From 79603a35009ff39562cd5634fa1cf513eb080f27 Mon Sep 17 00:00:00 2001 From: Mark Gross Date: Mon, 22 Jan 2007 20:40:44 -0800 Subject: [PATCH] [PATCH] tlclk: bug fix + misc fixes The following patch fixes a few problems with the tlclk driver. * bug in the select_amcb1_transmit_clock * racy read sys call * racy open sys call * use of add_timer where mod_timer would be better * change to the timer data parameter use Signed-off-by: Mark Gross Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/tlclk.c | 43 ++++++++++++++++++++++++++++--------------- 1 file changed, 28 insertions(+), 15 deletions(-) diff --git a/drivers/char/tlclk.c b/drivers/char/tlclk.c index 448d508..4fac2bd 100644 --- a/drivers/char/tlclk.c +++ b/drivers/char/tlclk.c @@ -186,6 +186,7 @@ static int got_event; /* if events processing have been done */ static void switchover_timeout(unsigned long data); static struct timer_list switchover_timer = TIMER_INITIALIZER(switchover_timeout , 0, 0); +static unsigned long tlclk_timer_data; static struct tlclk_alarms *alarm_events; @@ -197,10 +198,19 @@ static irqreturn_t tlclk_interrupt(int irq, void *dev_id); static DECLARE_WAIT_QUEUE_HEAD(wq); +static unsigned long useflags; +static DEFINE_MUTEX(tlclk_mutex); + static int tlclk_open(struct inode *inode, struct file *filp) { int result; + if (test_and_set_bit(0, &useflags)) + return -EBUSY; + /* this legacy device is always one per system and it doesn't + * know how to handle multiple concurrent clients. + */ + /* Make sure there is no interrupt pending while * initialising interrupt handler */ inb(TLCLK_REG6); @@ -221,6 +231,7 @@ static int tlclk_open(struct inode *inode, struct file *filp) static int tlclk_release(struct inode *inode, struct file *filp) { free_irq(telclk_interrupt, tlclk_interrupt); + clear_bit(0, &useflags); return 0; } @@ -230,26 +241,25 @@ static ssize_t tlclk_read(struct file *filp, char __user *buf, size_t count, { if (count < sizeof(struct tlclk_alarms)) return -EIO; + if (mutex_lock_interruptible(&tlclk_mutex)) + return -EINTR; + wait_event_interruptible(wq, got_event); - if (copy_to_user(buf, alarm_events, sizeof(struct tlclk_alarms))) + if (copy_to_user(buf, alarm_events, sizeof(struct tlclk_alarms))) { + mutex_unlock(&tlclk_mutex); return -EFAULT; + } memset(alarm_events, 0, sizeof(struct tlclk_alarms)); got_event = 0; + mutex_unlock(&tlclk_mutex); return sizeof(struct tlclk_alarms); } -static ssize_t tlclk_write(struct file *filp, const char __user *buf, size_t count, - loff_t *f_pos) -{ - return 0; -} - static const struct file_operations tlclk_fops = { .read = tlclk_read, - .write = tlclk_write, .open = tlclk_open, .release = tlclk_release, @@ -540,7 +550,7 @@ static ssize_t store_select_amcb1_transmit_clock(struct device *d, SET_PORT_BITS(TLCLK_REG3, 0xf8, 0x7); switch (val) { case CLK_8_592MHz: - SET_PORT_BITS(TLCLK_REG0, 0xfc, 1); + SET_PORT_BITS(TLCLK_REG0, 0xfc, 2); break; case CLK_11_184MHz: SET_PORT_BITS(TLCLK_REG0, 0xfc, 0); @@ -549,7 +559,7 @@ static ssize_t store_select_amcb1_transmit_clock(struct device *d, SET_PORT_BITS(TLCLK_REG0, 0xfc, 3); break; case CLK_44_736MHz: - SET_PORT_BITS(TLCLK_REG0, 0xfc, 2); + SET_PORT_BITS(TLCLK_REG0, 0xfc, 1); break; } } else @@ -839,11 +849,13 @@ static void __exit tlclk_cleanup(void) static void switchover_timeout(unsigned long data) { - if ((data & 1)) { - if ((inb(TLCLK_REG1) & 0x08) != (data & 0x08)) + unsigned long flags = *(unsigned long *) data; + + if ((flags & 1)) { + if ((inb(TLCLK_REG1) & 0x08) != (flags & 0x08)) alarm_events->switchover_primary++; } else { - if ((inb(TLCLK_REG1) & 0x08) != (data & 0x08)) + if ((inb(TLCLK_REG1) & 0x08) != (flags & 0x08)) alarm_events->switchover_secondary++; } @@ -901,8 +913,9 @@ static irqreturn_t tlclk_interrupt(int irq, void *dev_id) /* TIMEOUT in ~10ms */ switchover_timer.expires = jiffies + msecs_to_jiffies(10); - switchover_timer.data = inb(TLCLK_REG1); - add_timer(&switchover_timer); + tlclk_timer_data = inb(TLCLK_REG1); + switchover_timer.data = (unsigned long) &tlclk_timer_data; + mod_timer(&switchover_timer, switchover_timer.expires); } else { got_event = 1; wake_up(&wq); -- 2.7.4