diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/Makefile | 4 | ||||
| -rw-r--r-- | drivers/clocksource/acpi_pm.c | 250 | ||||
| -rw-r--r-- | drivers/clocksource/cyclone.c | 119 | ||||
| -rw-r--r-- | drivers/clocksource/scx200_hrt.c | 101 | ||||
| -rw-r--r-- | drivers/clocksource/tcb_clksrc.c | 302 |
5 files changed, 776 insertions, 0 deletions
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile new file mode 100644 index 0000000..1525882 --- /dev/null +++ b/drivers/clocksource/Makefile @@ -0,0 +1,4 @@ +obj-$(CONFIG_ATMEL_TCB_CLKSRC) += tcb_clksrc.o +obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclone.o +obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o +obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c new file mode 100644 index 0000000..c201710 --- /dev/null +++ b/drivers/clocksource/acpi_pm.c @@ -0,0 +1,250 @@ +/* + * 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 <linux@brodo.de> 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. + * + * This file is licensed under the GPL v2. + */ + +#include <linux/acpi_pmtmr.h> +#include <linux/clocksource.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/pci.h> +#include <linux/delay.h> +#include <asm/io.h> + +/* + * 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 cycle_t acpi_pm_read_slow(void) +{ + return (cycle_t)acpi_pm_read_verified(); +} + +static cycle_t acpi_pm_read(void) +{ + return (cycle_t)read_pmtmr(); +} + +static struct clocksource clocksource_acpi_pm = { + .name = "acpi_pm", + .rating = 200, + .read = acpi_pm_read, + .mask = (cycle_t)ACPI_PM_MASK, + .mult = 0, /*to be calculated*/ + .shift = 22, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + +}; + + +#ifdef CONFIG_PCI +static int __devinitdata 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 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 __devinit acpi_pm_check_blacklist(struct pci_dev *dev) +{ + if (acpi_pm_good) + return; + + /* the bug has been fixed in PIIX4M */ + if (dev->revision < 3) { + printk(KERN_WARNING "* 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 __devinit acpi_pm_check_graylist(struct pci_dev *dev) +{ + if (acpi_pm_good) + return; + + printk(KERN_WARNING "* 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 "mach_timer.h" +#define PMTMR_EXPECTED_RATE \ + ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_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) +{ + cycle_t value1, value2; + unsigned long count, delta; + + mach_prepare_counter(); + value1 = clocksource_acpi_pm.read(); + mach_countup(&count); + value2 = clocksource_acpi_pm.read(); + 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; +} +#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) +{ + cycle_t value1, value2; + unsigned int i, j = 0; + + if (!pmtmr_ioport) + return -ENODEV; + + clocksource_acpi_pm.mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC, + clocksource_acpi_pm.shift); + + /* "verify" this timing source: */ + for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) { + udelay(100 * j); + value1 = clocksource_acpi_pm.read(); + for (i = 0; i < ACPI_PM_READ_CHECKS; i++) { + value2 = clocksource_acpi_pm.read(); + if (value2 == value1) + continue; + if (value2 > value1) + break; + if ((value2 < value1) && ((value2) < 0xFFF)) + break; + printk(KERN_INFO "PM-Timer had inconsistent results:" + " 0x%#llx, 0x%#llx - aborting.\n", + value1, value2); + return -EINVAL; + } + if (i == ACPI_PM_READ_CHECKS) { + printk(KERN_INFO "PM-Timer failed consistency check " + " (0x%#llx) - aborting.