3  *  linux/arch/arm/kernel/dma.c
7  *  Front-end to the DMA handling.  This handles the allocation/freeing
8  *  of DMA channels, and provides a unified interface to the machines
9  *  DMA facilities.
19 #include <asm/dma.h>
21 #include <asm/mach/dma.h>
36 int __init isa_dma_add(unsigned int chan, dma_t *dma)  in isa_dma_add()  argument
38 	if (!dma->d_ops)  in isa_dma_add()
41 	sg_init_table(&dma->buf, 1);  in isa_dma_add()
45 	dma_chan[chan] = dma;  in isa_dma_add()
50  * Request DMA channel
56 	dma_t *dma = dma_channel(chan);  in request_dma()  local
59 	if (!dma)  in request_dma()
62 	if (xchg(&dma->lock, 1) != 0)  in request_dma()
65 	dma->device_id = device_id;  in request_dma()
66 	dma->active    = 0;  in request_dma()
67 	dma->invalid   = 1;  in request_dma()
70 	if (dma->d_ops->request)  in request_dma()
71 		ret = dma->d_ops->request(chan, dma);  in request_dma()
74 		xchg(&dma->lock, 0);  in request_dma()
79 	pr_err("dma: trying to allocate DMA%d\n", chan);  in request_dma()
88  * Free DMA channel
94 	dma_t *dma = dma_channel(chan);  in free_dma()  local
96 	if (!dma)  in free_dma()
99 	if (dma->active) {  in free_dma()
100 		pr_err("dma%d: freeing active DMA\n", chan);  in free_dma()
101 		dma->d_ops->disable(chan, dma);  in free_dma()
102 		dma->active = 0;  in free_dma()
105 	if (xchg(&dma->lock, 0) != 0) {  in free_dma()
106 		if (dma->d_ops->free)  in free_dma()
107 			dma->d_ops->free(chan, dma);  in free_dma()
111 	pr_err("dma%d: trying to free free DMA\n", chan);  in free_dma()
115 	pr_err("dma: trying to free DMA%d\n", chan);  in free_dma()
119 /* Set DMA Scatter-Gather list
123 	dma_t *dma = dma_channel(chan);  in set_dma_sg()  local
125 	if (dma->active)  in set_dma_sg()
126 		pr_err("dma%d: altering DMA SG while DMA active\n", chan);  in set_dma_sg()
128 	dma->sg = sg;  in set_dma_sg()
129 	dma->sgcount = nr_sg;  in set_dma_sg()
130 	dma->invalid = 1;  in set_dma_sg()
134 /* Set DMA address
140 	dma_t *dma = dma_channel(chan);  in __set_dma_addr()  local
142 	if (dma->active)  in __set_dma_addr()
143 		pr_err("dma%d: altering DMA address while DMA active\n", chan);  in __set_dma_addr()
145 	dma->sg = NULL;  in __set_dma_addr()
146 	dma->addr = addr;  in __set_dma_addr()
147 	dma->invalid = 1;  in __set_dma_addr()
151 /* Set DMA byte count
157 	dma_t *dma = dma_channel(chan);  in set_dma_count()  local
159 	if (dma->active)  in set_dma_count()
160 		pr_err("dma%d: altering DMA count while DMA active\n", chan);  in set_dma_count()
162 	dma->sg = NULL;  in set_dma_count()
163 	dma->count = count;  in set_dma_count()
164 	dma->invalid = 1;  in set_dma_count()
168 /* Set DMA direction mode
172 	dma_t *dma = dma_channel(chan);  in set_dma_mode()  local
174 	if (dma->active)  in set_dma_mode()
175 		pr_err("dma%d: altering DMA mode while DMA active\n", chan);  in set_dma_mode()
177 	dma->dma_mode = mode;  in set_dma_mode()
178 	dma->invalid = 1;  in set_dma_mode()
182 /* Enable DMA channel
186 	dma_t *dma = dma_channel(chan);  in enable_dma()  local
188 	if (!dma->lock)  in enable_dma()
191 	if (dma->active == 0) {  in enable_dma()
192 		dma->active = 1;  in enable_dma()
193 		dma->d_ops->enable(chan, dma);  in enable_dma()
198 	pr_err("dma%d: trying to enable free DMA\n", chan);  in enable_dma()
203 /* Disable DMA channel
207 	dma_t *dma = dma_channel(chan);  in disable_dma()  local
209 	if (!dma->lock)  in disable_dma()
212 	if (dma->active == 1) {  in disable_dma()
213 		dma->active = 0;  in disable_dma()
214 		dma->d_ops->disable(chan, dma);  in disable_dma()
219 	pr_err("dma%d: trying to disable free DMA\n", chan);  in disable_dma()
225  * Is the specified DMA channel active?
229 	dma_t *dma = dma_channel(chan);  in dma_channel_active()  local
230 	return dma->active;  in dma_channel_active()
236 	pr_err("dma%d: trying to set_dma_page\n", chan);  in set_dma_page()
242 	dma_t *dma = dma_channel(chan);  in set_dma_speed()  local
245 	if (dma->d_ops->setspeed)  in set_dma_speed()
246 		ret = dma->d_ops->setspeed(chan, dma, cycle_ns);  in set_dma_speed()
247 	dma->speed = ret;  in set_dma_speed()
253 	dma_t *dma = dma_channel(chan);  in get_dma_residue()  local
256 	if (dma->d_ops->residue)  in get_dma_residue()
257 		ret = dma->d_ops->residue(chan, dma);  in get_dma_residue()
269 		dma_t *dma = dma_channel(i);  in proc_dma_show()  local
270 		if (dma && dma->lock)  in proc_dma_show()
271 			seq_printf(m, "%2d: %s\n", i, dma->device_id);  in proc_dma_show()
278 	proc_create_single("dma", 0, NULL, proc_dma_show);  in proc_dma_init()