[PATCH v2 04/21] ACPI: CPPC: add cppc enable register function

[Huang Rui]

From: Jinzhou Su <Jinzhou.Su@xxxxxxx>

Add a new function to enable CPPC feature. This function
will write Continuous Performance Control package
EnableRegister field on the processor.

Signed-off-by: Jinzhou Su <Jinzhou.Su@xxxxxxx>
Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
---
 drivers/acpi/cppc_acpi.c | 48 ++++++++++++++++++++++++++++++++++++++++
 include/acpi/cppc_acpi.h |  5 +++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 2efe2ba97d96..b285960c35e7 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1220,6 +1220,54 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
 
+/**
+ * cppc_set_enable - Set to enable CPPC on the processor by writing the
+ * Continuous Performance Control package EnableRegister feild.
+ * @cpu: CPU for which to enable CPPC register.
+ * @enable: 0 - disable, 1 - enable CPPC feature on the processor.
+ *
+ * Return: 0 for success, -ERRNO or -EIO otherwise.
+ */
+int cppc_set_enable(int cpu, u32 enable)
+{
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
+	struct cpc_register_resource *enable_reg;
+	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
+	struct cppc_pcc_data *pcc_ss_data = NULL;
+	int ret = -1;
+
+	/* check the input value*/
+	if (cpu < 0 || cpu > num_possible_cpus() - 1 || enable > 1)
+		return -ENODEV;
+
+	if (!cpc_desc) {
+		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
+		return -ENODEV;
+	}
+
+	enable_reg = &cpc_desc->cpc_regs[ENABLE];
+
+	if (CPC_IN_PCC(enable_reg)) {
+
+		if (pcc_ss_id < 0)
+			return -EIO;
+
+		ret = cpc_write(cpu, enable_reg, enable);
+		if (ret)
+			return ret;
+
+		pcc_ss_data = pcc_data[pcc_ss_id];
+
+		down_write(&pcc_ss_data->pcc_lock);
+		/* after writing CPC, transfer the ownership of PCC to platfrom */
+		ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
+		up_write(&pcc_ss_data->pcc_lock);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cppc_set_enable);
+
 /**
  * cppc_set_perf - Set a CPU's performance controls.
  * @cpu: CPU for which to set performance controls.
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 9f4985b4d64d..3fdae40a75fc 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -137,6 +137,7 @@ struct cppc_cpudata {
 extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
 extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
 extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
+extern int cppc_set_enable(int cpu, u32 enable);
 extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
 extern bool acpi_cpc_valid(void);
 extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data);
@@ -157,6 +158,10 @@ static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 {
 	return -ENOTSUPP;
 }
+static inline int cppc_set_enable(int cpu, u32 enable)
+{
+	return -ENOTSUPP;
+}
 static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
 {
 	return -ENOTSUPP;
-- 
2.25.1