1 // SPDX-License-Identifier: GPL-2.0-only
5  *  Copyright (C) 1995-2000 Russell King
7  *  Front-end to the DMA handling.  This handles the allocation/freeing
38 	if (!dma->d_ops)  in isa_dma_add()
39 		return -EINVAL;  in isa_dma_add()
41 	sg_init_table(&dma->buf, 1);  in isa_dma_add()
44 		return -EBUSY;  in isa_dma_add()
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()
80 	return -EINVAL;  in request_dma()
83 	return -EBUSY;  in request_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()
119 /* Set DMA Scatter-Gather list
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()
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()
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()
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()
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()
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()
225  * Is the specified DMA channel active?
230 	return dma->active;  in dma_channel_active()
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()
256 	if (dma->d_ops->residue)  in get_dma_residue()
257 		ret = dma->d_ops->residue(chan, dma);  in get_dma_residue()
270 		if (dma && dma->lock)  in proc_dma_show()
271 			seq_printf(m, "%2d: %s\n", i, dma->device_id);  in proc_dma_show()