diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/Makefile | 2 | ||||
| -rw-r--r-- | drivers/char/apm-emulation.c | 672 |
2 files changed, 674 insertions, 0 deletions
diff --git a/drivers/char/Makefile b/drivers/char/Makefile index 0326ca1a848..ae8567cc529 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -60,6 +60,8 @@ obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o obj-$(CONFIG_PRINTER) += lp.o obj-$(CONFIG_TIPAR) += tipar.o +obj-$(CONFIG_APM_EMULATION) += apm-emulation.o + obj-$(CONFIG_DTLK) += dtlk.o obj-$(CONFIG_R3964) += n_r3964.o obj-$(CONFIG_APPLICOM) += applicom.o diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c new file mode 100644 index 00000000000..179c7a3b6e7 --- /dev/null +++ b/drivers/char/apm-emulation.c @@ -0,0 +1,672 @@ +/* + * bios-less APM driver for ARM Linux + * Jamey Hicks <jamey@crl.dec.com> + * adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com) + * + * APM 1.2 Reference: + * Intel Corporation, Microsoft Corporation. Advanced Power Management + * (APM) BIOS Interface Specification, Revision 1.2, February 1996. + * + * [This document is available from Microsoft at: + * http://www.microsoft.com/hwdev/busbios/amp_12.htm] + */ +#include <linux/module.h> +#include <linux/poll.h> +#include <linux/slab.h> +#include <linux/proc_fs.h> +#include <linux/miscdevice.h> +#include <linux/apm_bios.h> +#include <linux/capability.h> +#include <linux/sched.h> +#include <linux/pm.h> +#include <linux/apm-emulation.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/init.h> +#include <linux/completion.h> +#include <linux/kthread.h> +#include <linux/delay.h> + +#include <asm/system.h> + +/* + * The apm_bios device is one of the misc char devices. + * This is its minor number. + */ +#define APM_MINOR_DEV 134 + +/* + * See Documentation/Config.help for the configuration options. + * + * Various options can be changed at boot time as follows: + * (We allow underscores for compatibility with the modules code) + * apm=on/off enable/disable APM + */ + +/* + * Maximum number of events stored + */ +#define APM_MAX_EVENTS 16 + +struct apm_queue { + unsigned int event_head; + unsigned int event_tail; + apm_event_t events[APM_MAX_EVENTS]; +}; + +/* + * The per-file APM data + */ +struct apm_user { + struct list_head list; + + unsigned int suser: 1; + unsigned int writer: 1; + unsigned int reader: 1; + + int suspend_result; + unsigned int suspend_state; +#define SUSPEND_NONE 0 /* no suspend pending */ +#define SUSPEND_PENDING 1 /* suspend pending read */ +#define SUSPEND_READ 2 /* suspend read, pending ack */ +#define SUSPEND_ACKED 3 /* suspend acked */ +#define SUSPEND_WAIT 4 /* waiting for suspend */ +#define SUSPEND_DONE 5 /* suspend completed */ + + struct apm_queue queue; +}; + +/* + * Local variables + */ +static int suspends_pending; +static int apm_disabled; +static struct task_struct *kapmd_tsk; + +static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); +static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); + +/* + * This is a list of everyone who has opened /dev/apm_bios + */ +static DECLARE_RWSEM(user_list_lock); +static LIST_HEAD(apm_user_list); + +/* + * kapmd info. kapmd provides us a process context to handle + * "APM" events within - specifically necessary if we're going + * to be suspending the system. + */ +static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait); +static DEFINE_SPINLOCK(kapmd_queue_lock); +static struct apm_queue kapmd_queue; + +static DEFINE_MUTEX(state_lock); + +static const char driver_version[] = "1.13"; /* no spaces */ + + + +/* + * Compatibility cruft until the IPAQ people move over to the new + * interface. + */ +static void __apm_get_power_status(struct apm_power_info *info) +{ +} + +/* + * This allows machines to provide their own "apm get power status" function. + */ +void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status; +EXPORT_SYMBOL(apm_get_power_status); + + +/* + * APM event queue management. + */ +static inline int queue_empty(struct apm_queue *q) +{ + return q->event_head == q->event_tail; +} + +static inline apm_event_t queue_get_event(struct apm_queue *q) +{ + q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; + return q->events[q->event_tail]; +} + +static void queue_add_event(struct apm_queue *q, apm_event_t event) +{ + q->event_head = (q->event_head + 1) % APM_MAX_EVENTS; + if (q->event_head == q->event_tail) { + static int notified; + + if (notified++ == 0) + printk(KERN_ERR "apm: an event queue overflowed\n"); + q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; + } + q->events[q->event_head] = event; +} + +static void queue_event(apm_event_t event) +{ + struct apm_user *as; + + down_read(&user_list_lock); + list_for_each_entry(as, &apm_user_list, list) { + if (as->reader) + queue_add_event(&as->queue, event); + } + up_read(&user_list_lock); + wake_up_interruptible(&apm_waitqueue); +} + +/* + * queue_suspend_event - queue an APM suspend event. + * + * Check that we're in a state where we can suspend. If not, + * return -EBUSY. Otherwise, queue an event to all "writer" + * users. If there are no "writer" users, return '1' to + * indicate that we can immediately suspend. + */ +static int queue_suspend_event(apm_event_t event, struct apm_user *sender) +{ + struct apm_user *as; + int ret = 1; + + mutex_lock(&state_lock); + down_read(&user_list_lock); + + /* + * If a thread is still processing, we can't suspend, so reject + * the request. + */ + list_for_each_entry(as, &apm_user_list, list) { + if (as != sender && as->reader && as->writer && as->suser && + as->suspend_state != SUSPEND_NONE) { + ret = -EBUSY; + goto out; + } + } + + list_for_each_entry(as, &apm_user_list, list) { + if (as != sender && as->reader && as->writer && as->suser) { + as->suspend_state = SUSPEND_PENDING; + suspends_pending++; + queue_add_event(&as->queue, event); + ret = 0; + } + } + out: + up_read(&user_list_lock); + mutex_unlock(&state_lock); + wake_up_interruptible(&apm_waitqueue); + return ret; +} + +static void apm_suspend(void) +{ + struct apm_user *as; + int err = pm_suspend(PM_SUSPEND_MEM); + + /* + * Anyone on the APM queues will think we're still suspended. + * Send a message so everyone knows we're now awake again. + */ + queue_event(APM_NORMAL_RESUME); + + /* + * Finally, wake up anyone who is sleeping on the suspend. + */ + mutex_lock(&state_lock); + down_read(&user_list_lock); + list_for_each_entry(as, &apm_user_list, list) { + if (as->suspend_state == SUSPEND_WAIT || + as->suspend_state == SUSPEND_ACKED) { + as->suspend_result = err; + as->suspend_state = SUSPEND_DONE; + } + } + up_read(&user_list_lock); + mutex_unlock(&state_lock); + + wake_up(&apm_suspend_waitqueue); +} + +static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos) +{ + struct apm_user *as = fp->private_data; + apm_event_t event; + int i = count, ret = 0; + + if (count < sizeof(apm_event_t)) + return -EINVAL; + + if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK) + return -EAGAIN; + + wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue)); + + while ((i >= sizeof(event)) && !queue_empty(&as->queue)) { + event = queue_get_event(&as->queue); + + ret = -EFAULT; + if (copy_to_user(buf, &event, sizeof(event))) + break; + + mutex_lock(&state_lock); + if (as->suspend_state == SUSPEND_PENDING && + (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)) + as->suspend_state = SUSPEND_READ; + mutex_unlock(&state_lock); + + buf += sizeof(event); + i -= sizeof(event); + } + + if (i < count) + ret = count - i; + + return ret; +} + +static unsigned int apm_poll(struct file *fp, poll_table * wait) +{ + struct apm_user *as = fp->private_data; + + poll_wait(fp, &apm_waitqueue, wait); + return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM; +} + +/* + * apm_ioctl - handle APM ioctl + * + * APM_IOC_SUSPEND + * This IOCTL is overloaded, and performs two functions. It is used to: + * - initiate a suspend + * - acknowledge a suspend read from /dev/apm_bios. + * Only when everyone who has opened /dev/apm_bios with write permission + * has acknowledge does the actual suspend happen. + */ +static int +apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg) +{ + struct apm_user *as = filp->private_data; + unsigned long flags; + int err = -EINVAL; + + if (!as->suser || !as->writer) + return -EPERM; + + switch (cmd) { + case APM_IOC_SUSPEND: + mutex_lock(&state_lock); + + as->suspend_result = -EINTR; + + if (as->suspend_state == SUSPEND_READ) { + int pending; + + /* + * If we read a suspend command from /dev/apm_bios, + * then the corresponding APM_IOC_SUSPEND ioctl is + * interpreted as an acknowledge. + */ + as->suspend_state = SUSPEND_ACKED; + suspends_pending--; + pending = suspends_pending == 0; + mutex_unlock(&state_lock); + + /* + * If there are no further acknowledges required, + * suspend the system. + */ + if (pending) + apm_suspend(); + + /* + * Wait for the suspend/resume to complete. If there + * are pending acknowledges, we wait here for them. + * + * Note: we need to ensure that the PM subsystem does + * not kick us out of the wait when it suspends the + * threads. + */ + flags = current->flags; + current->flags |= PF_NOFREEZE; + + wait_event(apm_suspend_waitqueue, + as->suspend_state == SUSPEND_DONE); + } else { + as->suspend_state = SUSPEND_WAIT; + mutex_unlock(&state_lock); + + /* + * Otherwise it is a request to suspend the system. + * Queue an event for all readers, and expect an + * acknowledge from all writers who haven't already + * acknowledged. + */ + err = queue_suspend_event(APM_USER_SUSPEND, as); + if (err < 0) { + /* + * Avoid taking the lock here - this + * should be fine. + */ + as->suspend_state = SUSPEND_NONE; + break; + } + + if (err > 0) + apm_suspend(); + + /* + * Wait for the suspend/resume to complete. If there + * are pending acknowledges, we wait here for them. + * + * Note: we need to ensure that the PM subsystem does + * not kick us out of the wait when it suspends the + * threads. + */ + flags = current->flags; + current->flags |= PF_NOFREEZE; + + wait_event_interruptible(apm_suspend_waitqueue, + as->suspend_state == SUSPEND_DONE); + } + + current->flags = flags; + + mutex_lock(&state_lock); + err = as->suspend_result; + as->suspend_state = SUSPEND_NONE; + mutex_unlock(&state_lock); + break; + } + + return err; +} + +static int apm_release(struct inode * inode, struct file * filp) +{ + struct apm_user *as = filp->private_data; + int pending = 0; + + filp->private_data = NULL; + + down_write(&user_list_lock); + list_del(&as->list); + up_write(&user_list_lock); + + /* + * We are now unhooked from the chain. As far as new + * events are concerned, we no longer exist. However, we + * need to balance suspends_pending, which means the + * possibility of sleeping. + */ + mutex_lock(&state_lock); + if (as->suspend_state != SUSPEND_NONE) { + suspends_pending -= 1; + pending = suspends_pending == 0; + } + mutex_unlock(&state_lock); + if (pending) + apm_suspend(); + + kfree(as); + return 0; +} + +static int apm_open(struct inode * inode, struct file * filp) +{ + struct apm_user *as; + + as = kzalloc(sizeof(*as), GFP_KERNEL); + if (as) { + /* + * XXX - this is a tiny bit broken, when we consider BSD + * process accounting. If the device is opened by root, we + * instantly flag that we used superuser privs. Who knows, + * we might close the device immediately without doing a + * privileged operation -- cevans + */ + as->suser = capable(CAP_SYS_ADMIN); + as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE; + as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ; + + down_write(&user_list_lock); + list_add(&as->list, &apm_user_list); + up_write(&user_list_lock); + + filp->private_data = as; + } + + return as ? 0 : -ENOMEM; +} + +static struct file_operations apm_bios_fops = { + .owner = THIS_MODULE, + .read = apm_read, + .poll = apm_poll, + .ioctl = apm_ioctl, + .open = apm_open, + .release = apm_release, +}; + +static struct miscdevice apm_device = { + .minor = APM_MINOR_DEV, + .name = "apm_bios", + .fops = &apm_bios_fops +}; + + +#ifdef CONFIG_PROC_FS +/* + * Arguments, with symbols from linux/apm_bios.h. + * + * 0) Linux driver version (this will change if format changes) + * 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2. + * 2) APM flags from APM Installation Check (0x00): + * bit 0: APM_16_BIT_SUPPORT + * bit 1: APM_32_BIT_SUPPORT + * bit 2: APM_IDLE_SLOWS_CLOCK + * bit 3: APM_BIOS_DISABLED + * bit 4: APM_BIOS_DISENGAGED + * 3) AC line status + * 0x00: Off-line + * 0x01: On-line + * 0x02: On backup power (BIOS >= 1.1 only) + * 0xff: Unknown + * 4) Battery status + * 0x00: High + * 0x01: Low + * 0x02: Critical + * 0x03: Charging + * 0x04: Selected battery not present (BIOS >= 1.2 only) + * 0xff: Unknown + * 5) Battery flag + * bit 0: High + * bit 1: Low + * bit 2: Critical + * bit 3: Charging + * bit 7: No system battery + * 0xff: Unknown + * 6) Remaining battery life (percentage of charge): + * 0-100: valid + * -1: Unknown + * 7) Remaining battery life (time units): + * Number of remaining minutes or seconds + * -1: Unknown + * 8) min = minutes; sec = seconds + */ +static int apm_get_info(char *buf, char **start, off_t fpos, int length) +{ + struct apm_power_info info; + char *units; + int ret; + + info.ac_line_status = 0xff; + info.battery_status = 0xff; + info.battery_flag = 0xff; + info.battery_life = -1; + info.time = -1; + info.units = -1; + + if (apm_get_power_status) + apm_get_power_status(&info); + + switch (info.units) { + default: units = "?"; break; + case 0: units = "min"; break; + case 1: units = "sec"; break; + } + + ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n", + driver_version, APM_32_BIT_SUPPORT, + info.ac_line_status, info.battery_status, + info.battery_flag, info.battery_life, + info.time, units); + + return ret; +} +#endif + +static int kapmd(void *arg) +{ + do { + apm_event_t event; + int ret; + + wait_event_interruptible(kapmd_wait, + !queue_empty(&kapmd_queue) || kthread_should_stop()); + + if (kthread_should_stop()) + break; + + spin_lock_irq(&kapmd_queue_lock); + event = 0; + if (!queue_empty(&kapmd_queue)) + event = queue_get_event(&kapmd_queue); + spin_unlock_irq(&kapmd_queue_lock); + + switch (event) { + case 0: + break; + + case APM_LOW_BATTERY: + case APM_POWER_STATUS_CHANGE: + queue_event(event); + break; + + case APM_USER_SUSPEND: + case APM_SYS_SUSPEND: + ret = queue_suspend_event(event, NULL); + if (ret < 0) { + /* + * We were busy. Try again in 50ms. + */ + queue_add_event(&kapmd_queue, event); + msleep(50); + } + if (ret > 0) + apm_suspend(); + break; + + case APM_CRITICAL_SUSPEND: + apm_suspend(); + break; + } + } while (1); + + return 0; +} + +static int __init apm_init(void) +{ + int ret; + + if (apm_disabled) { + printk(KERN_NOTICE "apm: disabled on user request.\n"); + return -ENODEV; + } + + kapmd_tsk = kthread_create(kapmd, NULL, "kapmd"); + if (IS_ERR(kapmd_tsk)) { + ret = PTR_ERR(kapmd_tsk); + kapmd_tsk = NULL; + return ret; + } + kapmd_tsk->flags |= PF_NOFREEZE; + wake_up_process(kapmd_tsk); + +#ifdef CONFIG_PROC_FS + create_proc_info_entry("apm", 0, NULL, apm_get_info); +#endif + + ret = misc_register(&apm_device); + if (ret != 0) { + remove_proc_entry("apm", NULL); + kthread_stop(kapmd_tsk); + } + + return ret; +} + +static void __exit apm_exit(void) +{ + misc_deregister(&apm_device); + remove_proc_entry("apm", NULL); + + kthread_stop(kapmd_tsk); +} + +module_init(apm_init); +module_exit(apm_exit); + +MODULE_AUTHOR("Stephen Rothwell"); +MODULE_DESCRIPTION("Advanced Power Management"); +MODULE_LICENSE("GPL"); + +#ifndef MODULE +static int __init apm_setup(char *str) +{ + while ((str != NULL) && (*str != '\0')) { + if (strncmp(str, "off", 3) == 0) + apm_disabled = 1; + if (strncmp(str, "on", 2) == 0) + apm_disabled = 0; + str = strchr(str, ','); + if (str != NULL) + str += strspn(str, ", \t"); + } + return 1; +} + +__setup("apm=", apm_setup); +#endif + +/** + * apm_queue_event - queue an APM event for kapmd + * @event: APM event + * + * Queue an APM event for kapmd to process and ultimately take the + * appropriate action. Only a subset of events are handled: + * %APM_LOW_BATTERY + * %APM_POWER_STATUS_CHANGE + * %APM_USER_SUSPEND + * %APM_SYS_SUSPEND + * %APM_CRITICAL_SUSPEND + */ +void apm_queue_event(apm_event_t event) +{ + unsigned long flags; + + spin_lock_irqsave(&kapmd_queue_lock, flags); + queue_add_event(&kapmd_queue, event); + spin_unlock_irqrestore(&kapmd_queue_lock, flags); + + wake_up_interruptible(&kapmd_wait); +} +EXPORT_SYMBOL(apm_queue_event); |