xref: /openbmc/linux/arch/mips/alchemy/common/dbdma.c (revision f71a261a)
1 /*
2  *
3  * BRIEF MODULE DESCRIPTION
4  *      The Descriptor Based DMA channel manager that first appeared
5  *	on the Au1550.  I started with dma.c, but I think all that is
6  *	left is this initial comment :-)
7  *
8  * Copyright 2004 Embedded Edge, LLC
9  *	dan@embeddededge.com
10  *
11  *  This program is free software; you can redistribute  it and/or modify it
12  *  under  the terms of  the GNU General  Public License as published by the
13  *  Free Software Foundation;  either version 2 of the  License, or (at your
14  *  option) any later version.
15  *
16  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
17  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
18  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
19  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
20  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
22  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
23  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
24  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  *
27  *  You should have received a copy of the  GNU General Public License along
28  *  with this program; if not, write  to the Free Software Foundation, Inc.,
29  *  675 Mass Ave, Cambridge, MA 02139, USA.
30  *
31  */
32 
33 #include <linux/init.h>
34 #include <linux/kernel.h>
35 #include <linux/slab.h>
36 #include <linux/spinlock.h>
37 #include <linux/interrupt.h>
38 #include <linux/export.h>
39 #include <linux/syscore_ops.h>
40 #include <asm/mach-au1x00/au1000.h>
41 #include <asm/mach-au1x00/au1xxx_dbdma.h>
42 
43 /*
44  * The Descriptor Based DMA supports up to 16 channels.
45  *
46  * There are 32 devices defined. We keep an internal structure
47  * of devices using these channels, along with additional
48  * information.
49  *
50  * We allocate the descriptors and allow access to them through various
51  * functions.  The drivers allocate the data buffers and assign them
52  * to the descriptors.
53  */
54 static DEFINE_SPINLOCK(au1xxx_dbdma_spin_lock);
55 
56 /* I couldn't find a macro that did this... */
57 #define ALIGN_ADDR(x, a)	((((u32)(x)) + (a-1)) & ~(a-1))
58 
59 static dbdma_global_t *dbdma_gptr =
60 			(dbdma_global_t *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
61 static int dbdma_initialized;
62 
63 static dbdev_tab_t *dbdev_tab;
64 
65 static dbdev_tab_t au1550_dbdev_tab[] __initdata = {
66 	/* UARTS */
67 	{ AU1550_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8, 0x11100004, 0, 0 },
68 	{ AU1550_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8, 0x11100000, 0, 0 },
69 	{ AU1550_DSCR_CMD0_UART3_TX, DEV_FLAGS_OUT, 0, 8, 0x11400004, 0, 0 },
70 	{ AU1550_DSCR_CMD0_UART3_RX, DEV_FLAGS_IN,  0, 8, 0x11400000, 0, 0 },
71 
72 	/* EXT DMA */
73 	{ AU1550_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
74 	{ AU1550_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },
75 	{ AU1550_DSCR_CMD0_DMA_REQ2, 0, 0, 0, 0x00000000, 0, 0 },
76 	{ AU1550_DSCR_CMD0_DMA_REQ3, 0, 0, 0, 0x00000000, 0, 0 },
77 
78 	/* USB DEV */
79 	{ AU1550_DSCR_CMD0_USBDEV_RX0, DEV_FLAGS_IN,  4, 8, 0x10200000, 0, 0 },
80 	{ AU1550_DSCR_CMD0_USBDEV_TX0, DEV_FLAGS_OUT, 4, 8, 0x10200004, 0, 0 },
81 	{ AU1550_DSCR_CMD0_USBDEV_TX1, DEV_FLAGS_OUT, 4, 8, 0x10200008, 0, 0 },
82 	{ AU1550_DSCR_CMD0_USBDEV_TX2, DEV_FLAGS_OUT, 4, 8, 0x1020000c, 0, 0 },
83 	{ AU1550_DSCR_CMD0_USBDEV_RX3, DEV_FLAGS_IN,  4, 8, 0x10200010, 0, 0 },
84 	{ AU1550_DSCR_CMD0_USBDEV_RX4, DEV_FLAGS_IN,  4, 8, 0x10200014, 0, 0 },
85 
86 	/* PSCs */
87 	{ AU1550_DSCR_CMD0_PSC0_TX, DEV_FLAGS_OUT, 0, 0, 0x11a0001c, 0, 0 },
88 	{ AU1550_DSCR_CMD0_PSC0_RX, DEV_FLAGS_IN,  0, 0, 0x11a0001c, 0, 0 },
89 	{ AU1550_DSCR_CMD0_PSC1_TX, DEV_FLAGS_OUT, 0, 0, 0x11b0001c, 0, 0 },
90 	{ AU1550_DSCR_CMD0_PSC1_RX, DEV_FLAGS_IN,  0, 0, 0x11b0001c, 0, 0 },
91 	{ AU1550_DSCR_CMD0_PSC2_TX, DEV_FLAGS_OUT, 0, 0, 0x10a0001c, 0, 0 },
92 	{ AU1550_DSCR_CMD0_PSC2_RX, DEV_FLAGS_IN,  0, 0, 0x10a0001c, 0, 0 },
93 	{ AU1550_DSCR_CMD0_PSC3_TX, DEV_FLAGS_OUT, 0, 0, 0x10b0001c, 0, 0 },
94 	{ AU1550_DSCR_CMD0_PSC3_RX, DEV_FLAGS_IN,  0, 0, 0x10b0001c, 0, 0 },
95 
96 	{ AU1550_DSCR_CMD0_PCI_WRITE,  0, 0, 0, 0x00000000, 0, 0 },  /* PCI */
97 	{ AU1550_DSCR_CMD0_NAND_FLASH, 0, 0, 0, 0x00000000, 0, 0 }, /* NAND */
