[PATCH v8 8/8] xen/cpufreq: 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.

In get_cpufreq_cppc()/set_cpufreq_cppc(), we include
"processor_pminfo[cpuid]->init & XEN_CPPC_INIT" condition check to deal with
cpufreq driver in amd-cppc.
We also borrow governor field to indicate policy info for CPPC active mode.

Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
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
---
v4 -> v5:
- add new field "policy" in "struct xen_cppc_para"
- add new performamce policy XEN_CPUFREQ_POLICY_BALANCE
- drop string comparisons with "processor_pminfo[cpuid]->init & XEN_CPPC_INIT"
and "cpufreq.setpolicy == NULL"
- Blank line ahead of the main "return" of a function
- refactor comments, commit message and title
---
v5 -> v6:
- remove duplicated manifest constants, and just move it to public header
- use "else if" to avoid confusion that it looks as if both paths could be taken
- add check for legitimate perf values
- use "unknown" instead of "none"
- introduce "CPUFREQ_POLICY_END" for array overrun check in user space tools
---
v6 -> v7:
- use ARRAY_SIZE() instead
- ->policy print is avoided in passive mode and print "unknown" in invalid
cases
- let cpufreq_is_governorless() being the variable's initializer
- refactor with the conditional operator to increase readability
- move duplicated defination ahead and use local variable
- avoid using "else-condition" to bring "dead code" in Misra's nomeclature
- move the comment out of public header and into the respective internal
struct field
- wrap set{,get}_amd_cppc_para() with CONFIG_PM_OP
- add symmetry scenario for maximum check
---
v7 -> v8:
- change function name to amd_cppc_get{,set}_para()
- fix too deep indentation, and indent according to pending open parentheses
- missing -EINVAL when no flag is set at all
- use new helper amd_cppc_prepare_policy() to reduce redundancy
- borrow governor field to indicate policy info
---
 tools/misc/xenpm.c                   |  13 ++-
 xen/arch/x86/acpi/cpufreq/amd-cppc.c | 164 +++++++++++++++++++++++++++
 xen/drivers/acpi/pm-op.c             |  28 +++--
 xen/include/acpi/cpufreq/cpufreq.h   |   4 +
 4 files changed, 196 insertions(+), 13 deletions(-)

diff --git a/tools/misc/xenpm.c b/tools/misc/xenpm.c
index 893a0afe11..bda9c62aa0 100644
--- a/tools/misc/xenpm.c
+++ b/tools/misc/xenpm.c
@@ -832,11 +832,14 @@ static void print_cppc_para(unsigned int cpuid,
 /* print out parameters about cpu frequency */
 static void print_cpufreq_para(int cpuid, struct xc_get_cpufreq_para 
*p_cpufreq)
 {
-    bool is_governor_less = false;
+    bool is_governor_less = false, is_cppc_active = false;
     int i;
 
-    if ( !strcmp(p_cpufreq->scaling_driver, XEN_HWP_DRIVER_NAME) ||
-         !strcmp(p_cpufreq->scaling_driver, XEN_AMD_CPPC_EPP_DRIVER_NAME) )
+    if ( !strcmp(p_cpufreq->scaling_driver, XEN_AMD_CPPC_EPP_DRIVER_NAME) )
+        is_cppc_active = true;
+
+    if ( is_cppc_active ||
+         !strcmp(p_cpufreq->scaling_driver, XEN_HWP_DRIVER_NAME) )
         is_governor_less = true;
 
     printf("cpu id               : %d\n", cpuid);
@@ -899,6 +902,10 @@ static void print_cpufreq_para(int cpuid, struct 
xc_get_cpufreq_para *p_cpufreq)
                p_cpufreq->u.s.scaling_cur_freq);
     }
 
+    /* Translate governor info to policy info in CPPC active mode */
+    if ( is_cppc_active )
+        printf("policy               : %s\n", p_cpufreq->u.s.scaling_governor);
+
     printf("turbo mode           : %s\n",
            p_cpufreq->turbo_enabled ? "enabled" : "disabled or n/a");
     printf("\n");
diff --git a/xen/arch/x86/acpi/cpufreq/amd-cppc.c 
b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
index bb7f4e4a9e..eca455240f 100644
--- a/xen/arch/x86/acpi/cpufreq/amd-cppc.c
+++ b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
@@ -566,6 +566,170 @@ static int cf_check amd_cppc_epp_set_policy(struct 
cpufreq_policy *policy)
     return 0;
 }
 
