GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/unicore32/kernel/dma.c |
| 3 | * |
| 4 | * Code specific to PKUnity SoC and UniCore ISA |
| 5 | * |
| 6 | * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> |
| 7 | * Copyright (C) 2001-2010 Guan Xuetao |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/errno.h> |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 19 | #include <linux/io.h> |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 20 | |
| 21 | #include <asm/system.h> |
| 22 | #include <asm/irq.h> |
| 23 | #include <mach/hardware.h> |
| 24 | #include <mach/dma.h> |
| 25 | |
| 26 | struct dma_channel { |
| 27 | char *name; |
| 28 | puv3_dma_prio prio; |
| 29 | void (*irq_handler)(int, void *); |
| 30 | void (*err_handler)(int, void *); |
| 31 | void *data; |
| 32 | }; |
| 33 | |
| 34 | static struct dma_channel dma_channels[MAX_DMA_CHANNELS]; |
| 35 | |
| 36 | int puv3_request_dma(char *name, puv3_dma_prio prio, |
| 37 | void (*irq_handler)(int, void *), |
| 38 | void (*err_handler)(int, void *), |
| 39 | void *data) |
| 40 | { |
| 41 | unsigned long flags; |
| 42 | int i, found = 0; |
| 43 | |
| 44 | /* basic sanity checks */ |
| 45 | if (!name) |
| 46 | return -EINVAL; |
| 47 | |
| 48 | local_irq_save(flags); |
| 49 | |
| 50 | do { |
| 51 | /* try grabbing a DMA channel with the requested priority */ |
| 52 | for (i = 0; i < MAX_DMA_CHANNELS; i++) { |
| 53 | if ((dma_channels[i].prio == prio) && |
| 54 | !dma_channels[i].name) { |
| 55 | found = 1; |
| 56 | break; |
| 57 | } |
| 58 | } |
| 59 | /* if requested prio group is full, try a hier priority */ |
| 60 | } while (!found && prio--); |
| 61 | |
| 62 | if (found) { |
| 63 | dma_channels[i].name = name; |
| 64 | dma_channels[i].irq_handler = irq_handler; |
| 65 | dma_channels[i].err_handler = err_handler; |
| 66 | dma_channels[i].data = data; |
| 67 | } else { |
| 68 | printk(KERN_WARNING "No more available DMA channels for %s\n", |
| 69 | name); |
| 70 | i = -ENODEV; |
| 71 | } |
| 72 | |
| 73 | local_irq_restore(flags); |
| 74 | return i; |
| 75 | } |
| 76 | EXPORT_SYMBOL(puv3_request_dma); |
| 77 | |
| 78 | void puv3_free_dma(int dma_ch) |
| 79 | { |
| 80 | unsigned long flags; |
| 81 | |
| 82 | if (!dma_channels[dma_ch].name) { |
| 83 | printk(KERN_CRIT |
| 84 | "%s: trying to free channel %d which is already freed\n", |
| 85 | __func__, dma_ch); |
| 86 | return; |
| 87 | } |
| 88 | |
| 89 | local_irq_save(flags); |
| 90 | dma_channels[dma_ch].name = NULL; |
| 91 | dma_channels[dma_ch].err_handler = NULL; |
| 92 | local_irq_restore(flags); |
| 93 | } |
| 94 | EXPORT_SYMBOL(puv3_free_dma); |
| 95 | |
| 96 | static irqreturn_t dma_irq_handler(int irq, void *dev_id) |
| 97 | { |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 98 | int i, dint; |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 99 | |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 100 | dint = readl(DMAC_ITCSR); |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 101 | for (i = 0; i < MAX_DMA_CHANNELS; i++) { |
| 102 | if (dint & DMAC_CHANNEL(i)) { |
| 103 | struct dma_channel *channel = &dma_channels[i]; |
| 104 | |
| 105 | /* Clear TC interrupt of channel i */ |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 106 | writel(DMAC_CHANNEL(i), DMAC_ITCCR); |
| 107 | writel(0, DMAC_ITCCR); |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 108 | |
| 109 | if (channel->name && channel->irq_handler) { |
| 110 | channel->irq_handler(i, channel->data); |
| 111 | } else { |
| 112 | /* |
| 113 | * IRQ for an unregistered DMA channel: |
| 114 | * let's clear the interrupts and disable it. |
| 115 | */ |
| 116 | printk(KERN_WARNING "spurious IRQ for" |
| 117 | " DMA channel %d\n", i); |
| 118 | } |
| 119 | } |
| 120 | } |
| 121 | return IRQ_HANDLED; |
| 122 | } |
| 123 | |
| 124 | static irqreturn_t dma_err_handler(int irq, void *dev_id) |
| 125 | { |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 126 | int i, dint; |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 127 | |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 128 | dint = readl(DMAC_IESR); |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 129 | for (i = 0; i < MAX_DMA_CHANNELS; i++) { |
| 130 | if (dint & DMAC_CHANNEL(i)) { |
| 131 | struct dma_channel *channel = &dma_channels[i]; |
| 132 | |
| 133 | /* Clear Err interrupt of channel i */ |
GuanXuetao | e5abf78 | 2011-02-26 21:21:18 +0800 | [diff] [blame] | 134 | writel(DMAC_CHANNEL(i), DMAC_IECR); |
| 135 | writel(0, DMAC_IECR); |
GuanXuetao | 10c9c10 | 2011-01-15 18:18:29 +0800 | [diff] [blame] | 136 | |
| 137 | if (channel->name && channel->err_handler) { |
| 138 | channel->err_handler(i, channel->data); |
| 139 | } else { |
| 140 | /* |
| 141 | * IRQ for an unregistered DMA channel: |
| 142 | * let's clear the interrupts and disable it. |
| 143 | */ |
| 144 | printk(KERN_WARNING "spurious IRQ for" |
| 145 | " DMA channel %d\n", i); |
| 146 | } |
| 147 | } |
| 148 | } |
| 149 | return IRQ_HANDLED; |
| 150 | } |
| 151 | |
| 152 | int __init puv3_init_dma(void) |
| 153 | { |
| 154 | int i, ret; |
| 155 | |
| 156 | /* dma channel priorities on v8 processors: |
| 157 | * ch 0 - 1 <--> (0) DMA_PRIO_HIGH |
| 158 | * ch 2 - 3 <--> (1) DMA_PRIO_MEDIUM |
| 159 | * ch 4 - 5 <--> (2) DMA_PRIO_LOW |
| 160 | */ |
| 161 | for (i = 0; i < MAX_DMA_CHANNELS; i++) { |
| 162 | puv3_stop_dma(i); |
| 163 | dma_channels[i].name = NULL; |
| 164 | dma_channels[i].prio = min((i & 0x7) >> 1, DMA_PRIO_LOW); |
| 165 | } |
| 166 | |
| 167 | ret = request_irq(IRQ_DMA, dma_irq_handler, 0, "DMA", NULL); |
| 168 | if (ret) { |
| 169 | printk(KERN_CRIT "Can't register IRQ for DMA\n"); |
| 170 | return ret; |
| 171 | } |
| 172 | |
| 173 | ret = request_irq(IRQ_DMAERR, dma_err_handler, 0, "DMAERR", NULL); |
| 174 | if (ret) { |
| 175 | printk(KERN_CRIT "Can't register IRQ for DMAERR\n"); |
| 176 | free_irq(IRQ_DMA, "DMA"); |
| 177 | return ret; |
| 178 | } |
| 179 | |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | postcore_initcall(puv3_init_dma); |