2 * arch/sh/drivers/dma/dma-sh.c
4 * SuperH On-chip DMAC Support
6 * Copyright (C) 2000 Takashi YOSHII
7 * Copyright (C) 2003, 2004 Paul Mundt
8 * Copyright (C) 2005 Andriy Skulysh
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <asm/dreamcast/dma.h>
22 static inline unsigned int get_dmte_irq(unsigned int chan)
27 * Normally we could just do DMTE0_IRQ + chan outright, though in the
28 * case of the 7751R, the DMTE IRQs for channels > 4 start right above
32 irq = DMTE0_IRQ + chan;
35 irq = DMTE4_IRQ + chan - 4;
43 * We determine the correct shift size based off of the CHCR transmit size
44 * for the given channel. Since we know that it will take:
46 * info->count >> ts_shift[transmit_size]
48 * iterations to complete the transfer.
50 static inline unsigned int calc_xmit_shift(struct dma_channel *chan)
52 u32 chcr = ctrl_inl(CHCR[chan->chan]);
54 return ts_shift[(chcr & CHCR_TS_MASK)>>CHCR_TS_SHIFT];
58 * The transfer end interrupt must read the chcr register to end the
59 * hardware interrupt active condition.
60 * Besides that it needs to waken any waiting process, which should handle
61 * setting up the next transfer.
63 static irqreturn_t dma_tei(int irq, void *dev_id, struct pt_regs *regs)
65 struct dma_channel *chan = (struct dma_channel *)dev_id;
68 chcr = ctrl_inl(CHCR[chan->chan]);
70 if (!(chcr & CHCR_TE))
73 chcr &= ~(CHCR_IE | CHCR_DE);
74 ctrl_outl(chcr, CHCR[chan->chan]);
76 wake_up(&chan->wait_queue);
81 static int sh_dmac_request_dma(struct dma_channel *chan)
85 snprintf(name, sizeof(name), "DMAC Transfer End (Channel %d)",
88 return request_irq(get_dmte_irq(chan->chan), dma_tei,
89 IRQF_DISABLED, name, chan);
92 static void sh_dmac_free_dma(struct dma_channel *chan)
94 free_irq(get_dmte_irq(chan->chan), chan);
98 sh_dmac_configure_channel(struct dma_channel *chan, unsigned long chcr)
101 chcr = RS_DUAL | CHCR_IE;
103 if (chcr & CHCR_IE) {
105 chan->flags |= DMA_TEI_CAPABLE;
107 chan->flags &= ~DMA_TEI_CAPABLE;
110 ctrl_outl(chcr, CHCR[chan->chan]);
112 chan->flags |= DMA_CONFIGURED;
115 static void sh_dmac_enable_dma(struct dma_channel *chan)
120 chcr = ctrl_inl(CHCR[chan->chan]);
123 if (chan->flags & DMA_TEI_CAPABLE)
126 ctrl_outl(chcr, CHCR[chan->chan]);
128 if (chan->flags & DMA_TEI_CAPABLE) {
129 irq = get_dmte_irq(chan->chan);
134 static void sh_dmac_disable_dma(struct dma_channel *chan)
139 if (chan->flags & DMA_TEI_CAPABLE) {
140 irq = get_dmte_irq(chan->chan);
144 chcr = ctrl_inl(CHCR[chan->chan]);
145 chcr &= ~(CHCR_DE | CHCR_TE | CHCR_IE);
146 ctrl_outl(chcr, CHCR[chan->chan]);
149 static int sh_dmac_xfer_dma(struct dma_channel *chan)
152 * If we haven't pre-configured the channel with special flags, use
155 if (unlikely(!(chan->flags & DMA_CONFIGURED)))
156 sh_dmac_configure_channel(chan, 0);
158 sh_dmac_disable_dma(chan);
161 * Single-address mode usage note!
163 * It's important that we don't accidentally write any value to SAR/DAR
164 * (this includes 0) that hasn't been directly specified by the user if
165 * we're in single-address mode.
