[PATCH 2/2 V2] hwmon: (coretemp) Get TjMax value from MSR

From: Huaxu Wan
Date: Sun May 09 2010 - 23:41:24 EST


The MSR IA32_TEMPERATURE_TARGET contains the TjMax value in the newer
processers.

Signed-off-by: Huaxu Wan <huaxu.wan@xxxxxxxxxxxxxxx>
Signed-off-by: Carsten Emde <C.Emde@xxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 2 +
drivers/hwmon/coretemp.c | 52 ++++++++++++++++++++++++++++++++++++-
2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 4604e6a..9bc0cf8 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -232,6 +232,8 @@

#define MSR_IA32_MISC_ENABLE 0x000001a0

+#define MSR_IA32_TEMPERATURE_TARGET 0x000001a2
+
/* MISC_ENABLE bits: architectural */
#define MSR_IA32_MISC_ENABLE_FAST_STRING (1ULL << 0)
#define MSR_IA32_MISC_ENABLE_TCC (1ULL << 1)
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index d194207..9959390 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -241,6 +241,54 @@ static int __devinit adjust_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *
return tjmax;
}

+static int __devinit get_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
+{
+ /* The 100C is default for both mobile and non mobile CPUs */
+ int err;
+ u32 eax, edx;
+ u32 val;
+
+ /* A new feature of current Intel(R) processors, the
+ IA32_TEMPERATURE_TARGET contains the TjMax value */
+ err = rdmsr_safe_on_cpu(id, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
+ if (err){
+ dev_warn(dev, "Unable to read TjMax from CPU.\n");
+ } else {
+ val = (eax >> 16 ) & 0xff;
+ /*
+ * If the TjMax is not plausible, an assumption
+ * will be used
+ */
+ if (( val > 80) && (val < 120)){
+ dev_info(dev, "TjMax is %d C. \n", val);
+ return val * 1000;
+ }
+ }
+
+ /*
+ * An assumption is made for early CPUs and unreadable MSR.
+ * NOTE: the given value may not be correct.
+ */
+
+ switch(c->x86_model){
+ case 0xe :
+ case 0xf :
+ case 0x16 :
+ case 0x1a :
+ dev_warn(dev, "TjMax is assumed as 100 C! \n");
+ return 100000;
+ break;
+ case 0x17 :
+ case 0x1c : /* Atom CPUs */
+ return adjust_tjmax(c, id, dev);
+ break;
+ default :
+ dev_warn(dev, "CPU (model=0x%x) is not supported yet,"
+ " using default TjMax of 100C.\n", c->x86_model);
+ return 100000;
+ }
+}
+
static int __devinit coretemp_probe(struct platform_device *pdev)
{
struct coretemp_data *data;
@@ -283,14 +331,14 @@ static int __devinit coretemp_probe(struct platform_device *pdev)
}
}

- data->tjmax = adjust_tjmax(c, data->id, &pdev->dev);
+ data->tjmax = get_tjmax(c, data->id, &pdev->dev);
platform_set_drvdata(pdev, data);

/* read the still undocumented IA32_TEMPERATURE_TARGET it exists
on older CPUs but not in this register, Atoms don't have it either */

if ((c->x86_model > 0xe) && (c->x86_model != 0x1c)) {
- err = rdmsr_safe_on_cpu(data->id, 0x1a2, &eax, &edx);
+ err = rdmsr_safe_on_cpu(data->id, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
if (err) {
dev_warn(&pdev->dev, "Unable to read"
" IA32_TEMPERATURE_TARGET MSR\n");
--
1.6.3.3.363.g725cf7

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