On 05-12-18, 09:07, Taniya Das wrote:
> Hello Stephen, Viresh
> 
> Thanks for the code and suggestions.
> 
> Having a NR_DOMAINS '2' makes the driver not scalable for re-use.

Sure, I didn't like it either and that wasn't really what I was suggesting in
the first place. I didn't wanted to write the code myself and pass it on, but I
have it now anyway :)

It may have a bug or two in there, but compiles just fine and is rebased over
your patch Taniya.

-- 
viresh

-------------------------8<-------------------------

 drivers/cpufreq/qcom-cpufreq-hw.c | 156 +++++++++++-------------------
 1 file changed, 57 insertions(+), 99 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c 
b/drivers/cpufreq/qcom-cpufreq-hw.c
index 8dc6b73c2f22..bcf9bb37298a 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -23,13 +23,8 @@
 #define REG_LUT_TABLE                  0x110
 #define REG_PERF_STATE                 0x920
 
-struct cpufreq_qcom {
-       struct cpufreq_frequency_table *table;
-       void __iomem *perf_state_reg;
-       cpumask_t related_cpus;
-};
-
-static struct cpufreq_qcom *qcom_freq_domain_map[NR_CPUS];
+static unsigned long cpu_hw_rate, xo_rate;
+static struct platform_device *global_pdev;
 
 static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
                                        unsigned int index)
@@ -74,53 +69,17 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct 
cpufreq_policy *policy,
        return policy->freq_table[index].frequency;
 }
 
-static int qcom_cpufreq_hw_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->perf_state_reg;
-
-       return 0;
-}
-
-static struct freq_attr *qcom_cpufreq_hw_attr[] = {
-       &cpufreq_freq_attr_scaling_available_freqs,
-       &cpufreq_freq_attr_scaling_boost_freqs,
-       NULL
-};
-
-static struct cpufreq_driver cpufreq_qcom_hw_driver = {
-       .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
-                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
-       .verify         = cpufreq_generic_frequency_table_verify,
-       .target_index   = qcom_cpufreq_hw_target_index,
-       .get            = qcom_cpufreq_hw_get,
-       .init           = qcom_cpufreq_hw_cpu_init,
-       .fast_switch    = qcom_cpufreq_hw_fast_switch,
-       .name           = "qcom-cpufreq-hw",
-       .attr           = qcom_cpufreq_hw_attr,
-};
-
-static int qcom_cpufreq_hw_read_lut(struct device *dev, struct cpufreq_qcom *c,
-                                   void __iomem *base, unsigned long xo_rate,
-                                   unsigned long cpu_hw_rate)
+static int qcom_cpufreq_hw_read_lut(struct device *dev,
+                                   struct cpufreq_policy *policy,
+                                   void __iomem *base)
 {
        u32 data, src, lval, i, core_count, prev_cc = 0, prev_freq = 0, freq;
-       unsigned int max_cores = cpumask_weight(&c->related_cpus);
+       unsigned int max_cores = cpumask_weight(policy->cpus);
+       struct cpufreq_frequency_table  *table;
 
-       c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
-                               sizeof(*c->table), GFP_KERNEL);
-       if (!c->table)
+       table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
+                               sizeof(*table), GFP_KERNEL);
+       if (!table)
                return -ENOMEM;
 
        for (i = 0; i < LUT_MAX_ENTRIES; i++) {
@@ -136,9 +95,9 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev, 
struct cpufreq_qcom *c,
 
                /* Ignore boosts in the middle of the table */
                if (core_count != max_cores) {
-                       c->table[i].frequency = CPUFREQ_ENTRY_INVALID;
+                       table[i].frequency = CPUFREQ_ENTRY_INVALID;
                } else {
-                       c->table[i].frequency = freq;
+                       table[i].frequency = freq;
                        dev_dbg(dev, "index=%d freq=%d, core_count %d\n", i,
                                freq, core_count);
                }
@@ -148,7 +107,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev, 
struct cpufreq_qcom *c,
                 * end of table
                 */
                if (i > 0 && prev_freq == freq && prev_cc == core_count) {
-                       struct cpufreq_frequency_table *prev = &c->table[i - 1];
+                       struct cpufreq_frequency_table *prev = &table[i - 1];
 
                        /*
                         * Only treat the last frequency that might be a boost
@@ -166,7 +125,8 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev, 
struct cpufreq_qcom *c,
                prev_freq = freq;
        }
 
-       c->table[i].frequency = CPUFREQ_TABLE_END;
+       table[i].frequency = CPUFREQ_TABLE_END;
+       policy->freq_table = table;
 
        return 0;
 }
@@ -194,22 +154,29 @@ static void qcom_get_related_cpus(int index, struct 
cpumask *m)
        }
 }
 