98 
99 	/* MAC 0 */
100 	{ AU1550_DSCR_CMD0_MAC0_RX, DEV_FLAGS_IN,  0, 0, 0x00000000, 0, 0 },
101 	{ AU1550_DSCR_CMD0_MAC0_TX, DEV_FLAGS_OUT, 0, 0, 0x00000000, 0, 0 },
102 
103 	/* MAC 1 */
104 	{ AU1550_DSCR_CMD0_MAC1_RX, DEV_FLAGS_IN,  0, 0, 0x00000000, 0, 0 },
105 	{ AU1550_DSCR_CMD0_MAC1_TX, DEV_FLAGS_OUT, 0, 0, 0x00000000, 0, 0 },
106 
107 	{ DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
108 	{ DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
109 };
110 
111 static dbdev_tab_t au1200_dbdev_tab[] __initdata = {
112 	{ AU1200_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8, 0x11100004, 0, 0 },
113 	{ AU1200_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8, 0x11100000, 0, 0 },
114 	{ AU1200_DSCR_CMD0_UART1_TX, DEV_FLAGS_OUT, 0, 8, 0x11200004, 0, 0 },
115 	{ AU1200_DSCR_CMD0_UART1_RX, DEV_FLAGS_IN,  0, 8, 0x11200000, 0, 0 },
116 
117 	{ AU1200_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
118 	{ AU1200_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },
119 
120 	{ AU1200_DSCR_CMD0_MAE_BE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
121 	{ AU1200_DSCR_CMD0_MAE_FE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
122 	{ AU1200_DSCR_CMD0_MAE_BOTH, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
123 	{ AU1200_DSCR_CMD0_LCD, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
124 
125 	{ AU1200_DSCR_CMD0_SDMS_TX0, DEV_FLAGS_OUT, 4, 8, 0x10600000, 0, 0 },
126 	{ AU1200_DSCR_CMD0_SDMS_RX0, DEV_FLAGS_IN,  4, 8, 0x10600004, 0, 0 },
127 	{ AU1200_DSCR_CMD0_SDMS_TX1, DEV_FLAGS_OUT, 4, 8, 0x10680000, 0, 0 },
128 	{ AU1200_DSCR_CMD0_SDMS_RX1, DEV_FLAGS_IN,  4, 8, 0x10680004, 0, 0 },
129 
130 	{ AU1200_DSCR_CMD0_AES_RX, DEV_FLAGS_IN , 4, 32, 0x10300008, 0, 0 },
131 	{ AU1200_DSCR_CMD0_AES_TX, DEV_FLAGS_OUT, 4, 32, 0x10300004, 0, 0 },
132 
133 	{ AU1200_DSCR_CMD0_PSC0_TX,   DEV_FLAGS_OUT, 0, 16, 0x11a0001c, 0, 0 },
134 	{ AU1200_DSCR_CMD0_PSC0_RX,   DEV_FLAGS_IN,  0, 16, 0x11a0001c, 0, 0 },
135 	{ AU1200_DSCR_CMD0_PSC0_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
136 	{ AU1200_DSCR_CMD0_PSC1_TX,   DEV_FLAGS_OUT, 0, 16, 0x11b0001c, 0, 0 },
137 	{ AU1200_DSCR_CMD0_PSC1_RX,   DEV_FLAGS_IN,  0, 16, 0x11b0001c, 0, 0 },
138 	{ AU1200_DSCR_CMD0_PSC1_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
139 
140 	{ AU1200_DSCR_CMD0_CIM_RXA,  DEV_FLAGS_IN, 0, 32, 0x14004020, 0, 0 },
141 	{ AU1200_DSCR_CMD0_CIM_RXB,  DEV_FLAGS_IN, 0, 32, 0x14004040, 0, 0 },
142 	{ AU1200_DSCR_CMD0_CIM_RXC,  DEV_FLAGS_IN, 0, 32, 0x14004060, 0, 0 },
143 	{ AU1200_DSCR_CMD0_CIM_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
144 
145 	{ AU1200_DSCR_CMD0_NAND_FLASH, DEV_FLAGS_IN, 0, 0, 0x00000000, 0, 0 },
146 
147 	{ DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
148 	{ DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
149 };
150 
151 static dbdev_tab_t au1300_dbdev_tab[] __initdata = {
152 	{ AU1300_DSCR_CMD0_UART0_TX, DEV_FLAGS_OUT, 0, 8,  0x10100004, 0, 0 },
153 	{ AU1300_DSCR_CMD0_UART0_RX, DEV_FLAGS_IN,  0, 8,  0x10100000, 0, 0 },
154 	{ AU1300_DSCR_CMD0_UART1_TX, DEV_FLAGS_OUT, 0, 8,  0x10101004, 0, 0 },
155 	{ AU1300_DSCR_CMD0_UART1_RX, DEV_FLAGS_IN,  0, 8,  0x10101000, 0, 0 },
156 	{ AU1300_DSCR_CMD0_UART2_TX, DEV_FLAGS_OUT, 0, 8,  0x10102004, 0, 0 },
157 	{ AU1300_DSCR_CMD0_UART2_RX, DEV_FLAGS_IN,  0, 8,  0x10102000, 0, 0 },
158 	{ AU1300_DSCR_CMD0_UART3_TX, DEV_FLAGS_OUT, 0, 8,  0x10103004, 0, 0 },
159 	{ AU1300_DSCR_CMD0_UART3_RX, DEV_FLAGS_IN,  0, 8,  0x10103000, 0, 0 },
160 
161 	{ AU1300_DSCR_CMD0_SDMS_TX0, DEV_FLAGS_OUT, 4, 8,  0x10600000, 0, 0 },
162 	{ AU1300_DSCR_CMD0_SDMS_RX0, DEV_FLAGS_IN,  4, 8,  0x10600004, 0, 0 },
163 	{ AU1300_DSCR_CMD0_SDMS_TX1, DEV_FLAGS_OUT, 8, 8,  0x10601000, 0, 0 },
164 	{ AU1300_DSCR_CMD0_SDMS_RX1, DEV_FLAGS_IN,  8, 8,  0x10601004, 0, 0 },
165 
166 	{ AU1300_DSCR_CMD0_AES_RX, DEV_FLAGS_IN ,   4, 32, 0x10300008, 0, 0 },
167 	{ AU1300_DSCR_CMD0_AES_TX, DEV_FLAGS_OUT,   4, 32, 0x10300004, 0, 0 },
168 
169 	{ AU1300_DSCR_CMD0_PSC0_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0001c, 0, 0 },
170 	{ AU1300_DSCR_CMD0_PSC0_RX, DEV_FLAGS_IN,   0, 16, 0x10a0001c, 0, 0 },
171 	{ AU1300_DSCR_CMD0_PSC1_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0101c, 0, 0 },
172 	{ AU1300_DSCR_CMD0_PSC1_RX, DEV_FLAGS_IN,   0, 16, 0x10a0101c, 0, 0 },
