1 files changed, 353 insertions, 0 deletions
diff --git a/drivers/cpufreq/sparc-us2e-cpufreq.c b/drivers/cpufreq/sparc-us2e-cpufreq.c
new file mode 100644
index 0000000000..2783d3d55f
--- /dev/null
+++ b/drivers/cpufreq/sparc-us2e-cpufreq.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* us2e_cpufreq.c: UltraSPARC-IIe cpu frequency support
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ *
+ * Many thanks to Dominik Brodowski for fixing up the cpufreq
+ * infrastructure in order to make this driver easier to implement.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/cpufreq.h>
+#include <linux/threads.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+
+#include <asm/asi.h>
+#include <asm/timer.h>
+
+struct us2e_freq_percpu_info {
+	struct cpufreq_frequency_table table[6];
+};
+
+/* Indexed by cpu number. */
+static struct us2e_freq_percpu_info *us2e_freq_table;
+
+#define HBIRD_MEM_CNTL0_ADDR	0x1fe0000f010UL
+#define HBIRD_ESTAR_MODE_ADDR	0x1fe0000f080UL
+
+/* UltraSPARC-IIe has five dividers: 1, 2, 4, 6, and 8.  These are controlled
+ * in the ESTAR mode control register.
+ */
+#define ESTAR_MODE_DIV_1	0x0000000000000000UL
+#define ESTAR_MODE_DIV_2	0x0000000000000001UL
+#define ESTAR_MODE_DIV_4	0x0000000000000003UL
+#define ESTAR_MODE_DIV_6	0x0000000000000002UL
+#define ESTAR_MODE_DIV_8	0x0000000000000004UL
+#define ESTAR_MODE_DIV_MASK	0x0000000000000007UL
+
+#define MCTRL0_SREFRESH_ENAB	0x0000000000010000UL
+#define MCTRL0_REFR_COUNT_MASK	0x0000000000007f00UL
+#define MCTRL0_REFR_COUNT_SHIFT	8
+#define MCTRL0_REFR_INTERVAL	7800
+#define MCTRL0_REFR_CLKS_P_CNT	64
+
+static unsigned long read_hbreg(unsigned long addr)
+{
+	unsigned long ret;
+
+	__asm__ __volatile__("ldxa	[%1] %2, %0"
+			     : "=&r" (ret)
+			     : "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E));
+	return ret;
+}
+
+static void write_hbreg(unsigned long addr, unsigned long val)
+{
+	__asm__ __volatile__("stxa	%0, [%1] %2\n\t"
+			     "membar	#Sync"
+			     : /* no outputs */
+			     : "r" (val), "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E)
+			     : "memory");
+	if (addr == HBIRD_ESTAR_MODE_ADDR) {
+		/* Need to wait 16 clock cycles for the PLL to lock.  */
+		udelay(1);
+	}
+}
+
+static void self_refresh_ctl(int enable)
+{
+	unsigned long mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
+
+	if (enable)
+		mctrl |= MCTRL0_SREFRESH_ENAB;
+	else
+		mctrl &= ~MCTRL0_SREFRESH_ENAB;
+	write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
+	(void) read_hbreg(HBIRD_MEM_CNTL0_ADDR);
+}
+
+static void frob_mem_refresh(int cpu_slowing_down,
+			     unsigned long clock_tick,
+			     unsigned long old_divisor, unsigned long divisor)
+{
+	unsigned long old_refr_count, refr_count, mctrl;
+
+	refr_count  = (clock_tick * MCTRL0_REFR_INTERVAL);
+	refr_count /= (MCTRL0_REFR_CLKS_P_CNT * divisor * 1000000000UL);
+
+	mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
+	old_refr_count = (mctrl & MCTRL0_REFR_COUNT_MASK)
+		>> MCTRL0_REFR_COUNT_SHIFT;
+
+	mctrl &= ~MCTRL0_REFR_COUNT_MASK;
+	mctrl |= refr_count << MCTRL0_REFR_COUNT_SHIFT;
+	write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
+	mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
+
+	if (cpu_slowing_down && !(mctrl & MCTRL0_SREFRESH_ENAB)) {
+		unsigned long usecs;
+
+		/* We have to wait for both refresh counts (old
+		 * and new) to go to zero.