+#ifdef CONFIG_PM_OP
+int amd_cppc_get_para(const struct cpufreq_policy *policy,
+                      struct xen_get_cppc_para *cppc_para)
+{
+    const struct amd_cppc_drv_data *data = per_cpu(amd_cppc_drv_data,
+                                                   policy->cpu);
+
+    if ( data == NULL )
+        return -ENODATA;
+
+    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 amd_cppc_set_para(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, epp;
+    bool active_mode = cpufreq_is_governorless(cpu);
+
+    if ( data == NULL )
+        return -ENOENT;
+
+    /* 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;
+
+    /* Return if there is nothing to do. */
+    if ( set_cppc->set_params == 0 )
+        return 0;
+
+    /*
+     * Validate all parameters
+     * Maximum performance may be set to any performance value in the range
+     * [Nonlinear Lowest Performance, Highest Performance], inclusive but must
+     * be set to a value that is larger than or equal to minimum Performance.
+     */
+    if ( (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
+         (set_cppc->maximum > data->caps.highest_perf ||
+          (set_cppc->maximum <
+           (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM
+            ? set_cppc->minimum
+            : data->req.min_perf))) )
+        return -EINVAL;
+    /*
+     * Minimum performance may be set to any performance value in the range
+     * [Nonlinear Lowest Performance, Highest Performance], inclusive but must
+     * be set to a value that is less than or equal to Maximum Performance.
+     */
+    if ( (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM) &&
+         (set_cppc->minimum < data->caps.lowest_nonlinear_perf ||
+          (set_cppc->minimum >
+           (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM
+            ? set_cppc->maximum
+            : data->req.max_perf))) )
+        return -EINVAL;
+    /*
+     * Desired performance may be set to any performance value in the range
+     * [Minimum Performance, Maximum Performance], inclusive.
+     */
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
+    {
+        if ( active_mode )
+            return -EOPNOTSUPP;
+
+        if ( (set_cppc->desired >
+              (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM
+               ? set_cppc->maximum
+               : data->req.max_perf)) ||
+             (set_cppc->desired <
+              (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM
+               ? set_cppc->minimum
+               : data->req.min_perf)) )
+            return -EINVAL;
+    }
+    /*
+     * Energy Performance Preference may be set with a range of values
+     * from 0 to 0xFF
+     */
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ENERGY_PERF )
+    {
+        if ( !active_mode )
+            return -EOPNOTSUPP;
+
+        if ( set_cppc->energy_perf > UINT8_MAX )
+            return -EINVAL;
+    }
+
+    /* Activity window not supported in MSR */
+    if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ACT_WINDOW )
+        return -EOPNOTSUPP;
+
+    des_perf = data->req.des_perf;
+    /*
+     * Apply presets:
+     * XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE/PERFORMANCE/ONDEMAND are
+     * only available when CPPC in active mode
+     */
+    switch ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_PRESET_MASK )
+    {
+    case XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE:
+        if ( !active_mode )
+            return -EINVAL;
+        policy->policy = CPUFREQ_POLICY_POWERSAVE;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_PERFORMANCE:
+        if ( !active_mode )
+            return -EINVAL;
+        policy->policy = CPUFREQ_POLICY_PERFORMANCE;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_ONDEMAND:
+        if ( !active_mode )
+            return -EINVAL;
+        policy->policy = CPUFREQ_POLICY_ONDEMAND;
+        break;
+
+    case XEN_SYSCTL_CPPC_SET_PRESET_NONE:
+        if ( active_mode )
+            policy->policy = CPUFREQ_POLICY_UNKNOWN;
+        break;
+
+    default:
+        return -EINVAL;
+    }
+    amd_cppc_prepare_policy(policy, &max_perf, &min_perf, &epp);
+
+    /* 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;
+}
+#endif /* CONFIG_PM_OP */
+
 static const struct cpufreq_driver __initconst_cf_clobber
 amd_cppc_cpufreq_driver =
 {
diff --git a/xen/drivers/acpi/pm-op.c b/xen/drivers/acpi/pm-op.c
index 371deaf678..bcb3b9b2a7 100644
--- a/xen/drivers/acpi/pm-op.c
+++ b/xen/drivers/acpi/pm-op.c
@@ -84,6 +84,8 @@ static int get_cpufreq_cppc(unsigned int cpu,
 
     if ( hwp_active() )
         ret = get_hwp_para(cpu, cppc_para);
+    else if ( processor_pminfo[cpu]->init & XEN_CPPC_INIT )
+        ret = amd_cppc_get_para(per_cpu(cpufreq_cpu_policy, cpu), cppc_para);
 
     return ret;
 }
@@ -154,6 +156,17 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
     else
         strlcpy(op->u.get_para.scaling_driver, "Unknown", CPUFREQ_NAME_LEN);
 
+    /*
+     * In CPPC active mode, we are borrowing governor field to indicate
+     * policy info.
+     */
+    if ( policy->governor->name[0] )
+        strlcpy(op->u.get_para.u.s.scaling_governor,
+                policy->governor->name, CPUFREQ_NAME_LEN);
+    else
+        strlcpy(op->u.get_para.u.s.scaling_governor, "Unknown",
+                CPUFREQ_NAME_LEN);
+
     if ( !cpufreq_is_governorless(op->cpuid) )
     {
         if ( !(scaling_available_governors =
@@ -178,13 +191,6 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
         op->u.get_para.u.s.scaling_max_freq = policy->max;
         op->u.get_para.u.s.scaling_min_freq = policy->min;
 
-        if ( policy->governor->name[0] )
-            strlcpy(op->u.get_para.u.s.scaling_governor,
-                    policy->governor->name, CPUFREQ_NAME_LEN);
-        else
-            strlcpy(op->u.get_para.u.s.scaling_governor, "Unknown",
-                    CPUFREQ_NAME_LEN);
-
         /* governor specific para */
         if ( !strncasecmp(op->u.get_para.u.s.scaling_governor,
                           "userspace", CPUFREQ_NAME_LEN) )
@@ -321,10 +327,12 @@ 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 ( processor_pminfo[op->cpuid]->init & XEN_CPPC_INIT )
+        return amd_cppc_set_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 7caeae26cf..e8b4e955a2 100644
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -293,6 +293,10 @@ int acpi_cpufreq_register(void);
 
 int amd_cppc_cmdline_parse(const char *s, const char *e);
 int amd_cppc_register_driver(void);
+int amd_cppc_get_para(const struct cpufreq_policy *policy,
+                      struct xen_get_cppc_para *cppc_para);
+int amd_cppc_set_para(struct cpufreq_policy *policy,
+                      const struct xen_set_cppc_para *set_cppc);
 
 /*
  * Governor-less cpufreq driver indicates the driver doesn't rely on Xen
-- 
2.34.1