The CPUfreq FW present in some QCOM chipsets offloads the steps necessary
for changing the frequency of CPUs. The driver implements the cpufreq
driver interface for this firmware.

Signed-off-by: Saravana Kannan <skan...@codeaurora.org>
Signed-off-by: Taniya Das <t...@codeaurora.org>
---
 drivers/cpufreq/Kconfig.arm       |   9 +
 drivers/cpufreq/Makefile          |   1 +
 drivers/cpufreq/qcom-cpufreq-fw.c | 336 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 346 insertions(+)
 create mode 100644 drivers/cpufreq/qcom-cpufreq-fw.c

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 52f5f1a..2683716 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -312,3 +312,12 @@ config ARM_PXA2xx_CPUFREQ
          This add the CPUFreq driver support for Intel PXA2xx SOCs.

          If in doubt, say N.
+
+config ARM_QCOM_CPUFREQ_FW
+       bool "QCOM CPUFreq FW driver"
+       help
+        Support for the CPUFreq FW driver.
+        The CPUfreq FW preset in some QCOM chipsets offloads the steps
+        necessary for changing the frequency of CPUs. The driver
+        implements the cpufreq driver interface for this firmware.
+        Say Y if you want to support CPUFreq FW.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index fb4a2ec..34691a2 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)    += tegra124-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA186_CPUFREQ)     += tegra186-cpufreq.o
 obj-$(CONFIG_ARM_TI_CPUFREQ)           += ti-cpufreq.o
 obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
+obj-$(CONFIG_ARM_QCOM_CPUFREQ_FW)      += qcom-cpufreq-fw.o


 
##################################################################################
diff --git a/drivers/cpufreq/qcom-cpufreq-fw.c 
b/drivers/cpufreq/qcom-cpufreq-fw.c
new file mode 100644
index 0000000..62f4452
--- /dev/null
+++ b/drivers/cpufreq/qcom-cpufreq-fw.c
@@ -0,0 +1,336 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#define INIT_RATE                      300000000UL
+#define XO_RATE                                19200000UL
+#define LUT_MAX_ENTRIES                        40U
+#define CORE_COUNT_VAL(val)            (((val) & (GENMASK(18, 16))) >> 16)
+#define LUT_ROW_SIZE                   32
+
+struct cpufreq_qcom {
+       struct cpufreq_frequency_table *table;
+       struct device *dev;
+       void __iomem *perf_base;
+       void __iomem *lut_base;
+       cpumask_t related_cpus;
+       unsigned int max_cores;
+};
+
+static struct cpufreq_qcom *qcom_freq_domain_map[NR_CPUS];
+
+static int
+qcom_cpufreq_fw_target_index(struct cpufreq_policy *policy,
+                            unsigned int index)
+{
+       struct cpufreq_qcom *c = policy->driver_data;
+
+       writel_relaxed(index, c->perf_base);
+
+       return 0;
+}
+
+static unsigned int qcom_cpufreq_fw_get(unsigned int cpu)
+{
+       struct cpufreq_qcom *c;
+       struct cpufreq_policy *policy;
+       unsigned int index;
+
+       policy = cpufreq_cpu_get_raw(cpu);
+       if (!policy)
+               return 0;
+
+       c = policy->driver_data;
+
+       index = readl_relaxed(c->perf_base);
+       index = min(index, LUT_MAX_ENTRIES - 1);
+
+       return policy->freq_table[index].frequency;
+}
+
+static unsigned int
+qcom_cpufreq_fw_fast_switch(struct cpufreq_policy *policy,
+                           unsigned int target_freq)
+{
+       struct cpufreq_qcom *c = policy->driver_data;
+       int index;
+
+       index = cpufreq_table_find_index_l(policy, target_freq);
+       if (index < 0)
+               return 0;
+
+       writel_relaxed(index, c->perf_base);
+
+       return policy->freq_table[index].frequency;
+}
+
+static int qcom_cpufreq_fw_cpu_init(struct cpufreq_policy *policy)
+{
+       struct cpufreq_qcom *c;
+
+       c = qcom_freq_domain_map[policy->cpu];
+       if (!c) {
+               pr_err("No scaling support for CPU%d\n", policy->cpu);
+               return -ENODEV;
+       }
+
