#include <linux/module.h>
#include <linux/device.h>
#include <linux/init.h>
+#include <linux/pci.h>
#include <asm/types.h>
#include <asm/timer.h>
#include <asm/smp.h>
#include <asm/io.h>
#include <asm/arch_hooks.h>
+#include <linux/timex.h>
+#include "mach_timer.h"
+
+/* Number of PMTMR ticks expected during calibration run */
+#define PMTMR_TICKS_PER_SEC 3579545
+#define PMTMR_EXPECTED_RATE \
+ ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_TICK_RATE>>10))
+
/* The I/O port the PMTMR resides at.
* The location is detected during setup_arch(),
#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
+static int pmtmr_need_workaround __read_mostly = 1;
+
/*helper function to safely read acpi pm timesource*/
static inline 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(pmtmr_ioport);
- v2 = inl(pmtmr_ioport);
- v3 = inl(pmtmr_ioport);
- } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
- || (v3 > v1 && v3 < v2));
-
- /* mask the output to 24 bits */
- return v2 & ACPI_PM_MASK;
+ if (pmtmr_need_workaround) {
+ u32 v1, v2, v3;
+
+ /* 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(pmtmr_ioport);
+ v2 = inl(pmtmr_ioport);
+ v3 = inl(pmtmr_ioport);
+ } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+ || (v3 > v1 && v3 < v2));
+
+ /* mask the output to 24 bits */
+ return v2 & ACPI_PM_MASK;
+ }
+
+ return inl(pmtmr_ioport) & ACPI_PM_MASK;
+}
+
+
+/*
+ * Some boards have the PMTMR running way too fast. We check
+ * the PMTMR rate against PIT channel 2 to catch these cases.
+ */
+static int verify_pmtmr_rate(void)
+{
+ u32 value1, value2;
+ unsigned long count, delta;
+
+ mach_prepare_counter();
+ value1 = read_pmtmr();
+ mach_countup(&count);
+ value2 = read_pmtmr();
+ delta = (value2 - value1) & ACPI_PM_MASK;
+
+ /* Check that the PMTMR delta is within 5% of what we expect */
+ if (delta < (PMTMR_EXPECTED_RATE * 19) / 20 ||
+ delta > (PMTMR_EXPECTED_RATE * 21) / 20) {
+ printk(KERN_INFO "PM-Timer running at invalid rate: %lu%% of normal - aborting.\n", 100UL * delta / PMTMR_EXPECTED_RATE);
+ return -1;
+ }
+
+ return 0;
}
+
static int init_pmtmr(char* override)
{
u32 value1, value2;
return -ENODEV;
pm_good:
+ if (verify_pmtmr_rate() != 0)
+ return -ENODEV;
+
init_cpu_khz();
return 0;
}
}
}
+static int pmtmr_resume(void)
+{
+ write_seqlock(&monotonic_lock);
+ /* Assume this is the last mark offset time */
+ offset_tick = read_pmtmr();
+ write_sequnlock(&monotonic_lock);
+ return 0;
+}
static unsigned long long monotonic_clock_pmtmr(void)
{
/* acpi timer_opts struct */
-struct timer_opts timer_pmtmr = {
+static struct timer_opts timer_pmtmr = {
.name = "pmtmr",
- .init = init_pmtmr,
.mark_offset = mark_offset_pmtmr,
.get_offset = get_offset_pmtmr,
.monotonic_clock = monotonic_clock_pmtmr,
.delay = delay_pmtmr,
+ .read_timer = read_timer_tsc,
+ .resume = pmtmr_resume,
};
+struct init_timer_opts __initdata timer_pmtmr_init = {
+ .init = init_pmtmr,
+ .opts = &timer_pmtmr,
+};
+
+#ifdef CONFIG_PCI
+/*
+ * PIIX4 Errata:
+ *
+ * The power management timer may return improper results when read.
+ * Although the timer value settles properly after incrementing,
+ * while incrementing there is a 3 ns window every 69.8 ns where the
+ * timer value is indeterminate (a 4.2% chance that the data will be
+ * incorrect when read). As a result, the ACPI free running count up
+ * timer specification is violated due to erroneous reads.
+ */
+static int __init pmtmr_bug_check(void)
+{
+ static struct pci_device_id gray_list[] __initdata = {
+ /* these chipsets may have bug. */
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82801DB_0) },
+ { },
+ };
+ struct pci_dev *dev;
+ int pmtmr_has_bug = 0;
+ u8 rev;
+
+ if (cur_timer != &timer_pmtmr || !pmtmr_need_workaround)
+ return 0;
+
+ dev = pci_get_device(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82371AB_3, NULL);
+ if (dev) {
+ pci_read_config_byte(dev, PCI_REVISION_ID, &rev);
+ /* the bug has been fixed in PIIX4M */
+ if (rev < 3) {
+ printk(KERN_WARNING "* Found PM-Timer Bug on this "
+ "chipset. Due to workarounds for a bug,\n"
+ "* this time source is slow. Consider trying "
+ "other time sources (clock=)\n");
+ pmtmr_has_bug = 1;
+ }
+ pci_dev_put(dev);
+ }
+
+ if (pci_dev_present(gray_list)) {
+ printk(KERN_WARNING "* This chipset may have PM-Timer Bug. Due"
+ " to workarounds for a bug,\n"
+ "* this time source is slow. If you are sure your timer"
+ " does not have\n"
+ "* this bug, please use \"pmtmr_good\" to disable the "
+ "workaround\n");
+ pmtmr_has_bug = 1;
+ }
+
+ if (!pmtmr_has_bug)
+ pmtmr_need_workaround = 0;
+
+ return 0;
+}
+device_initcall(pmtmr_bug_check);
+#endif
+
+static int __init pmtr_good_setup(char *__str)
+{
+ pmtmr_need_workaround = 0;
+ return 1;
+}
+__setup("pmtmr_good", pmtr_good_setup);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
git://git.onelab.eu / linux-2.6.git / blobdiff