\n", value1); + return -ENODEV; + } + } + + if (verify_pmtmr_rate() != 0) + return -ENODEV; + + return clocksource_register(&clocksource_acpi_pm); +} + +/* 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 long base; + + if (strict_strtoul(arg, 16, &base)) + return -EINVAL; +#ifdef CONFIG_X86_64 + if (base > UINT_MAX) + return -ERANGE; +#endif + printk(KERN_INFO "PMTMR IOPort override: 0x%04x -> 0x%04lx\n", + pmtmr_ioport, base); + pmtmr_ioport = base; + + return 1; +} +__setup("pmtmr=", parse_pmtmr); diff --git a/drivers/clocksource/cyclone.c b/drivers/clocksource/cyclone.c new file mode 100644 index 0000000..1bde303 --- /dev/null +++ b/drivers/clocksource/cyclone.c @@ -0,0 +1,119 @@ +#include <linux/clocksource.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/timex.h> +#include <linux/init.h> + +#include <asm/pgtable.h> +#include <asm/io.h> + +#include "mach_timer.h" + +#define CYCLONE_CBAR_ADDR 0xFEB00CD0 /* base address ptr */ +#define CYCLONE_PMCC_OFFSET 0x51A0 /* offset to control register */ +#define CYCLONE_MPCS_OFFSET 0x51A8 /* offset to select register */ +#define CYCLONE_MPMC_OFFSET 0x51D0 /* offset to count register */ +#define CYCLONE_TIMER_FREQ 99780000 /* 100Mhz, but not really */ +#define CYCLONE_TIMER_MASK CLOCKSOURCE_MASK(32) /* 32 bit mask */ + +int use_cyclone = 0; +static void __iomem *cyclone_ptr; + +static cycle_t read_cyclone(void) +{ + return (cycle_t)readl(cyclone_ptr); +} + +static struct clocksource clocksource_cyclone = { + .name = "cyclone", + .rating = 250, + .read = read_cyclone, + .mask = CYCLONE_TIMER_MASK, + .mult = 10, + .shift = 0, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init init_cyclone_clocksource(void) +{ + unsigned long base; /* saved value from CBAR */ + unsigned long offset; + u32 __iomem* volatile cyclone_timer; /* Cyclone MPMC0 register */ + u32 __iomem* reg; + int i; + + /* make sure we're on a summit box: */ + if (!use_cyclone) + return -ENODEV; + + printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n"); + + /* find base address: */ + offset = CYCLONE_CBAR_ADDR; + reg = ioremap_nocache(offset, sizeof(reg)); + if (!reg) { + printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n"); + return -ENODEV; + } + /* even on 64bit systems, this is only 32bits: */ + base = readl(reg); + if (!base) { + printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n"); + return -ENODEV; + } + iounmap(reg); + + /* setup PMCC: */ + offset = base + CYCLONE_PMCC_OFFSET; + reg = ioremap_nocache(offset, sizeof(reg)); + if (!reg) { + printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n"); + return -ENODEV; + } + writel(0x00000001,reg); + iounmap(reg); + + /* setup MPCS: */ + offset = base + CYCLONE_MPCS_OFFSET; + reg = ioremap_nocache(offset, sizeof(reg)); + if (!reg) { + printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n"); + return -ENODEV; + } + writel(0x00000001,reg); + iounmap(reg); + + /* map in cyclone_timer: */ + offset = base + CYCLONE_MPMC_OFFSET; + cyclone_timer = ioremap_nocache(offset, sizeof(u64)); + if (!cyclone_timer) { + printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n"); + return -ENODEV; + } + + /* quick test to make sure its ticking: */ + for (i = 0; i < 3; i++){ + u32 old = readl(cyclone_timer); + int stall = 100; + + while (stall--) + barrier(); + + if (readl(cyclone_timer) == old) { + printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n"); + iounmap(cyclone_timer); + cyclone_timer = NULL; + return -ENODEV; + } + } + cyclone_ptr = cyclone_timer; + + /* sort out mult/shift values: */ + clocksource_cyclone.shift = 22; + clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ, + clocksource_cyclone.shift); + + return clocksource_register(&clocksource_cyclone); +} + +arch_initcall(init_cyclone_clocksource); diff --git a/drivers/clocksource/scx200_hrt.c b/drivers/clocksource/scx200_hrt.c new file mode 100644 index 0000000..b92da67 --- /dev/null +++ b/drivers/clocksource/scx200_hrt.c @@ -0,0 +1,101 @@ +/* + * Copyright (C) 2006 Jim Cromie + * + * This is a clocksource driver for the Geode SCx200's 1 or 27 MHz + * high-resolution timer. The Geode SC-1100 (at least) has a buggy + * time stamp counter (TSC), which loses time unless 'idle=poll' is + * given as a boot-arg. In its absence, the Generic Timekeeping code + * will detect and de-rate the bad TSC, allowing this timer to take + * over timekeeping duties. + * + * Based on work by John Stultz, and Ted Phelps (in a 2.6.12-rc6 patch) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + */ + +#include <linux/clocksource.