1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * arch/arm/plat-spear/pl080.c
4 *
5 * DMAC pl080 definitions for SPEAr platform
6 *
7 * Copyright (C) 2012 ST Microelectronics
8 * Viresh Kumar <vireshk@kernel.org>
9 */
10
11#include <linux/amba/pl08x.h>
12#include <linux/amba/bus.h>
13#include <linux/bug.h>
14#include <linux/err.h>
15#include <linux/io.h>
16#include <linux/spinlock_types.h>
17#include "spear.h"
18#include "misc_regs.h"
19#include "pl080.h"
20
21static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
22
23struct {
24	unsigned char busy;
25	unsigned char val;
26} signals[16] = {{0, 0}, };
27
28int pl080_get_signal(const struct pl08x_channel_data *cd)
29{
30	unsigned int signal = cd->min_signal, val;
31	unsigned long flags;
32
33	spin_lock_irqsave(&lock, flags);
34
35	/* Return if signal is already acquired by somebody else */
36	if (signals[signal].busy &&
37			(signals[signal].val != cd->muxval)) {
38		spin_unlock_irqrestore(&lock, flags);
39		return -EBUSY;
40	}
41
42	/* If acquiring for the first time, configure it */
43	if (!signals[signal].busy) {
44		val = readl(DMA_CHN_CFG);
45
46		/*
47		 * Each request line has two bits in DMA_CHN_CFG register. To
48		 * goto the bits of current request line, do left shift of
49		 * value by 2 * signal number.
50		 */
51		val &= ~(0x3 << (signal * 2));
52		val |= cd->muxval << (signal * 2);
53		writel(val, DMA_CHN_CFG);
54	}
55
56	signals[signal].busy++;
57	signals[signal].val = cd->muxval;
58	spin_unlock_irqrestore(&lock, flags);
59
60	return signal;
61}
62
63void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
64{
65	unsigned long flags;
66
67	spin_lock_irqsave(&lock, flags);
68
69	/* if signal is not used */
70	if (!signals[signal].busy)
71		BUG();
72
73	signals[signal].busy--;
74
75	spin_unlock_irqrestore(&lock, flags);
76}
77