2 files changed, 136 insertions, 0 deletions

diff --git a/tools/power/cpupower/debug/kernel/Makefile b/tools/power/cpupower/debug/kernel/Makefile
new file mode 100644
index 00000000000..96b146fe6f8
--- /dev/null
+++ b/tools/power/cpupower/debug/kernel/Makefile
@@ -0,0 +1,23 @@
+obj-m   :=
+
+KDIR    := /lib/modules/$(shell uname -r)/build
+PWD             := $(shell pwd)
+KMISC   := /lib/modules/$(shell uname -r)/cpufrequtils/
+
+ifeq ("$(CONFIG_X86_TSC)", "y")
+  obj-m  += cpufreq-test_tsc.o
+endif
+
+default:
+        $(MAKE) -C $(KDIR) M=$(PWD)
+
+clean:
+        - rm -rf *.o *.ko .tmp-versions .*.cmd .*.mod.* *.mod.c
+        - rm -rf .tmp_versions* Module.symvers modules.order
+
+install: default
+        install -d $(KMISC)
+        install -m 644 -c *.ko $(KMISC)
+        /sbin/depmod -a
+
+all:    default
diff --git a/tools/power/cpupower/debug/kernel/cpufreq-test_tsc.c b/tools/power/cpupower/debug/kernel/cpufreq-test_tsc.c
new file mode 100644
index 00000000000..66cace601e5
--- /dev/null
+++ b/tools/power/cpupower/debug/kernel/cpufreq-test_tsc.c
@@ -0,0 +1,113 @@
+/*
+ * test module to check whether the TSC-based delay routine continues
+ * to work properly after cpufreq transitions. Needs ACPI to work
+ * properly.
+ *
+ * Based partly on the Power Management Timer (PMTMR) code to be found
+ * in arch/i386/kernel/timers/timer_pm.c on recent 2.6. kernels, especially
+ * code written by John Stultz. The read_pmtmr function was copied verbatim
+ * from that file.
+ *
+ * (C) 2004 Dominik Brodowski
+ *
+ * To use:
+ * 1.) pass clock=tsc to the kernel on your bootloader
+ * 2.) modprobe this module (it'll fail)
+ * 3.) change CPU frequency
+ * 4.) modprobe this module again
+ * 5.) if the third value, "diff_pmtmr", changes between 2. and 4., the
+ *     TSC-based delay routine on the Linux kernel does not correctly
+ *     handle the cpufreq transition. Please report this to
+ *     cpufreq@vger.kernel.org
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+
+#include <asm/io.h>
+
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+
+static int pm_tmr_ioport = 0;
+
+/*helper function to safely read acpi pm timesource*/
+static u32 read_pmtmr(void)
+{
+        u32 v1=0,v2=0,v3=0;
+        /* It has been reported that because of various broken
+         * chipsets (ICH4, PIIX4 and PIIX4E) where the ACPI PM time
+         * source is not latched, so you must read it multiple
+         * times to insure a safe value is read.
+         */
+        do {
+                v1 = inl(pm_tmr_ioport);
+                v2 = inl(pm_tmr_ioport);
+                v3 = inl(pm_tmr_ioport);
+        } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+                 || (v3 > v1 && v3 < v2));
+
+        /* mask the output to 24 bits */
+        return (v2 & 0xFFFFFF);
+}
+
+static int __init cpufreq_test_tsc(void)
+{
+        u32 now, then, diff;
+        u64 now_tsc, then_tsc, diff_tsc;
+        int i;
+
+        /* the following code snipped is copied from arch/x86/kernel/acpi/boot.c
+           of Linux v2.6.25. */
+
+        /* detect the location of the ACPI PM Timer */
+        if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) {
+                /* FADT rev. 2 */
+                if (acpi_gbl_FADT.xpm_timer_block.space_id !=
+                    ACPI_ADR_SPACE_SYSTEM_IO)
+                        return 0;
+
+                pm_tmr_ioport = acpi_gbl_FADT.xpm_timer_block.address;
+                /*
+                 * "X" fields are optional extensions to the original V1.0
+                 * fields, so we must selectively expand V1.0 fields if the
+                 * corresponding X field is zero.
+                 */
+                if (!pm_tmr_ioport)
+                        pm_tmr_ioport = acpi_gbl_FADT.pm_timer_block;
+        } else {
+                /* FADT rev. 1 */
+                pm_tmr_ioport = acpi_gbl_FADT.pm_timer_block;
+        }
+
+        printk(KERN_DEBUG "start--> \n");
+        then = read_pmtmr();
+        rdtscll(then_tsc);
+        for (i=0;i<20;i++) {
+                mdelay(100);
+                now = read_pmtmr();
+                rdtscll(now_tsc);
+                diff = (now - then) & 0xFFFFFF;
+                diff_tsc = now_tsc - then_tsc;
+                printk(KERN_DEBUG "t1: %08u t2: %08u diff_pmtmr: %08u diff_tsc: %016llu\n", then, now, diff, diff_tsc);
+                then = now;
+                then_tsc = now_tsc;
+        }
+        printk(KERN_DEBUG "<-- end \n");
+        return -ENODEV;
+}
+
+static void __exit cpufreq_none(void)
+{
+        return;
+}
+
+module_init(cpufreq_test_tsc)
+module_exit(cpufreq_none)
+
+
+MODULE_AUTHOR("Dominik Brodowski");
+MODULE_DESCRIPTION("Verify the TSC cpufreq notifier working correctly -- needs ACPI-enabled system");
+MODULE_LICENSE ("GPL");