| /* |
| * Driver for the CS5535/CS5536 Multi-Function General Purpose Timers (MFGPT) |
| * |
| * Copyright (C) 2006, Advanced Micro Devices, Inc. |
| * Copyright (C) 2007 Andres Salomon <dilinger@debian.org> |
| * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of version 2 of the GNU General Public License |
| * as published by the Free Software Foundation. |
| * |
| * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/spinlock.h> |
| #include <linux/interrupt.h> |
| #include <linux/module.h> |
| #include <linux/platform_device.h> |
| #include <linux/cs5535.h> |
| #include <linux/slab.h> |
| |
| #define DRV_NAME "cs5535-mfgpt" |
| |
| static int mfgpt_reset_timers; |
| module_param_named(mfgptfix, mfgpt_reset_timers, int, 0644); |
| MODULE_PARM_DESC(mfgptfix, "Reset the MFGPT timers during init; " |
| "required by some broken BIOSes (ie, TinyBIOS < 0.99)."); |
| |
| struct cs5535_mfgpt_timer { |
| struct cs5535_mfgpt_chip *chip; |
| int nr; |
| }; |
| |
| static struct cs5535_mfgpt_chip { |
| DECLARE_BITMAP(avail, MFGPT_MAX_TIMERS); |
| resource_size_t base; |
| |
| struct platform_device *pdev; |
| spinlock_t lock; |
| int initialized; |
| } cs5535_mfgpt_chip; |
| |
| int cs5535_mfgpt_toggle_event(struct cs5535_mfgpt_timer *timer, int cmp, |
| int event, int enable) |
| { |
| uint32_t msr, mask, value, dummy; |
| int shift = (cmp == MFGPT_CMP1) ? 0 : 8; |
| |
| if (!timer) { |
| WARN_ON(1); |
| return -EIO; |
| } |
| |
| /* |
| * The register maps for these are described in sections 6.17.1.x of |
| * the AMD Geode CS5536 Companion Device Data Book. |
| */ |
| switch (event) { |
| case MFGPT_EVENT_RESET: |
| /* |
| * XXX: According to the docs, we cannot reset timers above |
| * 6; that is, resets for 7 and 8 will be ignored. Is this |
| * a problem? -dilinger |
| */ |
| msr = MSR_MFGPT_NR; |
| mask = 1 << (timer->nr + 24); |
| break; |
| |
| case MFGPT_EVENT_NMI: |
| msr = MSR_MFGPT_NR; |
| mask = 1 << (timer->nr + shift); |
| break; |
| |
| case MFGPT_EVENT_IRQ: |
| msr = MSR_MFGPT_IRQ; |
| mask = 1 << (timer->nr + shift); |
| break; |
| |
| default: |
| return -EIO; |
| } |
| |
| rdmsr(msr, value, dummy); |
| |
| if (enable) |
| value |= mask; |
| else |
| value &= ~mask; |
| |
| wrmsr(msr, value, dummy); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_toggle_event); |
| |
| int cs5535_mfgpt_set_irq(struct cs5535_mfgpt_timer *timer, int cmp, int *irq, |
| int enable) |
| { |
| uint32_t zsel, lpc, dummy; |
| int shift; |
| |
| if (!timer) { |
| WARN_ON(1); |
| return -EIO; |
| } |
| |
| /* |
| * Unfortunately, MFGPTs come in pairs sharing their IRQ lines. If VSA |
| * is using the same CMP of the timer's Siamese twin, the IRQ is set to |
| * 2, and we mustn't use nor change it. |
| * XXX: Likewise, 2 Linux drivers might clash if the 2nd overwrites the |
| * IRQ of the 1st. This can only happen if forcing an IRQ, calling this |
| * with *irq==0 is safe. Currently there _are_ no 2 drivers. |
| */ |
| rdmsr(MSR_PIC_ZSEL_LOW, zsel, dummy); |
| shift = ((cmp == MFGPT_CMP1 ? 0 : 4) + timer->nr % 4) * 4; |
| if (((zsel >> shift) & 0xF) == 2) |
| return -EIO; |
| |
| /* Choose IRQ: if none supplied, keep IRQ already set or use default */ |
| if (!*irq) |
| *irq = (zsel >> shift) & 0xF; |
| if (!*irq) |
| *irq = CONFIG_CS5535_MFGPT_DEFAULT_IRQ; |
| |
| /* Can't use IRQ if it's 0 (=disabled), 2, or routed to LPC */ |
| if (*irq < 1 || *irq == 2 || *irq > 15) |
