[PATCH v4 06/12] cpufreq: qcom: Update the bandwidth levels on frequency change

[Sibi Sankar]

Add support to parse optional OPP table attached to the cpu node when
the OPP bandwidth values are populated. This allows for scaling of
DDR/L3 bandwidth levels with frequency change.

Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
---

v4:
 * Split fast switch disable into another patch [Lukasz]

 drivers/cpufreq/qcom-cpufreq-hw.c | 85 ++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index fc92a8842e252..4fb489b69bc61 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -6,6 +6,7 @@
 #include <linux/bitfield.h>
 #include <linux/cpufreq.h>
 #include <linux/init.h>
+#include <linux/interconnect.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
@@ -31,6 +32,63 @@
 static unsigned long cpu_hw_rate, xo_rate;
 static struct platform_device *global_pdev;
 
+static int qcom_cpufreq_set_bw(struct cpufreq_policy *policy,
+			       unsigned long freq_khz)
+{
+	unsigned long freq_hz = freq_khz * 1000;
+	struct dev_pm_opp *opp;
+	struct device *dev;
+	int ret;
+
+	dev = get_cpu_device(policy->cpu);
+	if (!dev)
+		return -ENODEV;
+
+	opp = dev_pm_opp_find_freq_exact(dev, freq_hz, true);
+	if (IS_ERR(opp))
+		return PTR_ERR(opp);
+
+	ret = dev_pm_opp_set_bw(dev, opp);
+	dev_pm_opp_put(opp);
+	return ret;
+}
+
+static int qcom_cpufreq_update_opp(struct device *cpu_dev,
+				   unsigned long freq_khz,
+				   unsigned long volt)
+{
+	unsigned long freq_hz = freq_khz * 1000;
+
+	if (dev_pm_opp_update_voltage(cpu_dev, freq_hz, volt))
+		return dev_pm_opp_add(cpu_dev, freq_hz, volt);
+
+	/* Enable the opp after voltage update*/
+	return dev_pm_opp_enable(cpu_dev, freq_hz);
+}
+
+/* Check for optional interconnect paths on CPU0 */
+static int qcom_cpufreq_verify_icc_paths(struct device *dev)
+{
+	struct device *cpu_dev;
+	struct icc_path *path;
+	int ret;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev)
+		return -EPROBE_DEFER;
+
+	path = of_icc_get(cpu_dev, NULL);
+	ret = PTR_ERR_OR_ZERO(path);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(cpu_dev, "Failed to get paths ddr/l3 scaling off\n");
+		return ret;
+	}
+
+	icc_put(path);
+	return ret;
+}
+
 static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
 					unsigned int index)
 {
@@ -39,6 +97,8 @@ static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
 
 	writel_relaxed(index, perf_state_reg);
 
+	qcom_cpufreq_set_bw(policy, freq);
+
 	arch_set_freq_scale(policy->related_cpus, freq,
 			    policy->cpuinfo.max_freq);
 	return 0;
@@ -88,12 +148,27 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
 {
 	u32 data, src, lval, i, core_count, prev_freq = 0, freq;
 	u32 volt;
+	u64 rate;
 	struct cpufreq_frequency_table	*table;
+	struct device_node *opp_table_np, *np;
+	int ret;
 
 	table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
 	if (!table)
 		return -ENOMEM;
 
+	ret = dev_pm_opp_of_add_table(cpu_dev);
+	if (!ret) {
+		/* Disable all opps and cross-validate against LUT */
+		opp_table_np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+		for_each_available_child_of_node(opp_table_np, np) {
+			ret = of_property_read_u64(np, "opp-hz", &rate);
+			if (!ret)
+				dev_pm_opp_disable(cpu_dev, rate);
+		}
+		of_node_put(opp_table_np);
+	}
+
 	for (i = 0; i < LUT_MAX_ENTRIES; i++) {
 		data = readl_relaxed(base + REG_FREQ_LUT +
 				      i * LUT_ROW_SIZE);
@@ -112,7 +187,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
 
 		if (freq != prev_freq && core_count != LUT_TURBO_IND) {
 			table[i].frequency = freq;
-			dev_pm_opp_add(cpu_dev, freq * 1000, volt);
+			qcom_cpufreq_update_opp(cpu_dev, freq, volt);
 			dev_dbg(cpu_dev, "index=%d freq=%d, core_count %d\n", i,
 				freq, core_count);
 		} else if (core_count == LUT_TURBO_IND) {
@@ -133,7 +208,8 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
 			if (prev->frequency == CPUFREQ_ENTRY_INVALID) {
 				prev->frequency = prev_freq;
 				prev->flags = CPUFREQ_BOOST_FREQ;
-				dev_pm_opp_add(cpu_dev,	prev_freq * 1000, volt);
+				qcom_cpufreq_update_opp(cpu_dev, prev_freq,
+							volt);
 			}
 
 			break;
@@ -254,6 +330,7 @@ static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
 	void __iomem *base = policy->driver_data - REG_PERF_STATE;
 
 	dev_pm_opp_remove_all_dynamic(cpu_dev);
+	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 	kfree(policy->freq_table);
 	devm_iounmap(&global_pdev->dev, base);
 
@@ -301,6 +378,10 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
 
 	global_pdev = pdev;
 
+	ret = qcom_cpufreq_verify_icc_paths(&pdev->dev);
+	if (ret)
+		return ret;
+
 	ret = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
 	if (ret)
 		dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n");
-- 
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