1 /* 2 * arch/sh/drivers/dma/dma-pvr2.c 3 * 4 * NEC PowerVR 2 (Dreamcast) DMA support 5 * 6 * Copyright (C) 2003, 2004 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 <mach/sysasic.h> 17 #include <mach/dma.h> 18 #include <asm/dma.h> 19 #include <asm/io.h> 20 21 static unsigned int xfer_complete; 22 static int count; 23 24 static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id) 25 { 26 if (get_dma_residue(PVR2_CASCADE_CHAN)) { 27 printk(KERN_WARNING "DMA: SH DMAC did not complete transfer " 28 "on channel %d, waiting..\n", PVR2_CASCADE_CHAN); 29 dma_wait_for_completion(PVR2_CASCADE_CHAN); 30 } 31 32 if (count++ < 10) 33 pr_debug("Got a pvr2 dma interrupt for channel %d\n", 34 irq - HW_EVENT_PVR2_DMA); 35 36 xfer_complete = 1; 37 38 return IRQ_HANDLED; 39 } 40 41 static int pvr2_request_dma(struct dma_channel *chan) 42 { 43 if (__raw_readl(PVR2_DMA_MODE) != 0) 44 return -EBUSY; 45 46 __raw_writel(0, PVR2_DMA_LMMODE0); 47 48 return 0; 49 } 50 51 static int pvr2_get_dma_residue(struct dma_channel *chan) 52 { 53 return xfer_complete == 0; 54 } 55 56 static int pvr2_xfer_dma(struct dma_channel *chan) 57 { 58 if (chan->sar || !chan->dar) 59 return -EINVAL; 60 61 xfer_complete = 0; 62 63 __raw_writel(chan->dar, PVR2_DMA_ADDR); 64 __raw_writel(chan->count, PVR2_DMA_COUNT); 65 __raw_writel(chan->mode & DMA_MODE_MASK, PVR2_DMA_MODE); 66 67 return 0; 68 } 69 70 static struct irqaction pvr2_dma_irq = { 71 .name = "pvr2 DMA handler", 72 .handler = pvr2_dma_interrupt, 73 }; 74 75 static struct dma_ops pvr2_dma_ops = { 76 .request = pvr2_request_dma, 77 .get_residue = pvr2_get_dma_residue, 78 .xfer = pvr2_xfer_dma, 79 }; 80 81 static struct dma_info pvr2_dma_info = { 82 .name = "pvr2_dmac", 83 .nr_channels = 1, 84 .ops = &pvr2_dma_ops, 85 .flags = DMAC_CHANNELS_TEI_CAPABLE, 86 }; 87 88 static int __init pvr2_dma_init(void) 89 { 90 setup_irq(HW_EVENT_PVR2_DMA, &pvr2_dma_irq); 91 request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade"); 92 93 return register_dmac(&pvr2_dma_info); 94 } 95 96 static void __exit pvr2_dma_exit(void) 97 { 98 free_dma(PVR2_CASCADE_CHAN); 99 free_irq(HW_EVENT_PVR2_DMA, 0); 100 unregister_dmac(&pvr2_dma_info); 101 } 102 103 subsys_initcall(pvr2_dma_init); 104 module_exit(pvr2_dma_exit); 105 106 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 107 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver"); 108 MODULE_LICENSE("GPL"); 109