, 109 .twr = 8, 110 .refresh = 64000, 111 .cas_latency = 3, 112 }, 113 }; 114 115 static struct sdram_params sdram_params; 116 117 /* 118 * Given a period in ns and frequency in khz, calculate the number of 119 * cycles of frequency in period. Note that we round up to the next 120 * cycle, even if we are only slightly over. 121 */ 122 static inline u_int ns_to_cycles(u_int ns, u_int khz) 123 { 124 return (ns * khz + 999999) / 1000000; 125 } 126 127 /* 128 * Create the MDCAS register bit pattern. 129 */ 130 static inline void set_mdcas(u_int *mdcas, int delayed, u_int rcd) 131 { 132 u_int shift; 133 134 rcd = 2 * rcd - 1; 135 shift = delayed + 1 + rcd; 136 137 mdcas[0] = (1 << rcd) - 1; 138 mdcas[0] |= 0x55555555 << shift; 139 mdcas[1] = mdcas[2] = 0x55555555 << (shift & 1); 140 } 141 142 static void 143 sdram_calculate_timing(struct sdram_info *sd, u_int cpu_khz, 144 struct sdram_params *sdram) 145 { 146 u_int mem_khz, sd_khz, trp, twr; 147 148 mem_khz = cpu_khz / 2; 149 sd_khz = mem_khz; 150 151 /* 152 * If SDCLK would invalidate the SDRAM timings, 153 * run SDCLK at half speed. 154 * 155 * CPU steppings prior to B2 must either run the memory at 156 * half speed or use delayed read latching (errata 13). 157 */ 158 if ((ns_to_cycles(sdram->tck, sd_khz) > 1) || 159 (read_cpuid_revision() < ARM_CPU_REV_SA1110_B2 && sd_khz < 62000)) 160 sd_khz /= 2; 161 162 sd->mdcnfg = MDCNFG & 0x007f007f; 163 164 twr = ns_to_cycles(sdram->twr, mem_khz); 165 166 /* trp should always be >1 */ 167 trp = ns_to_cycles(sdram->trp, mem_khz) - 1; 168 if (trp < 1) 169 trp = 1; 170 171 sd->mdcnfg |= trp << 8; 172 sd->mdcnfg |= trp << 24; 173 sd->mdcnfg |= sdram->cas_latency << 12; 174 sd->mdcnfg |= sdram->cas_latency << 28; 175 sd->mdcnfg |= twr << 14; 176 sd->mdcnfg |= twr << 30; 177 178 sd->mdrefr = MDREFR & 0xffbffff0; 179 sd->mdrefr |= 7; 180 181 if (sd_khz != mem_khz) 182 sd->mdrefr |= MDREFR_K1DB2; 183 184 /* initial number of '1's in MDCAS + 1 */ 185 set_mdcas(sd->mdcas, sd_khz >= 62000, 186 ns_to_cycles(sdram->trcd, mem_khz)); 187 188 #ifdef DEBUG 189 printk(KERN_DEBUG "MDCNFG: %08x MDREFR: %08x MDCAS0: %08x MDCAS1: %08x MDCAS2: %08x\n", 190 sd->mdcnfg, sd->mdrefr, sd->mdcas[0], sd->mdcas[1], 191 sd->mdcas[2]); 192 #endif 193 } 194 195 /* 196 * Set the SDRAM refresh rate. 197 */ 198 static inline void sdram_set_refresh(u_int dri) 199 { 200 MDREFR = (MDREFR & 0xffff000f) | (dri << 4); 201 (void) MDREFR; 202 } 203 204 /* 205 * Update the refresh period. We do this such that we always refresh 206 * the SDRAMs within their permissible period. The refresh period is 207 * always a multiple of the memory clock (fixed at cpu_clock / 2). 208 * 209 * FIXME: we don't currently take account of burst accesses here, 210 * but neither do Intels DM nor Angel. 211 */ 212 static void 213 sdram_update_refresh(u_int cpu_khz, struct sdram_params *sdram) 214 { 215 u_int ns_row = (sdram->refresh * 1000) >> sdram->rows; 216 u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32; 217 218 #ifdef DEBUG 219 mdelay(250); 220 printk(KERN_DEBUG "new dri value = %d\n", dri); 221 #endif 222 223 sdram_set_refresh(dri); 224 } 225 226 /* 227 * Ok, set the CPU frequency. 