173 	{ AU1300_DSCR_CMD0_PSC2_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0201c, 0, 0 },
174 	{ AU1300_DSCR_CMD0_PSC2_RX, DEV_FLAGS_IN,   0, 16, 0x10a0201c, 0, 0 },
175 	{ AU1300_DSCR_CMD0_PSC3_TX, DEV_FLAGS_OUT,  0, 16, 0x10a0301c, 0, 0 },
176 	{ AU1300_DSCR_CMD0_PSC3_RX, DEV_FLAGS_IN,   0, 16, 0x10a0301c, 0, 0 },
177 
178 	{ AU1300_DSCR_CMD0_LCD, DEV_FLAGS_ANYUSE,   0, 0,  0x00000000, 0, 0 },
179 	{ AU1300_DSCR_CMD0_NAND_FLASH, DEV_FLAGS_IN, 0, 0, 0x00000000, 0, 0 },
180 
181 	{ AU1300_DSCR_CMD0_SDMS_TX2, DEV_FLAGS_OUT, 4, 8,  0x10602000, 0, 0 },
182 	{ AU1300_DSCR_CMD0_SDMS_RX2, DEV_FLAGS_IN,  4, 8,  0x10602004, 0, 0 },
183 
184 	{ AU1300_DSCR_CMD0_CIM_SYNC, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
185 
186 	{ AU1300_DSCR_CMD0_UDMA, DEV_FLAGS_ANYUSE,  0, 32, 0x14001810, 0, 0 },
187 
188 	{ AU1300_DSCR_CMD0_DMA_REQ0, 0, 0, 0, 0x00000000, 0, 0 },
189 	{ AU1300_DSCR_CMD0_DMA_REQ1, 0, 0, 0, 0x00000000, 0, 0 },
190 
191 	{ DSCR_CMD0_THROTTLE, DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
192 	{ DSCR_CMD0_ALWAYS,   DEV_FLAGS_ANYUSE, 0, 0, 0x00000000, 0, 0 },
193 };
194 
195 /* 32 predefined plus 32 custom */
196 #define DBDEV_TAB_SIZE		64
197 
198 static chan_tab_t *chan_tab_ptr[NUM_DBDMA_CHANS];
199 
200 static dbdev_tab_t *find_dbdev_id(u32 id)
201 {
202 	int i;
203 	dbdev_tab_t *p;
204 	for (i = 0; i < DBDEV_TAB_SIZE; ++i) {
205 		p = &dbdev_tab[i];
206 		if (p->dev_id == id)
207 			return p;
208 	}
209 	return NULL;
210 }
211 
212 void *au1xxx_ddma_get_nextptr_virt(au1x_ddma_desc_t *dp)
213 {
214 	return phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
215 }
216 EXPORT_SYMBOL(au1xxx_ddma_get_nextptr_virt);
217 
218 u32 au1xxx_ddma_add_device(dbdev_tab_t *dev)
219 {
220 	u32 ret = 0;
221 	dbdev_tab_t *p;
222 	static u16 new_id = 0x1000;
223 
224 	p = find_dbdev_id(~0);
225 	if (NULL != p) {
226 		memcpy(p, dev, sizeof(dbdev_tab_t));
227 		p->dev_id = DSCR_DEV2CUSTOM_ID(new_id, dev->dev_id);
228 		ret = p->dev_id;
229 		new_id++;
230 #if 0
231 		printk(KERN_DEBUG "add_device: id:%x flags:%x padd:%x\n",
232 				  p->dev_id, p->dev_flags, p->dev_physaddr);
233 #endif
234 	}
235 
236 	return ret;
237 }
238 EXPORT_SYMBOL(au1xxx_ddma_add_device);
239 
240 void au1xxx_ddma_del_device(u32 devid)
241 {
242 	dbdev_tab_t *p = find_dbdev_id(devid);
243 
244 	if (p != NULL) {
245 		memset(p, 0, sizeof(dbdev_tab_t));
246 		p->dev_id = ~0;
247 	}
248 }
249 EXPORT_SYMBOL(au1xxx_ddma_del_device);
250 
251 /* Allocate a channel and return a non-zero descriptor if successful. */
252 u32 au1xxx_dbdma_chan_alloc(u32 srcid, u32 destid,
253        void (*callback)(int, void *), void *callparam)
254 {
255 	unsigned long	flags;
256 	u32		used, chan;
257 	u32		dcp;
258 	int		i;
259 	dbdev_tab_t	*stp, *dtp;
260 	chan_tab_t	*ctp;
261 	au1x_dma_chan_t *cp;
262 
263 	/*
264 	 * We do the initialization on the first channel allocation.
265 	 * We have to wait because of the interrupt handler initialization
266 	 * which can't be done successfully during board set up.
267 	 */
268 	if (!dbdma_initialized)
269 		return 0;
270 
271 	stp = find_dbdev_id(srcid);
272 	if (stp == NULL)
273 		return 0;
274 	dtp = find_dbdev_id(destid);
275 	if (dtp == NULL)
276 		return 0;
277 
278 	used = 0;
279 
280 	/* Check to see if we can get both channels. */
281 	spin_lock_irqsave(&au1xxx_dbdma_spin_lock, flags);
282 	if (!(stp->dev_flags & DEV_FLAGS_INUSE) ||
283 	     (stp->dev_flags & DEV_FLAGS_ANYUSE)) {
284 		/* Got source */
285 		stp->dev_flags |= DEV_FLAGS_INUSE;
286 		if (!(dtp->dev_flags & DEV_FLAGS_INUSE) ||
287 		     (dtp->dev_flags & DEV_FLAGS_ANYUSE)) {
288 			/* Got destination */
289 			dtp->dev_flags |= DEV_FLAGS_INUSE;
290 		} else {
291 			/* Can't get dest.  Release src. */
292 			stp->dev_flags &= ~DEV_FLAGS_INUSE;
293 			used++;
294 		}
295 	} else
296 		used++;
297 	spin_unlock_irqrestore(&au1xxx_dbdma_spin_lock, flags);
298 
299 	if (used)
300 		return 0;
301 
302 	/* Let's see if we can allocate a channel for it. */
303 	ctp = NULL;
304 	chan = 0;
305 	spin_lock_irqsave(&au1xxx_dbdma_spin_lock, flags);
306 	for (i = 0; i < NUM_DBDMA_CHANS; i++)
307 		if (chan_tab_ptr[i] == NULL) {
308 			/*
309 			 * If kmalloc fails, it is caught below same
310 			 * as a channel not available.
