spi: change post transfer udelay() to usleep_range() for long delays

The spi_transfer parameter delay_usecs allows specifying a time to wait
after transferring a spi message.  This wait can be quite long - some
devices, such as some Chrome OS ECs, require as much as 2000 usecs after
a SPI transaction, before it can respond.

(cf: arch/arm64/boot/dts/nvidia/tegra132-norrin.dts:
   google,cros-ec-spi-msg-delay = <2000>
)

Blocking a CPU for 2 msecs in a busy loop like this doesn't seem very
friendly to other processes, so change the blocking delay to a sleep
to allow other things to use this CPU (or so it can sleep).

This should be safe to do, because:
 (a) A post-transaction delay like this is always specified as a minimum
     wait time
 (b) A delay here is most likely not very time sensitive, as it occurs
     after all data has been transferred
 (c) This delay occurs in a non-critical section of the spi worker thread
     so where it is safe to sleep.

Two caveats:
 1) To avoid penalizing short delays, still use udelay for delays < 10us.
 2) usleep_range() very often picks the upper bound, an upper bounds 10%
    should be plenty.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

path: root/dissector_80211.h

/*
 * netsniff-ng - the packet sniffing beast
 * Copyright 2009, 2010 Daniel Borkmann.
 * Subject to the GPL, version 2.
 */

#ifndef DISSECTOR_80211_H
#define DISSECTOR_80211_H

#include "hash.h"
#include "proto.h"
#include "protos.h"
#include "tprintf.h"
#include "oui.h"

extern struct hash_table ieee80211_lay2;

extern void dissector_init_ieee80211(int fnttype);
extern void dissector_cleanup_ieee80211(void);

#ifdef HAVE_DISSECTOR_PROTOS
static inline struct protocol *dissector_get_ieee80211_entry_point(void)
{
	return &ieee80211_ops;
}

static inline struct protocol *dissector_get_ieee80211_exit_point(void)
{
	return &none_ops;
}
#else
static inline struct protocol *dissector_get_ieee80211_entry_point(void)
{
	return NULL;
}

static inline struct protocol *dissector_get_ieee80211_exit_point(void)
{
	return NULL;
}
#endif
#endif /* DISSECTOR_80211_H */