1 /* 2 * arch/sh/drivers/dma/dma-g2.c 3 * 4 * G2 bus DMA support 5 * 6 * Copyright (C) 2003 - 2006 Paul Mundt 7 * 8 * This file is subject to the terms and conditions of the GNU General Public 9 * License. See the file "COPYING" in the main directory of this archive 10 * for more details. 11 */ 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/interrupt.h> 16 #include <asm/cacheflush.h> 17 #include <mach/sysasic.h> 18 #include <mach/dma.h> 19 #include <asm/dma.h> 20 21 struct g2_channel { 22 unsigned long g2_addr; /* G2 bus address */ 23 unsigned long root_addr; /* Root bus (SH-4) address */ 24 unsigned long size; /* Size (in bytes), 32-byte aligned */ 25 unsigned long direction; /* Transfer direction */ 26 unsigned long ctrl; /* Transfer control */ 27 unsigned long chan_enable; /* Channel enable */ 28 unsigned long xfer_enable; /* Transfer enable */ 29 unsigned long xfer_stat; /* Transfer status */ 30 } __attribute__ ((aligned(32))); 31 32 struct g2_status { 33 unsigned long g2_addr; 34 unsigned long root_addr; 35 unsigned long size; 36 unsigned long status; 37 } __attribute__ ((aligned(16))); 38 39 struct g2_dma_info { 40 struct g2_channel channel[G2_NR_DMA_CHANNELS]; 41 unsigned long pad1[G2_NR_DMA_CHANNELS]; 42 unsigned long wait_state; 43 unsigned long pad2[10]; 44 unsigned long magic; 45 struct g2_status status[G2_NR_DMA_CHANNELS]; 46 } __attribute__ ((aligned(256))); 47 48 static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800; 49 50 #define g2_bytes_remaining(i) \ 51 ((g2_dma->channel[i].size - \ 52 g2_dma->status[i].size) & 0x0fffffff) 53 54 static irqreturn_t g2_dma_interrupt(int irq, void *dev_id) 55 { 56 int i; 57 58 for (i = 0; i < G2_NR_DMA_CHANNELS; i++) { 59 if (g2_dma->status[i].status & 0x20000000) { 60 unsigned int bytes = g2_bytes_remaining(i); 61 62 if (likely(bytes == 0)) { 63 struct dma_info *info = dev_id; 64 struct dma_channel *chan = info->channels + i; 65 66 wake_up(&chan->wait_queue); 67 68 return IRQ_HANDLED; 69 } 70 } 71 } 72 73 return IRQ_NONE; 74 } 75 76 static int g2_enable_dma(struct dma_channel *chan) 77 { 78 unsigned int chan_nr = chan->chan; 79 80 g2_dma->channel[chan_nr].chan_enable = 1; 81 g2_dma->channel[chan_nr].xfer_enable = 1; 82 83 return 0; 84 } 85 86 static int g2_disable_dma(struct dma_channel *chan) 87 { 88 unsigned int chan_nr = chan->chan; 89 90 g2_dma->channel[chan_nr].chan_enable = 0; 91 g2_dma->channel[chan_nr].xfer_enable = 0; 92 93 return 0; 94 } 95 96 static int g2_xfer_dma(struct dma_channel *chan) 97 { 98 unsigned int chan_nr = chan->chan; 99 100 if (chan->sar & 31) { 101 printk("g2dma: unaligned source 0x%lx\n", chan->sar); 102 return -EINVAL; 103 } 104 105 if (chan->dar & 31) { 106 printk("g2dma: unaligned dest 0x%lx\n", chan->dar); 107 return -EINVAL; 108 } 109 110 /* Align the count */ 111 if (chan->count & 31) 112 chan->count = (chan->count + (32 - 1)) & ~(32 - 1); 113 114 /* Fixup destination */ 115 chan->dar += 0xa0800000; 116 117 /* Fixup direction */ 118 chan->mode = !chan->mode; 119 120 flush_icache_range((unsigned long)chan->sar, chan->count); 121 122 g2_disable_dma(chan); 123 124 g2_dma->channel[chan_nr].g2_addr = chan->dar & 0x1fffffe0; 125 g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0; 126 g2_dma->channel[chan_nr].size = (chan->count & ~31) | 0x80000000; 127 g2_dma->channel[chan_nr].direction = chan->mode; 128 129 /* 130 * bit 0 - ??? 131 * bit 1 - if set, generate a hardware event on transfer completion 132 * bit 2 - ??? something to do with suspend? 133 */ 134 g2_dma->channel[chan_nr].ctrl = 5; /* ?? */ 135 136 g2_enable_dma(chan); 137 138 /* debug cruft */ 139 pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, " 140 "0x%08lx, %ld, %ld, %ld, %ld\n", 141 g2_dma->channel[chan_nr].size, 142 g2_dma->channel[chan_nr].root_addr, 143 g2_dma->channel[chan_nr].g2_addr, 144 g2_dma->channel[chan_nr].direction, 145 g2_dma->channel[chan_nr].ctrl, 146 g2_dma->channel[chan_nr].chan_enable, 147 g2_dma->channel[chan_nr].xfer_enable); 148 149 return 0; 150 } 151 152 static int g2_get_residue(struct dma_channel *chan) 153 { 154 return g2_bytes_remaining(chan->chan); 155 } 156 157 static struct dma_ops g2_dma_ops = { 158 .xfer = g2_xfer_dma, 159 .get_residue = g2_get_residue, 160 }; 161 162 static struct dma_info g2_dma_info = { 163 .name = "g2_dmac", 164 .nr_channels = 4, 165 .ops = &g2_dma_ops, 166 .flags = DMAC_CHANNELS_TEI_CAPABLE, 167 }; 168 169 static int __init g2_dma_init(void) 170 { 171 int ret; 172 173 ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, 0, 174 "g2 DMA handler", &g2_dma_info); 175 if (unlikely(ret)) 176 return -EINVAL; 177 178 /* Magic */ 179 g2_dma->wait_state = 27; 180 g2_dma->magic = 0x4659404f; 181 182 ret = register_dmac(&g2_dma_info); 183 if (unlikely(ret != 0)) 184 free_irq(HW_EVENT_G2_DMA, 0); 185 186 return ret; 187 } 188 189 static void __exit g2_dma_exit(void) 190 { 191 free_irq(HW_EVENT_G2_DMA, 0); 192 unregister_dmac(&g2_dma_info); 193 } 194 195 subsys_initcall(g2_dma_init); 196 module_exit(g2_dma_exit); 197 198 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 199 MODULE_DESCRIPTION("G2 bus DMA driver"); 200 MODULE_LICENSE("GPL"); 201