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Subject[PATCHv3 3/6] acpi/cppc: Rework cppc_set_perf() to use cppc_regs index
Date
From: Yazen Ghannam <Yazen.Ghannam@amd.com>

The cppc_set_perf() currently only works for DESIRED_PERF. To make it
generic, pass in the index of the register being accessed.

Also, rename cppc_set_perf() to cppc_set_reg(). This is in preparation
for it to be used for more than just the DESIRED_PERF register.

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 | 36 ++++++++++++++++++++++------------
drivers/cpufreq/cppc_cpufreq.c | 6 +++---
include/acpi/cppc_acpi.h | 2 +-
3 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 53a9dc9960b6..c13dacea4a8b 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -56,7 +56,7 @@ struct cppc_pcc_data {
/*
* Lock to provide controlled access to the PCC channel.
*
- * For performance critical usecases(currently cppc_set_perf)
+ * For performance-critical usecases(currently cppc_set_reg)
* We need to take read_lock and check if channel belongs to OSPM
* before reading or writing to PCC subspace
* We need to take write_lock before transferring the channel
@@ -1341,26 +1341,38 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);

/**
- * cppc_set_perf - Set a CPU's performance controls.
- * @cpu: CPU for which to set performance controls.
+ * 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
+ * @reg_idx: Index of the register being accessed
*
* Return: 0 for success, -ERRNO otherwise.
*/
-int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+int cppc_set_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls,
+ enum cppc_regs reg_idx)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
- struct cpc_register_resource *desired_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cppc_pcc_data *pcc_ss_data = NULL;
+ struct cpc_register_resource *reg;
int ret = 0;
+ u32 value;

if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpu);
return -ENODEV;
}

- desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
+ switch (reg_idx) {
+ case DESIRED_PERF:
+ value = perf_ctrls->desired_perf;
+ break;
+ default:
+ pr_debug("CPC register index #%d not writeable\n", reg_idx);
+ return -EINVAL;
+ }
+
+ reg = &cpc_desc->cpc_regs[reg_idx];

/*
* This is Phase-I where we want to write to CPC registers
@@ -1369,7 +1381,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
* Since read_lock can be acquired by multiple CPUs simultaneously we
* achieve that goal here
*/
- if (CPC_IN_PCC(desired_reg)) {
+ if (CPC_IN_PCC(reg)) {
if (pcc_ss_id < 0) {
pr_debug("Invalid pcc_ss_id\n");
return -ENODEV;
@@ -1396,14 +1408,14 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
* Skip writing MIN/MAX until Linux knows how to come up with
* useful values.
*/
- cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
+ cpc_write(cpu, reg, value);

- if (CPC_IN_PCC(desired_reg))
+ if (CPC_IN_PCC(reg))
up_read(&pcc_ss_data->pcc_lock); /* END Phase-I */
/*
* This is Phase-II where we transfer the ownership of PCC to Platform
*
- * Short Summary: Basically if we think of a group of cppc_set_perf
+ * Short Summary: Basically if we think of a group of cppc_set_reg
* requests that happened in short overlapping interval. The last CPU to
* come out of Phase-I will enter Phase-II and ring the doorbell.
*
@@ -1446,7 +1458,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
* case during a CMD_READ and if there are pending writes it delivers
* the write command before servicing the read command
*/
- if (CPC_IN_PCC(desired_reg)) {
+ if (CPC_IN_PCC(reg)) {
if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
/* Update only if there are pending write commands */
if (pcc_ss_data->pending_pcc_write_cmd)
@@ -1462,7 +1474,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
}
return ret;
}
-EXPORT_SYMBOL_GPL(cppc_set_perf);
+EXPORT_SYMBOL_GPL(cppc_set_reg);

/**
* cppc_get_transition_latency - returns frequency transition latency in ns
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 8d8da763adc5..81e9dff03c92 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -207,7 +207,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
freqs.new = target_freq;

cpufreq_freq_transition_begin(policy, &freqs);
- ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
+ ret = cppc_set_reg(cpu->cpu, &cpu->perf_ctrls, DESIRED_PERF);
cpufreq_freq_transition_end(policy, &freqs, ret != 0);

if (ret)
@@ -231,7 +231,7 @@ static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)

cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

- ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
+ ret = cppc_set_reg(cpu_num, &cpu->perf_ctrls, DESIRED_PERF);
if (ret)
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
cpu->perf_caps.lowest_perf, cpu_num, ret);
@@ -344,7 +344,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
cpu->perf_caps.highest_perf);
cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

- ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
+ ret = cppc_set_reg(cpu_num, &cpu->perf_ctrls, DESIRED_PERF);
if (ret)
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
cpu->perf_caps.highest_perf, cpu_num, ret);
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index a6a9373ab863..f229e903525d 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -135,7 +135,7 @@ 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_reg(int cpu, struct cppc_perf_ctrls *perf_ctrls, enum cppc_regs reg_idx);
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
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