xref: /openbmc/linux/include/linux/shdma-base.h (revision 9be92baa)
1 /* SPDX-License-Identifier: GPL-2.0
2  *
3  * Dmaengine driver base library for DMA controllers, found on SH-based SoCs
4  *
5  * extracted from shdma.c and headers
6  *
7  * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
8  * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
9  * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
10  * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
11  */
12 
13 #ifndef SHDMA_BASE_H
14 #define SHDMA_BASE_H
15 
16 #include <linux/dmaengine.h>
17 #include <linux/interrupt.h>
18 #include <linux/list.h>
19 #include <linux/types.h>
20 
21 /**
22  * shdma_pm_state - DMA channel PM state
23  * SHDMA_PM_ESTABLISHED:	either idle or during data transfer
24  * SHDMA_PM_BUSY:		during the transfer preparation, when we have to
25  *				drop the lock temporarily
26  * SHDMA_PM_PENDING:	transfers pending
27  */
28 enum shdma_pm_state {
29 	SHDMA_PM_ESTABLISHED,
30 	SHDMA_PM_BUSY,
31 	SHDMA_PM_PENDING,
32 };
33 
34 struct device;
35 
36 /*
37  * Drivers, using this library are expected to embed struct shdma_dev,
38  * struct shdma_chan, struct shdma_desc, and struct shdma_slave
39  * in their respective device, channel, descriptor and slave objects.
40  */
41 
42 struct shdma_slave {
43 	int slave_id;
44 };
45 
46 struct shdma_desc {
47 	struct list_head node;
48 	struct dma_async_tx_descriptor async_tx;
49 	enum dma_transfer_direction direction;
50 	size_t partial;
51 	dma_cookie_t cookie;
52 	int chunks;
53 	int mark;
54 	bool cyclic;			/* used as cyclic transfer */
55 };
56 
57 struct shdma_chan {
58 	spinlock_t chan_lock;		/* Channel operation lock */
59 	struct list_head ld_queue;	/* Link descriptors queue */
60 	struct list_head ld_free;	/* Free link descriptors */
61 	struct dma_chan dma_chan;	/* DMA channel */
62 	struct device *dev;		/* Channel device */
63 	void *desc;			/* buffer for descriptor array */
64 	int desc_num;			/* desc count */
65 	size_t max_xfer_len;		/* max transfer length */
66 	int id;				/* Raw id of this channel */
67 	int irq;			/* Channel IRQ */
68 	int slave_id;			/* Client ID for slave DMA */
69 	int real_slave_id;		/* argument passed to filter function */
70 	int hw_req;			/* DMA request line for slave DMA - same
71 					 * as MID/RID, used with DT */
72 	enum shdma_pm_state pm_state;
73 };
74 
75 /**
76  * struct shdma_ops - simple DMA driver operations
77  * desc_completed:	return true, if this is the descriptor, that just has
78  *			completed (atomic)
79  * halt_channel:	stop DMA channel operation (atomic)
80  * channel_busy:	return true, if the channel is busy (atomic)
81  * slave_addr:		return slave DMA address
82  * desc_setup:		set up the hardware specific descriptor portion (atomic)
83  * set_slave:		bind channel to a slave
84  * setup_xfer:		configure channel hardware for operation (atomic)
85  * start_xfer:		start the DMA transfer (atomic)
86  * embedded_desc:	return Nth struct shdma_desc pointer from the
87  *			descriptor array
88  * chan_irq:		process channel IRQ, return true if a transfer has
89  *			completed (atomic)
90  */
91 struct shdma_ops {
92 	bool (*desc_completed)(struct shdma_chan *, struct shdma_desc *);
93 	void (*halt_channel)(struct shdma_chan *);
94 	bool (*channel_busy)(struct shdma_chan *);
95 	dma_addr_t (*slave_addr)(struct shdma_chan *);
96 	int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,
97 			  dma_addr_t, dma_addr_t, size_t *);
98 	int (*set_slave)(struct shdma_chan *, int, dma_addr_t, bool);
99 	void (*setup_xfer)(struct shdma_chan *, int);
100 	void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);
101 	struct shdma_desc *(*embedded_desc)(void *, int);
102 	bool (*chan_irq)(struct shdma_chan *, int);
103 	size_t (*get_partial)(struct shdma_chan *, struct shdma_desc *);
104 };
105 
106 struct shdma_dev {
107 	struct dma_device dma_dev;
108 	struct shdma_chan **schan;
109 	const struct shdma_ops *ops;
110 	size_t desc_size;
111 };
112 
113 #define shdma_for_each_chan(c, d, i) for (i = 0, c = (d)->schan[0]; \
114 				i < (d)->dma_dev.chancnt; c = (d)->schan[++i])
115 
116 int shdma_request_irq(struct shdma_chan *, int,
117 			   unsigned long, const char *);
118 bool shdma_reset(struct shdma_dev *sdev);
119 void shdma_chan_probe(struct shdma_dev *sdev,
120 			   struct shdma_chan *schan, int id);
121 void shdma_chan_remove(struct shdma_chan *schan);
122 int shdma_init(struct device *dev, struct shdma_dev *sdev,
123 		    int chan_num);
124 void shdma_cleanup(struct shdma_dev *sdev);
125 #if IS_ENABLED(CONFIG_SH_DMAE_BASE)
126 bool shdma_chan_filter(struct dma_chan *chan, void *arg);
127 #else
shdma_chan_filter(struct dma_chan * chan,void * arg)128 static inline bool shdma_chan_filter(struct dma_chan *chan, void *arg)
129 {
130 	return false;
131 }
132 #endif
133 
134 #endif
135