[PATCH] ieee1394: fix calculation of csr->expire (f0cbefe6) · Commits · 戴 / test

drivers/ieee1394/csr.c

+10 −21

Original line number	Diff line number	Diff line
		@@ -17,11 +17,13 @@
		*
		*/

		#include <linux/string.h>
		#include <linux/jiffies.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/moduleparam.h>
		#include <linux/param.h>
		#include <linux/spinlock.h>
		#include <linux/string.h>

		#include "csr1212.h"
		#include "ieee1394_types.h"
		@@ -149,31 +151,18 @@ static void host_reset(struct hpsb_host *host)

		/*
		* HI == seconds (bits 0:2)
		* LO == fraction units of 1/8000 of a second, as per 1394 (bits 19:31)
		*
		* Convert to units and then to HZ, for comparison to jiffies.
		*
		* By default this will end up being 800 units, or 100ms (125usec per
		* unit).
		* LO == fractions of a second in units of 125usec (bits 19:31)
		*
		* NOTE: The spec says 1/8000, but also says we can compute based on 1/8192
		* like CSR specifies. Should make our math less complex.
		* Convert SPLIT_TIMEOUT to jiffies.
		* The default and minimum as per 1394a-2000 clause 8.3.2.2.6 is 100ms.
		*/
		static inline void calculate_expire(struct csr_control *csr)
		{
		unsigned long units;

		/* Take the seconds, and convert to units */
		units = (unsigned long)(csr->split_timeout_hi & 0x07) << 13;

		/* Add in the fractional units */
		units += (unsigned long)(csr->split_timeout_lo >> 19);

		/* Convert to jiffies */
		csr->expire = (unsigned long)(units * HZ) >> 13UL;
		unsigned long usecs =
		(csr->split_timeout_hi & 0x07) * USEC_PER_SEC +
		(csr->split_timeout_lo >> 19) * 125L;

		/* Just to keep from rounding low */
		csr->expire++;
		csr->expire = usecs_to_jiffies(usecs > 100000L ? usecs : 100000L);

		HPSB_VERBOSE("CSR: setting expire to %lu, HZ=%u", csr->expire, HZ);
		}

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