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-rw-r--r--drivers/cpufreq/sa1110-cpufreq.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/cpufreq/sa1110-cpufreq.c b/drivers/cpufreq/sa1110-cpufreq.c
new file mode 100644
index 0000000000..bb7f591a8b
--- /dev/null
+++ b/drivers/cpufreq/sa1110-cpufreq.c
@@ -0,0 +1,367 @@
+// 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_jornada720() || machine_is_h3600())
+ name = "K4S281632B-1H";
+ }
+
+ 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 15:19:50 +0000