diff options
Diffstat (limited to 'drivers/firewire')
| -rw-r--r-- | drivers/firewire/core-cdev.c | 16 | ||||
| -rw-r--r-- | drivers/firewire/ohci.c | 57 |
2 files changed, 36 insertions, 37 deletions
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c index e6d63849e78..ecd0a4d81ab 100644 --- a/drivers/firewire/core-cdev.c +++ b/drivers/firewire/core-cdev.c @@ -25,6 +25,7 @@ #include <linux/firewire.h> #include <linux/firewire-cdev.h> #include <linux/idr.h> +#include <linux/irqflags.h> #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/kref.h> @@ -32,7 +33,6 @@ #include <linux/module.h> #include <linux/mutex.h> #include <linux/poll.h> -#include <linux/preempt.h> #include <linux/sched.h> #include <linux/spinlock.h> #include <linux/time.h> @@ -1013,21 +1013,19 @@ static int ioctl_get_cycle_timer(struct client *client, void *buffer) { struct fw_cdev_get_cycle_timer *request = buffer; struct fw_card *card = client->device->card; - unsigned long long bus_time; struct timeval tv; - unsigned long flags; + u32 cycle_time; - preempt_disable(); - local_irq_save(flags); + local_irq_disable(); - bus_time = card->driver->get_bus_time(card); + cycle_time = card->driver->get_bus_time(card); do_gettimeofday(&tv); - local_irq_restore(flags); - preempt_enable(); + local_irq_enable(); request->local_time = tv.tv_sec * 1000000ULL + tv.tv_usec; - request->cycle_timer = bus_time & 0xffffffff; + request->cycle_timer = cycle_time; + return 0; } diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index bf5e1128442..c3eb471d22f 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1795,60 +1795,61 @@ static int ohci_enable_phys_dma(struct fw_card *card, #endif /* CONFIG_FIREWIRE_OHCI_REMOTE_DMA */ } -static inline u32 cycle_timer_ticks(u32 cycle_timer) +static u32 cycle_timer_ticks(u32 cycle_timer) { u32 ticks; ticks = cycle_timer & 0xfff; ticks += 3072 * ((cycle_timer >> 12) & 0x1fff); ticks += (3072 * 8000) * (cycle_timer >> 25); + return ticks; } +/* + * Some controllers exhibit one or more of the following bugs when updating the + * iso cycle timer register: + * - When the lowest six bits are wrapping around to zero, a read that happens + * at the same time will return garbage in the lowest ten bits. + * - When the cycleOffset field wraps around to zero, the cycleCount field is + * not incremented for about 60 ns. + * - Occasionally, the entire register reads zero. + * + * To catch these, we read the register three times and ensure that the + * difference between each two consecutive reads is approximately the same, i.e. + * less than twice the other. Furthermore, any negative difference indicates an + * error. (A PCI read should take at least 20 ticks of the 24.576 MHz timer to + * execute, so we have enough precision to compute the ratio of the differences.) + */ static u64 ohci_get_bus_time(struct fw_card *card) { struct fw_ohci *ohci = fw_ohci(card); u32 c0, c1, c2; u32 t0, t1, t2; s32 diff01, diff12; - u64 bus_time; + int i; - if (!ohci->iso_cycle_timer_quirk) { + c2 = reg_read(ohci, OHCI1394_IsochronousCycleTimer); + + if (ohci->iso_cycle_timer_quirk) { + i = 0; + c1 = c2; c2 = reg_read(ohci, OHCI1394_IsochronousCycleTimer); - } else { - /* - * Some controllers exhibit one or more of the following bugs - * when updating the iso cycle timer register: - * - When the lowest six bits are wrapping around to zero, - * a read that happens at the same time will return garbage - * in the lowest ten bits. - * - When the cycleOffset field wraps around to zero, the - * cycleCount field is not incremented for about 60 ns. - * - Occasionally, the entire register reads zero. - * - * To catch these, we read the register three times and ensure - * that the difference between each two consecutive reads is - * approximately the same, i.e., less than twice the other. - * Furthermore, any negative difference indicates an error. - * (A PCI read should take at least 20 ticks of the 24.576 MHz - * timer to execute, so we have enough precision to compute the - * ratio of the differences.) - */ do { - c0 = reg_read(ohci, OHCI1394_IsochronousCycleTimer); - c1 = reg_read(ohci, OHCI1394_IsochronousCycleTimer); + c0 = c1; + c1 = c2; c2 = reg_read(ohci, OHCI1394_IsochronousCycleTimer); t0 = cycle_timer_ticks(c0); t1 = cycle_timer_ticks(c1); t2 = cycle_timer_ticks(c2); diff01 = t1 - t0; diff12 = t2 - t1; - } while (diff01 <= 0 || diff12 <= 0 || - diff01 / diff12 >= 2 || diff12 / diff01 >= 2); + } while ((diff01 <= 0 || diff12 <= 0 || + diff01 / diff12 >= 2 || diff12 / diff01 >= 2) + && i++ < 20); } - bus_time = ((u64)atomic_read(&ohci->bus_seconds) << 32) | c2; - return bus_time; + return ((u64)atomic_read(&ohci->bus_seconds) << 32) | c2; } static void copy_iso_headers(struct iso_context *ctx, void *p) |