[PATCHv3 5/6] acpi/cppc: Add support for CPPC Enable register

["Natarajan, Janakarajan" <Janakarajan.Natarajan@amd.com>]

From: Yazen Ghannam <Yazen.Ghannam@amd.com>

To enable CPPC on a processor, the OS should write a value "1" to the
CPPC Enable register. Add support for this register.

Since we have a new variable "enable" in cppc_perf_ctrls, rename it
and the associated functions i.e. cppc_perf_ctrls->cppc_ctrls and
cppc_get_perf()->cppc_get_ctrls().

Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
[ carved out into a patch, cleaned up, productized ]
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
---
 drivers/acpi/cppc_acpi.c | 44 ++++++++++++++++++++++++----------------
 include/acpi/cppc_acpi.h | 10 +++++----
 2 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index b24e54263efb..3199433e3f71 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1343,12 +1343,12 @@ EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
 /**
  * cppc_set_reg - Set the CPUs control register.
  * @cpu: CPU for which to set the register.
- * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
+ * @ctrls: ptr to cppc_ctrls. See cppc_acpi.h
  * @reg_idx: Index of the register being accessed
  *
  * Return: 0 for success, -ERRNO otherwise.
  */
-int cppc_set_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls,
+int cppc_set_reg(int cpu, struct cppc_ctrls *ctrls,
 		 enum cppc_regs reg_idx)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
@@ -1364,20 +1364,23 @@ int cppc_set_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls,
 	}
 
 	switch (reg_idx) {
+	case ENABLE:
+		value = ctrls->enable;
+		break;
 	case DESIRED_PERF:
-		value = perf_ctrls->desired_perf;
+		value = ctrls->desired_perf;
 		break;
 	case MAX_PERF:
-		value = perf_ctrls->max_perf;
+		value = ctrls->max_perf;
 		break;
 	case MIN_PERF:
-		value = perf_ctrls->min_perf;
+		value = ctrls->min_perf;
 		break;
 	case ENERGY_PERF:
-		value = perf_ctrls->energy_perf;
+		value = ctrls->energy_perf;
 		break;
 	case AUTO_SEL_ENABLE:
-		value = perf_ctrls->auto_sel_enable;
+		value = ctrls->auto_sel_enable;
 		break;
 	default:
 		pr_debug("CPC register index #%d not writeable\n", reg_idx);
@@ -1485,13 +1488,14 @@ int cppc_set_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls,
 }
 EXPORT_SYMBOL_GPL(cppc_set_reg);
 
-int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+int cppc_get_ctrls(int cpu, struct cppc_ctrls *ctrls)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
 	struct cpc_register_resource *desired_reg, *max_reg, *min_reg;
 	struct cpc_register_resource *energy_reg, *auto_sel_enable_reg;
+	struct cpc_register_resource *enable_reg;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
-	u64 desired, max, min, energy, auto_sel_enable;
+	u64 desired, max, min, energy, auto_sel_enable, enable;
 	struct cppc_pcc_data *pcc_ss_data = NULL;
 	int ret = 0, regs_in_pcc = 0;
 
@@ -1500,6 +1504,7 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 		return -ENODEV;
 	}
 
+	enable_reg = &cpc_desc->cpc_regs[ENABLE];
 	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
 	max_reg = &cpc_desc->cpc_regs[MAX_PERF];
 	min_reg = &cpc_desc->cpc_regs[MIN_PERF];
@@ -1509,7 +1514,7 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 	/* Check if any of the perf registers are in PCC */
 	if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(max_reg) ||
 	    CPC_IN_PCC(min_reg) || CPC_IN_PCC(energy_reg) ||
-	    CPC_IN_PCC(auto_sel_enable_reg)) {
+	    CPC_IN_PCC(auto_sel_enable_reg) || CPC_IN_PCC(enable_reg)) {
 		pcc_ss_data = pcc_data[pcc_ss_id];
 		down_write(&pcc_ss_data->pcc_lock);
 		regs_in_pcc = 1;
@@ -1521,10 +1526,14 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 		}
 	}
 
-	/* desired_perf is the only mandatory value in perf_ctrls */
+	/* desired_perf is the only mandatory value in ctrls */
 	if (cpc_read(cpu, desired_reg, &desired))
 		ret = -EFAULT;
 
+	if (CPC_SUP_BUFFER_ONLY(enable_reg) &&
+	    cpc_read(cpu, enable_reg, &enable))
+		ret = -EFAULT;
+
 	if (CPC_SUP_BUFFER_ONLY(max_reg) && cpc_read(cpu, max_reg, &max))
 		ret = -EFAULT;
 
@@ -1540,11 +1549,12 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 		ret = -EFAULT;
 
 	if (!ret) {
-		perf_ctrls->desired_perf = desired;
-		perf_ctrls->max_perf = max;
-		perf_ctrls->min_perf = min;
-		perf_ctrls->energy_perf = energy;
-		perf_ctrls->auto_sel_enable = auto_sel_enable;
+		ctrls->enable = enable;
+		ctrls->desired_perf = desired;
+		ctrls->max_perf = max;
+		ctrls->min_perf = min;
+		ctrls->energy_perf = energy;
+		ctrls->auto_sel_enable = auto_sel_enable;
 	}
 
 out_err:
@@ -1552,7 +1562,7 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 		up_write(&pcc_ss_data->pcc_lock);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(cppc_get_perf);
+EXPORT_SYMBOL_GPL(cppc_get_ctrls);
 
 /**
  * cppc_get_transition_latency - returns frequency transition latency in ns
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 80720b246c51..e6cd2a487874 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -109,7 +109,8 @@ struct cppc_perf_caps {
 	u32 nominal_freq;
 };
 
-struct cppc_perf_ctrls {
+struct cppc_ctrls {
+	bool enable;
 	u32 max_perf;
 	u32 min_perf;
 	u32 desired_perf;
@@ -128,17 +129,18 @@ struct cppc_perf_fb_ctrs {
 struct cppc_cpudata {
 	int cpu;
 	struct cppc_perf_caps perf_caps;
-	struct cppc_perf_ctrls perf_ctrls;
+	struct cppc_ctrls ctrls;
 	struct cppc_perf_fb_ctrs perf_fb_ctrs;
 	struct cpufreq_policy *cur_policy;
 	unsigned int shared_type;
 	cpumask_var_t shared_cpu_map;
 };
 
+extern int cppc_get_enable(int cpu);
 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_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls, enum cppc_regs reg_idx);
-extern int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
+extern int cppc_set_reg(int cpu, struct cppc_ctrls *ctrls, enum cppc_regs reg_idx);
+extern int cppc_get_ctrls(int cpu, struct cppc_ctrls *ctrls);
 extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
 extern int acpi_get_psd_map(struct cppc_cpudata **);
 extern unsigned int cppc_get_transition_latency(int cpu);
-- 
2.17.1