+       cpumask_copy(policy->cpus, &c->related_cpus);
+
+       policy->fast_switch_possible = true;
+       policy->freq_table = c->table;
+       policy->driver_data = c;
+
+       return 0;
+}
+
+static struct freq_attr *qcom_cpufreq_fw_attr[] = {
+       &cpufreq_freq_attr_scaling_available_freqs,
+       &cpufreq_freq_attr_scaling_boost_freqs,
+       NULL
+};
+
+static struct cpufreq_driver cpufreq_qcom_fw_driver = {
+       .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
+       .verify         = cpufreq_generic_frequency_table_verify,
+       .target_index   = qcom_cpufreq_fw_target_index,
+       .get            = qcom_cpufreq_fw_get,
+       .init           = qcom_cpufreq_fw_cpu_init,
+       .fast_switch    = qcom_cpufreq_fw_fast_switch,
+       .name           = "qcom-cpufreq-fw",
+       .attr           = qcom_cpufreq_fw_attr,
+       .boost_enabled  = true,
+};
+
+static int qcom_read_lut(struct platform_device *pdev,
+                        struct cpufreq_qcom *c)
+{
+       struct device *dev = &pdev->dev;
+       u32 data, src, lval, i, core_count, prev_cc, prev_freq, cur_freq;
+
+       c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
+                               sizeof(*c->table), GFP_KERNEL);
+       if (!c->table)
+               return -ENOMEM;
+
+       for (i = 0; i < LUT_MAX_ENTRIES; i++) {
+               data = readl_relaxed(c->lut_base + i * LUT_ROW_SIZE);
+               src = ((data & GENMASK(31, 30)) >> 30);
+               lval = (data & GENMASK(7, 0));
+               core_count = CORE_COUNT_VAL(data);
+
+               if (!src)
+                       c->table[i].frequency = INIT_RATE / 1000;
+               else
+                       c->table[i].frequency = XO_RATE * lval / 1000;
+
+               cur_freq = c->table[i].frequency;
+
+               dev_dbg(dev, "index=%d freq=%d, core_count %d\n",
+                       i, c->table[i].frequency, core_count);
+
+               if (core_count != c->max_cores)
+                       cur_freq = CPUFREQ_ENTRY_INVALID;
+
+               /*
+                * Two of the same frequencies with the same core counts means
+                * end of table.
+                */
+               if (i > 0 && c->table[i - 1].frequency ==
+                  c->table[i].frequency && prev_cc == core_count) {
+                       struct cpufreq_frequency_table *prev = &c->table[i - 1];
+
+                       if (prev_freq == CPUFREQ_ENTRY_INVALID)
+                               prev->flags = CPUFREQ_BOOST_FREQ;
+                       break;
+               }
+               prev_cc = core_count;
+               prev_freq = cur_freq;
+       }
+
+       c->table[i].frequency = CPUFREQ_TABLE_END;
+
+       return 0;
+}
+
+static int qcom_get_related_cpus(struct device_node *np, struct cpumask *m)
+{
+       struct device_node *cpu_np, *freq_np;
+       int cpu;
+
+       for_each_possible_cpu(cpu) {
+               cpu_np = of_cpu_device_node_get(cpu);
+               if (!cpu_np)
+                       continue;
+               freq_np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
+               if (!freq_np)
+                       continue;
+               if (freq_np == np)
+                       cpumask_set_cpu(cpu, m);
+       }
+
+       return 0;
+}
+
+static int qcom_cpu_resources_init(struct platform_device *pdev,
+                                  struct device_node *np, unsigned int cpu)
+{
+       struct cpufreq_qcom *c;
+       struct resource res;
+       struct device *dev = &pdev->dev;
+       void __iomem *en_base;
+       int index, ret;
+
+       c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
+       if (!c)
+               return -ENOMEM;
+
+       index = of_property_match_string(np, "reg-names", "enable");
+       if (index < 0)
+               return index;
+
+       if (of_address_to_resource(np, index, &res))
+               return -ENOMEM;
+
