[PATCH V2 13/15] cpufreq: mediatek: Link CCI device to CPU

[Rex-BC Chen]

From: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>

In some MediaTek SoCs, like MT8183, CPU and CCI share the same power
supplies. Cpufreq needs to check if CCI devfreq exists and wait until
CCI devfreq ready before scaling frequency.

- Add is_ccifreq_ready() to link CCI device to CPI, and CPU will start
  DVFS when CCI is ready.
- Add platform data for MT8183.

Signed-off-by: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>
---
 drivers/cpufreq/mediatek-cpufreq.c | 69 +++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index b08ab7c14818..cebe5af2ef5d 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -22,6 +22,7 @@ struct mtk_cpufreq_platform_data {
 	int proc_max_volt;
 	int sram_min_volt;
 	int sram_max_volt;
+	bool is_ccifreq_support;
 };
 
 /*
@@ -38,6 +39,7 @@ struct mtk_cpufreq_platform_data {
 struct mtk_cpu_dvfs_info {
 	struct cpumask cpus;
 	struct device *cpu_dev;
+	struct device *cci_dev;
 	struct regulator *proc_reg;
 	struct regulator *sram_reg;
 	struct clk *cpu_clk;
@@ -52,6 +54,7 @@ struct mtk_cpu_dvfs_info {
 	int opp_cpu;
 	unsigned long opp_freq;
 	const struct mtk_cpufreq_platform_data *soc_data;
+	bool is_ccifreq_bounded;
 };
 
 static struct platform_device *cpufreq_pdev;
@@ -171,6 +174,29 @@ static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
 	return ret;
 }
 
+static bool is_ccifreq_ready(struct mtk_cpu_dvfs_info *info)
+{
+	struct device_link *sup_link;
+
+	if (info->is_ccifreq_bounded)
+		return true;
+
+	sup_link = device_link_add(info->cpu_dev, info->cci_dev,
+				   DL_FLAG_AUTOREMOVE_CONSUMER);
+	if (!sup_link) {
+		dev_err(info->cpu_dev, "cpu%d: sup_link is NULL\n",
+			info->opp_cpu);
+		return false;
+	}
+
+	if (sup_link->supplier->links.status != DL_DEV_DRIVER_BOUND)
+		return false;
+
+	info->is_ccifreq_bounded = true;
+
+	return true;
+}
+
 static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
 				  unsigned int index)
 {
@@ -183,6 +209,9 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
 	long freq_hz, old_freq_hz;
 	int vproc, old_vproc, inter_vproc, target_vproc, ret;
 
+	if (info->soc_data->is_ccifreq_support && !is_ccifreq_ready(info))
+		return 0;
+
 	inter_vproc = info->intermediate_voltage;
 
 	freq_hz = freq_table[index].frequency * 1000;
@@ -329,6 +358,23 @@ static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
 	return notifier_from_errno(ret);
 }
 
+static struct device *of_get_cci(struct device *cpu_dev)
+{
+	struct device_node *np;
+	struct platform_device *pdev;
+
+	np = of_parse_phandle(cpu_dev->of_node, "cci", 0);
+	if (IS_ERR(np))
+		return NULL;
+
+	pdev = of_find_device_by_node(np);
+	of_node_put(np);
+	if (IS_ERR(pdev))
+		return NULL;
+
+	return &pdev->dev;
+}
+
 static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 {
 	struct device *cpu_dev;
@@ -343,6 +389,17 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 	}
 	info->cpu_dev = cpu_dev;
 
+	info->is_ccifreq_bounded = false;
+	if (info->soc_data->is_ccifreq_support) {
+		info->cci_dev = of_get_cci(info->cpu_dev);
+		if (IS_ERR_OR_NULL(info->cci_dev)) {
+			ret = PTR_ERR(info->cci_dev);
+			dev_err(cpu_dev, "cpu%d: failed to get cci device\n",
+				cpu);
+			return -ENODEV;
+		}
+	}
+
 	info->cpu_clk = clk_get(cpu_dev, "cpu");
 	if (IS_ERR(info->cpu_clk)) {
 		ret = PTR_ERR(info->cpu_clk);
@@ -620,6 +677,16 @@ static const struct mtk_cpufreq_platform_data mtk_platform_data = {
 	.proc_max_volt = 1150000,
 	.sram_min_volt = 0,
 	.sram_max_volt = 1150000,
+	.is_ccifreq_support = false,
+};
+
+static const struct mtk_cpufreq_platform_data mt8183_platform_data = {
+	.min_volt_shift = 100000,
+	.max_volt_shift = 200000,
+	.proc_max_volt = 1150000,
+	.sram_min_volt = 0,
+	.sram_max_volt = 1150000,
+	.is_ccifreq_support = true,
 };
 
 /* List of machines supported by this driver */
@@ -632,7 +699,7 @@ static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
 	{ .compatible = "mediatek,mt817x", .data = &mtk_platform_data },
 	{ .compatible = "mediatek,mt8173", .data = &mtk_platform_data },
 	{ .compatible = "mediatek,mt8176", .data = &mtk_platform_data },
-	{ .compatible = "mediatek,mt8183", .data = &mtk_platform_data },
+	{ .compatible = "mediatek,mt8183", .data = &mt8183_platform_data },
 	{ .compatible = "mediatek,mt8365", .data = &mtk_platform_data },
 	{ .compatible = "mediatek,mt8516", .data = &mtk_platform_data },
 	{ }
-- 
2.18.0