[PATCH v4 15/15] xen/xenpm: Adapt SET/GET_CPUFREQ_CPPC xen_sysctl_pm_op for amd-cppc driver

[Penny Zheng <Penny.Zheng@xxxxxxx>]

Introduce helper set_amd_cppc_para and get_amd_cppc_para to
SET/GET CPPC-related para for amd-cppc/amd-cppc-epp driver.

Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
---
v1 -> v2:
- Give the variable des_perf an initializer of 0
- Use the strncmp()s directly in the if()
---
v3 -> v4
- refactor comments
- remove double blank lines
- replace amd_cppc_in_use flag with XEN_PROCESSOR_PM_CPPC
---
 xen/arch/x86/acpi/cpufreq/amd-cppc.c | 121 +++++++++++++++++++++++++++
 xen/drivers/acpi/pmstat.c            |  22 ++++-
 xen/include/acpi/cpufreq/cpufreq.h   |   4 +
 3 files changed, 143 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/acpi/cpufreq/amd-cppc.c 
b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
index 3a576fd4be..95d04bf77a 100644
--- a/xen/arch/x86/acpi/cpufreq/amd-cppc.c
+++ b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
@@ -540,6 +540,127 @@ static int cf_check amd_cppc_epp_set_policy(struct 
cpufreq_policy *policy)
     return 0;
 }
 
