Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
| 30 | void (*irq_handler)(int, void *, struct pt_regs *); |
| 31 | void *data; |
| 32 | } dma_channels[PXA_DMA_CHANNELS]; |
| 33 | |
| 34 | |
| 35 | int pxa_request_dma (char *name, pxa_dma_prio prio, |
| 36 | void (*irq_handler)(int, void *, struct pt_regs *), |
| 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 | |
Nicolas Pitre | 9953255 | 2006-05-05 22:32:24 +0100 | [diff] [blame] | 48 | do { |
| 49 | /* try grabbing a DMA channel with the requested priority */ |
| 50 | pxa_for_each_dma_prio (i, prio) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | if (!dma_channels[i].name) { |
| 52 | found = 1; |
| 53 | break; |
| 54 | } |
| 55 | } |
Nicolas Pitre | 9953255 | 2006-05-05 22:32:24 +0100 | [diff] [blame] | 56 | /* if requested prio group is full, try a hier priority */ |
| 57 | } while (!found && prio--); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
| 90 | static irqreturn_t dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs) |
| 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) { |
| 98 | channel->irq_handler(i, channel->data, regs); |
| 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 | |