+		 */
+		usecs = (MCTRL0_REFR_CLKS_P_CNT *
+			 (refr_count + old_refr_count) *
+			 1000000UL *
+			 old_divisor) / clock_tick;
+		udelay(usecs + 1UL);
+	}
+}
+
+static void us2e_transition(unsigned long estar, unsigned long new_bits,
+			    unsigned long clock_tick,
+			    unsigned long old_divisor, unsigned long divisor)
+{
+	estar &= ~ESTAR_MODE_DIV_MASK;
+
+	/* This is based upon the state transition diagram in the IIe manual.  */
+	if (old_divisor == 2 && divisor == 1) {
+		self_refresh_ctl(0);
+		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
+		frob_mem_refresh(0, clock_tick, old_divisor, divisor);
+	} else if (old_divisor == 1 && divisor == 2) {
+		frob_mem_refresh(1, clock_tick, old_divisor, divisor);
+		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
+		self_refresh_ctl(1);
+	} else if (old_divisor == 1 && divisor > 2) {
+		us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
+				1, 2);
+		us2e_transition(estar, new_bits, clock_tick,
+				2, divisor);
+	} else if (old_divisor > 2 && divisor == 1) {
+		us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
+				old_divisor, 2);
+		us2e_transition(estar, new_bits, clock_tick,
+				2, divisor);
+	} else if (old_divisor < divisor) {
+		frob_mem_refresh(0, clock_tick, old_divisor, divisor);
+		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
+	} else if (old_divisor > divisor) {
+		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
+		frob_mem_refresh(1, clock_tick, old_divisor, divisor);
+	} else {
+		BUG();
+	}
+}
+
+static unsigned long index_to_estar_mode(unsigned int index)
+{
+	switch (index) {
+	case 0:
+		return ESTAR_MODE_DIV_1;
+
+	case 1:
+		return ESTAR_MODE_DIV_2;
+
+	case 2:
+		return ESTAR_MODE_DIV_4;
+
+	case 3:
+		return ESTAR_MODE_DIV_6;
+
+	case 4:
+		return ESTAR_MODE_DIV_8;
+
+	default:
+		BUG();
+	}
+}
+
+static unsigned long index_to_divisor(unsigned int index)
+{
+	switch (index) {
+	case 0:
+		return 1;
+
+	case 1:
+		return 2;
+
+	case 2:
+		return 4;
+
+	case 3:
+		return 6;
+
+	case 4:
+		return 8;
+
+	default:
+		BUG();
+	}
+}
+
+static unsigned long estar_to_divisor(unsigned long estar)
+{
+	unsigned long ret;
+
+	switch (estar & ESTAR_MODE_DIV_MASK) {
+	case ESTAR_MODE_DIV_1:
+		ret = 1;
+		break;
+	case ESTAR_MODE_DIV_2:
+		ret = 2;
+		break;
+	case ESTAR_MODE_DIV_4:
+		ret = 4;
+		break;
+	case ESTAR_MODE_DIV_6:
+		ret = 6;
+		break;
+	case ESTAR_MODE_DIV_8:
+		ret = 8;
+		break;
+	default:
+		BUG();
+	}
+
+	return ret;
+}
+
+static void __us2e_freq_get(void *arg)
+{
+	unsigned long *estar = arg;
+
+	*estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);
+}
+
+static unsigned int us2e_freq_get(unsigned int cpu)
+{
+	unsigned long clock_tick, estar;
+
+	clock_tick = sparc64_get_clock_tick(cpu) / 1000;
+	if (smp_call_function_single(cpu, __us2e_freq_get, &estar, 1))
+		return 0;
+
+	return clock_tick / estar_to_divisor(estar);
+}
+
+static void __us2e_freq_target(void *arg)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned int *index = arg;
+	unsigned long new_bits, new_freq;
+	unsigned long clock_tick, divisor, old_divisor, estar;
+
+	new_freq = clock_tick = sparc64_get_clock_tick(cpu) / 1000;
+	new_bits = index_to_estar_mode(*index);
+	divisor = index_to_divisor(*index);
+	new_freq /= divisor;
+
+	estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);
+
+	old_divisor = estar_to_divisor(estar);
+
+	if (old_divisor != divisor) {
+		us2e_transition(estar, new_bits, clock_tick * 1000,
+				old_divisor, divisor);
+	}
+}
+
+static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	unsigned int cpu = policy->cpu;
+
+	return smp_call_function_single(cpu, __us2e_freq_target, &index, 1);
+}
+
+static int us2e_freq_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned int cpu = policy->cpu;
+	unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
+	struct cpufreq_frequency_table *table =
+		&us2e_freq_table[cpu].table[0];
+
+	table[0].driver_data = 0;
+	table[0].frequency = clock_tick / 1;
+	table[1].driver_data = 1;
+	table[1].frequency = clock_tick / 2;
+	table[2].driver_data = 2;
+	table[2].frequency = clock_tick / 4;
+	table[2].driver_data = 3;
+	table[2].frequency = clock_tick / 6;
+	table[2].driver_data = 4;
+	table[2].frequency = clock_tick / 8;
+	table[2].driver_data = 5;
+	table[3].frequency = CPUFREQ_TABLE_END;
+
+	policy->cpuinfo.transition_latency = 0;
+	policy->cur = clock_tick;
+	policy->freq_table = table;
+
+	return 0;
+}
+
+static int us2e_freq_cpu_exit(struct cpufreq_policy *policy)
+{
+	us2e_freq_target(policy, 0);
+	return 0;
+}
+
+static struct cpufreq_driver cpufreq_us2e_driver = {
+	.name = "UltraSPARC-IIe",
+	.init = us2e_freq_cpu_init,
+	.verify = cpufreq_generic_frequency_table_verify,
+	.target_index = us2e_freq_target,
+	.get = us2e_freq_get,
+	.exit = us2e_freq_cpu_exit,
+};
+
+static int __init us2e_freq_init(void)
+{
+	unsigned long manuf, impl, ver;
+	int ret;
+
+	if (tlb_type != spitfire)
+		return -ENODEV;
+
+	__asm__("rdpr %%ver, %0" : "=r" (ver));
+	manuf = ((ver >> 48) & 0xffff);
+	impl  = ((ver >> 32) & 0xffff);
+
+	if (manuf == 0x17 && impl == 0x13) {
+		us2e_freq_table = kzalloc(NR_CPUS * sizeof(*us2e_freq_table),
+					  GFP_KERNEL);
+		if (!us2e_freq_table)
+			return -ENOMEM;
+
+		ret = cpufreq_register_driver(&cpufreq_us2e_driver);
+		if (ret)
+			kfree(us2e_freq_table);
+
+		return ret;
+	}
+
+	return -ENODEV;
+}
+
+static void __exit us2e_freq_exit(void)
+{
+	cpufreq_unregister_driver(&cpufreq_us2e_driver);
+	kfree(us2e_freq_table);
+}
+
+MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
+MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-IIe");
+MODULE_LICENSE("GPL");
+
+module_init(us2e_freq_init);
+module_exit(us2e_freq_exit);