228 */ 229 static int sa1110_target(struct cpufreq_policy *policy, unsigned int ppcr) 230 { 231 struct sdram_params *sdram = &sdram_params; 232 struct sdram_info sd; 233 unsigned long flags; 234 unsigned int unused; 235 236 sdram_calculate_timing(&sd, sa11x0_freq_table[ppcr].frequency, sdram); 237 238 #if 0 239 /* 240 * These values are wrong according to the SA1110 documentation 241 * and errata, but they seem to work. Need to get a storage 242 * scope on to the SDRAM signals to work out why. 243 */ 244 if (policy->max < 147500) { 245 sd.mdrefr |= MDREFR_K1DB2; 246 sd.mdcas[0] = 0xaaaaaa7f; 247 } else { 248 sd.mdrefr &= ~MDREFR_K1DB2; 249 sd.mdcas[0] = 0xaaaaaa9f; 250 } 251 sd.mdcas[1] = 0xaaaaaaaa; 252 sd.mdcas[2] = 0xaaaaaaaa; 253 #endif 254 255 /* 256 * The clock could be going away for some time. Set the SDRAMs 257 * to refresh rapidly (every 64 memory clock cycles). To get 258 * through the whole array, we need to wait 262144 mclk cycles. 259 * We wait 20ms to be safe. 260 */ 261 sdram_set_refresh(2); 262 if (!irqs_disabled()) 263 msleep(20); 264 else 265 mdelay(20); 266 267 /* 268 * Reprogram the DRAM timings with interrupts disabled, and 269 * ensure that we are doing this within a complete cache line. 270 * This means that we won't access SDRAM for the duration of 271 * the programming. 272 */ 273 local_irq_save(flags); 274 asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0)); 275 udelay(10); 276 __asm__ __volatile__("\n\ 277 b 2f \n\ 278 .align 5 \n\ 279 1: str %3, [%1, #0] @ MDCNFG \n\ 280 str %4, [%1, #28] @ MDREFR \n\ 281 str %5, [%1, #4] @ MDCAS0 \n\ 282 str %6, [%1, #8] @ MDCAS1 \n\ 283 str %7, [%1, #12] @ MDCAS2 \n\ 284 str %8, [%2, #0] @ PPCR \n\ 285 ldr %0, [%1, #0] \n\ 286 b 3f \n\ 287 2: b 1b \n\ 288 3: nop \n\ 289 nop" 290 : "=&r" (unused) 291 : "r" (&MDCNFG), "r" (&PPCR), "0" (sd.mdcnfg), 292 "r" (sd.mdrefr), "r" (sd.mdcas[0]), 293 "r" (sd.mdcas[1]), "r" (sd.mdcas[2]), "r" (ppcr)); 294 local_irq_restore(flags); 295 296 /* 297 * Now, return the SDRAM refresh back to normal. 298 */ 299 sdram_update_refresh(sa11x0_freq_table[ppcr].frequency, sdram); 300 301 return 0; 302 } 303 304 static int __init sa1110_cpu_init(struct cpufreq_policy *policy) 305 { 306 cpufreq_generic_init(policy, sa11x0_freq_table, 0); 307 return 0; 308 } 309 310 /* sa1110_driver needs __refdata because it must remain after init registers 311 * it with cpufreq_register_driver() */ 312 static struct cpufreq_driver sa1110_driver __refdata = { 313 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK | 314 CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, 315 .verify = cpufreq_generic_frequency_table_verify, 316 .target_index = sa1110_target, 317 .get = sa11x0_getspeed, 318 .init = sa1110_cpu_init, 319 .name = "sa1110", 320 }; 321 322 static struct sdram_params *sa1110_find_sdram(const char *name) 323 { 324 struct sdram_params *sdram; 325 326 for (sdram = sdram_tbl; sdram < sdram_tbl + ARRAY_SIZE(sdram_tbl); 327 sdram++) 328 if (strcmp(name, sdram->name) == 0) 329 return sdram; 330 331 return NULL; 332 } 333 334 static char sdram_name[16]; 335 336 static int __init sa1110_clk_init(void) 337 { 338 struct sdram_params *sdram; 339 const char *name = sdram_name; 340 341 if (!cpu_is_sa1110()) 342 return -ENODEV; 343 344 if (!name[0]) { 345 if (machine_is_assabet()) 346 name = "TC59SM716-CL3"; 347 if (machine_is_jornada720() || machine_is_h3600()) 348 name = "K4S281632B-1H"; 349 } 350 351 sdram = sa1110_find_sdram(name); 352 if (sdram) { 353 printk(KERN_DEBUG "SDRAM: tck: %d trcd: %d trp: %d" 354 " twr: %d refresh: %d cas_latency: %d\n", 355 sdram->tck, sdram->trcd, sdram->trp, 356 sdram->twr, sdram->refresh, sdram->cas_latency); 357 358 memcpy(&sdram_params, sdram, sizeof(sdram_params)); 359 360 return cpufreq_register_driver(&sa1110_driver); 361 } 362 363 return 0; 364 } 365 366 module_param_string(sdram, sdram_name, sizeof(sdram_name), 0); 367 arch_initcall(sa1110_clk_init); 368