167 * In this case, only one address can be defined, anything else will
168 * result in a DMA address error interrupt (at least on the SH-4),
169 * which will subsequently halt the transfer.
171 * Channel 2 on the Dreamcast is a special case, as this is used for
172 * cascading to the PVR2 DMAC. In this case, we still need to write
173 * SAR and DAR, regardless of value, in order for cascading to work.
175 if (chan->sar || (mach_is_dreamcast() &&
176 chan->chan == PVR2_CASCADE_CHAN))
177 ctrl_outl(chan->sar, SAR[chan->chan]);
178 if (chan->dar || (mach_is_dreamcast() &&
179 chan->chan == PVR2_CASCADE_CHAN))
180 ctrl_outl(chan->dar, DAR[chan->chan]);
182 ctrl_outl(chan->count >> calc_xmit_shift(chan), DMATCR[chan->chan]);
184 sh_dmac_enable_dma(chan);
189 static int sh_dmac_get_dma_residue(struct dma_channel *chan)
191 if (!(ctrl_inl(CHCR[chan->chan]) & CHCR_DE))
194 return ctrl_inl(DMATCR[chan->chan]) << calc_xmit_shift(chan);
197 #ifdef CONFIG_CPU_SUBTYPE_SH7780
198 #define dmaor_read_reg() ctrl_inw(DMAOR)
199 #define dmaor_write_reg(data) ctrl_outw(data, DMAOR)
201 #define dmaor_read_reg() ctrl_inl(DMAOR)
202 #define dmaor_write_reg(data) ctrl_outl(data, DMAOR)
205 static inline int dmaor_reset(void)
207 unsigned long dmaor = dmaor_read_reg();
209 /* Try to clear the error flags first, incase they are set */
210 dmaor &= ~(DMAOR_NMIF | DMAOR_AE);
211 dmaor_write_reg(dmaor);
214 dmaor_write_reg(dmaor);
216 /* See if we got an error again */
217 if ((dmaor_read_reg() & (DMAOR_AE | DMAOR_NMIF))) {
218 printk(KERN_ERR "dma-sh: Can't initialize DMAOR.\n");
225 #if defined(CONFIG_CPU_SH4)
226 static irqreturn_t dma_err(int irq, void *dev_id, struct pt_regs *regs)
235 static struct dma_ops sh_dmac_ops = {
236 .request = sh_dmac_request_dma,
237 .free = sh_dmac_free_dma,
238 .get_residue = sh_dmac_get_dma_residue,
239 .xfer = sh_dmac_xfer_dma,
240 .configure = sh_dmac_configure_channel,
243 static struct dma_info sh_dmac_info = {
245 .nr_channels = CONFIG_NR_ONCHIP_DMA_CHANNELS,
247 .flags = DMAC_CHANNELS_TEI_CAPABLE,
250 static int __init sh_dmac_init(void)
252 struct dma_info *info = &sh_dmac_info;
255 #ifdef CONFIG_CPU_SH4
256 make_ipr_irq(DMAE_IRQ, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY);
257 i = request_irq(DMAE_IRQ, dma_err, IRQF_DISABLED, "DMAC Address Error", 0);
262 for (i = 0; i < info->nr_channels; i++) {
263 int irq = get_dmte_irq(i);
265 make_ipr_irq(irq, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY);
269 * Initialize DMAOR, and clean up any error flags that may have
276 return register_dmac(info);
279 static void __exit sh_dmac_exit(void)
281 #ifdef CONFIG_CPU_SH4
282 free_irq(DMAE_IRQ, 0);
284 unregister_dmac(&sh_dmac_info);
287 subsys_initcall(sh_dmac_init);
288 module_exit(sh_dmac_exit);
290 MODULE_AUTHOR("Takashi YOSHII, Paul Mundt, Andriy Skulysh");
291 MODULE_DESCRIPTION("SuperH On-Chip DMAC Support");
292 MODULE_LICENSE("GPL");