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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mach-pxa/dma.c | |
3 | * | |
4 | * PXA DMA registration and IRQ dispatching | |
5 | * | |
6 | * Author: Nicolas Pitre | |
7 | * Created: Nov 15, 2001 | |
8 | * Copyright: MontaVista Software Inc. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/errno.h> | |
20 | ||
21 | #include <asm/system.h> | |
22 | #include <asm/irq.h> | |
23 | #include <asm/hardware.h> | |
24 | #include <asm/dma.h> | |
25 | ||
26 | #include <asm/arch/pxa-regs.h> | |
27 | ||
28 | static struct dma_channel { | |
29 | char *name; | |
0cd61b68 | 30 | void (*irq_handler)(int, void *); |
1da177e4 LT |
31 | void *data; |
32 | } dma_channels[PXA_DMA_CHANNELS]; | |
33 | ||
34 | ||
35 | int pxa_request_dma (char *name, pxa_dma_prio prio, | |
0cd61b68 | 36 | void (*irq_handler)(int, void *), |
1da177e4 LT |
37 | void *data) |
38 | { | |
39 | unsigned long flags; | |
40 | int i, found = 0; | |
41 | ||
42 | /* basic sanity checks */ | |
43 | if (!name || !irq_handler) | |
44 | return -EINVAL; | |
45 | ||
46 | local_irq_save(flags); | |
47 | ||
99532559 NP |
48 | do { |
49 | /* try grabbing a DMA channel with the requested priority */ | |
50 | pxa_for_each_dma_prio (i, prio) { | |
1da177e4 LT |
51 | if (!dma_channels[i].name) { |
52 | found = 1; | |
53 | break; | |
54 | } | |
55 | } | |
99532559 NP |
56 | /* if requested prio group is full, try a hier priority */ |
57 | } while (!found && prio--); | |
1da177e4 LT |
58 | |
59 | if (found) { | |
60 | DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; | |
61 | dma_channels[i].name = name; | |
62 | dma_channels[i].irq_handler = irq_handler; | |
63 | dma_channels[i].data = data; | |
64 | } else { | |
65 | printk (KERN_WARNING "No more available DMA channels for %s\n", name); | |
66 | i = -ENODEV; | |
67 | } | |
68 | ||
69 | local_irq_restore(flags); | |
70 | return i; | |
71 | } | |
72 | ||
73 | void pxa_free_dma (int dma_ch) | |
74 | { | |
75 | unsigned long flags; | |
76 | ||
77 | if (!dma_channels[dma_ch].name) { | |
78 | printk (KERN_CRIT | |
79 | "%s: trying to free channel %d which is already freed\n", | |
80 | __FUNCTION__, dma_ch); | |
81 | return; | |
82 | } | |
83 | ||
84 | local_irq_save(flags); | |
85 | DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; | |
86 | dma_channels[dma_ch].name = NULL; | |
87 | local_irq_restore(flags); | |
88 | } | |
89 | ||
0cd61b68 | 90 | static irqreturn_t dma_irq_handler(int irq, void *dev_id) |
1da177e4 LT |
91 | { |
92 | int i, dint = DINT; | |
93 | ||
94 | for (i = 0; i < PXA_DMA_CHANNELS; i++) { | |
95 | if (dint & (1 << i)) { | |
96 | struct dma_channel *channel = &dma_channels[i]; | |
97 | if (channel->name && channel->irq_handler) { | |
0cd61b68 | 98 | channel->irq_handler(i, channel->data); |
1da177e4 LT |
99 | } else { |
100 | /* | |
101 | * IRQ for an unregistered DMA channel: | |
102 | * let's clear the interrupts and disable it. | |
103 | */ | |
104 | printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i); | |
105 | DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; | |
106 | } | |
107 | } | |
108 | } | |
109 | return IRQ_HANDLED; | |
110 | } | |
111 | ||
112 | static int __init pxa_dma_init (void) | |
113 | { | |
114 | int ret; | |
115 | ||
116 | ret = request_irq (IRQ_DMA, dma_irq_handler, 0, "DMA", NULL); | |
117 | if (ret) | |
118 | printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n"); | |
119 | return ret; | |
120 | } | |
121 | ||
122 | arch_initcall(pxa_dma_init); | |
123 | ||
124 | EXPORT_SYMBOL(pxa_request_dma); | |
125 | EXPORT_SYMBOL(pxa_free_dma); | |
126 |