311 			 */
312 			ctp = kmalloc(sizeof(chan_tab_t), GFP_ATOMIC);
313 			chan_tab_ptr[i] = ctp;
314 			break;
315 		}
316 	spin_unlock_irqrestore(&au1xxx_dbdma_spin_lock, flags);
317 
318 	if (ctp != NULL) {
319 		memset(ctp, 0, sizeof(chan_tab_t));
320 		ctp->chan_index = chan = i;
321 		dcp = KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
322 		dcp += (0x0100 * chan);
323 		ctp->chan_ptr = (au1x_dma_chan_t *)dcp;
324 		cp = (au1x_dma_chan_t *)dcp;
325 		ctp->chan_src = stp;
326 		ctp->chan_dest = dtp;
327 		ctp->chan_callback = callback;
328 		ctp->chan_callparam = callparam;
329 
330 		/* Initialize channel configuration. */
331 		i = 0;
332 		if (stp->dev_intlevel)
333 			i |= DDMA_CFG_SED;
334 		if (stp->dev_intpolarity)
335 			i |= DDMA_CFG_SP;
336 		if (dtp->dev_intlevel)
337 			i |= DDMA_CFG_DED;
338 		if (dtp->dev_intpolarity)
339 			i |= DDMA_CFG_DP;
340 		if ((stp->dev_flags & DEV_FLAGS_SYNC) ||
341 			(dtp->dev_flags & DEV_FLAGS_SYNC))
342 				i |= DDMA_CFG_SYNC;
343 		cp->ddma_cfg = i;
344 		wmb(); /* drain writebuffer */
345 
346 		/*
347 		 * Return a non-zero value that can be used to find the channel
348 		 * information in subsequent operations.
349 		 */
350 		return (u32)(&chan_tab_ptr[chan]);
351 	}
352 
353 	/* Release devices */
354 	stp->dev_flags &= ~DEV_FLAGS_INUSE;
355 	dtp->dev_flags &= ~DEV_FLAGS_INUSE;
356 
357 	return 0;
358 }
359 EXPORT_SYMBOL(au1xxx_dbdma_chan_alloc);
360 
361 /*
362  * Set the device width if source or destination is a FIFO.
363  * Should be 8, 16, or 32 bits.
364  */
365 u32 au1xxx_dbdma_set_devwidth(u32 chanid, int bits)
366 {
367 	u32		rv;
368 	chan_tab_t	*ctp;
369 	dbdev_tab_t	*stp, *dtp;
370 
371 	ctp = *((chan_tab_t **)chanid);
372 	stp = ctp->chan_src;
373 	dtp = ctp->chan_dest;
374 	rv = 0;
375 
376 	if (stp->dev_flags & DEV_FLAGS_IN) {	/* Source in fifo */
377 		rv = stp->dev_devwidth;
378 		stp->dev_devwidth = bits;
379 	}
380 	if (dtp->dev_flags & DEV_FLAGS_OUT) {	/* Destination out fifo */
381 		rv = dtp->dev_devwidth;
382 		dtp->dev_devwidth = bits;
383 	}
384 
385 	return rv;
386 }
387 EXPORT_SYMBOL(au1xxx_dbdma_set_devwidth);
388 
389 /* Allocate a descriptor ring, initializing as much as possible. */
390 u32 au1xxx_dbdma_ring_alloc(u32 chanid, int entries)
391 {
392 	int			i;
393 	u32			desc_base, srcid, destid;
394 	u32			cmd0, cmd1, src1, dest1;
395 	u32			src0, dest0;
396 	chan_tab_t		*ctp;
397 	dbdev_tab_t		*stp, *dtp;
398 	au1x_ddma_desc_t	*dp;
399 
400 	/*
401 	 * I guess we could check this to be within the
402 	 * range of the table......
403 	 */
404 	ctp = *((chan_tab_t **)chanid);
405 	stp = ctp->chan_src;
406 	dtp = ctp->chan_dest;
407 
408 	/*
409 	 * The descriptors must be 32-byte aligned.  There is a
410 	 * possibility the allocation will give us such an address,
411 	 * and if we try that first we are likely to not waste larger
412 	 * slabs of memory.
413 	 */
414 	desc_base = (u32)kmalloc_array(entries, sizeof(au1x_ddma_desc_t),
415 				       GFP_KERNEL|GFP_DMA);
416 	if (desc_base == 0)
417 		return 0;
418 
419 	if (desc_base & 0x1f) {
420 		/*
421 		 * Lost....do it again, allocate extra, and round
422 		 * the address base.
423 		 */
424 		kfree((const void *)desc_base);
425 		i = entries * sizeof(au1x_ddma_desc_t);
426 		i += (sizeof(au1x_ddma_desc_t) - 1);
427 		desc_base = (u32)kmalloc(i, GFP_KERNEL|GFP_DMA);
428 		if (desc_base == 0)
429 			return 0;
430 
431 		ctp->cdb_membase = desc_base;
432 		desc_base = ALIGN_ADDR(desc_base, sizeof(au1x_ddma_desc_t));
433 	} else
434 		ctp->cdb_membase = desc_base;
435 
436 	dp = (au1x_ddma_desc_t *)desc_base;
437 
438 	/* Keep track of the base descriptor. */
439 	ctp->chan_desc_base = dp;
440 
441 	/* Initialize the rings with as much information as we know. */
442 	srcid = stp->dev_id;
443 	destid = dtp->dev_id;
444 
445 	cmd0 = cmd1 = src1 = dest1 = 0;
446 	src0 = dest0 = 0;
447 
448 	cmd0 |= DSCR_CMD0_SID(srcid);
449 	cmd0 |= DSCR_CMD0_DID(destid);
450 	cmd0 |= DSCR_CMD0_IE | DSCR_CMD0_CV;
451 	cmd0 |= DSCR_CMD0_ST(DSCR_CMD0_ST_NOCHANGE);
452 
453 	/* Is it mem to mem transfer? */
454 	if (((DSCR_CUSTOM2DEV_ID(srcid) == DSCR_CMD0_THROTTLE) ||
455 	     (DSCR_CUSTOM2DEV_ID(srcid) == DSCR_CMD0_ALWAYS)) &&
456 	    ((DSCR_CUSTOM2DEV_ID(destid) == DSCR_CMD0_THROTTLE) ||
457 	     (DSCR_CUSTOM2DEV_ID(destid) == DSCR_CMD0_ALWAYS)))
458 		cmd0 |= DSCR_CMD0_MEM;
459 
460 	switch (stp->dev_devwidth) {
461 	case 8:
462 		cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_BYTE);
463 		break;
464 	case 16:
465 		cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_HALFWORD);
466 		break;
467 	case 32:
468 	default:
469 		cmd0 |= DSCR_CMD0_SW(DSCR_CMD0_WORD);
470 		break;
471 	}
472 
473 	switch (dtp->dev_devwidth) {
474 	case 8:
475 		cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_BYTE);
476 		break;
477 	case 16:
478 		cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_HALFWORD);
479 		break;
480 	case 32:
481 	default:
482 		cmd0 |= DSCR_CMD0_DW(DSCR_CMD0_WORD);
483 		break;
484 	}
485 
486 	/*
487 	 * If the device is marked as an in/out FIFO, ensure it is
488 	 * set non-coherent.