+int get_amd_cppc_para(unsigned int cpu,
+                      struct xen_cppc_para *cppc_para)
+{
+    const struct amd_cppc_drv_data *data = per_cpu(amd_cppc_drv_data, cpu);
+
+    if ( data == NULL )
+        return -ENODATA;
+
+    cppc_para->features         = 0;
+    cppc_para->lowest           = data->caps.lowest_perf;
+    cppc_para->lowest_nonlinear = data->caps.lowest_nonlinear_perf;
+    cppc_para->nominal          = data->caps.nominal_perf;
+    cppc_para->highest          = data->caps.highest_perf;
+    cppc_para->minimum          = data->req.min_perf;
+    cppc_para->maximum          = data->req.max_perf;
+    cppc_para->desired          = data->req.des_perf;
+    cppc_para->energy_perf      = data->req.epp;
+
+    return 0;
+}
+
+int set_amd_cppc_para(const struct cpufreq_policy *policy,
+                      const struct xen_set_cppc_para *set_cppc)
+{
+    unsigned int cpu = policy->cpu;
+    struct amd_cppc_drv_data *data = per_cpu(amd_cppc_drv_data, cpu);
+    uint8_t max_perf, min_perf, des_perf = 0, epp;
+
+    if ( data == NULL )
+        return -ENOENT;
+
+    /* Validate all parameters - Disallow reserved bits. */
+    if ( set_cppc->minimum > UINT8_MAX || set_cppc->maximum > UINT8_MAX ||
+         set_cppc->desired > UINT8_MAX || set_cppc->energy_perf > UINT8_MAX )
+        return -EINVAL;
+
+    /* Only allow values if params bit is set. */
+    if ( (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED) &&
+          set_cppc->desired) ||
+         (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM) &&
+          set_cppc->minimum) ||
+         (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
+          set_cppc->maximum) ||
+         (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ENERGY_PERF) &&
+          set_cppc->energy_perf) )
+        return -EINVAL;
+
+    /* Activity window not supported in MSR */
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ACT_WINDOW )
+        return -EOPNOTSUPP;
+
+    /* Return if there is nothing to do. */
+    if ( set_cppc->set_params == 0 )
+        return 0;
+
+    epp = per_cpu(epp_init, cpu);
+    /*
+     * Apply presets:
+     * XEN_SYSCTL_CPPC_SET_DESIRED reflects whether desired perf is set, which
+     * is also the flag to distiguish between passive mode and active mode.
+     * When it is set, CPPC in passive mode, only
+     * XEN_SYSCTL_CPPC_SET_PRESET_NONE could be chosen, where min_perf =
+     * lowest_nonlinear_perf to ensures performance in P-state range.
+     * when it is not set, CPPC in active mode, three different profile
+     * XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE/PERFORMANCE/BALANCE are provided,
+     * where min_perf = lowest_perf having T-state range of performance.
+     */
+    switch ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_PRESET_MASK )
+    {
+    case XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE:
+        if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
+            return -EINVAL;
+        min_perf = data->caps.lowest_perf;
+        /* Lower max frequency to nominal */
+        max_perf = data->caps.nominal_perf;
+        epp = CPPC_ENERGY_PERF_MAX_POWERSAVE;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_PERFORMANCE:
+        if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
+            return -EINVAL;
+        /* Increase idle frequency to highest */
+        min_perf = data->caps.highest_perf;
+        max_perf = data->caps.highest_perf;
+        epp = CPPC_ENERGY_PERF_MAX_PERFORMANCE;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_BALANCE:
+        if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
+            return -EINVAL;
+        min_perf = data->caps.lowest_perf;
+        max_perf = data->caps.highest_perf;
+        epp = CPPC_ENERGY_PERF_BALANCE;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_NONE:
+        min_perf = data->caps.lowest_nonlinear_perf;
+        max_perf = data->caps.highest_perf;
+        break;
+
+    default:
+        return -EINVAL;
+    }
+
+    /* Further customize presets if needed */
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM )
+        min_perf = set_cppc->minimum;
+
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM )
+        max_perf = set_cppc->maximum;
+
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ENERGY_PERF )
+        epp = set_cppc->energy_perf;
+
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
+        des_perf = set_cppc->desired;
+
+    amd_cppc_write_request(cpu, min_perf, des_perf, max_perf, epp);
+    return 0;
+}
+
 static const struct cpufreq_driver __initconst_cf_clobber
 amd_cppc_cpufreq_driver =
 {
diff --git a/xen/drivers/acpi/pmstat.c b/xen/drivers/acpi/pmstat.c
index 83cfef398e..876d82036d 100644
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -257,7 +257,18 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
          !strncmp(op->u.get_para.scaling_driver, XEN_HWP_DRIVER_NAME,
                   CPUFREQ_NAME_LEN) )
         ret = get_hwp_para(policy->cpu, &op->u.get_para.u.cppc_para);
-    else
+    else if ( !strncmp(op->u.get_para.scaling_driver,
+                       XEN_AMD_CPPC_DRIVER_NAME,
+                       CPUFREQ_NAME_LEN) ||
+              !strncmp(op->u.get_para.scaling_driver,
+                       XEN_AMD_CPPC_EPP_DRIVER_NAME,
+                       CPUFREQ_NAME_LEN) )
+        ret = get_amd_cppc_para(policy->cpu, &op->u.get_para.u.cppc_para);
+
+    if ( strncmp(op->u.get_para.scaling_driver, XEN_HWP_DRIVER_NAME,
+                 CPUFREQ_NAME_LEN) &&
+         strncmp(op->u.get_para.scaling_driver, XEN_AMD_CPPC_EPP_DRIVER_NAME,
+                 CPUFREQ_NAME_LEN) )
     {
         if ( !(scaling_available_governors =
                xzalloc_array(char, gov_num * CPUFREQ_NAME_LEN)) )
@@ -413,10 +424,13 @@ static int set_cpufreq_cppc(struct xen_sysctl_pm_op *op)
     if ( !policy || !policy->governor )
         return -ENOENT;
 
-    if ( !hwp_active() )
-        return -EOPNOTSUPP;
+    if ( hwp_active() )
+        return set_hwp_para(policy, &op->u.set_cppc);
+
+    if ( xen_processor_pmbits & XEN_PROCESSOR_PM_CPPC )
+        return set_amd_cppc_para(policy, &op->u.set_cppc);
 
-    return set_hwp_para(policy, &op->u.set_cppc);
+    return -EOPNOTSUPP;
 }
 
 int do_pm_op(struct xen_sysctl_pm_op *op)
diff --git a/xen/include/acpi/cpufreq/cpufreq.h 
b/xen/include/acpi/cpufreq/cpufreq.h
index 6f31009e82..4d786ce92b 100644
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -292,5 +292,9 @@ int acpi_cpufreq_register(void);
 
 int amd_cppc_cmdline_parse(const char *s, const char *e);
 int amd_cppc_register_driver(void);
+int get_amd_cppc_para(unsigned int cpu,
+                      struct xen_cppc_para *cppc_para);
+int set_amd_cppc_para(const struct cpufreq_policy *policy,
+                      const struct xen_set_cppc_para *set_cppc);
 
 #endif /* __XEN_CPUFREQ_PM_H__ */
-- 
2.34.1