From: Pieter Palmers <[email protected]>
This implements the simultaneous read of the isochronous cycle timer and
the system clock (in usecs). This allows to express the exact receive
time of an ISO packet as a system time with microsecond accuracy.
http://bugzilla.kernel.org/show_bug.cgi?id=7773
The counterpart patch for libraw1394 can be found at
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/8934
Patch update (Stefan R.):
- Disable preemption and local interrupts.
- Fix integer overflow.
- Add paranoid error checks and kerneldoc to hpsb_read_cycle_timer.
Move it to other ieee1394_core high-level API functions.
- Rename userspace-exported struct _raw1394_cycle_timer to
raw1394_cycle_timer. Change comments in raw1394.
- Adjust whitespace.
Signed-off-by: Stefan Richter <[email protected]>
---
Pieter, Dan, is this OK? I only compile-tested.
drivers/ieee1394/ieee1394-ioctl.h | 2 +
drivers/ieee1394/ieee1394_core.c | 43 ++++++++++++++++++++++++++++++
drivers/ieee1394/ieee1394_core.h | 3 ++
drivers/ieee1394/raw1394.c | 20 +++++++++++++
drivers/ieee1394/raw1394.h | 10 ++++++
5 files changed, 78 insertions(+)
Index: linux/drivers/ieee1394/ieee1394-ioctl.h
===================================================================
--- linux.orig/drivers/ieee1394/ieee1394-ioctl.h 2007-01-01 01:53:20.000000000 +0100
+++ linux/drivers/ieee1394/ieee1394-ioctl.h 2007-02-03 13:47:33.000000000 +0100
@@ -100,5 +100,7 @@
_IO ('#', 0x28)
#define RAW1394_IOC_ISO_RECV_FLUSH \
_IO ('#', 0x29)
+#define RAW1394_IOC_GET_CYCLE_TIMER \
+ _IOR ('#', 0x30, struct raw1394_cycle_timer)
#endif /* __IEEE1394_IOCTL_H */
Index: linux/drivers/ieee1394/ieee1394_core.c
===================================================================
--- linux.orig/drivers/ieee1394/ieee1394_core.c 2007-01-27 14:07:00.000000000 +0100
+++ linux/drivers/ieee1394/ieee1394_core.c 2007-02-03 13:47:33.000000000 +0100
@@ -33,6 +33,9 @@
#include <linux/skbuff.h>
#include <linux/suspend.h>
#include <linux/kthread.h>
+#include <linux/irqflags.h>
+#include <linux/preempt.h>
+#include <linux/time.h>
#include <asm/byteorder.h>
@@ -186,6 +189,45 @@ int hpsb_reset_bus(struct hpsb_host *hos
}
}
+/**
+ * hpsb_read_cycle_timer - read cycle timer register and system time
+ * @host: host whose isochronous cycle timer register is read
+ * @cycle_timer: address of bitfield to return the register contents
+ * @local_time: address to return the system time
+ *
+ * The format of * @cycle_timer, is described in OHCI 1.1 clause 5.13. This
+ * format is also read from non-OHCI controllers. * @local_time contains the
+ * system time in microseconds since the Epoch, read at the moment when the
+ * cycle timer was read.
+ *
+ * Return value: 0 for success or error number otherwise.
