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1 | /* |
2 | * arch/arm/plat-spear/pl080.c | |
3 | * | |
4 | * DMAC pl080 definitions for SPEAr platform | |
5 | * | |
6 | * Copyright (C) 2012 ST Microelectronics | |
da89947b | 7 | * Viresh Kumar <vireshk@kernel.org> |
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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> | |
5019f0b1 | 20 | #include <mach/spear.h> |
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21 | #include <mach/misc_regs.h> |
22 | ||
23 | static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x); | |
24 | ||
25 | struct { | |
26 | unsigned char busy; | |
27 | unsigned char val; | |
28 | } signals[16] = {{0, 0}, }; | |
29 | ||
a8fb688e | 30 | int pl080_get_signal(const struct pl08x_channel_data *cd) |
0b7ee717 | 31 | { |
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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 | ||
a8fb688e | 65 | void pl080_put_signal(const struct pl08x_channel_data *cd, int signal) |
0b7ee717 | 66 | { |
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67 | unsigned long flags; |
68 | ||
69 | spin_lock_irqsave(&lock, flags); | |
70 | ||
71 | /* if signal is not used */ | |
a8fb688e | 72 | if (!signals[signal].busy) |
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73 | BUG(); |
74 | ||
a8fb688e | 75 | signals[signal].busy--; |
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76 | |
77 | spin_unlock_irqrestore(&lock, flags); | |
78 | } |