From: Finley Xiao <finley.x...@rock-chips.com>

This patch supports adjusting opp's voltage according to leakage

Signed-off-by: Finley Xiao <finley.x...@rock-chips.com>
---
 .../devicetree/bindings/power/rockchip-cpu-avs.txt |  37 +++
 drivers/power/avs/Kconfig                          |   8 +
 drivers/power/avs/Makefile                         |   1 +
 drivers/power/avs/rockchip-cpu-avs.c               | 314 +++++++++++++++++++++
 4 files changed, 360 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
 create mode 100644 drivers/power/avs/rockchip-cpu-avs.c

diff --git a/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt 
b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
new file mode 100644
index 0000000..90f6b08
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
@@ -0,0 +1,37 @@
+Rockchip cpu avs device tree bindings
+-------------------------------------
+
+Under the same frequency, the operating voltage tends to decrease with
+increasing leakage. so it is necessary to adjust opp's voltage according
+to leakage for power.
+
+
+Required properties:
+- compatible: Should be one of the following.
+  - "rockchip,rk3399-cpu-avs" - for RK3399 SoCs.
+- leakage-volt-<name>: Named leakage-volt property. At runtime, the
+  platform can find a cpu's cluster_id according to it's cpu_id and match
+  leakage-volt-<name> property. The property is an array of 3-tuples
+  items, and each item consists of leakage and voltage like
+  <min-leakage-mA max-leakage-mA vol-uV>.
+       min-leakage: minimum leakage in mA.
+       max-leakage: maximum leakage in mA.
+       vol: voltage in microvolt.
+
+Example:
+
+       cpu_avs: cpu-avs {
+               compatible = "rockchip,rk3399-cpu-avs";
+               leakage-volt-cluster0 = <
+               /*  mA        mA         uV*/
+                   0         100        0
+                   101       200        (-25000)
+                   201       300        (-50000)
+               >;
+               leakage-volt-cluster1 = <
+               /*  mA        mA         uV*/
+                   0         100        0
+                   101       200        (-25000)
+                   201       300        (-50000)
+               >;
+       };
diff --git a/drivers/power/avs/Kconfig b/drivers/power/avs/Kconfig
index a67eeac..c8f2d09 100644
--- a/drivers/power/avs/Kconfig
+++ b/drivers/power/avs/Kconfig
@@ -18,3 +18,11 @@ config ROCKCHIP_IODOMAIN
           Say y here to enable support io domains on Rockchip SoCs. It is
           necessary for the io domain setting of the SoC to match the
           voltage supplied by the regulators.
+
+config ROCKCHIP_CPU_AVS
+        bool "Rockchip CPU AVS support"
+        depends on POWER_AVS && ARCH_ROCKCHIP && OF
+        help
+          Say y here to enable support CPU AVS on Rockchip SoCs.
+          The cpu's operating voltage is adapted depending on leakage
+          or pvtm.
diff --git a/drivers/power/avs/Makefile b/drivers/power/avs/Makefile
index ba4c7bc..11ce242 100644
--- a/drivers/power/avs/Makefile
+++ b/drivers/power/avs/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_POWER_AVS_OMAP)           += smartreflex.o
 obj-$(CONFIG_ROCKCHIP_IODOMAIN)                += rockchip-io-domain.o
+obj-$(CONFIG_ROCKCHIP_CPU_AVS)         += rockchip-cpu-avs.o
diff --git a/drivers/power/avs/rockchip-cpu-avs.c 
b/drivers/power/avs/rockchip-cpu-avs.c
new file mode 100644
index 0000000..8266c02
--- /dev/null
+++ b/drivers/power/avs/rockchip-cpu-avs.c
@@ -0,0 +1,314 @@
+/*
+ * Rockchip CPU AVS support.
