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Viresh Kumar0b7ee712012-03-26 10:29:23 +05301/*
2 * arch/arm/plat-spear/pl080.c
3 *
4 * DMAC pl080 definitions for SPEAr platform
5 *
6 * Copyright (C) 2012 ST Microelectronics
Viresh Kumar10d89352012-06-20 12:53:02 -07007 * Viresh Kumar <viresh.linux@gmail.com>
Viresh Kumar0b7ee712012-03-26 10:29:23 +05308 *
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>
Arnd Bergmann5019f0b2012-04-11 17:30:11 +000020#include <mach/spear.h>
Viresh Kumar0b7ee712012-03-26 10:29:23 +053021#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
Russell Kinga8fb6882012-06-08 09:46:23 +010030int pl080_get_signal(const struct pl08x_channel_data *cd)
Viresh Kumar0b7ee712012-03-26 10:29:23 +053031{
Viresh Kumar0b7ee712012-03-26 10:29:23 +053032 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
Russell Kinga8fb6882012-06-08 09:46:23 +010065void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
Viresh Kumar0b7ee712012-03-26 10:29:23 +053066{
Viresh Kumar0b7ee712012-03-26 10:29:23 +053067 unsigned long flags;
68
69 spin_lock_irqsave(&lock, flags);
70
71 /* if signal is not used */
Russell Kinga8fb6882012-06-08 09:46:23 +010072 if (!signals[signal].busy)
Viresh Kumar0b7ee712012-03-26 10:29:23 +053073 BUG();
74
Russell Kinga8fb6882012-06-08 09:46:23 +010075 signals[signal].busy--;
Viresh Kumar0b7ee712012-03-26 10:29:23 +053076
77 spin_unlock_irqrestore(&lock, flags);
78}