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/scx200.h> + +#define NAME "scx200_hrt" + +static int mhz27; +module_param(mhz27, int, 0); /* load time only */ +MODULE_PARM_DESC(mhz27, "count at 27.0 MHz (default is 1.0 MHz)"); + +static int ppm; +module_param(ppm, int, 0); /* load time only */ +MODULE_PARM_DESC(ppm, "+-adjust to actual XO freq (ppm)"); + +/* HiRes Timer configuration register address */ +#define SCx200_TMCNFG_OFFSET (SCx200_TIMER_OFFSET + 5) + +/* and config settings */ +#define HR_TMEN (1 << 0) /* timer interrupt enable */ +#define HR_TMCLKSEL (1 << 1) /* 1|0 counts at 27|1 MHz */ +#define HR_TM27MPD (1 << 2) /* 1 turns off input clock (power-down) */ + +/* The base timer frequency, * 27 if selected */ +#define HRT_FREQ 1000000 + +static cycle_t read_hrt(void) +{ + /* Read the timer value */ + return (cycle_t) inl(scx200_cb_base + SCx200_TIMER_OFFSET); +} + +#define HRT_SHIFT_1 22 +#define HRT_SHIFT_27 26 + +static struct clocksource cs_hrt = { + .name = "scx200_hrt", + .rating = 250, + .read = read_hrt, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + /* mult, shift are set based on mhz27 flag */ +}; + +static int __init init_hrt_clocksource(void) +{ + /* Make sure scx200 has initialized the configuration block */ + if (!scx200_cb_present()) + return -ENODEV; + + /* Reserve the timer's ISA io-region for ourselves */ + if (!request_region(scx200_cb_base + SCx200_TIMER_OFFSET, + SCx200_TIMER_SIZE, + "NatSemi SCx200 High-Resolution Timer")) { + printk(KERN_WARNING NAME ": unable to lock timer region\n"); + return -ENODEV; + } + + /* write timer config */ + outb(HR_TMEN | (mhz27 ? HR_TMCLKSEL : 0), + scx200_cb_base + SCx200_TMCNFG_OFFSET); + + if (mhz27) { + cs_hrt.shift = HRT_SHIFT_27; + cs_hrt.mult = clocksource_hz2mult((HRT_FREQ + ppm) * 27, + cs_hrt.shift); + } else { + cs_hrt.shift = HRT_SHIFT_1; + cs_hrt.mult = clocksource_hz2mult(HRT_FREQ + ppm, + cs_hrt.shift); + } + printk(KERN_INFO "enabling scx200 high-res timer (%s MHz +%d ppm)\n", + mhz27 ? "27":"1", ppm); + + return clocksource_register(&cs_hrt); +} + +module_init(init_hrt_clocksource); + +MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>"); +MODULE_DESCRIPTION("clocksource on SCx200 HiRes Timer"); +MODULE_LICENSE("GPL"); diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c new file mode 100644 index 0000000..f450588 --- /dev/null +++ b/drivers/clocksource/tcb_clksrc.c @@ -0,0 +1,302 @@ +#include <linux/init.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/ioport.h> +#include <linux/io.h> +#include <linux/platform_device.h> +#include <linux/atmel_tc.h> + + +/* + * We're configured to use a specific TC block, one that's not hooked + * up to external hardware, to provide a time solution: + * + * - Two channels combine to create a free-running 32 bit counter + * with a base rate of 5+ MHz, packaged as a clocksource (with + * resolution better than 200 nsec). + * + * - The third channel may be used to provide a 16-bit clockevent + * source, used in either periodic or oneshot mode. This runs + * at 32 KiHZ, and can handle delays of up to two seconds. + * + * A boot clocksource and clockevent source are also currently needed, + * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so + * this code can be used when init_timers() is called, well before most + * devices are set