| return -EIO; |
| rdmsr(MSR_PIC_IRQM_LPC, lpc, dummy); |
| if (lpc & (1 << *irq)) |
| return -EIO; |
| |
| /* All chosen and checked - go for it */ |
| if (cs5535_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable)) |
| return -EIO; |
| if (enable) { |
| zsel = (zsel & ~(0xF << shift)) | (*irq << shift); |
| wrmsr(MSR_PIC_ZSEL_LOW, zsel, dummy); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_set_irq); |
| |
| struct cs5535_mfgpt_timer *cs5535_mfgpt_alloc_timer(int timer_nr, int domain) |
| { |
| struct cs5535_mfgpt_chip *mfgpt = &cs5535_mfgpt_chip; |
| struct cs5535_mfgpt_timer *timer = NULL; |
| unsigned long flags; |
| int max; |
| |
| if (!mfgpt->initialized) |
| goto done; |
| |
| /* only allocate timers from the working domain if requested */ |
| if (domain == MFGPT_DOMAIN_WORKING) |
| max = 6; |
| else |
| max = MFGPT_MAX_TIMERS; |
| |
| if (timer_nr >= max) { |
| /* programmer error. silly programmers! */ |
| WARN_ON(1); |
| goto done; |
| } |
| |
| spin_lock_irqsave(&mfgpt->lock, flags); |
| if (timer_nr < 0) { |
| unsigned long t; |
| |
| /* try to find any available timer */ |
| t = find_first_bit(mfgpt->avail, max); |
| /* set timer_nr to -1 if no timers available */ |
| timer_nr = t < max ? (int) t : -1; |
| } else { |
| /* check if the requested timer's available */ |
| if (!test_bit(timer_nr, mfgpt->avail)) |
| timer_nr = -1; |
| } |
| |
| if (timer_nr >= 0) |
| /* if timer_nr is not -1, it's an available timer */ |
| __clear_bit(timer_nr, mfgpt->avail); |
| spin_unlock_irqrestore(&mfgpt->lock, flags); |
| |
| if (timer_nr < 0) |
| goto done; |
| |
| timer = kmalloc(sizeof(*timer), GFP_KERNEL); |
| if (!timer) { |
| /* aw hell */ |
| spin_lock_irqsave(&mfgpt->lock, flags); |
| __set_bit(timer_nr, mfgpt->avail); |
| spin_unlock_irqrestore(&mfgpt->lock, flags); |
| goto done; |
| } |
| timer->chip = mfgpt; |
| timer->nr = timer_nr; |
| dev_info(&mfgpt->pdev->dev, "registered timer %d\n", timer_nr); |
| |
| done: |
| return timer; |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_alloc_timer); |
| |
| /* |
| * XXX: This frees the timer memory, but never resets the actual hardware |
| * timer. The old geode_mfgpt code did this; it would be good to figure |
| * out a way to actually release the hardware timer. See comments below. |
| */ |
| void cs5535_mfgpt_free_timer(struct cs5535_mfgpt_timer *timer) |
| { |
| unsigned long flags; |
| uint16_t val; |
| |
| /* timer can be made available again only if never set up */ |
| val = cs5535_mfgpt_read(timer, MFGPT_REG_SETUP); |
| if (!(val & MFGPT_SETUP_SETUP)) { |
| spin_lock_irqsave(&timer->chip->lock, flags); |
| __set_bit(timer->nr, timer->chip->avail); |
| spin_unlock_irqrestore(&timer->chip->lock, flags); |
| } |
| |
| kfree(timer); |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_free_timer); |
| |
| uint16_t cs5535_mfgpt_read(struct cs5535_mfgpt_timer *timer, uint16_t reg) |
| { |
| return inw(timer->chip->base + reg + (timer->nr * 8)); |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_read); |
| |
| void cs5535_mfgpt_write(struct cs5535_mfgpt_timer *timer, uint16_t reg, |
| uint16_t value) |
| { |
| outw(value, timer->chip->base + reg + (timer->nr * 8)); |
| } |
| EXPORT_SYMBOL_GPL(cs5535_mfgpt_write); |
| |
| /* |
| * This is a sledgehammer that resets all MFGPT timers. This is required by |
| * some broken BIOSes which leave the system in an unstable state |