+       en_base = devm_ioremap(dev, res.start, resource_size(&res));
+       if (!en_base) {
+               dev_err(dev, "Unable to map %s enable-base\n", np->name);
+               return -ENOMEM;
+       }
+
+       /* FW should be in enabled state to proceed */
+       if (!(readl_relaxed(en_base) & 0x1)) {
+               dev_err(dev, "%s firmware not enabled\n", np->name);
+               return -ENODEV;
+       }
+       devm_iounmap(&pdev->dev, en_base);
+
+       index = of_property_match_string(np, "reg-names", "perf");
+       if (index < 0)
+               return index;
+
+       if (of_address_to_resource(np, index, &res))
+               return -ENOMEM;
+
+       c->perf_base = devm_ioremap(dev, res.start, resource_size(&res));
+       if (!c->perf_base) {
+               dev_err(dev, "Unable to map %s perf-base\n", np->name);
+               return -ENOMEM;
+       }
+
+       index = of_property_match_string(np, "reg-names", "lut");
+       if (index < 0)
+               return index;
+
+       if (of_address_to_resource(np, index, &res))
+               return -ENOMEM;
+
+       c->lut_base = devm_ioremap(dev, res.start, resource_size(&res));
+       if (!c->lut_base) {
+               dev_err(dev, "Unable to map %s lut-base\n", np->name);
+               return -ENOMEM;
+       }
+
+       ret = qcom_get_related_cpus(np, &c->related_cpus);
+       if (ret) {
+               dev_err(dev, "%s failed to get related CPUs\n", np->name);
+               return ret;
+       }
+
+       c->max_cores = cpumask_weight(&c->related_cpus);
+       if (!c->max_cores)
+               return -ENOENT;
+
+       ret = qcom_read_lut(pdev, c);
+       if (ret) {
+               dev_err(dev, "%s failed to read LUT\n", np->name);
+               return ret;
+       }
+
+       qcom_freq_domain_map[cpu] = c;
+
+       return 0;
+}
+
+static int qcom_resources_init(struct platform_device *pdev)
+{
+       struct device_node *np, *cpu_np;
+       unsigned int cpu;
+       int ret;
+
+       for_each_possible_cpu(cpu) {
+               cpu_np = of_cpu_device_node_get(cpu);
+               if (!cpu_np) {
+                       dev_err(&pdev->dev, "Failed to get cpu %d device\n",
+                               cpu);
+                       continue;
+               }
+
+               np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
+               if (!np) {
+                       dev_err(&pdev->dev, "Failed to get freq-domain 
device\n");
+                       return -EINVAL;
+               }
+
+               of_node_put(cpu_np);
+
+               ret = qcom_cpu_resources_init(pdev, np, cpu);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
+static int qcom_cpufreq_fw_driver_probe(struct platform_device *pdev)
+{
+       int rc;
+
+       /* Get the bases of cpufreq for domains */
+       rc = qcom_resources_init(pdev);
+       if (rc) {
+               dev_err(&pdev->dev, "CPUFreq resource init failed\n");
+               return rc;
+       }
+
+       rc = cpufreq_register_driver(&cpufreq_qcom_fw_driver);
+       if (rc) {
+               dev_err(&pdev->dev, "CPUFreq FW driver failed to register\n");
+               return rc;
+       }
+
+       dev_info(&pdev->dev, "QCOM CPUFreq FW driver initialized\n");
+
+       return 0;
+}
+
+static const struct of_device_id match_table[] = {
+       { .compatible = "qcom,cpufreq-fw" },
+       {}
+};
+
+static struct platform_driver qcom_cpufreq_fw_driver = {
+       .probe = qcom_cpufreq_fw_driver_probe,
+       .driver = {
+               .name = "qcom-cpufreq-fw",
+               .of_match_table = match_table,
+               .owner = THIS_MODULE,
+       },
+};
+
+static int __init qcom_cpufreq_fw_init(void)
+{
+       return platform_driver_register(&qcom_cpufreq_fw_driver);
+}
+subsys_initcall(qcom_cpufreq_fw_init);
+
+MODULE_DESCRIPTION("QCOM CPU Frequency FW");
+MODULE_LICENSE("GPL v2");
--
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