diff options
Diffstat (limited to 'arch/arm/plat-spear/pl080.c')
-rw-r--r-- | arch/arm/plat-spear/pl080.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/arch/arm/plat-spear/pl080.c b/arch/arm/plat-spear/pl080.c new file mode 100644 index 000000000000..a56a067717c1 --- /dev/null +++ b/arch/arm/plat-spear/pl080.c | |||
@@ -0,0 +1,80 @@ | |||
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/spear.h> | ||
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 | |||
30 | int pl080_get_signal(struct pl08x_dma_chan *ch) | ||
31 | { | ||
32 | const struct pl08x_channel_data *cd = ch->cd; | ||
33 | unsigned int signal = cd->min_signal, val; | ||
34 | unsigned long flags; | ||
35 | |||
36 | spin_lock_irqsave(&lock, flags); | ||
37 | |||
38 | /* Return if signal is already acquired by somebody else */ | ||
39 | if (signals[signal].busy && | ||
40 | (signals[signal].val != cd->muxval)) { | ||
41 | spin_unlock_irqrestore(&lock, flags); | ||
42 | return -EBUSY; | ||
43 | } | ||
44 | |||
45 | /* If acquiring for the first time, configure it */ | ||
46 | if (!signals[signal].busy) { | ||
47 | val = readl(DMA_CHN_CFG); | ||
48 | |||
49 | /* | ||
50 | * Each request line has two bits in DMA_CHN_CFG register. To | ||
51 | * goto the bits of current request line, do left shift of | ||
52 | * value by 2 * signal number. | ||
53 | */ | ||
54 | val &= ~(0x3 << (signal * 2)); | ||
55 | val |= cd->muxval << (signal * 2); | ||
56 | writel(val, DMA_CHN_CFG); | ||
57 | } | ||
58 | |||
59 | signals[signal].busy++; | ||
60 | signals[signal].val = cd->muxval; | ||
61 | spin_unlock_irqrestore(&lock, flags); | ||
62 | |||
63 | return signal; | ||
64 | } | ||
65 | |||
66 | void pl080_put_signal(struct pl08x_dma_chan *ch) | ||
67 | { | ||
68 | const struct pl08x_channel_data *cd = ch->cd; | ||
69 | unsigned long flags; | ||
70 | |||
71 | spin_lock_irqsave(&lock, flags); | ||
72 | |||
73 | /* if signal is not used */ | ||
74 | if (!signals[cd->min_signal].busy) | ||
75 | BUG(); | ||
76 | |||
77 | signals[cd->min_signal].busy--; | ||
78 | |||
79 | spin_unlock_irqrestore(&lock, flags); | ||
80 | } | ||