Skip to main content

Browse the archive

Revision 9a765881bf3dcd32847d7108cf48cb04a4ed993f authored by Bjørn Mork on 10 October 2016, 19:12:49 UTC, committed by David S. Miller on 13 October 2016, 14:05:06 UTC 
qmi_wwan: add support for Quectel EC21 and EC25
 
The Quectel EC21 and EC25 need the same "set DTR" request as devices
based on the MDM9230 chipset, but has no USB3 support. Our best guess
is that the "set DTR" functionality depends on chipset and/or
baseband firmware generation. But USB3 is still an optional feature.

Since we cannot enable this unconditionally for all older devices, and
there doesn't appear to be anything we can use in the USB descriptors
to identify these chips, we are forced to use a device specific quirk
flag.

Reported-and-tested-by: Sebastian Sjoholm <sebastian.sjoholm@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 4013bee
Raw File
gcd.c 
#include <linux/kernel.h>
#include <linux/gcd.h>
#include <linux/export.h>

/*
 * This implements the binary GCD algorithm. (Often attributed to Stein,
 * but as Knuth has noted, appears in a first-century Chinese math text.)
 *
 * This is faster than the division-based algorithm even on x86, which
 * has decent hardware division.
 */

#if !defined(CONFIG_CPU_NO_EFFICIENT_FFS) && !defined(CPU_NO_EFFICIENT_FFS)

/* If __ffs is available, the even/odd algorithm benchmarks slower. */
unsigned long gcd(unsigned long a, unsigned long b)
{
	unsigned long r = a | b;

	if (!a || !b)
		return r;

	b >>= __ffs(b);
	if (b == 1)
		return r & -r;

	for (;;) {
		a >>= __ffs(a);
		if (a == 1)
			return r & -r;
		if (a == b)
			return a << __ffs(r);

		if (a < b)
			swap(a, b);
		a -= b;
	}
}

#else

/* If normalization is done by loops, the even/odd algorithm is a win. */
unsigned long gcd(unsigned long a, unsigned long b)
{
	unsigned long r = a | b;

	if (!a || !b)
		return r;

	/* Isolate lsbit of r */
	r &= -r;

	while (!(b & r))
		b >>= 1;
	if (b == r)
		return r;

	for (;;) {
		while (!(a & r))
			a >>= 1;
		if (a == r)
			return r;
		if (a == b)
			return a;

		if (a < b)
			swap(a, b);
		a -= b;
		a >>= 1;
		if (a & r)
			a += b;
		a >>= 1;
	}
}

#endif

EXPORT_SYMBOL_GPL(gcd);
back to top