1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * arch/arm/plat-spear/pl080.c |
4 | * |
5 | * DMAC pl080 definitions for SPEAr platform |
6 | * |
7 | * Copyright (C) 2012 ST Microelectronics |
8 | * Viresh Kumar <vireshk@kernel.org> |
9 | */ |
10 | |
11 | #include <linux/amba/pl08x.h> |
12 | #include <linux/amba/bus.h> |
13 | #include <linux/bug.h> |
14 | #include <linux/err.h> |
15 | #include <linux/io.h> |
16 | #include <linux/spinlock_types.h> |
17 | #include "spear.h" |
18 | #include "misc_regs.h" |
19 | #include "pl080.h" |
20 | |
21 | static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x); |
22 | |
23 | struct { |
24 | unsigned char busy; |
25 | unsigned char val; |
26 | } signals[16] = {{0, 0}, }; |
27 | |
28 | int pl080_get_signal(const struct pl08x_channel_data *cd) |
29 | { |
30 | unsigned int signal = cd->min_signal, val; |
31 | unsigned long flags; |
32 | |
33 | spin_lock_irqsave(&lock, flags); |
34 | |
35 | /* Return if signal is already acquired by somebody else */ |
36 | if (signals[signal].busy && |
37 | (signals[signal].val != cd->muxval)) { |
38 | spin_unlock_irqrestore(lock: &lock, flags); |
39 | return -EBUSY; |
40 | } |
41 | |
42 | /* If acquiring for the first time, configure it */ |
43 | if (!signals[signal].busy) { |
44 | val = readl(DMA_CHN_CFG); |
45 | |
46 | /* |
47 | * Each request line has two bits in DMA_CHN_CFG register. To |
48 | * goto the bits of current request line, do left shift of |
49 | * value by 2 * signal number. |
50 | */ |
51 | val &= ~(0x3 << (signal * 2)); |
52 | val |= cd->muxval << (signal * 2); |
53 | writel(val, DMA_CHN_CFG); |
54 | } |
55 | |
56 | signals[signal].busy++; |
57 | signals[signal].val = cd->muxval; |
58 | spin_unlock_irqrestore(lock: &lock, flags); |
59 | |
60 | return signal; |
61 | } |
62 | |
63 | void pl080_put_signal(const struct pl08x_channel_data *cd, int signal) |
64 | { |
65 | unsigned long flags; |
66 | |
67 | spin_lock_irqsave(&lock, flags); |
68 | |
69 | /* if signal is not used */ |
70 | if (!signals[signal].busy) |
71 | BUG(); |
72 | |
73 | signals[signal].busy--; |
74 | |
75 | spin_unlock_irqrestore(lock: &lock, flags); |
76 | } |
77 | |