// SPDX-License-Identifier: GPL-2.0-only /* * linux/arch/arm/mach-sa1100/cpu-sa1110.c * * Copyright (C) 2001 Russell King * * Note: there are two erratas that apply to the SA1110 here: * 7 - SDRAM auto-power-up failure (rev A0) * 13 - Corruption of internal register reads/writes following * SDRAM reads (rev A0, B0, B1) * * We ignore rev. A0 and B0 devices; I don't think they're worth supporting. * * The SDRAM type can be passed on the command line as cpu_sa1110.sdram=type */ #include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <asm/cputype.h> #include <asm/mach-types.h> #include <mach/generic.h> #include <mach/hardware.h> #undef DEBUG struct sdram_params { const char name[20]; u_char rows; /* bits */ u_char cas_latency; /* cycles */ u_char tck; /* clock cycle time (ns) */ u_char trcd; /* activate to r/w (ns) */ u_char trp; /* precharge to activate (ns) */ u_char twr; /* write recovery time (ns) */ u_short refresh; /* refresh time for array (us) */ }; struct sdram_info { u_int mdcnfg; u_int mdrefr; u_int mdcas[3]; }; static struct sdram_params sdram_tbl[] __initdata = { { /* Toshiba TC59SM716 CL2 */ .name = "TC59SM716-CL2", .rows = 12, .tck = 10, .trcd = 20, .trp = 20, .twr = 10, .refresh = 64000, .cas_latency = 2, }, { /* Toshiba TC59SM716 CL3 */ .name = "TC59SM716-CL3", .rows = 12, .tck = 8, .trcd = 20, .trp = 20, .twr = 8, .refresh = 64000, .cas_latency = 3, }, { /* Samsung K4S641632D TC75 */ .name = "K4S641632D", .rows = 14, .tck = 9, .trcd = 27, .trp = 20, .twr = 9, .refresh = 64000, .cas_latency = 3, }, { /* Samsung K4S281632B-1H */ .name = "K4S281632B-1H", .rows = 12, .tck = 10, .trp = 20, .twr = 10, .refresh = 64000, .cas_latency = 3, }, { /* Samsung KM416S4030CT */ .name = "KM416S4030CT", .rows = 13, .tck = 8, .trcd = 24, /* 3 CLKs */ .trp = 24, /* 3 CLKs */ .twr = 16, /* Trdl: 2 CLKs */ .refresh = 64000, .cas_latency = 3, }, { /* Winbond W982516AH75L CL3 */ .name = "W982516AH75L", .rows = 16, .tck = 8, .trcd = 20, .trp = 20, .twr = 8, .refresh = 64000, .cas_latency = 3, }, { /* Micron MT48LC8M16A2TG-75 */ .name = "MT48LC8M16A2TG-75", .rows = 12, .tck = 8, .trcd = 20, .trp = 20, .twr = 8, .refresh = 64000, .cas_latency = 3, }, }; static struct sdram_params sdram_params; /* * Given a period in ns and frequency in khz, calculate the number of * cycles of frequency in period. Note that we round up to the next * cycle, even if we are only slightly over. */ static inline u_int ns_to_cycles(u_int ns, u_int khz) { return (ns * khz + 999999) / 1000000; } /* * Create the MDCAS register bit pattern. */ static inline void set_mdcas(u_int *mdcas, int delayed, u_int rcd) { u_int shift; rcd = 2 * rcd - 1; shift = delayed + 1 + rcd; mdcas[0] = (1 << rcd) - 1; mdcas[0] |= 0x55555555 << shift; mdcas[1] = mdcas[2] = 0x55555555 << (shift & 1); } static void sdram_calculate_timing(struct sdram_info *sd, u_int cpu_khz, struct sdram_params *sdram) { u_int mem_khz, sd_khz, trp, twr; mem_khz = cpu_khz / 2; sd_khz = mem_khz; /* * If SDCLK would invalidate the SDRAM timings, * run SDCLK at half speed. * * CPU steppings prior to B2 must either run the memory at * half speed or use delayed read latching (errata 13). */ if ((ns_to_cycles(sdram->tck, sd_khz) > 1) || (read_cpuid_revision() < ARM_CPU_REV_SA1110_B2 && sd_khz < 62000)) sd_khz /= 2; sd->mdcnfg = MDCNFG & 0x007f007f; twr = ns_to_cycles(sdram->twr, mem_khz); /* trp should always be >1 */ trp = ns_to_cycles(sdram->trp, mem_khz) - 1; if (trp < 1) trp = 1; sd->mdcnfg |= trp << 8; sd->mdcnfg |= trp << 24; sd->mdcnfg |= sdram->cas_latency << 12; sd->mdcnfg |= sdram->cas_latency << 28; sd->mdcnfg |= twr << 14; sd->mdcnfg |= twr << 30; sd->mdrefr = MDREFR & 0xffbffff0; sd->mdrefr |= 7; if (sd_khz != mem_khz) sd->mdrefr |= MDREFR_K1DB2; /* initial number of '1's in MDCAS + 1 */ set_mdcas(sd->mdcas, sd_khz >= 62000, ns_to_cycles(sdram->trcd, mem_khz)); #ifdef DEBUG printk(KERN_DEBUG "MDCNFG: %08x MDREFR: %08x MDCAS0: %08x MDCAS1: %08x MDCAS2: %08x\n", sd->mdcnfg, sd->mdrefr, sd->mdcas[0], sd->mdcas[1], sd->mdcas[2]); #endif } /* * Set the SDRAM refresh rate. */ static inline void sdram_set_refresh(u_int dri) { MDREFR = (MDREFR & 0xffff000f) | (dri << 4); (void) MDREFR; } /* * Update