From a6adb8aa62960abf0722099bc527637bd068099e Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir.fraser@citrix.com>
Date: Fri, 9 Apr 2010 08:53:19 +0100
Subject: [PATCH] Add Xen support for AMD Turbo/Boost

Add support for disabling AMD's Boost feature.  Boost is similar to
Intel's Turbo and uses the same high level interface.  The low
level implementation is different and encapsulated in the powernow
driver for cpufreq.

Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com>
---
 xen/arch/x86/acpi/cpufreq/powernow.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/acpi/cpufreq/powernow.c b/xen/arch/x86/acpi/cpufreq/powernow.c
index bcbcc25d35..6b64bd46ba 100644
--- a/xen/arch/x86/acpi/cpufreq/powernow.c
+++ b/xen/arch/x86/acpi/cpufreq/powernow.c
@@ -39,6 +39,7 @@
 #include <acpi/cpufreq/cpufreq.h>
 
 #define CPUID_FREQ_VOLT_CAPABILITIES    0x80000007
+#define CPB_CAPABLE             0x00000200
 #define USE_HW_PSTATE           0x00000080
 #define HW_PSTATE_MASK          0x00000007
 #define HW_PSTATE_VALID_MASK    0x80000000
@@ -48,6 +49,7 @@
 #define MSR_PSTATE_STATUS       0xc0010063 /* Pstate Status MSR */
 #define MSR_PSTATE_CTRL         0xc0010062 /* Pstate control MSR */
 #define MSR_PSTATE_CUR_LIMIT    0xc0010061 /* pstate current limit MSR */
+#define MSR_HWCR_CPBDIS_MASK    0x02000000
 
 struct powernow_cpufreq_data {
     struct processor_performance *acpi_data;
@@ -62,8 +64,8 @@ static struct powernow_cpufreq_data *drv_data[NR_CPUS];
 struct drv_cmd {
     unsigned int type;
     cpumask_t mask;
-    u64 addr;
     u32 val;
+    int turbo;
 };
 
 static void transition_pstate(void *drvcmd)
@@ -71,6 +73,15 @@ static void transition_pstate(void *drvcmd)
     struct drv_cmd *cmd;
     cmd = (struct drv_cmd *) drvcmd;
 
+    if (cmd->turbo != CPUFREQ_TURBO_UNSUPPORTED) {
+        u32 lo, hi;
+        rdmsr(MSR_K8_HWCR, lo, hi);
+        if (cmd->turbo == CPUFREQ_TURBO_ENABLED)
+            lo &= ~MSR_HWCR_CPBDIS_MASK;
+        else
+            lo |= MSR_HWCR_CPBDIS_MASK; 
+        wrmsr(MSR_K8_HWCR, lo, hi);
+    }
     wrmsr(MSR_PSTATE_CTRL, cmd->val, 0);
 }
 
@@ -121,6 +132,7 @@ static int powernow_cpufreq_target(struct cpufreq_policy *policy,
     freqs.new = data->freq_table[next_state].frequency;
 
     cmd.val = next_perf_state;
+    cmd.turbo = policy->turbo;
 
     on_selected_cpus(&cmd.mask, transition_pstate, &cmd, 0);
 
@@ -159,6 +171,7 @@ static int powernow_cpufreq_cpu_init(struct cpufreq_policy *policy)
     unsigned int result = 0;
     struct processor_performance *perf;
     u32 max_hw_pstate, hi = 0, lo = 0;
+    struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 
     data = xmalloc(struct powernow_cpufreq_data);
     if (!data)
@@ -234,6 +247,15 @@ static int powernow_cpufreq_cpu_init(struct cpufreq_policy *policy)
     if (result)
         goto err_freqfree;
 
+    if (c->cpuid_level >= 6) {
+        unsigned int edx;
+        edx = cpuid_edx(CPUID_FREQ_VOLT_CAPABILITIES);
+        if ((edx & CPB_CAPABLE) == CPB_CAPABLE) {
+            policy->turbo = CPUFREQ_TURBO_ENABLED;
+            printk(XENLOG_INFO "Core Boost/Turbo detected and enabled\n");
+        }
+    }
+      
     /*
      * the first call to ->target() should result in us actually
      * writing something to the appropriate registers.
-- 
2.30.2