489 	 */
490 	if (stp->dev_flags & DEV_FLAGS_IN)
491 		cmd0 |= DSCR_CMD0_SN;		/* Source in FIFO */
492 	if (dtp->dev_flags & DEV_FLAGS_OUT)
493 		cmd0 |= DSCR_CMD0_DN;		/* Destination out FIFO */
494 
495 	/*
496 	 * Set up source1.  For now, assume no stride and increment.
497 	 * A channel attribute update can change this later.
498 	 */
499 	switch (stp->dev_tsize) {
500 	case 1:
501 		src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE1);
502 		break;
503 	case 2:
504 		src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE2);
505 		break;
506 	case 4:
507 		src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE4);
508 		break;
509 	case 8:
510 	default:
511 		src1 |= DSCR_SRC1_STS(DSCR_xTS_SIZE8);
512 		break;
513 	}
514 
515 	/* If source input is FIFO, set static address. */
516 	if (stp->dev_flags & DEV_FLAGS_IN) {
517 		if (stp->dev_flags & DEV_FLAGS_BURSTABLE)
518 			src1 |= DSCR_SRC1_SAM(DSCR_xAM_BURST);
519 		else
520 			src1 |= DSCR_SRC1_SAM(DSCR_xAM_STATIC);
521 	}
522 
523 	if (stp->dev_physaddr)
524 		src0 = stp->dev_physaddr;
525 
526 	/*
527 	 * Set up dest1.  For now, assume no stride and increment.
528 	 * A channel attribute update can change this later.
529 	 */
530 	switch (dtp->dev_tsize) {
531 	case 1:
532 		dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE1);
533 		break;
534 	case 2:
535 		dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE2);
536 		break;
537 	case 4:
538 		dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE4);
539 		break;
540 	case 8:
541 	default:
542 		dest1 |= DSCR_DEST1_DTS(DSCR_xTS_SIZE8);
543 		break;
544 	}
545 
546 	/* If destination output is FIFO, set static address. */
547 	if (dtp->dev_flags & DEV_FLAGS_OUT) {
548 		if (dtp->dev_flags & DEV_FLAGS_BURSTABLE)
549 			dest1 |= DSCR_DEST1_DAM(DSCR_xAM_BURST);
550 		else
551 			dest1 |= DSCR_DEST1_DAM(DSCR_xAM_STATIC);
552 	}
553 
554 	if (dtp->dev_physaddr)
555 		dest0 = dtp->dev_physaddr;
556 
557 #if 0
558 		printk(KERN_DEBUG "did:%x sid:%x cmd0:%x cmd1:%x source0:%x "
559 				  "source1:%x dest0:%x dest1:%x\n",
560 				  dtp->dev_id, stp->dev_id, cmd0, cmd1, src0,
561 				  src1, dest0, dest1);
562 #endif
563 	for (i = 0; i < entries; i++) {
564 		dp->dscr_cmd0 = cmd0;
565 		dp->dscr_cmd1 = cmd1;
566 		dp->dscr_source0 = src0;
567 		dp->dscr_source1 = src1;
568 		dp->dscr_dest0 = dest0;
569 		dp->dscr_dest1 = dest1;
570 		dp->dscr_stat = 0;
571 		dp->sw_context = 0;
572 		dp->sw_status = 0;
573 		dp->dscr_nxtptr = DSCR_NXTPTR(virt_to_phys(dp + 1));
574 		dp++;
575 	}
576 
577 	/* Make last descriptor point to the first. */
578 	dp--;
579 	dp->dscr_nxtptr = DSCR_NXTPTR(virt_to_phys(ctp->chan_desc_base));
580 	ctp->get_ptr = ctp->put_ptr = ctp->cur_ptr = ctp->chan_desc_base;
581 
582 	return (u32)ctp->chan_desc_base;
583 }
584 EXPORT_SYMBOL(au1xxx_dbdma_ring_alloc);
585 
586 /*
587  * Put a source buffer into the DMA ring.
588  * This updates the source pointer and byte count.  Normally used
589  * for memory to fifo transfers.
590  */
591 u32 au1xxx_dbdma_put_source(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
592 {
593 	chan_tab_t		*ctp;
594 	au1x_ddma_desc_t	*dp;
595 
596 	/*
597 	 * I guess we could check this to be within the
598 	 * range of the table......
599 	 */
600 	ctp = *(chan_tab_t **)chanid;
601 
602 	/*
603 	 * We should have multiple callers for a particular channel,
604 	 * an interrupt doesn't affect this pointer nor the descriptor,
605 	 * so no locking should be needed.
606 	 */
607 	dp = ctp->put_ptr;
608 
609 	/*
610 	 * If the descriptor is valid, we are way ahead of the DMA
611 	 * engine, so just return an error condition.
612 	 */
613 	if (dp->dscr_cmd0 & DSCR_CMD0_V)
614 		return 0;
615 
616 	/* Load up buffer address and byte count. */
617 	dp->dscr_source0 = buf & ~0UL;
618 	dp->dscr_cmd1 = nbytes;
619 	/* Check flags */
620 	if (flags & DDMA_FLAGS_IE)
621 		dp->dscr_cmd0 |= DSCR_CMD0_IE;
622 	if (flags & DDMA_FLAGS_NOIE)
623 		dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
624 
625 	/*
626 	 * There is an errata on the Au1200/Au1550 parts that could result
627 	 * in "stale" data being DMA'ed. It has to do with the snoop logic on
628 	 * the cache eviction buffer.  DMA_NONCOHERENT is on by default for
629 	 * these parts. If it is fixed in the future, these dma_cache_inv will
630 	 * just be nothing more than empty macros. See io.h.
631 	 */
632 	dma_cache_wback_inv((unsigned long)buf, nbytes);
633 	dp->dscr_cmd0 |= DSCR_CMD0_V;	/* Let it rip */
634 	wmb(); /* drain writebuffer */
635 	dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
636 	ctp->chan_ptr->ddma_dbell = 0;
637 
638 	/* Get next descriptor pointer. */
639 	ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
640 
641 	/* Return something non-zero. */
642 	return nbytes;
643 }
644 EXPORT_SYMBOL(au1xxx_dbdma_put_source);
645 
646 /* Put a destination buffer into the DMA ring.