+ */
+int hpsb_read_cycle_timer(struct hpsb_host *host, u32 *cycle_timer,
+ u64 *local_time)
+{
+ int ctr;
+ struct timeval tv;
+ unsigned long flags;
+
+ if (!host || !cycle_timer || !local_time)
+ return -EINVAL;
+
+ preempt_disable();
+ local_irq_save(flags);
+
+ ctr = host->driver->devctl(host, GET_CYCLE_COUNTER, 0);
+ if (ctr)
+ do_gettimeofday(&tv);
+
+ local_irq_restore(flags);
+ preempt_enable();
+
+ if (!ctr)
+ return -EIO;
+ *cycle_timer = ctr;
+ *local_time = tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
+ return 0;
+}
int hpsb_bus_reset(struct hpsb_host *host)
{
@@ -1190,6 +1232,7 @@ EXPORT_SYMBOL(hpsb_alloc_packet);
EXPORT_SYMBOL(hpsb_free_packet);
EXPORT_SYMBOL(hpsb_send_packet);
EXPORT_SYMBOL(hpsb_reset_bus);
+EXPORT_SYMBOL(hpsb_read_cycle_timer);
EXPORT_SYMBOL(hpsb_bus_reset);
EXPORT_SYMBOL(hpsb_selfid_received);
EXPORT_SYMBOL(hpsb_selfid_complete);
Index: linux/drivers/ieee1394/ieee1394_core.h
===================================================================
--- linux.orig/drivers/ieee1394/ieee1394_core.h 2007-01-01 01:53:20.000000000 +0100
+++ linux/drivers/ieee1394/ieee1394_core.h 2007-02-03 13:47:33.000000000 +0100
@@ -127,6 +127,9 @@ int hpsb_send_packet_and_wait(struct hps
* progress, 0 otherwise. */
int hpsb_reset_bus(struct hpsb_host *host, int type);
+int hpsb_read_cycle_timer(struct hpsb_host *host, u32 *cycle_timer,
+ u64 *local_time);
+
/*
* The following functions are exported for host driver module usage. All of
* them are safe to use in interrupt contexts, although some are quite
Index: linux/drivers/ieee1394/raw1394.c
===================================================================
--- linux.orig/drivers/ieee1394/raw1394.c 2007-01-27 14:07:00.000000000 +0100
+++ linux/drivers/ieee1394/raw1394.c 2007-02-03 13:47:34.000000000 +0100
@@ -2664,6 +2664,18 @@ static void raw1394_iso_shutdown(struct
fi->iso_state = RAW1394_ISO_INACTIVE;
}
+static int raw1394_read_cycle_timer(struct file_info *fi, void __user * uaddr)
+{
+ struct raw1394_cycle_timer ct;
+ int err;
+
+ err = hpsb_read_cycle_timer(fi->host, &ct.cycle_timer, &ct.local_time);
+ if (!err)
+ if (copy_to_user(uaddr, &ct, sizeof(ct)))
+ err = -EFAULT;
+ return err;
+}
+
/* mmap the rawiso xmit/recv buffer */
static int raw1394_mmap(struct file *file, struct vm_area_struct *vma)
{
@@ -2772,6 +2784,14 @@ static int raw1394_ioctl(struct inode *i
break;
}
+ /* state-independent commands */
+ switch(cmd) {
+ case RAW1394_IOC_GET_CYCLE_TIMER:
+ return raw1394_read_cycle_timer(fi, argp);
+ default:
+ break;
+ }
+
return -EINVAL;
}
Index: linux/drivers/ieee1394/raw1394.h
===================================================================
--- linux.orig/drivers/ieee1394/raw1394.h 2007-01-01 01:53:20.000000000 +0100
+++ linux/drivers/ieee1394/raw1394.h 2007-02-03 13:47:34.000000000 +0100
@@ -178,4 +178,14 @@ struct raw1394_iso_status {
__s16 xmit_cycle;
};
+/* argument to RAW1394_IOC_GET_CYCLE_TIMER ioctl */
+struct raw1394_cycle_timer {
+ /* contents of Isochronous Cycle Timer register,
+ as in OHCI 1.1 clause 5.13 (also with non-OHCI hosts) */
+ __u32 cycle_timer;
+
+ /* local time in microseconds since Epoch,
+ simultaneously read with cycle timer */
+ __u64 local_time;
+};
#endif /* IEEE1394_RAW1394_H */
--
Stefan Richter
-=====-=-=== --=- ---==
http://arcgraph.de/sr/
-
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