diff options
Diffstat (limited to 'arch/powerpc/platforms/52xx/mpc52xx_gpt.c')
| -rw-r--r-- | arch/powerpc/platforms/52xx/mpc52xx_gpt.c | 432 |
1 files changed, 417 insertions, 15 deletions
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c index bfbcd418e690..6f8ebe1085b3 100644 --- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c +++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c @@ -16,8 +16,14 @@ * output signals or measure input signals. * * This driver supports the GPIO and IRQ controller functions of the GPT - * device. Timer functions are not yet supported, nor is the watchdog - * timer. + * device. Timer functions are not yet supported. + * + * The timer gpt0 can be used as watchdog (wdt). If the wdt mode is used, + * this prevents the use of any gpt0 gpt function (i.e. they will fail with + * -EBUSY). Thus, the safety wdt function always has precedence over the gpt + * function. If the kernel has been compiled with CONFIG_WATCHDOG_NOWAYOUT, + * this means that gpt0 is locked in wdt mode until the next reboot - this + * may be a requirement in safety applications. * * To use the GPIO function, the following two properties must be added * to the device tree node for the gpt device (typically in the .dts file @@ -46,17 +52,24 @@ * the output mode. This driver does not change the output mode setting. */ +#include <linux/device.h> #include <linux/irq.h> #include <linux/interrupt.h> #include <linux/io.h> +#include <linux/list.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/of_platform.h> #include <linux/of_gpio.h> #include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/miscdevice.h> +#include <linux/uaccess.h> +#include <asm/div64.h> #include <asm/mpc52xx.h> MODULE_DESCRIPTION("Freescale MPC52xx gpt driver"); -MODULE_AUTHOR("Sascha Hauer, Grant Likely"); +MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß"); MODULE_LICENSE("GPL"); /** @@ -66,18 +79,27 @@ MODULE_LICENSE("GPL"); * @lock: spinlock to coordinate between different functions. * @of_gc: of_gpio_chip instance structure; used when GPIO is enabled * @irqhost: Pointer to irq_host instance; used when IRQ mode is supported + * @wdt_mode: only relevant for gpt0: bit 0 (MPC52xx_GPT_CAN_WDT) indicates + * if the gpt may be used as wdt, bit 1 (MPC52xx_GPT_IS_WDT) indicates + * if the timer is actively used as wdt which blocks gpt functions */ struct mpc52xx_gpt_priv { + struct list_head list; /* List of all GPT devices */ struct device *dev; struct mpc52xx_gpt __iomem *regs; spinlock_t lock; struct irq_host *irqhost; + u32 ipb_freq; + u8 wdt_mode; #if defined(CONFIG_GPIOLIB) struct of_gpio_chip of_gc; #endif }; +LIST_HEAD(mpc52xx_gpt_list); +DEFINE_MUTEX(mpc52xx_gpt_list_mutex); + #define MPC52xx_GPT_MODE_MS_MASK (0x07) #define MPC52xx_GPT_MODE_MS_IC (0x01) #define MPC52xx_GPT_MODE_MS_OC (0x02) @@ -88,15 +110,25 @@ struct mpc52xx_gpt_priv { #define MPC52xx_GPT_MODE_GPIO_OUT_LOW (0x20) #define MPC52xx_GPT_MODE_GPIO_OUT_HIGH (0x30) +#define MPC52xx_GPT_MODE_COUNTER_ENABLE (0x1000) +#define MPC52xx_GPT_MODE_CONTINUOUS (0x0400) +#define MPC52xx_GPT_MODE_OPEN_DRAIN (0x0200) #define MPC52xx_GPT_MODE_IRQ_EN (0x0100) +#define MPC52xx_GPT_MODE_WDT_EN (0x8000) #define MPC52xx_GPT_MODE_ICT_MASK (0x030000) #define MPC52xx_GPT_MODE_ICT_RISING (0x010000) #define MPC52xx_GPT_MODE_ICT_FALLING (0x020000) #define MPC52xx_GPT_MODE_ICT_TOGGLE (0x030000) +#define MPC52xx_GPT_MODE_WDT_PING (0xa5) + #define MPC52xx_GPT_STATUS_IRQMASK (0x000f) +#define MPC52xx_GPT_CAN_WDT (1 << 0) +#define MPC52xx_GPT_IS_WDT (1 << 1) + + /* --------------------------------------------------------------------- * Cascaded interrupt controller hooks */ @@ -149,7 +181,7 @@ static int mpc52xx_gpt_irq_set_type(unsigned int virq, unsigned int flow_type) } static struct irq_chip mpc52xx_gpt_irq_chip = { - .typename = "MPC52xx GPT", + .name = "MPC52xx GPT", .unmask = mpc52xx_gpt_irq_unmask, .mask = mpc52xx_gpt_irq_mask, .ack = mpc52xx_gpt_irq_ack, @@ -182,7 +214,7 @@ static int mpc52xx_gpt_irq_map(struct irq_host *h, unsigned int virq, } static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct, - u32 *intspec, unsigned int intsize, + const u32 *intspec, unsigned