647  * This updates the destination pointer and byte count.  Normally used
648  * to place an empty buffer into the ring for fifo to memory transfers.
649  */
650 u32 au1xxx_dbdma_put_dest(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
651 {
652 	chan_tab_t		*ctp;
653 	au1x_ddma_desc_t	*dp;
654 
655 	/* I guess we could check this to be within the
656 	 * range of the table......
657 	 */
658 	ctp = *((chan_tab_t **)chanid);
659 
660 	/* We should have multiple callers for a particular channel,
661 	 * an interrupt doesn't affect this pointer nor the descriptor,
662 	 * so no locking should be needed.
663 	 */
664 	dp = ctp->put_ptr;
665 
666 	/* If the descriptor is valid, we are way ahead of the DMA
667 	 * engine, so just return an error condition.
668 	 */
669 	if (dp->dscr_cmd0 & DSCR_CMD0_V)
670 		return 0;
671 
672 	/* Load up buffer address and byte count */
673 
674 	/* Check flags  */
675 	if (flags & DDMA_FLAGS_IE)
676 		dp->dscr_cmd0 |= DSCR_CMD0_IE;
677 	if (flags & DDMA_FLAGS_NOIE)
678 		dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
679 
680 	dp->dscr_dest0 = buf & ~0UL;
681 	dp->dscr_cmd1 = nbytes;
682 #if 0
683 	printk(KERN_DEBUG "cmd0:%x cmd1:%x source0:%x source1:%x dest0:%x dest1:%x\n",
684 			  dp->dscr_cmd0, dp->dscr_cmd1, dp->dscr_source0,
685 			  dp->dscr_source1, dp->dscr_dest0, dp->dscr_dest1);
686 #endif
687 	/*
688 	 * There is an errata on the Au1200/Au1550 parts that could result in
689 	 * "stale" data being DMA'ed. It has to do with the snoop logic on the
690 	 * cache eviction buffer.  DMA_NONCOHERENT is on by default for these
691 	 * parts. If it is fixed in the future, these dma_cache_inv will just
692 	 * be nothing more than empty macros. See io.h.
693 	 */
694 	dma_cache_inv((unsigned long)buf, nbytes);
695 	dp->dscr_cmd0 |= DSCR_CMD0_V;	/* Let it rip */
696 	wmb(); /* drain writebuffer */
697 	dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
698 	ctp->chan_ptr->ddma_dbell = 0;
699 
700 	/* Get next descriptor pointer. */
701 	ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
702 
703 	/* Return something non-zero. */
704 	return nbytes;
705 }
706 EXPORT_SYMBOL(au1xxx_dbdma_put_dest);
707 
708 /*
709  * Get a destination buffer into the DMA ring.
710  * Normally used to get a full buffer from the ring during fifo
711  * to memory transfers.  This does not set the valid bit, you will
712  * have to put another destination buffer to keep the DMA going.
713  */
714 u32 au1xxx_dbdma_get_dest(u32 chanid, void **buf, int *nbytes)
715 {
716 	chan_tab_t		*ctp;
717 	au1x_ddma_desc_t	*dp;
718 	u32			rv;
719 
720 	/*
721 	 * I guess we could check this to be within the
722 	 * range of the table......
723 	 */
724 	ctp = *((chan_tab_t **)chanid);
725 
726 	/*
727 	 * We should have multiple callers for a particular channel,
728 	 * an interrupt doesn't affect this pointer nor the descriptor,
729 	 * so no locking should be needed.
730 	 */
731 	dp = ctp->get_ptr;
732 
733 	/*
734 	 * If the descriptor is valid, we are way ahead of the DMA
735 	 * engine, so just return an error condition.
736 	 */
737 	if (dp->dscr_cmd0 & DSCR_CMD0_V)
738 		return 0;
739 
740 	/* Return buffer address and byte count. */
741 	*buf = (void *)(phys_to_virt(dp->dscr_dest0));
742 	*nbytes = dp->dscr_cmd1;
743 	rv = dp->dscr_stat;
744 
745 	/* Get next descriptor pointer. */
746 	ctp->get_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
747 
748 	/* Return something non-zero. */
749 	return rv;
750 }
751 EXPORT_SYMBOL_GPL(au1xxx_dbdma_get_dest);
752 
753 void au1xxx_dbdma_stop(u32 chanid)
754 {
755 	chan_tab_t	*ctp;
756 	au1x_dma_chan_t *cp;
757 	int halt_timeout = 0;
758 
759 	ctp = *((chan_tab_t **)chanid);
760 
761 	cp = ctp->chan_ptr;
762 	cp->ddma_cfg &= ~DDMA_CFG_EN;	/* Disable channel */
763 	wmb(); /* drain writebuffer */
764 	while (!(cp->ddma_stat & DDMA_STAT_H)) {
765 		udelay(1);
766 		halt_timeout++;
767 		if (halt_timeout > 100) {
768 			printk(KERN_WARNING "warning: DMA channel won't halt\n");
769 			break;
770 		}
771 	}
772 	/* clear current desc valid and doorbell */
773 	cp->ddma_stat |= (DDMA_STAT_DB | DDMA_STAT_V);
774 	wmb(); /* drain writebuffer */
775 }
776 EXPORT_SYMBOL(au1xxx_dbdma_stop);
777 
778 /*
779  * Start using the current descriptor pointer.  If the DBDMA encounters
780  * a non-valid descriptor, it will stop.  In this case, we can just
781  * continue by adding a buffer to the list and starting again.
782  */
783 void au1xxx_dbdma_start(u32 chanid)
784 {
785 	chan_tab_t	*ctp;
786 	au1x_dma_chan_t *cp;
787 
788 	ctp = *((chan_tab_t **)chanid);
789 	cp = ctp->chan_ptr;
790 	cp->ddma_desptr = virt_to_phys(ctp->cur_ptr);
791 	cp->ddma_cfg |= DDMA_CFG_EN;	/* Enable channel */
792 	wmb(); /* drain writebuffer */
793 	cp->ddma_dbell = 0;
794 	wmb(); /* drain writebuffer */
795 }
796 EXPORT_SYMBOL(au1xxx_dbdma_start);
797 
798 void au1xxx_dbdma_reset(u32 chanid)
799 {
800 	chan_tab_t		*ctp;
801 	au1x_ddma_desc_t	*dp;
802 
803 	au1xxx_dbdma_stop(chanid);
804 
805 	ctp = *((chan_tab_t **)chanid);
806 	ctp->get_ptr = ctp->put_ptr = ctp->cur_ptr = ctp->chan_desc_base;
807 
808 	/* Run through the descriptors and reset the valid indicator. */
809 	dp = ctp->chan_desc_base;
810 
811 	do {
812 		dp->dscr_cmd0 &= ~DSCR_CMD0_V;
813 		/*
814 		 * Reset our software status -- this is used to determine
815 		 * if a descriptor is in use by upper level software. Since
816 		 * posting can reset 'V' bit.