up. (Some low end AT91 parts, which can run uClinux, + * have only the timers in one TC block... they currently don't support + * the tclib code, because of that initialization issue.) + * + * REVISIT behavior during system suspend states... we should disable + * all clocks and save the power. Easily done for clockevent devices, + * but clocksources won't necessarily get the needed notifications. + * For deeper system sleep states, this will be mandatory... + */ + +static void __iomem *tcaddr; + +static cycle_t tc_get_cycles(void) +{ + unsigned long flags; + u32 lower, upper; + + raw_local_irq_save(flags); + do { + upper = __raw_readl(tcaddr + ATMEL_TC_REG(1, CV)); + lower = __raw_readl(tcaddr + ATMEL_TC_REG(0, CV)); + } while (upper != __raw_readl(tcaddr + ATMEL_TC_REG(1, CV))); + + raw_local_irq_restore(flags); + return (upper << 16) | lower; +} + +static struct clocksource clksrc = { + .name = "tcb_clksrc", + .rating = 200, + .read = tc_get_cycles, + .mask = CLOCKSOURCE_MASK(32), + .shift = 18, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +#ifdef CONFIG_GENERIC_CLOCKEVENTS + +struct tc_clkevt_device { + struct clock_event_device clkevt; + struct clk *clk; + void __iomem *regs; +}; + +static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt) +{ + return container_of(clkevt, struct tc_clkevt_device, clkevt); +} + +/* For now, we always use the 32K clock ... this optimizes for NO_HZ, + * because using one of the divided clocks would usually mean the + * tick rate can never be less than several dozen Hz (vs 0.5 Hz). + * + * A divided clock could be good for high resolution timers, since + * 30.5 usec resolution can seem "low". + */ +static u32 timer_clock; + +static void tc_mode(enum clock_event_mode m, struct clock_event_device *d) +{ + struct tc_clkevt_device *tcd = to_tc_clkevt(d); + void __iomem *regs = tcd->regs; + + if (tcd->clkevt.mode == CLOCK_EVT_MODE_PERIODIC + || tcd->clkevt.mode == CLOCK_EVT_MODE_ONESHOT) { + __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR)); + __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR)); + clk_disable(tcd->clk); + } + + switch (m) { + + /* By not making the gentime core emulate periodic mode on top + * of oneshot, we get lower overhead and improved accuracy. + */ + case CLOCK_EVT_MODE_PERIODIC: + clk_enable(tcd->clk); + + /* slow clock, count up to RC, then irq and restart */ + __raw_writel(timer_clock + | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, + regs + ATMEL_TC_REG(2, CMR)); + __raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC)); + + /* Enable clock and interrupts on RC compare */ + __raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER)); + + /* go go gadget! */ + __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, + regs + ATMEL_TC_REG(2, CCR)); + break; + + case CLOCK_EVT_MODE_ONESHOT: + clk_enable(tcd->clk); + + /* slow clock, count up to RC, then irq and stop */ + __raw_writel(timer_clock | ATMEL_TC_CPCSTOP + | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, + regs + ATMEL_TC_REG(2, CMR)); + __raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER)); + + /* set_next_event() configures and starts the timer */ + break; + + default: + break; + } +} + +static int tc_next_event(unsigned long delta, struct clock_event_device *d) +{ + __raw_writel(delta, tcaddr + ATMEL_TC_REG(2, RC)); + + /* go go gadget! */ + __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, + tcaddr + ATMEL_TC_REG(2, CCR)); + return 0; +} + +static struct tc_clkevt_device clkevt = { + .clkevt = { + .name = "tc_clkevt", + .features = CLOCK_EVT_FEAT_PERIODIC + | CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + /* Should be lower than at91rm9200's system timer */ + .rating = 125, + .cpumask = CPU_MASK_CPU0, + .set_next_event = tc_next_event, + .set_mode = tc_mode, + }, +}; + +static irqreturn_t ch2_irq(int irq, void *handle) +{ + struct tc_clkevt_device *dev = handle; + unsigned int sr; + + sr = __raw_readl(dev->regs + ATMEL_TC_REG(2, SR)); + if (sr & ATMEL_TC_CPCS) { + dev->clkevt.event_handler(&dev->clkevt); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static struct irqaction tc_irqaction = { + .name = "tc_clkevt", + .flags = IRQF_TIMER | IRQF_DISABLED, + .handler = ch2_irq, +}; + +static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) +{ + struct clk *t2_clk = tc->clk[2]; + int irq = tc->irq[2]; + + clkevt.regs = tc->regs; + clkevt.clk = t2_clk; + tc_irqaction.dev_id = &clkevt; + + timer_clock = clk32k_divisor_idx; + + clkevt.clkevt.mult = div_sc(32768, NSEC_PER_SEC, clkevt.clkevt.shift); + clkevt.clkevt.max_delta_ns + = clockevent_delta2ns(0xffff, &clkevt.clkevt); + clkevt.clkevt.min_delta_ns = clockevent_delta2ns(1, &clkevt.clkevt) + 1; + + setup_irq(irq, &tc_irqaction); + + clockevents_register_device(&clkevt.clkevt); +} + +#else /* !CONFIG_GENERIC_CLOCKEVENTS */ + +static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) +{ + /* NOTHING */ +} + +#endif + +static int __init tcb_clksrc_init(void) +{ + static char bootinfo[] __initdata + = KERN_DEBUG "%s: tc%d at %d.%03d MHz\n"; + + struct platform_device *pdev; + struct atmel_tc *tc; + struct clk *t0_clk; + u32 rate, divided_rate = 0; + int best_divisor_idx = -1; + int clk32k_divisor_idx = -1; + int i; + + tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK, clksrc.name); + if (!tc) { + pr_debug("can't alloc TC for clocksource\n"); + return -ENODEV; + } + tcaddr = tc->regs; + pdev = tc->pdev; + + t0_clk = tc->clk[0]; + clk_enable(t0_clk); + + /* How fast will we be counting? Pick something over 5 MHz. */ + rate = (u32) clk_get_rate(t0_clk); + for (i = 0; i < 5; i++) { + unsigned divisor = atmel_tc_divisors[i]; + unsigned tmp; + + /* remember 32 KiHz clock for later */ + if (!divisor) { + clk32k_divisor_idx = i; + continue; + } + + tmp = rate / divisor; + pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp); + if (best_divisor_idx > 0) { + if (tmp < 5 * 1000 * 1000) + continue; + } + divided_rate = tmp; + best_divisor_idx = i; + } + + clksrc.mult = clocksource_hz2mult(divided_rate, clksrc.shift); + + printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK, + divided_rate / 1000000, + ((divided_rate + 500000) % 1000000) / 1000); + + /* tclib will give us three clocks no matter what the + * underlying platform supports. + */ + clk_enable(tc->clk[1]); + + /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */ + __raw_writel(best_divisor_idx /* likely divide-by-8 */ + | ATMEL_TC_WAVE + | ATMEL_TC_WAVESEL_UP /* free-run */ + | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */ + | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */ + tcaddr + ATMEL_TC_REG(0, CMR)); + __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA)); + __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC)); + __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */ + __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR)); + + /* channel 1: waveform mode, input TIOA0 */ + __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */ + | ATMEL_TC_WAVE + | ATMEL_TC_WAVESEL_UP, /* free-run */ + tcaddr + ATMEL_TC_REG(1, CMR)); + __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */ + __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR)); + + /* chain channel 0 to channel 1, then reset all the timers */ + __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR); + __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR); + + /* and away we go! */ + clocksource_register(&clksrc); + + /* channel 2: periodic and oneshot timer support */ + setup_clkevents(tc, clk32k_divisor_idx); + + return 0; +} +arch_initcall(tcb_clksrc_init); |