the refresh period. We do this such that we always refresh * the SDRAMs within their permissible period. The refresh period is * always a multiple of the memory clock (fixed at cpu_clock / 2). * * FIXME: we don't currently take account of burst accesses here, * but neither do Intels DM nor Angel. */ static void sdram_update_refresh(u_int cpu_khz, struct sdram_params *sdram) { u_int ns_row = (sdram->refresh * 1000) >> sdram->rows; u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32; #ifdef DEBUG mdelay(250); printk(KERN_DEBUG "new dri value = %d\n", dri); #endif sdram_set_refresh(dri); } /* * Ok, set the CPU frequency. */ static int sa1110_target(struct cpufreq_policy *policy, unsigned int ppcr) { struct sdram_params *sdram = &sdram_params; struct sdram_info sd; unsigned long flags; unsigned int unused; sdram_calculate_timing(&sd, sa11x0_freq_table[ppcr].frequency, sdram); #if 0 /* * These values are wrong according to the SA1110 documentation * and errata, but they seem to work. Need to get a storage * scope on to the SDRAM signals to work out why. */ if (policy->max < 147500) { sd.mdrefr |= MDREFR_K1DB2; sd.mdcas[0] = 0xaaaaaa7f; } else { sd.mdrefr &= ~MDREFR_K1DB2; sd.mdcas[0] = 0xaaaaaa9f; } sd.mdcas[1] = 0xaaaaaaaa; sd.mdcas[2] = 0xaaaaaaaa; #endif /* * The clock could be going away for some time. Set the SDRAMs * to refresh rapidly (every 64 memory clock cycles). To get * through the whole array, we need to wait 262144 mclk cycles. * We wait 20ms to be safe. */ sdram_set_refresh(2); if (!irqs_disabled()) msleep(20); else mdelay(20); /* * Reprogram the DRAM timings with interrupts disabled, and * ensure that we are doing this within a complete cache line. * This means that we won't access SDRAM for the duration of * the programming. */ local_irq_save(flags); asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0)); udelay(10); __asm__ __volatile__("\n\ b 2f \n\ .align 5 \n\ 1: str %3, [%1, #0] @ MDCNFG \n\ str %4, [%1, #28] @ MDREFR \n\ str %5, [%1, #4] @ MDCAS0 \n\ str %6, [%1, #8] @ MDCAS1 \n\ str %7, [%1, #12] @ MDCAS2 \n\ str %8, [%2, #0] @ PPCR \n\ ldr %0, [%1, #0] \n\ b 3f \n\ 2: b 1b \n\ 3: nop \n\ nop" : "=&r" (unused) : "r" (&MDCNFG), "r" (&PPCR), "0" (sd.mdcnfg), "r" (sd.mdrefr), "r" (sd.mdcas[0]), "r" (sd.mdcas[1]), "r" (sd.mdcas[2]), "r" (ppcr)); local_irq_restore(flags); /* * Now, return the SDRAM refresh back to normal. */ sdram_update_refresh(sa11x0_freq_table[ppcr].frequency, sdram); return 0; } static int __init sa1110_cpu_init(struct cpufreq_policy *policy) { cpufreq_generic_init(policy, sa11x0_freq_table, 0); return 0; } /* sa1110_driver needs __refdata because it must remain after init registers * it with cpufreq_register_driver() */ static struct cpufreq_driver sa1110_driver __refdata = { .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK | CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, .verify = cpufreq_generic_frequency_table_verify, .target_index = sa1110_target, .get = sa11x0_getspeed, .init = sa1110_cpu_init, .name = "sa1110", }; static struct sdram_params *sa1110_find_sdram(const char *name) { struct sdram_params *sdram; for (sdram = sdram_tbl; sdram < sdram_tbl + ARRAY_SIZE(sdram_tbl); sdram++) if (strcmp(name, sdram->name) == 0) return sdram; return NULL; } static char sdram_name[16]; static int __init sa1110_clk_init(void) { struct sdram_params *sdram; const char *name = sdram_name; if (!cpu_is_sa1110()) return -ENODEV; if (!name[0]) { if (machine_is_assabet()) name = "TC59SM716-CL3"; if (machine_is_pt_system3()) name = "K4S641632D"; if (machine_is_h3100()) name = "KM416S4030CT"; if (machine_is_jornada720() || machine_is_h3600()) name = "K4S281632B-1H"; if (machine_is_nanoengine()) name = "MT48LC8M16A2TG-75"; } sdram = sa1110_find_sdram(name); if (sdram) { printk(KERN_DEBUG "SDRAM: tck: %d trcd: %d trp: %d" " twr: %d refresh: %d cas_latency: %d\n", sdram->tck, sdram->trcd, sdram->trp, sdram->twr, sdram->refresh, sdram->cas_latency); memcpy(&sdram_params, sdram, sizeof(sdram_params)); return cpufreq_register_driver(&sa1110_driver); } return 0; } module_param_string(sdram, sdram_name, sizeof(sdram_name), 0); arch_initcall(sa1110_clk_init);