1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2004-2012 Cavium Networks
7 */
8
9#include <asm/cop2.h>
10#include <linux/export.h>
11#include <linux/interrupt.h>
12#include <linux/sched/task_stack.h>
13
14#include "octeon-crypto.h"
15
16/**
17 * Enable access to Octeon's COP2 crypto hardware for kernel use. Wrap any
18 * crypto operations in calls to octeon_crypto_enable/disable in order to make
19 * sure the state of COP2 isn't corrupted if userspace is also performing
20 * hardware crypto operations. Allocate the state parameter on the stack.
21 * Returns with preemption disabled.
22 *
23 * @state: Pointer to state structure to store current COP2 state in.
24 *
25 * Returns: Flags to be passed to octeon_crypto_disable()
26 */
27unsigned long octeon_crypto_enable(struct octeon_cop2_state *state)
28{
29	int status;
30	unsigned long flags;
31
32	preempt_disable();
33	local_irq_save(flags);
34	status = read_c0_status();
35	write_c0_status(status | ST0_CU2);
36	if (KSTK_STATUS(current) & ST0_CU2) {
37		octeon_cop2_save(&(current->thread.cp2));
38		KSTK_STATUS(current) &= ~ST0_CU2;
39		status &= ~ST0_CU2;
40	} else if (status & ST0_CU2) {
41		octeon_cop2_save(state);
42	}
43	local_irq_restore(flags);
44	return status & ST0_CU2;
45}
46EXPORT_SYMBOL_GPL(octeon_crypto_enable);
47
48/**
49 * Disable access to Octeon's COP2 crypto hardware in the kernel. This must be
50 * called after an octeon_crypto_enable() before any context switch or return to
51 * userspace.
52 *
53 * @state:	Pointer to COP2 state to restore
54 * @flags:	Return value from octeon_crypto_enable()
55 */
56void octeon_crypto_disable(struct octeon_cop2_state *state,
57			   unsigned long crypto_flags)
58{
59	unsigned long flags;
60
61	local_irq_save(flags);
62	if (crypto_flags & ST0_CU2)
63		octeon_cop2_restore(state);
64	else
65		write_c0_status(read_c0_status() & ~ST0_CU2);
66	local_irq_restore(flags);
67	preempt_enable();
68}
69EXPORT_SYMBOL_GPL(octeon_crypto_disable);
70