/*
 * Copyright (c) 2011 Broadcom Corporation
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <linux/module.h>
#include <linux/cordic.h>

#define CORDIC_ANGLE_GEN	39797
#define CORDIC_PRECISION_SHIFT	16
#define	CORDIC_NUM_ITER		(CORDIC_PRECISION_SHIFT + 2)

#define	FIXED(X)	((s32)((X) << CORDIC_PRECISION_SHIFT))
#define	FLOAT(X)	(((X) >= 0) \
		? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \
		: -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1))

static const s32 arctan_table[] = {
	2949120,
	1740967,
	919879,
	466945,
	234379,
	117304,
	58666,
	29335,
	14668,
	7334,
	3667,
	1833,
	917,
	458,
	229,
	115,
	57,
	29
};

/*
 * cordic_calc_iq() - calculates the i/q coordinate for given angle
 *
 * theta: angle in degrees for which i/q coordinate is to be calculated
 * coord: function output parameter holding the i/q coordinate
 */
struct cordic_iq cordic_calc_iq(s32 theta)
{
	struct cordic_iq coord;
	s32 angle, valtmp;
	unsigned iter;
	int signx = 1;
	int signtheta;

	coord.i = CORDIC_ANGLE_GEN;
	coord.q = 0;
	angle = 0;

	theta = FIXED(theta);
	signtheta = (theta < 0) ? -1 : 1;
	theta = ((theta + FIXED(180) * signtheta) % FIXED(360)) -
		FIXED(180) * signtheta;

	if (FLOAT(theta) > 90) {
		theta -= FIXED(180);
		signx = -1;
	} else if (FLOAT(theta) < -90) {
		theta += FIXED(180);
		signx = -1;
	}

	for (iter = 0; iter < CORDIC_NUM_ITER; iter++) {
		if (theta > angle) {
			valtmp = coord.i - (coord.q >> iter);
			coord.q += (coord.i >> iter);
			angle += arctan_table[iter];
		} else {
			valtmp = coord.i + (coord.q >> iter);
			coord.q -= (coord.i >> iter);
			angle -= arctan_table[iter];
		}
		coord.i = valtmp;
	}

	coord.i *= signx;
	coord.q *= signx;
	return coord;
}
EXPORT_SYMBOL(cordic_calc_iq);

MODULE_DESCRIPTION("CORDIC algorithm");
MODULE_AUTHOR("Broadcom Corporation");
MODULE_LICENSE("Dual BSD/GPL");
ue='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/sunrpc?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>sunrpc</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/sunrpc/xprtrdma?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>xprtrdma</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>svc_rdma_recvfrom.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='08d85f3ea99f1eeafc4e8507936190e86a16ee8c'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Marc Zyngier &lt;marc.zyngier@arm.com&gt;</td><td class='right'>2017-01-17 16:00:48 +0000</td></tr>
<tr><th>committer</th><td>Thomas Gleixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-30 15:18:56 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>08d85f3ea99f1eeafc4e8507936190e86a16ee8c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>410bb1acd0cd7dcfaad37ae7b63ff243b7fa4bee</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>net/sunrpc/xprtrdma/svc_rdma_recvfrom.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=566cf877a1fcb6d6dc0126b076aad062054c2637'>566cf877a1fcb6d6dc0126b076aad062054c2637</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c&amp;id2=566cf877a1fcb6d6dc0126b076aad062054c2637'>diff</a>)</td></tr></table>
<div class='commit-subject'>irqdomain: Avoid activating interrupts more than once</div><div class='commit-msg'>Since commit f3b0946d629c ("genirq/msi: Make sure PCI MSIs are
activated early"), we can end-up activating a PCI/MSI twice (once
at allocation time, and once at startup time).

This is normally of no consequences, except that there is some
HW out there that may misbehave if activate is used more than once
(the GICv3 ITS, for example, uses the activate callback
to issue the MAPVI command, and the architecture spec says that
"If there is an existing mapping for the EventID-DeviceID
combination, behavior is UNPREDICTABLE").

While this could be worked around in each individual driver, it may
make more sense to tackle the issue at the core level. In order to
avoid getting in that situation, let's have a per-interrupt flag
to remember if we have already activated that interrupt or not.

Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Reported-and-tested-by: Andre Przywara &lt;andre.przywara@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1484668848-24361-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>Diffstat</a> (limited to 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c')</div><table summary='diffstat' class='diffstat'>