| * (TinyBIOS 0.98, for example; fixed in 0.99). It's uncertain as to |
| * whether or not this secret MSR can be used to release individual timers. |
| * Jordan tells me that he and Mitch once played w/ it, but it's unclear |
| * what the results of that were (and they experienced some instability). |
| */ |
| static void reset_all_timers(void) |
| { |
| uint32_t val, dummy; |
| |
| /* The following undocumented bit resets the MFGPT timers */ |
| val = 0xFF; dummy = 0; |
| wrmsr(MSR_MFGPT_SETUP, val, dummy); |
| } |
| |
| /* |
| * Check whether any MFGPTs are available for the kernel to use. In most |
| * cases, firmware that uses AMD's VSA code will claim all timers during |
| * bootup; we certainly don't want to take them if they're already in use. |
| * In other cases (such as with VSAless OpenFirmware), the system firmware |
| * leaves timers available for us to use. |
| */ |
| static int scan_timers(struct cs5535_mfgpt_chip *mfgpt) |
| { |
| struct cs5535_mfgpt_timer timer = { .chip = mfgpt }; |
| unsigned long flags; |
| int timers = 0; |
| uint16_t val; |
| int i; |
| |
| /* bios workaround */ |
| if (mfgpt_reset_timers) |
| reset_all_timers(); |
| |
| /* just to be safe, protect this section w/ lock */ |
| spin_lock_irqsave(&mfgpt->lock, flags); |
| for (i = 0; i < MFGPT_MAX_TIMERS; i++) { |
| timer.nr = i; |
| val = cs5535_mfgpt_read(&timer, MFGPT_REG_SETUP); |
| if (!(val & MFGPT_SETUP_SETUP)) { |
| __set_bit(i, mfgpt->avail); |
| timers++; |
| } |
| } |
| spin_unlock_irqrestore(&mfgpt->lock, flags); |
| |
| return timers; |
| } |
| |
| static int cs5535_mfgpt_probe(struct platform_device *pdev) |
| { |
| struct resource *res; |
| int err = -EIO, t; |
| |
| /* There are two ways to get the MFGPT base address; one is by |
| * fetching it from MSR_LBAR_MFGPT, the other is by reading the |
| * PCI BAR info. The latter method is easier (especially across |
| * different architectures), so we'll stick with that for now. If |
| * it turns out to be unreliable in the face of crappy BIOSes, we |
| * can always go back to using MSRs.. */ |
| |
| res = platform_get_resource(pdev, IORESOURCE_IO, 0); |
| if (!res) { |
| dev_err(&pdev->dev, "can't fetch device resource info\n"); |
| goto done; |
| } |
| |
| if (!request_region(res->start, resource_size(res), pdev->name)) { |
| dev_err(&pdev->dev, "can't request region\n"); |
| goto done; |
| } |
| |
| /* set up the driver-specific struct */ |
| cs5535_mfgpt_chip.base = res->start; |
| cs5535_mfgpt_chip.pdev = pdev; |
| spin_lock_init(&cs5535_mfgpt_chip.lock); |
| |
| dev_info(&pdev->dev, "reserved resource region %pR\n", res); |
| |
| /* detect the available timers */ |
| t = scan_timers(&cs5535_mfgpt_chip); |
| dev_info(&pdev->dev, "%d MFGPT timers available\n", t); |
| cs5535_mfgpt_chip.initialized = 1; |
| return 0; |
| |
| done: |
| return err; |
| } |
| |
| static struct platform_driver cs5535_mfgpt_driver = { |
| .driver = { |
| .name = DRV_NAME, |
| .owner = THIS_MODULE, |
| }, |
| .probe = cs5535_mfgpt_probe, |
| }; |
| |
| |
| static int __init cs5535_mfgpt_init(void) |
| { |
| return platform_driver_register(&cs5535_mfgpt_driver); |
| } |
| |
| module_init(cs5535_mfgpt_init); |
| |
| MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>"); |
| MODULE_DESCRIPTION("CS5535/CS5536 MFGPT timer driver"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("platform:" DRV_NAME); |