hwmon: (k8temp) Warn about fam F rev F errata

Add warning about wrong CPU temperature readouts on all fam F rev F.

The allowed combinations of processors ensure that all processors
in a multisocket system have similar characteristics, e.g.

(1) provide temperature sensor interface (>=RevC && <RevF)
(2) are affected by erratum #141 (>=RevF)

Thus it is sufficient to check the revision of the boot CPU.

For "mixed silicon support" refer to
"Revision Guide for AMD Athlon 64 and AMD Opteron Processors" (RevA-E) and
"Revision Guide for AMD NPT Family 0Fh Processors" (RefF-G).

Cc: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/drivers/hwmon/k8temp.c b/drivers/hwmon/k8temp.c
index bd2bde0..ca56f2e 100644 (file)
--- a/drivers/hwmon/k8temp.c
+++ b/drivers/hwmon/k8temp.c
@@ -31,6 +31,7 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
+#include <asm/processor.h>
 
 #define TEMP_FROM_REG(val)     (((((val) >> 16) & 0xff) - 49) * 1000)
 #define REG_TEMP       0xe4
@@ -141,20 +142,34 @@ static int __devinit k8temp_probe(struct pci_dev *pdev,
        int err;
        u8 scfg;
        u32 temp;
+       u8 model, stepping;
        struct k8temp_data *data;
-       u32 cpuid = cpuid_eax(1);
-
-       /* this feature should be available since SH-C0 core */
-       if ((cpuid == 0xf40) || (cpuid == 0xf50) || (cpuid == 0xf51)) {
-               err = -ENODEV;
-               goto exit;
-       }
 
        if (!(data = kzalloc(sizeof(struct k8temp_data), GFP_KERNEL))) {
                err = -ENOMEM;
                goto exit;
        }
 
+       model = boot_cpu_data.x86_model;
+       stepping = boot_cpu_data.x86_mask;
+
+       switch (boot_cpu_data.x86) {
+       case 0xf:
+               /* feature available since SH-C0, exclude older revisions */
+               if (((model == 4) && (stepping == 0)) ||
+                   ((model == 5) && (stepping <= 1))) {
+                       err = -ENODEV;
+                       goto exit_free;
+               }
+
+               if (model >= 0x40) {
+                       dev_warn(&pdev->dev, "Temperature readouts might be "
+                                "wrong - check erratum #141\n");
+               }
+
+               break;
+       }
+
        pci_read_config_byte(pdev, REG_TEMP, &scfg);
        scfg &= ~(SEL_PLACE | SEL_CORE);                /* Select sensor 0, core0 */
        pci_write_config_byte(pdev, REG_TEMP, scfg);