diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-sa1100/cpu-sa1110.c | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mach-sa1100/cpu-sa1110.c')
-rw-r--r-- | arch/arm/mach-sa1100/cpu-sa1110.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/cpu-sa1110.c b/arch/arm/mach-sa1100/cpu-sa1110.c new file mode 100644 index 0000000..8d2a89a --- /dev/null +++ b/arch/arm/mach-sa1100/cpu-sa1110.c @@ -0,0 +1,367 @@ +/* + * linux/arch/arm/mach-sa1100/cpu-sa1110.c + * + * Copyright (C) 2001 Russell King + * + * $Id: cpu-sa1110.c,v 1.9 2002/07/06 16:53:18 rmk Exp $ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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. + */ +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cpufreq.h> +#include <linux/delay.h> +#include <linux/init.h> + +#include <asm/hardware.h> +#include <asm/mach-types.h> +#include <asm/io.h> +#include <asm/system.h> + +#include "generic.h" + +#undef DEBUG + +static struct cpufreq_driver sa1110_driver; + +struct sdram_params { + 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 tc59sm716_cl2_params __initdata = { + .rows = 12, + .tck = 10, + .trcd = 20, + .trp = 20, + .twr = 10, + .refresh = 64000, + .cas_latency = 2, +}; + +static struct sdram_params tc59sm716_cl3_params __initdata = { + .rows = 12, + .tck = 8, + .trcd = 20, + .trp = 20, + .twr = 8, + .refresh = 64000, + .cas_latency = 3, +}; + +static struct sdram_params samsung_k4s641632d_tc75 __initdata = { + .rows = 14, + .tck = 9, + .trcd = 27, + .trp = 20, + .twr = 9, + .refresh = 64000, + .cas_latency = 3, +}; + +static struct sdram_params samsung_km416s4030ct __initdata = { + .rows = 13, + .tck = 8, + .trcd = 24, /* 3 CLKs */ + .trp = 24, /* 3 CLKs */ + .twr = 16, /* Trdl: 2 CLKs */ + .refresh = 64000, + .cas_latency = 3, +}; + +static struct sdram_params wbond_w982516ah75l_cl3_params __initdata = { + .rows = 16, + .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) || + (CPU_REVISION < CPU_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("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("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 target_freq, + unsigned int relation) +{ + struct sdram_params *sdram = &sdram_params; + struct cpufreq_freqs freqs; + struct sdram_info sd; + unsigned long flags; + unsigned int ppcr, unused; + + switch(relation){ + case CPUFREQ_RELATION_L: + ppcr = sa11x0_freq_to_ppcr(target_freq); + if (sa11x0_ppcr_to_freq(ppcr) > policy->max) + ppcr--; + break; + case CPUFREQ_RELATION_H: + ppcr = sa11x0_freq_to_ppcr(target_freq); + if (ppcr && (sa11x0_ppcr_to_freq(ppcr) > target_freq) && + (sa11x0_ppcr_to_freq(ppcr-1) >= policy->min)) + ppcr--; + break; + default: + return -EINVAL; + } + + freqs.old = sa11x0_getspeed(0); + freqs.new = sa11x0_ppcr_to_freq(ppcr); + freqs.cpu = 0; + + sdram_calculate_timing(&sd, freqs.new, 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 + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + /* + * 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()) { + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(20 * HZ / 1000); + } 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(freqs.new, sdram); + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return 0; +} + +static int __init sa1110_cpu_init(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + policy->cur = policy->min = policy->max = sa11x0_getspeed(0); + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + policy->cpuinfo.min_freq = 59000; + policy->cpuinfo.max_freq = 287000; + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + return 0; +} + +static struct cpufreq_driver sa1110_driver = { + .flags = CPUFREQ_STICKY, + .verify = sa11x0_verify_speed, + .target = sa1110_target, + .get = sa11x0_getspeed, + .init = sa1110_cpu_init, + .name = "sa1110", +}; + +static int __init sa1110_clk_init(void) +{ + struct sdram_params *sdram = NULL; + + if (machine_is_assabet()) + sdram = &tc59sm716_cl3_params; + + if (machine_is_pt_system3()) + sdram = &samsung_k4s641632d_tc75; + + if (machine_is_h3100()) + sdram = &samsung_km416s4030ct; + + 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; +} + +arch_initcall(sa1110_clk_init); |