1/*
2 * arch/arm/plat-spear/pl080.c
3 *
4 * DMAC pl080 definitions for SPEAr platform
5 *
6 * Copyright (C) 2012 ST Microelectronics
7 * Viresh Kumar <viresh.linux@gmail.com>
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14#include <linux/amba/pl08x.h>
15#include <linux/amba/bus.h>
16#include <linux/bug.h>
17#include <linux/err.h>
18#include <linux/io.h>
19#include <linux/spinlock_types.h>
20#include <mach/spear.h>
21#include <mach/misc_regs.h>
22
23static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
24
25struct {
26	unsigned char busy;
27	unsigned char val;
28} signals[16] = {{0, 0}, };
29
30int pl080_get_signal(const struct pl08x_channel_data *cd)
31{
32	unsigned int signal = cd->min_signal, val;
33	unsigned long flags;
34
35	spin_lock_irqsave(&lock, flags);
36
37	/* Return if signal is already acquired by somebody else */
38	if (signals[signal].busy &&
39			(signals[signal].val != cd->muxval)) {
40		spin_unlock_irqrestore(&lock, flags);
41		return -EBUSY;
42	}
43
44	/* If acquiring for the first time, configure it */
45	if (!signals[signal].busy) {
46		val = readl(DMA_CHN_CFG);
47
48		/*
49		 * Each request line has two bits in DMA_CHN_CFG register. To
50		 * goto the bits of current request line, do left shift of
51		 * value by 2 * signal number.
52		 */
53		val &= ~(0x3 << (signal * 2));
54		val |= cd->muxval << (signal * 2);
55		writel(val, DMA_CHN_CFG);
56	}
57
58	signals[signal].busy++;
59	signals[signal].val = cd->muxval;
60	spin_unlock_irqrestore(&lock, flags);
61
62	return signal;
63}
64
65void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
66{
67	unsigned long flags;
68
69	spin_lock_irqsave(&lock, flags);
70
71	/* if signal is not used */
72	if (!signals[signal].busy)
73		BUG();
74
75	signals[signal].busy--;
76
77	spin_unlock_irqrestore(&lock, flags);
78}
79