-static int qcom_cpu_resources_init(struct platform_device *pdev,
-                                  unsigned int cpu, int index,
-                                  unsigned long xo_rate,
-                                  unsigned long cpu_hw_rate)
+static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
 {
-       struct cpufreq_qcom *c;
+       struct device *dev = &global_pdev->dev;
+       struct of_phandle_args args;
+       struct device_node *cpu_np;
        struct resource *res;
-       struct device *dev = &pdev->dev;
        void __iomem *base;
-       int ret, cpu_r;
+       int ret, index;
 
-       c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
-       if (!c)
-               return -ENOMEM;
+       cpu_np = of_cpu_device_node_get(policy->cpu);
+       if (!cpu_np)
+               return -EINVAL;
+
+       ret = of_parse_phandle_with_args(cpu_np, "qcom,freq-domain",
+                       "#freq-domain-cells", 0, &args);
+       of_node_put(cpu_np);
 
-       res = platform_get_resource(pdev, IORESOURCE_MEM, index);
+       if (ret)
+               return ret;
+
+       index = args.args[0];
+
+       res = platform_get_resource(global_pdev, IORESOURCE_MEM, index);
        base = devm_ioremap_resource(dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);
@@ -220,33 +187,46 @@ static int qcom_cpu_resources_init(struct platform_device 
*pdev,
                return -ENODEV;
        }
 
-       qcom_get_related_cpus(index, &c->related_cpus);
-       if (!cpumask_weight(&c->related_cpus)) {
+       qcom_get_related_cpus(index, policy->cpus);
+       if (!cpumask_weight(policy->cpus)) {
                dev_err(dev, "Domain-%d failed to get related CPUs\n", index);
                return -ENOENT;
        }
 
-       c->perf_state_reg = base + REG_PERF_STATE;
+       policy->driver_data = base + REG_PERF_STATE;
 
-       ret = qcom_cpufreq_hw_read_lut(dev, c, base, xo_rate, cpu_hw_rate);
+       ret = qcom_cpufreq_hw_read_lut(dev, policy, base);
        if (ret) {
                dev_err(dev, "Domain-%d failed to read LUT\n", index);
                return ret;
        }
 
-       for_each_cpu(cpu_r, &c->related_cpus)
-               qcom_freq_domain_map[cpu_r] = c;
+       policy->fast_switch_possible = true;
 
        return 0;
 }
 
+static struct freq_attr *qcom_cpufreq_hw_attr[] = {
+       &cpufreq_freq_attr_scaling_available_freqs,
+       &cpufreq_freq_attr_scaling_boost_freqs,
+       NULL
+};
+
+static struct cpufreq_driver cpufreq_qcom_hw_driver = {
+       .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
+       .verify         = cpufreq_generic_frequency_table_verify,
+       .target_index   = qcom_cpufreq_hw_target_index,
+       .get            = qcom_cpufreq_hw_get,
+       .init           = qcom_cpufreq_hw_cpu_init,
+       .fast_switch    = qcom_cpufreq_hw_fast_switch,
+       .name           = "qcom-cpufreq-hw",
+       .attr           = qcom_cpufreq_hw_attr,
+};
+
 static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
 {
-       struct device_node *cpu_np;
-       struct of_phandle_args args;
        struct clk *clk;
-       unsigned int cpu;
-       unsigned long xo_rate, cpu_hw_rate;
        int ret;
 
        clk = clk_get(&pdev->dev, "xo");
@@ -263,29 +243,7 @@ static int qcom_cpufreq_hw_driver_probe(struct 
platform_device *pdev)
        cpu_hw_rate = clk_get_rate(clk) / CLK_HW_DIV;
        clk_put(clk);
 
-       for_each_possible_cpu(cpu) {
-               cpu_np = of_cpu_device_node_get(cpu);
-               if (!cpu_np) {
-                       dev_dbg(&pdev->dev, "Failed to get cpu %d device\n",
-                               cpu);
-                       continue;
-               }
-
-               ret = of_parse_phandle_with_args(cpu_np, "qcom,freq-domain",
-                                                "#freq-domain-cells", 0,
-                                                 &args);
-               of_node_put(cpu_np);
-               if (ret)
-                       return ret;
-
-               if (qcom_freq_domain_map[cpu])
-                       continue;
-
-               ret = qcom_cpu_resources_init(pdev, cpu, args.args[0],
-                                             xo_rate, cpu_hw_rate);
-               if (ret)
-                       return ret;
-       }
+       global_pdev = pdev;
 
        ret = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
        if (ret) {

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