[PATCH v3 1/4] ACPI: CPPC: Add cppc_get_reg_val and cppc_set_reg_val function

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Rename cppc_get_perf() to cppc_get_reg_val() as a generic function to read
cppc registers, with four changes:

1. Change the error kind to "no such device" when pcc_ss_id < 0, which
means that this cpu cannot get a valid pcc_ss_id.

2. Add a check to verify if the register is a cpc supported one before
using it.

3. Extract the operations if register is in pcc out as
cppc_get_reg_val_in_pcc().

4. Return the result of cpc_read() instead of 0.

Add cppc_set_reg_val_in_pcc() and cppc_set_reg_val() as generic functions
for setting cppc registers value. Unlike other set reg ABIs,
cppc_set_reg_val() checks CPC_SUPPORTED right after getting the register,
because the rest of the operations are meaningless if this register is not
a cpc supported one.

These functions can be used to reduce some existing code duplication.

Signed-off-by: Lifeng Zheng <zhenglifeng1@xxxxxxxxxx>
---
 drivers/acpi/cppc_acpi.c | 111 +++++++++++++++++++++++++++++----------
 1 file changed, 84 insertions(+), 27 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index c1f3568d0c50..bb5333a503a2 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1179,43 +1179,100 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 	return ret_val;
 }
 
-static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
+static int cppc_get_reg_val_in_pcc(int cpu, struct cpc_register_resource *reg, u64 *val)
 {
-	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
+	struct cppc_pcc_data *pcc_ss_data = NULL;
+	int ret;
+
+	if (pcc_ss_id < 0) {
+		pr_debug("Invalid pcc_ss_id\n");
+		return -ENODEV;
+	}
+
+	pcc_ss_data = pcc_data[pcc_ss_id];
+
+	down_write(&pcc_ss_data->pcc_lock);
+
+	if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
+		ret = cpc_read(cpu, reg, val);
+	else
+		ret = -EIO;
+
+	up_write(&pcc_ss_data->pcc_lock);
+
+	return ret;
+}
+
+static int cppc_get_reg_val(int cpu, enum cppc_regs reg_idx, u64 *val)
+{
+	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
 	struct cpc_register_resource *reg;
 
 	if (!cpc_desc) {
-		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
+		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
 		return -ENODEV;
 	}
 
 	reg = &cpc_desc->cpc_regs[reg_idx];
 
-	if (CPC_IN_PCC(reg)) {
-		int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
-		struct cppc_pcc_data *pcc_ss_data = NULL;
-		int ret = 0;
-
-		if (pcc_ss_id < 0)
-			return -EIO;
+	if (!CPC_SUPPORTED(reg)) {
+		pr_debug("CPC register (reg_idx=%d) is not supported\n", reg_idx);
+		return -EOPNOTSUPP;
+	}
 
-		pcc_ss_data = pcc_data[pcc_ss_id];
+	if (CPC_IN_PCC(reg))
+		return cppc_get_reg_val_in_pcc(cpu, reg, val);
 
-		down_write(&pcc_ss_data->pcc_lock);
+	return cpc_read(cpu, reg, val);
+}
 
-		if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
-			cpc_read(cpunum, reg, perf);
-		else
-			ret = -EIO;
+static int cppc_set_reg_val_in_pcc(int cpu, struct cpc_register_resource *reg, u64 val)
+{
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
+	struct cppc_pcc_data *pcc_ss_data = NULL;
+	int ret;
 
-		up_write(&pcc_ss_data->pcc_lock);
+	if (pcc_ss_id < 0) {
+		pr_debug("Invalid pcc_ss_id\n");
+		return -ENODEV;
+	}
 
+	ret = cpc_write(cpu, reg, val);
+	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 platform */
+	ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
+	up_write(&pcc_ss_data->pcc_lock);
+
+	return ret;
+}
+
+static int cppc_set_reg_val(int cpu, enum cppc_regs reg_idx, u64 val)
+{
+	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
+	struct cpc_register_resource *reg;
+
+	if (!cpc_desc) {
+		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
+		return -ENODEV;
 	}
 
-	cpc_read(cpunum, reg, perf);
+	reg = &cpc_desc->cpc_regs[reg_idx];
 
-	return 0;
+	if (!CPC_SUPPORTED(reg)) {
+		pr_debug("CPC register (reg_idx=%d) is not supported\n", reg_idx);
+		return -EOPNOTSUPP;
+	}
+
+	if (CPC_IN_PCC(reg))
+		return cppc_set_reg_val_in_pcc(cpu, reg, val);
+
+	return cpc_write(cpu, reg, val);
 }
 
 /**
@@ -1223,11 +1280,11 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
  * @cpunum: CPU from which to get desired performance.
  * @desired_perf: Return address.
  *
- * Return: 0 for success, -EIO otherwise.
+ * Return: 0 for success, -ERRNO otherwise.
  */
 int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
 {
-	return cppc_get_perf(cpunum, DESIRED_PERF, desired_perf);
+	return cppc_get_reg_val(cpunum, DESIRED_PERF, desired_perf);
 }
 EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
 
@@ -1236,11 +1293,11 @@ EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
  * @cpunum: CPU from which to get nominal performance.
  * @nominal_perf: Return address.
  *
- * Return: 0 for success, -EIO otherwise.
+ * Return: 0 for success, -ERRNO otherwise.
  */
 int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
 {
-	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
+	return cppc_get_reg_val(cpunum, NOMINAL_PERF, nominal_perf);
 }
 
 /**
@@ -1248,11 +1305,11 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
  * @cpunum: CPU from which to get highest performance.
  * @highest_perf: Return address.
  *
- * Return: 0 for success, -EIO otherwise.
+ * Return: 0 for success, -ERRNO otherwise.
  */
 int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
 {
-	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
+	return cppc_get_reg_val(cpunum, HIGHEST_PERF, highest_perf);
 }
 EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
 
@@ -1261,11 +1318,11 @@ EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
  * @cpunum: CPU from which to get epp preference value.
  * @epp_perf: Return address.
  *
- * Return: 0 for success, -EIO otherwise.
+ * Return: 0 for success, -ERRNO otherwise.
  */
 int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
 {
-	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf);
+	return cppc_get_reg_val(cpunum, ENERGY_PERF, epp_perf);
 }
 EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
 
-- 
2.33.0





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