1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * arch/arm/plat-spear/pl080.c
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * DMAC pl080 definitions for SPEAr platform
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Copyright (C) 2012 ST Microelectronics
7*4882a593Smuzhiyun * Viresh Kumar <vireshk@kernel.org>
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * This file is licensed under the terms of the GNU General Public
10*4882a593Smuzhiyun * License version 2. This program is licensed "as is" without any
11*4882a593Smuzhiyun * warranty of any kind, whether express or implied.
12*4882a593Smuzhiyun */
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <linux/amba/pl08x.h>
15*4882a593Smuzhiyun #include <linux/amba/bus.h>
16*4882a593Smuzhiyun #include <linux/bug.h>
17*4882a593Smuzhiyun #include <linux/err.h>
18*4882a593Smuzhiyun #include <linux/io.h>
19*4882a593Smuzhiyun #include <linux/spinlock_types.h>
20*4882a593Smuzhiyun #include <mach/spear.h>
21*4882a593Smuzhiyun #include <mach/misc_regs.h>
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun struct {
26*4882a593Smuzhiyun unsigned char busy;
27*4882a593Smuzhiyun unsigned char val;
28*4882a593Smuzhiyun } signals[16] = {{0, 0}, };
29*4882a593Smuzhiyun
pl080_get_signal(const struct pl08x_channel_data * cd)30*4882a593Smuzhiyun int pl080_get_signal(const struct pl08x_channel_data *cd)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun unsigned int signal = cd->min_signal, val;
33*4882a593Smuzhiyun unsigned long flags;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun spin_lock_irqsave(&lock, flags);
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun /* Return if signal is already acquired by somebody else */
38*4882a593Smuzhiyun if (signals[signal].busy &&
39*4882a593Smuzhiyun (signals[signal].val != cd->muxval)) {
40*4882a593Smuzhiyun spin_unlock_irqrestore(&lock, flags);
41*4882a593Smuzhiyun return -EBUSY;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun /* If acquiring for the first time, configure it */
45*4882a593Smuzhiyun if (!signals[signal].busy) {
46*4882a593Smuzhiyun val = readl(DMA_CHN_CFG);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun /*
49*4882a593Smuzhiyun * Each request line has two bits in DMA_CHN_CFG register. To
50*4882a593Smuzhiyun * goto the bits of current request line, do left shift of
51*4882a593Smuzhiyun * value by 2 * signal number.
52*4882a593Smuzhiyun */
53*4882a593Smuzhiyun val &= ~(0x3 << (signal * 2));
54*4882a593Smuzhiyun val |= cd->muxval << (signal * 2);
55*4882a593Smuzhiyun writel(val, DMA_CHN_CFG);
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun signals[signal].busy++;
59*4882a593Smuzhiyun signals[signal].val = cd->muxval;
60*4882a593Smuzhiyun spin_unlock_irqrestore(&lock, flags);
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun return signal;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
pl080_put_signal(const struct pl08x_channel_data * cd,int signal)65*4882a593Smuzhiyun void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
66*4882a593Smuzhiyun {
67*4882a593Smuzhiyun unsigned long flags;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun spin_lock_irqsave(&lock, flags);
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun /* if signal is not used */
72*4882a593Smuzhiyun if (!signals[signal].busy)
73*4882a593Smuzhiyun BUG();
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun signals[signal].busy--;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun spin_unlock_irqrestore(&lock, flags);
78*4882a593Smuzhiyun }
79