+ *
+ * Copyright (c) 2016 ROCKCHIP, Co. Ltd.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include "../../base/power/opp/opp.h"
+
+#define MAX_NAME_LEN           22
+#define LEAKAGE_TABLE_END      ~1
+#define INVALID_VALUE          0xff
+
+struct leakage_volt_table {
+       int    min;
+       int    max;
+       int    volt;
+};
+
+struct leakage_volt_table *leakage_volt_table;
+
+struct rockchip_cpu_avs {
+       struct leakage_volt_table **volt_table;
+       struct notifier_block   cpufreq_notify;
+};
+
+#define notifier_to_avs(_n) container_of(_n, struct rockchip_cpu_avs, \
+       cpufreq_notify)
+
+static unsigned char rockchip_fetch_leakage(struct device *dev)
+{
+       struct nvmem_cell *cell;
+       unsigned char *buf;
+       size_t len;
+       unsigned char leakage = INVALID_VALUE;
+
+       cell = nvmem_cell_get(dev, "cpu_leakage");
+       if (IS_ERR(cell)) {
+               pr_err("failed to get cpu_leakage cell\n");
+               return INVALID_VALUE;
+       }
+
+       buf = (unsigned char *)nvmem_cell_read(cell, &len);
+
+       nvmem_cell_put(cell);
+
+       if (IS_ERR(buf)) {
+               pr_err("failed to read nvmem cell\n");
+               return INVALID_VALUE;
+       }
+       leakage = buf[0];
+       kfree(buf);
+
+       return leakage;
+}
+
+static int rockchip_fetch_leakage_volt_table(
+       struct device_node *np,
+       struct leakage_volt_table **table,
+       const char *name)
+{
+       struct leakage_volt_table *volt_table = NULL;
+       const struct property *prop;
+       int count, i;
+
+       prop = of_find_property(np, name, NULL);
+       if (!prop) {
+               pr_err("failed to find prop %s\n", name);
+               return -EINVAL;
+       }
+       if (!prop->value) {
+               pr_err("%s value is NULL\n", name);
+               return -ENODATA;
+       }
+
+       count = of_property_count_u32_elems(np, name);
+       if (count < 0) {
+               pr_err("Invalid %s property (%d)\n", name, count);
+               return -EINVAL;
+       }
+       if (count % 3) {
+               pr_err("Invalid number of elements in %s property (%d)\n",
+                      name, count);
+               return -EINVAL;
+       }
+
+       volt_table = kzalloc(sizeof(*table) * (count / 3 + 1), GFP_KERNEL);
+       if (!volt_table)
+               return -ENOMEM;
+
+       if (volt_table) {
+               for (i = 0; i < count / 3; i++) {
+                       of_property_read_s32_index(np, name, 3 * i,
+                                                  &volt_table[i].min);
+                       of_property_read_s32_index(np, name, 3 * i + 1,
+                                                  &volt_table[i].max);
+                       of_property_read_s32_index(np, name, 3 * i + 2,
+                                                  &volt_table[i].volt);
+               }
+               volt_table[i].min = 0;
+               volt_table[i].max = 0;
+               volt_table[i].volt = LEAKAGE_TABLE_END;
+       }
+
+       *table = volt_table;
+
+       return 0;
+}
+
+static int rockchip_parse_leakage_volt(unsigned char leakage,
+                                      unsigned int cpu,
+                                      struct rockchip_cpu_avs *avs)
+{
+       struct leakage_volt_table *table;
+       unsigned int i, j, id;
+       int volt;
+
+       id = topology_physical_package_id(cpu);
+       if (id < 0)
+               id = 0;
+
+       table = avs->volt_table[id];
+       if (!table)
+               return 0;
+
+       for (i = 0; table[i].volt != LEAKAGE_TABLE_END; i++) {
+               if (leakage >= table[i].min)
+                       j = i;
+       }
+
+       volt = table[j].volt;
+
+       return volt;
+}
+
+static void rockchip_adjust_opp_table(struct device *dev,
+                                     struct cpufreq_frequency_table *table,
+                                     int volt)
+{
+       struct opp_table *opp_table;
+       struct cpufreq_frequency_table *pos;
+       struct dev_pm_opp *opp;
+       int ret;
+
+       rcu_read_lock();
+
+       opp_table = _find_opp_table(dev);
+       if (IS_ERR(opp_table)) {
+               pr_err("failed to find OPP table\n");
+               rcu_read_unlock();
+               return;
+       }
+
+       cpufreq_for_each_valid_entry(pos, table) {
+               opp = dev_pm_opp_find_freq_exact(dev, pos->frequency * 1000,