int intsize, irq_hw_number_t *out_hwirq, unsigned int *out_flags) { @@ -190,7 +222,7 @@ static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct, dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]); - if ((intsize < 1) || (intspec[0] < 1) || (intspec[0] > 3)) { + if ((intsize < 1) || (intspec[0] > 3)) { dev_err(gpt->dev, "bad irq specifier in %s\n", ct->full_name); return -EINVAL; } @@ -211,13 +243,11 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) { int cascade_virq; unsigned long flags; - - /* Only setup cascaded IRQ if device tree claims the GPT is - * an interrupt controller */ - if (!of_find_property(node, "interrupt-controller", NULL)) - return; + u32 mode; cascade_virq = irq_of_parse_and_map(node, 0); + if (!cascade_virq) + return; gpt->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR, 1, &mpc52xx_gpt_irq_ops, -1); @@ -227,14 +257,16 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) } gpt->irqhost->host_data = gpt; - set_irq_data(cascade_virq, gpt); set_irq_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade); - /* Set to Input Capture mode */ + /* If the GPT is currently disabled, then change it to be in Input + * Capture mode. If the mode is non-zero, then the pin could be + * already in use for something. */ spin_lock_irqsave(&gpt->lock, flags); - clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK, - MPC52xx_GPT_MODE_MS_IC); + mode = in_be32(&gpt->regs->mode); + if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0) + out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC); spin_unlock_irqrestore(&gpt->lock, flags); dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq); @@ -335,6 +367,354 @@ static void mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { } #endif /* defined(CONFIG_GPIOLIB) */ +/*********************************************************************** + * Timer API + */ + +/** + * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number + * @irq: irq of timer. + */ +struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq) +{ + struct mpc52xx_gpt_priv *gpt; + struct list_head *pos; + + /* Iterate over the list of timers looking for a matching device */ + mutex_lock(&mpc52xx_gpt_list_mutex); + list_for_each(pos, &mpc52xx_gpt_list) { + gpt = container_of(pos, struct mpc52xx_gpt_priv, list); + if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) { + mutex_unlock(&mpc52xx_gpt_list_mutex); + return gpt; + } + } + mutex_unlock(&mpc52xx_gpt_list_mutex); + + return NULL; +} +EXPORT_SYMBOL(mpc52xx_gpt_from_irq); + +static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period, + int continuous, int as_wdt) +{ + u32 clear, set; + u64 clocks; + u32 prescale; + unsigned long flags; + + clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS; + set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE; + if (as_wdt) { + clear |= MPC52xx_GPT_MODE_IRQ_EN; + set |= MPC52xx_GPT_MODE_WDT_EN; + } else if (continuous) + set |= MPC52xx_GPT_MODE_CONTINUOUS; + + /* Determine the number of clocks in the requested period. 64 bit + * arithmatic is done here to preserve the precision until the value + * is scaled back down into the u32 range. Period is in 'ns', bus + * frequency is in Hz. */ + clocks = period * (u64)gpt->ipb_freq; + do_div(clocks, 1000000000); /* Scale it down to ns range */ + + /* This device cannot handle a clock count greater than 32 bits */ + if (clocks > 0xffffffff) + return -EINVAL; + + /* Calculate the prescaler and count values from the clocks value. + * 'clocks' is the number of clock ticks in the period. The timer + * has 16 bit precision and a 16 bit prescaler. Prescaler is + * calculated by integer dividing the clocks by 0x10000 (shifting + * down 16 bits) to obtain the smallest possible divisor for clocks + * to get a 16 bit count value. + * + * Note: the prescale register is '1' based, not '0' based. ie. a + * value of '1' means divide the clock by one. 0xffff divides the + * clock by 0xffff. '0x0000' does not divide by zero, but wraps + * around and divides by 0x10000. That is why prescale must be + * a u32 variable, not a u16, for this calculation. */ + prescale = (clocks >> 16) + 1; + do_div(clocks, prescale); + if (clocks > 0xffff) { + pr_err("calculation error; prescale:%x clocks:%llx\n", + prescale, clocks); + return -EINVAL; + } + + /* Set and enable the timer, reject an attempt to use a wdt as gpt */ + spin_lock_irqsave(&gpt->lock, flags); + if (as_wdt) + gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; + else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { + spin_unlock_irqrestore(&gpt->lock, flags); + return -EBUSY; + } + out_be32(&gpt->regs->count, prescale << 16 | clocks); + clrsetbits_be32(&gpt->regs->mode, clear, set); + spin_unlock_irqrestore(&gpt->lock, flags); + + return 0; +} + +/** + * mpc52xx_gpt_start_timer - Set and enable the GPT timer + * @gpt: Pointer to gpt private data structure + * @period: period of timer in ns; max. ~130s @ 33MHz IPB clock + * @continuous: set to 1 to make timer continuous free running + * + * An interrupt will be generated every time the timer fires + */ +int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, u64 period, + int continuous) +{ + return mpc52xx_gpt_do_start(gpt, period, continuous, 0); +} +EXPORT_SYMBOL(mpc52xx_gpt_start_timer); + +/** + * mpc52xx_gpt_stop_timer - Stop a gpt + * @gpt: Pointer to gpt private data structure + * + * Returns an error if attempting to stop a wdt + */ +int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt) +{ + unsigned long flags; + + /* reject the operation if the timer is used as watchdog (gpt 0 only) */ + spin_lock_irqsave(&gpt->lock, flags); + if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { + spin_unlock_irqrestore(&gpt->lock, flags); + return -EBUSY; + } + + clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE); + spin_unlock_irqrestore(&gpt->lock, flags); + return 0; +} +EXPORT_SYMBOL(mpc52xx_gpt_stop_timer); + +/** + * mpc52xx_gpt_timer_period - Read the timer period + * @gpt: Pointer to gpt private data structure + * + * Returns the timer period in ns + */ +u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt) +{ + u64 period; + u64 prescale; + unsigned long flags; + + spin_lock_irqsave(&gpt->lock, flags); + period = in_be32(&gpt->regs->count); + spin_unlock_irqrestore(&gpt->lock, flags); + + prescale = period >> 16; + period &= 0xffff; + if (prescale == 0) + prescale = 0x10000; + period = period * prescale * 1000000000ULL; + do_div(period, (u64)gpt->ipb_freq); + return period; +} +EXPORT_SYMBOL(mpc52xx_gpt_timer_period); + +#if defined(CONFIG_MPC5200_WDT) +/*********************************************************************** + * Watchdog API for gpt0 + */ + +#define WDT_IDENTITY "mpc52xx watchdog on GPT0" + +/* wdt_is_active stores wether or not the /dev/watchdog device is opened */ +static unsigned long wdt_is_active; + +/* wdt-capable gpt */ +static struct mpc52xx_gpt_priv *mpc52xx_gpt_wdt; + +/* low-level wdt functions */ +static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt) +{ + unsigned long flags; + + spin_lock_irqsave(&gpt_wdt->lock, flags); + out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING); + spin_unlock_irqrestore(&gpt_wdt->lock, flags); +} + +/* wdt misc device api */ +static ssize_t mpc52xx_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + mpc52xx_gpt_wdt_ping(gpt_wdt); + return 0; +} + +static struct watchdog_info mpc5200_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = WDT_IDENTITY, +}; + +static long mpc52xx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + int __user *data = (int __user *)arg; + int timeout; + u64 real_timeout; + int ret = 0; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user(data, &mpc5200_wdt_info, + sizeof(mpc5200_wdt_info)); + if (ret) + ret = -EFAULT; + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, data); + break; + + case WDIOC_KEEPALIVE: + mpc52xx_gpt_wdt_ping(gpt_wdt); + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(timeout, data); + if (ret) + break; + real_timeout = (u64) timeout * 1000000000ULL; + ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1); + if (ret) + break; + /* fall through and return the timeout */ + + case WDIOC_GETTIMEOUT: + /* we need to round here as to avoid e.g. the following + * situation: + * - timeout requested is 1 second; + * - real