817 		 */
818 		dp->sw_status = 0;
819 		dp = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
820 	} while (dp != ctp->chan_desc_base);
821 }
822 EXPORT_SYMBOL(au1xxx_dbdma_reset);
823 
824 u32 au1xxx_get_dma_residue(u32 chanid)
825 {
826 	chan_tab_t	*ctp;
827 	au1x_dma_chan_t *cp;
828 	u32		rv;
829 
830 	ctp = *((chan_tab_t **)chanid);
831 	cp = ctp->chan_ptr;
832 
833 	/* This is only valid if the channel is stopped. */
834 	rv = cp->ddma_bytecnt;
835 	wmb(); /* drain writebuffer */
836 
837 	return rv;
838 }
839 EXPORT_SYMBOL_GPL(au1xxx_get_dma_residue);
840 
841 void au1xxx_dbdma_chan_free(u32 chanid)
842 {
843 	chan_tab_t	*ctp;
844 	dbdev_tab_t	*stp, *dtp;
845 
846 	ctp = *((chan_tab_t **)chanid);
847 	stp = ctp->chan_src;
848 	dtp = ctp->chan_dest;
849 
850 	au1xxx_dbdma_stop(chanid);
851 
852 	kfree((void *)ctp->cdb_membase);
853 
854 	stp->dev_flags &= ~DEV_FLAGS_INUSE;
855 	dtp->dev_flags &= ~DEV_FLAGS_INUSE;
856 	chan_tab_ptr[ctp->chan_index] = NULL;
857 
858 	kfree(ctp);
859 }
860 EXPORT_SYMBOL(au1xxx_dbdma_chan_free);
861 
862 static irqreturn_t dbdma_interrupt(int irq, void *dev_id)
863 {
864 	u32 intstat;
865 	u32 chan_index;
866 	chan_tab_t		*ctp;
867 	au1x_ddma_desc_t	*dp;
868 	au1x_dma_chan_t *cp;
869 
870 	intstat = dbdma_gptr->ddma_intstat;
871 	wmb(); /* drain writebuffer */
872 	chan_index = __ffs(intstat);
873 
874 	ctp = chan_tab_ptr[chan_index];
875 	cp = ctp->chan_ptr;
876 	dp = ctp->cur_ptr;
877 
878 	/* Reset interrupt. */
879 	cp->ddma_irq = 0;
880 	wmb(); /* drain writebuffer */
881 
882 	if (ctp->chan_callback)
883 		ctp->chan_callback(irq, ctp->chan_callparam);
884 
885 	ctp->cur_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
886 	return IRQ_RETVAL(1);
887 }
888 
889 void au1xxx_dbdma_dump(u32 chanid)
890 {
891 	chan_tab_t	 *ctp;
892 	au1x_ddma_desc_t *dp;
893 	dbdev_tab_t	 *stp, *dtp;
894 	au1x_dma_chan_t	 *cp;
895 	u32 i		 = 0;
896 
897 	ctp = *((chan_tab_t **)chanid);
898 	stp = ctp->chan_src;
899 	dtp = ctp->chan_dest;
900 	cp = ctp->chan_ptr;
901 
902 	printk(KERN_DEBUG "Chan %x, stp %x (dev %d)  dtp %x (dev %d)\n",
903 			  (u32)ctp, (u32)stp, stp - dbdev_tab, (u32)dtp,
904 			  dtp - dbdev_tab);
905 	printk(KERN_DEBUG "desc base %x, get %x, put %x, cur %x\n",
906 			  (u32)(ctp->chan_desc_base), (u32)(ctp->get_ptr),
907 			  (u32)(ctp->put_ptr), (u32)(ctp->cur_ptr));
908 
909 	printk(KERN_DEBUG "dbdma chan %x\n", (u32)cp);
910 	printk(KERN_DEBUG "cfg %08x, desptr %08x, statptr %08x\n",
911 			  cp->ddma_cfg, cp->ddma_desptr, cp->ddma_statptr);
912 	printk(KERN_DEBUG "dbell %08x, irq %08x, stat %08x, bytecnt %08x\n",
913 			  cp->ddma_dbell, cp->ddma_irq, cp->ddma_stat,
914 			  cp->ddma_bytecnt);
915 
916 	/* Run through the descriptors */
917 	dp = ctp->chan_desc_base;
918 
919 	do {
920 		printk(KERN_DEBUG "Dp[%d]= %08x, cmd0 %08x, cmd1 %08x\n",
921 				  i++, (u32)dp, dp->dscr_cmd0, dp->dscr_cmd1);
922 		printk(KERN_DEBUG "src0 %08x, src1 %08x, dest0 %08x, dest1 %08x\n",
923 				  dp->dscr_source0, dp->dscr_source1,
924 				  dp->dscr_dest0, dp->dscr_dest1);
925 		printk(KERN_DEBUG "stat %08x, nxtptr %08x\n",
926 				  dp->dscr_stat, dp->dscr_nxtptr);
927 		dp = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
928 	} while (dp != ctp->chan_desc_base);
929 }
930 
931 /* Put a descriptor into the DMA ring.
932  * This updates the source/destination pointers and byte count.
933  */
934 u32 au1xxx_dbdma_put_dscr(u32 chanid, au1x_ddma_desc_t *dscr)
935 {
936 	chan_tab_t *ctp;
937 	au1x_ddma_desc_t *dp;
938 	u32 nbytes = 0;
939 
940 	/*
941 	 * I guess we could check this to be within the
942 	 * range of the table......
943 	 */
944 	ctp = *((chan_tab_t **)chanid);
945 
946 	/*
947 	 * We should have multiple callers for a particular channel,
948 	 * an interrupt doesn't affect this pointer nor the descriptor,
949 	 * so no locking should be needed.
950 	 */
951 	dp = ctp->put_ptr;
952 
953 	/*
954 	 * If the descriptor is valid, we are way ahead of the DMA
955 	 * engine, so just return an error condition.
