From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/clocksource/acpi_pm.c | 245 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) create mode 100644 drivers/clocksource/acpi_pm.c (limited to 'drivers/clocksource/acpi_pm.c') diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c new file mode 100644 index 0000000000..8233877360 --- /dev/null +++ b/drivers/clocksource/acpi_pm.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/drivers/clocksource/acpi_pm.c + * + * This file contains the ACPI PM based clocksource. + * + * This code was largely moved from the i386 timer_pm.c file + * which was (C) Dominik Brodowski 2003 + * and contained the following comments: + * + * Driver to use the Power Management Timer (PMTMR) available in some + * southbridges as primary timing source for the Linux kernel. + * + * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c, + * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * The I/O port the PMTMR resides at. + * The location is detected during setup_arch(), + * in arch/i386/kernel/acpi/boot.c + */ +u32 pmtmr_ioport __read_mostly; + +static inline u32 read_pmtmr(void) +{ + /* mask the output to 24 bits */ + return inl(pmtmr_ioport) & ACPI_PM_MASK; +} + +u32 acpi_pm_read_verified(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 clock + * source is not latched, you must read it multiple + * times to ensure a safe value is read: + */ + do { + v1 = read_pmtmr(); + v2 = read_pmtmr(); + v3 = read_pmtmr(); + } while (unlikely((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1) + || (v3 > v1 && v3 < v2))); + + return v2; +} + +static u64 acpi_pm_read(struct clocksource *cs) +{ + return (u64)read_pmtmr(); +} + +static struct clocksource clocksource_acpi_pm = { + .name = "acpi_pm", + .rating = 200, + .read = acpi_pm_read, + .mask = (u64)ACPI_PM_MASK, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + + +#ifdef CONFIG_PCI +static int acpi_pm_good; +static int __init acpi_pm_good_setup(char *__str) +{ + acpi_pm_good = 1; + return 1; +} +__setup("acpi_pm_good", acpi_pm_good_setup); + +static u64 acpi_pm_read_slow(struct clocksource *cs) +{ + return (u64)acpi_pm_read_verified(); +} + +static inline void acpi_pm_need_workaround(void) +{ + clocksource_acpi_pm.read = acpi_pm_read_slow; + clocksource_acpi_pm.rating = 120; +} + +/* + * 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 void acpi_pm_check_blacklist(struct pci_dev *dev) +{ + if (acpi_pm_good) + return; + + /* the bug has been fixed in PIIX4M */ + if (dev->revision < 3) { + pr_warn("* Found PM-Timer Bug on the chipset. Due to workarounds for a bug,\n" + "* this clock source is slow. Consider trying other clock sources\n"); + + acpi_pm_need_workaround(); + } +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3, + acpi_pm_check_blacklist); + +static void acpi_pm_check_graylist(struct pci_dev *dev) +{ + if (acpi_pm_good) + return; + + pr_warn("* The chipset may have PM-Timer Bug. Due to workarounds for a bug,\n" + "* this clock source is slow. If you are sure your timer does not have\n" + "* this bug, please use \"acpi_pm_good\" to disable the workaround\n"); + + acpi_pm_need_workaround(); +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_0, + acpi_pm_check_graylist); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_LE, + acpi_pm_check_graylist); +#endif + +#ifndef CONFIG_X86_64 +#include +#define PMTMR_EXPECTED_RATE \ + ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (PIT_TICK_RATE>>10)) +/* + * 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) +{ + u64 value1, value2; + unsigned long count, delta; + + mach_prepare_counter(); + value1 = clocksource_acpi_pm.read(&clocksource_acpi_pm); + mach_countup(&count); + value2 = clocksource_acpi_pm.read(&clocksource_acpi_pm); + 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) { + pr_info("PM-Timer running at invalid rate: %lu%% of normal - aborting.\n", + 100UL * delta / PMTMR_EXPECTED_RATE); + return -1; + } + + return 0; +} +#else +#define verify_pmtmr_rate() (0) +#endif + +/* Number of monotonicity checks to perform during initialization */ +#define ACPI_PM_MONOTONICITY_CHECKS 10 +/* Number of reads we try to get two different values */ +#define ACPI_PM_READ_CHECKS 10000 + +static int __init init_acpi_pm_clocksource(void) +{ + u64 value1, value2; + unsigned int i, j = 0; + + if (!pmtmr_ioport) + return -ENODEV; + + /* "verify" this timing source: */ + for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) { + udelay(100 * j); + value1 = clocksource_acpi_pm.read(&clocksource_acpi_pm); + for (i = 0; i < ACPI_PM_READ_CHECKS; i++) { + value2 = clocksource_acpi_pm.read(&clocksource_acpi_pm); + if (value2 == value1) + continue; + if (value2 > value1) + break; + if ((value2 < value1) && ((value2) < 0xFFF)) + break; + pr_info("PM-Timer had inconsistent results: %#llx, %#llx - aborting.\n", + value1, value2); + pmtmr_ioport = 0; + return -EINVAL; + } + if (i == ACPI_PM_READ_CHECKS) { + pr_info("PM-Timer failed consistency check (%#llx) - aborting.\n", + value1); + pmtmr_ioport = 0; + return -ENODEV; + } + } + + if (verify_pmtmr_rate() != 0){ + pmtmr_ioport = 0; + return -ENODEV; + } + + if (tsc_clocksource_watchdog_disabled()) + clocksource_acpi_pm.flags |= CLOCK_SOURCE_MUST_VERIFY; + return clocksource_register_hz(&clocksource_acpi_pm, PMTMR_TICKS_PER_SEC); +} + +/* We use fs_initcall because we want the PCI fixups to have run + * but we still need to load before device_initcall + */ +fs_initcall(init_acpi_pm_clocksource); + +/* + * Allow an override of the IOPort. Stupid BIOSes do not tell us about + * the PMTimer, but we might know where it is. + */ +static int __init parse_pmtmr(char *arg) +{ + unsigned int base; + int ret; + + ret = kstrtouint(arg, 16, &base); + if (ret) { + pr_warn("PMTMR: invalid 'pmtmr=' value: '%s'\n", arg); + return 1; + } + + pr_info("PMTMR IOPort override: 0x%04x -> 0x%04x\n", pmtmr_ioport, + base); + pmtmr_ioport = base; + + return 1; +} +__setup("pmtmr=", parse_pmtmr); -- cgit v1.2.3