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0b7ee717 VK |
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.kumar@st.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/misc_regs.h> | |
21 | ||
22 | static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x); | |
23 | ||
24 | struct { | |
25 | unsigned char busy; | |
26 | unsigned char val; | |
27 | } signals[16] = {{0, 0}, }; | |
28 | ||
29 | int pl080_get_signal(struct pl08x_dma_chan *ch) | |
30 | { | |
31 | const struct pl08x_channel_data *cd = ch->cd; | |
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 | ||
65 | void pl080_put_signal(struct pl08x_dma_chan *ch) | |
66 | { | |
67 | const struct pl08x_channel_data *cd = ch->cd; | |
68 | unsigned long flags; | |
69 | ||
70 | spin_lock_irqsave(&lock, flags); | |
71 | ||
72 | /* if signal is not used */ | |
73 | if (!signals[cd->min_signal].busy) | |
74 | BUG(); | |
75 | ||
76 | signals[cd->min_signal].busy--; | |
77 | ||
78 | spin_unlock_irqrestore(&lock, flags); | |
79 | } |