956 	 */
957 	if (dp->dscr_cmd0 & DSCR_CMD0_V)
958 		return 0;
959 
960 	/* Load up buffer addresses and byte count. */
961 	dp->dscr_dest0 = dscr->dscr_dest0;
962 	dp->dscr_source0 = dscr->dscr_source0;
963 	dp->dscr_dest1 = dscr->dscr_dest1;
964 	dp->dscr_source1 = dscr->dscr_source1;
965 	dp->dscr_cmd1 = dscr->dscr_cmd1;
966 	nbytes = dscr->dscr_cmd1;
967 	/* Allow the caller to specify if an interrupt is generated */
968 	dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
969 	dp->dscr_cmd0 |= dscr->dscr_cmd0 | DSCR_CMD0_V;
970 	ctp->chan_ptr->ddma_dbell = 0;
971 
972 	/* Get next descriptor pointer. */
973 	ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
974 
975 	/* Return something non-zero. */
976 	return nbytes;
977 }
978 
979 
980 static unsigned long alchemy_dbdma_pm_data[NUM_DBDMA_CHANS + 1][6];
981 
982 static int alchemy_dbdma_suspend(void)
983 {
984 	int i;
985 	void __iomem *addr;
986 
987 	addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
988 	alchemy_dbdma_pm_data[0][0] = __raw_readl(addr + 0x00);
989 	alchemy_dbdma_pm_data[0][1] = __raw_readl(addr + 0x04);
990 	alchemy_dbdma_pm_data[0][2] = __raw_readl(addr + 0x08);
991 	alchemy_dbdma_pm_data[0][3] = __raw_readl(addr + 0x0c);
992 
993 	/* save channel configurations */
994 	addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
995 	for (i = 1; i <= NUM_DBDMA_CHANS; i++) {
996 		alchemy_dbdma_pm_data[i][0] = __raw_readl(addr + 0x00);
997 		alchemy_dbdma_pm_data[i][1] = __raw_readl(addr + 0x04);
998 		alchemy_dbdma_pm_data[i][2] = __raw_readl(addr + 0x08);
999 		alchemy_dbdma_pm_data[i][3] = __raw_readl(addr + 0x0c);
1000 		alchemy_dbdma_pm_data[i][4] = __raw_readl(addr + 0x10);
1001 		alchemy_dbdma_pm_data[i][5] = __raw_readl(addr + 0x14);
1002 
1003 		/* halt channel */
1004 		__raw_writel(alchemy_dbdma_pm_data[i][0] & ~1, addr + 0x00);
1005 		wmb();
1006 		while (!(__raw_readl(addr + 0x14) & 1))
1007 			wmb();
1008 
1009 		addr += 0x100;	/* next channel base */
1010 	}
1011 	/* disable channel interrupts */
1012 	addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
1013 	__raw_writel(0, addr + 0x0c);
1014 	wmb();
1015 
1016 	return 0;
1017 }
1018 
1019 static void alchemy_dbdma_resume(void)
1020 {
1021 	int i;
1022 	void __iomem *addr;
1023 
1024 	addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_CONF_PHYS_ADDR);
1025 	__raw_writel(alchemy_dbdma_pm_data[0][0], addr + 0x00);
1026 	__raw_writel(alchemy_dbdma_pm_data[0][1], addr + 0x04);
1027 	__raw_writel(alchemy_dbdma_pm_data[0][2], addr + 0x08);
1028 	__raw_writel(alchemy_dbdma_pm_data[0][3], addr + 0x0c);
1029 
1030 	/* restore channel configurations */
1031 	addr = (void __iomem *)KSEG1ADDR(AU1550_DBDMA_PHYS_ADDR);
1032 	for (i = 1; i <= NUM_DBDMA_CHANS; i++) {
1033 		__raw_writel(alchemy_dbdma_pm_data[i][0], addr + 0x00);
1034 		__raw_writel(alchemy_dbdma_pm_data[i][1], addr + 0x04);
1035 		__raw_writel(alchemy_dbdma_pm_data[i][2], addr + 0x08);
1036 		__raw_writel(alchemy_dbdma_pm_data[i][3], addr + 0x0c);
1037 		__raw_writel(alchemy_dbdma_pm_data[i][4], addr + 0x10);
1038 		__raw_writel(alchemy_dbdma_pm_data[i][5], addr + 0x14);
1039 		wmb();
1040 		addr += 0x100;	/* next channel base */
1041 	}
1042 }
1043 
1044 static struct syscore_ops alchemy_dbdma_syscore_ops = {
1045 	.suspend	= alchemy_dbdma_suspend,
1046 	.resume		= alchemy_dbdma_resume,
1047 };
1048 
1049 static int __init dbdma_setup(unsigned int irq, dbdev_tab_t *idtable)
1050 {
1051 	int ret;
1052 
1053 	dbdev_tab = kcalloc(DBDEV_TAB_SIZE, sizeof(dbdev_tab_t), GFP_KERNEL);
1054 	if (!dbdev_tab)
1055 		return -ENOMEM;
1056 
1057 	memcpy(dbdev_tab, idtable, 32 * sizeof(dbdev_tab_t));
1058 	for (ret = 32; ret < DBDEV_TAB_SIZE; ret++)
1059 		dbdev_tab[ret].dev_id = ~0;
1060 
1061 	dbdma_gptr->ddma_config = 0;
1062 	dbdma_gptr->ddma_throttle = 0;
1063 	dbdma_gptr->ddma_inten = 0xffff;
1064 	wmb(); /* drain writebuffer */
1065 
1066 	ret = request_irq(irq, dbdma_interrupt, 0, "dbdma", (void *)dbdma_gptr);
1067 	if (ret)
1068 		printk(KERN_ERR "Cannot grab DBDMA interrupt!\n");
1069 	else {
1070 		dbdma_initialized = 1;
1071 		register_syscore_ops(&alchemy_dbdma_syscore_ops);
1072 	}
1073 
1074 	return ret;
1075 }
1076 
1077 static int __init alchemy_dbdma_init(void)
1078 {
1079 	switch (alchemy_get_cputype()) {
1080 	case ALCHEMY_CPU_AU1550:
1081 		return dbdma_setup(AU1550_DDMA_INT, au1550_dbdev_tab);
1082 	case ALCHEMY_CPU_AU1200:
1083 		return dbdma_setup(AU1200_DDMA_INT, au1200_dbdev_tab);
1084 	case ALCHEMY_CPU_AU1300:
1085 		return dbdma_setup(AU1300_DDMA_INT, au1300_dbdev_tab);
1086 	}
1087 	return 0;
1088 }
1089 subsys_initcall(alchemy_dbdma_init);
1090