timeout @33MHz is 999997090ns + * - the int divide by 10^9 will return 0. + */ + real_timeout = + mpc52xx_gpt_timer_period(gpt_wdt) + 500000000ULL; + do_div(real_timeout, 1000000000ULL); + timeout = (int) real_timeout; + ret = put_user(timeout, data); + break; + + default: + ret = -ENOTTY; + } + return ret; +} + +static int mpc52xx_wdt_open(struct inode *inode, struct file *file) +{ + int ret; + + /* sanity check */ + if (!mpc52xx_gpt_wdt) + return -ENODEV; + + /* /dev/watchdog can only be opened once */ + if (test_and_set_bit(0, &wdt_is_active)) + return -EBUSY; + + /* Set and activate the watchdog with 30 seconds timeout */ + ret = mpc52xx_gpt_do_start(mpc52xx_gpt_wdt, 30ULL * 1000000000ULL, + 0, 1); + if (ret) { + clear_bit(0, &wdt_is_active); + return ret; + } + + file->private_data = mpc52xx_gpt_wdt; + return nonseekable_open(inode, file); +} + +static int mpc52xx_wdt_release(struct inode *inode, struct file *file) +{ + /* note: releasing the wdt in NOWAYOUT-mode does not stop it */ +#if !defined(CONFIG_WATCHDOG_NOWAYOUT) + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + unsigned long flags; + + spin_lock_irqsave(&gpt_wdt->lock, flags); + clrbits32(&gpt_wdt->regs->mode, + MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN); + gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT; + spin_unlock_irqrestore(&gpt_wdt->lock, flags); +#endif + clear_bit(0, &wdt_is_active); + return 0; +} + + +static const struct file_operations mpc52xx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = mpc52xx_wdt_write, + .unlocked_ioctl = mpc52xx_wdt_ioctl, + .open = mpc52xx_wdt_open, + .release = mpc52xx_wdt_release, +}; + +static struct miscdevice mpc52xx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &mpc52xx_wdt_fops, +}; + +static int __devinit mpc52xx_gpt_wdt_init(void) +{ + int err; + + /* try to register the watchdog misc device */ + err = misc_register(&mpc52xx_wdt_miscdev); + if (err) + pr_err("%s: cannot register watchdog device\n", WDT_IDENTITY); + else + pr_info("%s: watchdog device registered\n", WDT_IDENTITY); + return err; +} + +static int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, + const u32 *period) +{ + u64 real_timeout; + + /* remember the gpt for the wdt operation */ + mpc52xx_gpt_wdt = gpt; + + /* configure the wdt if the device tree contained a timeout */ + if (!period || *period == 0) + return 0; + + real_timeout = (u64) *period * 1000000000ULL; + if (mpc52xx_gpt_do_start(gpt, real_timeout, 0, 1)) + dev_warn(gpt->dev, "starting as wdt failed\n"); + else + dev_info(gpt->dev, "watchdog set to %us timeout\n", *period); + return 0; +} + +#else + +static int __devinit mpc52xx_gpt_wdt_init(void) +{ + return 0; +} + +#define mpc52xx_gpt_wdt_setup(x, y) (0) + +#endif /* CONFIG_MPC5200_WDT */ + /* --------------------------------------------------------------------- * of_platform bus binding code */ @@ -349,6 +729,7 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev, spin_lock_init(&gpt->lock); gpt->dev = &ofdev->dev; + gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->node); gpt->regs = of_iomap(ofdev->node, 0); if (!gpt->regs) { kfree(gpt); @@ -360,6 +741,26 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev, mpc52xx_gpt_gpio_setup(gpt, ofdev->node); mpc52xx_gpt_irq_setup(gpt, ofdev->node); + mutex_lock(&mpc52xx_gpt_list_mutex); + list_add(&gpt->list, &mpc52xx_gpt_list); + mutex_unlock(&mpc52xx_gpt_list_mutex); + + /* check if this device could be a watchdog */ + if (of_get_property(ofdev->node, "fsl,has-wdt", NULL) || + of_get_property(ofdev->node, "has-wdt", NULL)) { + const u32 *on_boot_wdt; + + gpt->wdt_mode = MPC52xx_GPT_CAN_WDT; + on_boot_wdt = of_get_property(ofdev->node, "fsl,wdt-on-boot", + NULL); + if (on_boot_wdt) { + dev_info(gpt->dev, "used as watchdog\n"); + gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; + } else + dev_info(gpt->dev, "can function as watchdog\n"); + mpc52xx_gpt_wdt_setup(gpt, on_boot_wdt); + } + return 0; } @@ -394,3 +795,4 @@ static int __init mpc52xx_gpt_init(void) /* Make sure GPIOs and IRQs get set up before anyone tries to use them */ subsys_initcall(mpc52xx_gpt_init); +device_initcall(mpc52xx_gpt_wdt_init); |