+                                                true);
+               if (IS_ERR(opp)) {
+                       pr_err("failed to find OPP for freq %d (%d)\n",
+                              pos->frequency, ret);
+                       continue;
+               }
+               opp->u_volt += volt;
+               opp->u_volt_min += volt;
+               opp->u_volt_max += volt;
+       }
+
+       rcu_read_unlock();
+}
+
+static void rockchip_adjust_volt_by_leakage(
+       struct device *dev,
+       struct cpufreq_frequency_table *table,
+       unsigned int cpu,
+       struct rockchip_cpu_avs *avs)
+{
+       unsigned char leakage;
+       int volt;
+
+       /* fetch leakage from efuse */
+       leakage = rockchip_fetch_leakage(dev);
+       if (leakage == INVALID_VALUE) {
+               pr_err("cpu%d leakage invalid\n", cpu);
+               return;
+       }
+
+       /* fetch adjust volt from table */
+       volt = rockchip_parse_leakage_volt(leakage, cpu, avs);
+       if (volt)
+               rockchip_adjust_opp_table(dev, table, volt);
+
+       pr_debug("cpu%d, leakage=%d, adjust_volt=%d\n", cpu, leakage, volt);
+}
+
+static int rockchip_cpu_avs_notifier(struct notifier_block *nb,
+                                    unsigned long event, void *data)
+{
+       struct rockchip_cpu_avs *avs = notifier_to_avs(nb);
+       struct cpufreq_policy *policy = data;
+       struct device *dev;
+
+       struct cpufreq_frequency_table *table;
+
+       if (event != CPUFREQ_START)
+               goto out;
+
+       dev = get_cpu_device(policy->cpu);
+       if (!dev) {
+               pr_err("cpu%d Failed to get device\n", policy->cpu);
+               goto out;
+       }
+
+       table = cpufreq_frequency_get_table(policy->cpu);
+       if (!table) {
+               pr_err("cpu%d CPUFreq table not found\n", policy->cpu);
+               goto out;
+       }
+
+       rockchip_adjust_volt_by_leakage(dev, table, policy->cpu, avs);
+
+out:
+
+       return NOTIFY_OK;
+}
+
+static const struct of_device_id rockchip_cpu_avs_match[] = {
+       {
+               .compatible = "rockchip,rk3399-cpu-avs",
+       },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, rockchip_cpu_avs_match);
+
+static int rockchip_cpu_avs_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct rockchip_cpu_avs *avs;
+       char name[MAX_NAME_LEN];
+       int i, ret, cpu, id;
+       int last_id = -1;
+       int cluster_num = 0;
+
+       avs = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_cpu_avs),
+                          GFP_KERNEL);
+       if (!avs)
+               return -ENOMEM;
+
+       avs->cpufreq_notify.notifier_call = rockchip_cpu_avs_notifier;
+
+       for_each_online_cpu(cpu) {
+               id = topology_physical_package_id(cpu);
+               if (id < 0)
+                       id = 0;
+               if (id != last_id) {
+                       last_id = id;
+                       cluster_num++;
+               }
+       }
+
+       avs->volt_table = devm_kzalloc(&pdev->dev,
+               sizeof(struct leakage_volt_table) * cluster_num, GFP_KERNEL);
+       if (!avs->volt_table)
+               return -ENOMEM;
+
+       for (i = 0; i < cluster_num; i++) {
+               snprintf(name, MAX_NAME_LEN, "leakage-volt-cluster%d", i);
+               ret = rockchip_fetch_leakage_volt_table(np, &avs->volt_table[i],
+                                                       name);
+               if (ret)
+                       continue;
+       }
+
+       return cpufreq_register_notifier(&avs->cpufreq_notify,
+               CPUFREQ_POLICY_NOTIFIER);
+}
+
+static struct platform_driver rockchip_cpu_avs_driver = {
+       .probe   = rockchip_cpu_avs_probe,
+       .driver  = {
+               .name  = "rockchip-cpu-avs",
+               .of_match_table = rockchip_cpu_avs_match,
+               .suppress_bind_attrs = true,
+       },
+};
+
+static int __init rockchip_cpu_avs_module_init(void)
+{
+       return platform_driver_probe(&rockchip_cpu_avs_driver,
+                                    rockchip_cpu_avs_probe);
+}
+
+subsys_initcall(rockchip_cpu_avs_module_init);
+
+MODULE_DESCRIPTION("Rockchip CPU AVS driver");
+MODULE_AUTHOR("Finley Xiao <finley.x...@rock-chips.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1


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