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@@ -128,3 +128,170 @@ static inline u_int ns_to_cycles(u_int ns, u_int khz)
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return (ns * khz + 999999) / 1000000;
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}
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+/*
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+ * Create the MDCAS register bit pattern.
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+ */
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+static inline void set_mdcas(u_int *mdcas, int delayed, u_int rcd)
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+{
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+ u_int shift;
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+
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+ rcd = 2 * rcd - 1;
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+ shift = delayed + 1 + rcd;
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+
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+ mdcas[0] = (1 << rcd) - 1;
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+ mdcas[0] |= 0x55555555 << shift;
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+ mdcas[1] = mdcas[2] = 0x55555555 << (shift & 1);
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+}
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+
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+static void
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+sdram_calculate_timing(struct sdram_info *sd, u_int cpu_khz,
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+ struct sdram_params *sdram)
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+{
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+ u_int mem_khz, sd_khz, trp, twr;
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+
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+ mem_khz = cpu_khz / 2;
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+ sd_khz = mem_khz;
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+
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+ /*
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+ * If SDCLK would invalidate the SDRAM timings,
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+ * run SDCLK at half speed.
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+ *
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+ * CPU steppings prior to B2 must either run the memory at
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+ * half speed or use delayed read latching (errata 13).
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+ */
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+ if ((ns_to_cycles(sdram->tck, sd_khz) > 1) ||
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+ (CPU_REVISION < CPU_SA1110_B2 && sd_khz < 62000))
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+ sd_khz /= 2;
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+
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+ sd->mdcnfg = MDCNFG & 0x007f007f;
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+
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+ twr = ns_to_cycles(sdram->twr, mem_khz);
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+
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+ /* trp should always be >1 */
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+ trp = ns_to_cycles(sdram->trp, mem_khz) - 1;
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+ if (trp < 1)
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+ trp = 1;
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+
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+ sd->mdcnfg |= trp << 8;
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+ sd->mdcnfg |= trp << 24;
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+ sd->mdcnfg |= sdram->cas_latency << 12;
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+ sd->mdcnfg |= sdram->cas_latency << 28;
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+ sd->mdcnfg |= twr << 14;
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+ sd->mdcnfg |= twr << 30;
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+
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+ sd->mdrefr = MDREFR & 0xffbffff0;
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+ sd->mdrefr |= 7;
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+
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+ if (sd_khz != mem_khz)
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+ sd->mdrefr |= MDREFR_K1DB2;
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+
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+ /* initial number of '1's in MDCAS + 1 */
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+ set_mdcas(sd->mdcas, sd_khz >= 62000,
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+ ns_to_cycles(sdram->trcd, mem_khz));
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+
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+#ifdef DEBUG
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+ printk(KERN_DEBUG "MDCNFG: %08x MDREFR: %08x MDCAS0: %08x MDCAS1: %08x MDCAS2: %08x\n",
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+ sd->mdcnfg, sd->mdrefr, sd->mdcas[0], sd->mdcas[1],
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+ sd->mdcas[2]);
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+#endif
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+}
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+
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+/*
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+ * Set the SDRAM refresh rate.
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+ */
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+static inline void sdram_set_refresh(u_int dri)
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+{
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+ MDREFR = (MDREFR & 0xffff000f) | (dri << 4);
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+ (void) MDREFR;
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+}
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+
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+/*
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+ * Update the refresh period. We do this such that we always refresh
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+ * the SDRAMs within their permissible period. The refresh period is
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+ * always a multiple of the memory clock (fixed at cpu_clock / 2).
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+ *
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+ * FIXME: we don't currently take account of burst accesses here,
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+ * but neither do Intels DM nor Angel.
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+ */
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+static void
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+sdram_update_refresh(u_int cpu_khz, struct sdram_params *sdram)
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+{
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+ u_int ns_row = (sdram->refresh * 1000) >> sdram->rows;
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+ u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32;
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+
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+#ifdef DEBUG
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+ mdelay(250);
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+ printk(KERN_DEBUG "new dri value = %d\n", dri);
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+#endif
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+
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+ sdram_set_refresh(dri);
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+}
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+
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+/*
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+ * Ok, set the CPU frequency.
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+ */
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+static int sa1110_target(struct cpufreq_policy *policy,
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+ unsigned int target_freq,
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+ unsigned int relation)
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+{
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+ struct sdram_params *sdram = &sdram_params;
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+ struct cpufreq_freqs freqs;
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+ struct sdram_info sd;
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+ unsigned long flags;
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+ unsigned int ppcr, unused;
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+
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+ switch (relation) {
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+ case CPUFREQ_RELATION_L:
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+ ppcr = sa11x0_freq_to_ppcr(target_freq);
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+ if (sa11x0_ppcr_to_freq(ppcr) > policy->max)
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+ ppcr--;
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+ break;
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+ case CPUFREQ_RELATION_H:
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+ ppcr = sa11x0_freq_to_ppcr(target_freq);
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+ if (ppcr && (sa11x0_ppcr_to_freq(ppcr) > target_freq) &&
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+ (sa11x0_ppcr_to_freq(ppcr-1) >= policy->min))
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+ ppcr--;
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+ break;
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+ default:
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+ return -EINVAL;
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+ }
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+
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+ freqs.old = sa11x0_getspeed(0);
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+ freqs.new = sa11x0_ppcr_to_freq(ppcr);
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+ freqs.cpu = 0;
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+
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+ sdram_calculate_timing(&sd, freqs.new, sdram);
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+
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+#if 0
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+ /*
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+ * These values are wrong according to the SA1110 documentation
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+ * and errata, but they seem to work. Need to get a storage
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+ * scope on to the SDRAM signals to work out why.
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+ */
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+ if (policy->max < 147500) {
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+ sd.mdrefr |= MDREFR_K1DB2;
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+ sd.mdcas[0] = 0xaaaaaa7f;
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+ } else {
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+ sd.mdrefr &= ~MDREFR_K1DB2;
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+ sd.mdcas[0] = 0xaaaaaa9f;
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+ }
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+ sd.mdcas[1] = 0xaaaaaaaa;
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+ sd.mdcas[2] = 0xaaaaaaaa;
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+#endif
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+
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+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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+
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+ /*
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+ * The clock could be going away for some time. Set the SDRAMs
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+ * to refresh rapidly (every 64 memory clock cycles). To get
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+ * through the whole array, we need to wait 262144 mclk cycles.
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+ * We wait 20ms to be safe.
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+ */
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+ sdram_set_refresh(2);
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+ if (!irqs_disabled())
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+ msleep(20);
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+ else
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+ mdelay(20);
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+
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+ /*
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+ * Reprogram the DRAM timings with interrupts disabled, and
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