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-rw-r--r--drivers/cpufreq/bmips-cpufreq.c189
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/cpufreq/bmips-cpufreq.c b/drivers/cpufreq/bmips-cpufreq.c
new file mode 100644
index 0000000000..39221a9a18
--- /dev/null
+++ b/drivers/cpufreq/bmips-cpufreq.c
@@ -0,0 +1,189 @@
+/*
+ * CPU frequency scaling for Broadcom BMIPS SoCs
+ *
+ * Copyright (c) 2017 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+/* for mips_hpt_frequency */
+#include <asm/time.h>
+
+#define BMIPS_CPUFREQ_PREFIX "bmips"
+#define BMIPS_CPUFREQ_NAME BMIPS_CPUFREQ_PREFIX "-cpufreq"
+
+#define TRANSITION_LATENCY (25 * 1000) /* 25 us */
+
+#define BMIPS5_CLK_DIV_SET_SHIFT 0x7
+#define BMIPS5_CLK_DIV_SHIFT 0x4
+#define BMIPS5_CLK_DIV_MASK 0xf
+
+enum bmips_type {
+ BMIPS5000,
+ BMIPS5200,
+};
+
+struct cpufreq_compat {
+ const char *compatible;
+ unsigned int bmips_type;
+ unsigned int clk_mult;
+ unsigned int max_freqs;
+};
+
+#define BMIPS(c, t, m, f) { \
+ .compatible = c, \
+ .bmips_type = (t), \
+ .clk_mult = (m), \
+ .max_freqs = (f), \
+}
+
+static struct cpufreq_compat bmips_cpufreq_compat[] = {
+ BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),
+ BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),
+ { }
+};
+
+static struct cpufreq_compat *priv;
+
+static int htp_freq_to_cpu_freq(unsigned int clk_mult)
+{
+ return mips_hpt_frequency * clk_mult / 1000;
+}
+
+static struct cpufreq_frequency_table *
+bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)
+{
+ struct cpufreq_frequency_table *table;
+ unsigned long cpu_freq;
+ int i;
+
+ cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);
+
+ table = kmalloc_array(priv->max_freqs + 1, sizeof(*table), GFP_KERNEL);
+ if (!table)
+ return ERR_PTR(-ENOMEM);
+
+ for (i = 0; i < priv->max_freqs; i++) {
+ table[i].frequency = cpu_freq / (1 << i);
+ table[i].driver_data = i;
+ }
+ table[i].frequency = CPUFREQ_TABLE_END;
+
+ return table;
+}
+
+static unsigned int bmips_cpufreq_get(unsigned int cpu)
+{
+ unsigned int div;
+ uint32_t mode;
+
+ switch (priv->bmips_type) {
+ case BMIPS5200:
+ case BMIPS5000:
+ mode = read_c0_brcm_mode();
+ div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);
+ break;
+ default:
+ div = 0;
+ }
+
+ return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);
+}
+
+static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ unsigned int div = policy->freq_table[index].driver_data;
+
+ switch (priv->bmips_type) {
+ case BMIPS5200:
+ case BMIPS5000:
+ change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,
+ (1 << BMIPS5_CLK_DIV_SET_SHIFT) |
+ (div << BMIPS5_CLK_DIV_SHIFT));
+ break;
+ default:
+ return -ENOTSUPP;
+ }
+
+ return 0;
+}
+
+static int bmips_cpufreq_exit(struct cpufreq_policy *policy)
+{
+ kfree(policy->freq_table);
+
+ return 0;
+}
+
+static int bmips_cpufreq_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_frequency_table *freq_table;
+
+ freq_table = bmips_cpufreq_get_freq_table(policy);
+ if (IS_ERR(freq_table)) {
+ pr_err("%s: couldn't determine frequency table (%ld).\n",
+ BMIPS_CPUFREQ_NAME, PTR_ERR(freq_table));
+ return PTR_ERR(freq_table);
+ }
+
+ cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);
+ pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);
+
+ return 0;
+}
+
+static struct cpufreq_driver bmips_cpufreq_driver = {
+ .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = bmips_cpufreq_target_index,
+ .get = bmips_cpufreq_get,
+ .init = bmips_cpufreq_init,
+ .exit = bmips_cpufreq_exit,
+ .attr = cpufreq_generic_attr,
+ .name = BMIPS_CPUFREQ_PREFIX,
+};
+
+static int __init bmips_cpufreq_driver_init(void)
+{
+ struct cpufreq_compat *cc;
+ struct device_node *np;
+
+ for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {
+ np = of_find_compatible_node(NULL, "cpu", cc->compatible);
+ if (np) {
+ of_node_put(np);
+ priv = cc;
+ break;
+ }
+ }
+
+ /* We hit the guard element of the array. No compatible CPU found. */
+ if (!cc->compatible)
+ return -ENODEV;
+
+ return cpufreq_register_driver(&bmips_cpufreq_driver);
+}
+module_init(bmips_cpufreq_driver_init);
+
+static void __exit bmips_cpufreq_driver_exit(void)
+{
+ cpufreq_unregister_driver(&bmips_cpufreq_driver);
+}
+module_exit(bmips_cpufreq_driver_exit);
+
+MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
+MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");
+MODULE_LICENSE("GPL");