1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/sh/drivers/dma/dma-g2.c
4 *
5 * G2 bus DMA support
6 *
7 * Copyright (C) 2003 - 2006 Paul Mundt
8 */
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <asm/cacheflush.h>
14 #include <mach/sysasic.h>
15 #include <mach/dma.h>
16 #include <asm/dma.h>
17
18 struct g2_channel {
19 unsigned long g2_addr; /* G2 bus address */
20 unsigned long root_addr; /* Root bus (SH-4) address */
21 unsigned long size; /* Size (in bytes), 32-byte aligned */
22 unsigned long direction; /* Transfer direction */
23 unsigned long ctrl; /* Transfer control */
24 unsigned long chan_enable; /* Channel enable */
25 unsigned long xfer_enable; /* Transfer enable */
26 unsigned long xfer_stat; /* Transfer status */
27 } __attribute__ ((aligned(32)));
28
29 struct g2_status {
30 unsigned long g2_addr;
31 unsigned long root_addr;
32 unsigned long size;
33 unsigned long status;
34 } __attribute__ ((aligned(16)));
35
36 struct g2_dma_info {
37 struct g2_channel channel[G2_NR_DMA_CHANNELS];
38 unsigned long pad1[G2_NR_DMA_CHANNELS];
39 unsigned long wait_state;
40 unsigned long pad2[10];
41 unsigned long magic;
42 struct g2_status status[G2_NR_DMA_CHANNELS];
43 } __attribute__ ((aligned(256)));
44
45 static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800;
46
47 #define g2_bytes_remaining(i) \
48 ((g2_dma->channel[i].size - \
49 g2_dma->status[i].size) & 0x0fffffff)
50
g2_dma_interrupt(int irq,void * dev_id)51 static irqreturn_t g2_dma_interrupt(int irq, void *dev_id)
52 {
53 int i;
54
55 for (i = 0; i < G2_NR_DMA_CHANNELS; i++) {
56 if (g2_dma->status[i].status & 0x20000000) {
57 unsigned int bytes = g2_bytes_remaining(i);
58
59 if (likely(bytes == 0)) {
60 struct dma_info *info = dev_id;
61 struct dma_channel *chan = info->channels + i;
62
63 wake_up(&chan->wait_queue);
64
65 return IRQ_HANDLED;
66 }
67 }
68 }
69
70 return IRQ_NONE;
71 }
72
g2_enable_dma(struct dma_channel * chan)73 static int g2_enable_dma(struct dma_channel *chan)
74 {
75 unsigned int chan_nr = chan->chan;
76
77 g2_dma->channel[chan_nr].chan_enable = 1;
78 g2_dma->channel[chan_nr].xfer_enable = 1;
79
80 return 0;
81 }
82
g2_disable_dma(struct dma_channel * chan)83 static int g2_disable_dma(struct dma_channel *chan)
84 {
85 unsigned int chan_nr = chan->chan;
86
87 g2_dma->channel[chan_nr].chan_enable = 0;
88 g2_dma->channel[chan_nr].xfer_enable = 0;
89
90 return 0;
91 }
92
g2_xfer_dma(struct dma_channel * chan)93 static int g2_xfer_dma(struct dma_channel *chan)
94 {
95 unsigned int chan_nr = chan->chan;
96
97 if (chan->sar & 31) {
98 printk("g2dma: unaligned source 0x%lx\n", chan->sar);
99 return -EINVAL;
100 }
101
102 if (chan->dar & 31) {
103 printk("g2dma: unaligned dest 0x%lx\n", chan->dar);
104 return -EINVAL;
105 }
106
107 /* Align the count */
108 if (chan->count & 31)
109 chan->count = (chan->count + (32 - 1)) & ~(32 - 1);
110
111 /* Fixup destination */
112 chan->dar += 0xa0800000;
113
114 /* Fixup direction */
115 chan->mode = !chan->mode;
116
117 flush_icache_range((unsigned long)chan->sar, chan->count);
118
119 g2_disable_dma(chan);
120
121 g2_dma->channel[chan_nr].g2_addr = chan->dar & 0x1fffffe0;
122 g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0;
123 g2_dma->channel[chan_nr].size = (chan->count & ~31) | 0x80000000;
124 g2_dma->channel[chan_nr].direction = chan->mode;
125
126 /*
127 * bit 0 - ???
128 * bit 1 - if set, generate a hardware event on transfer completion
129 * bit 2 - ??? something to do with suspend?
130 */
131 g2_dma->channel[chan_nr].ctrl = 5; /* ?? */
132
133 g2_enable_dma(chan);
134
135 /* debug cruft */
136 pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, "
137 "0x%08lx, %ld, %ld, %ld, %ld\n",
138 g2_dma->channel[chan_nr].size,
139 g2_dma->channel[chan_nr].root_addr,
140 g2_dma->channel[chan_nr].g2_addr,
141 g2_dma->channel[chan_nr].direction,
142 g2_dma->channel[chan_nr].ctrl,
143 g2_dma->channel[chan_nr].chan_enable,
144 g2_dma->channel[chan_nr].xfer_enable);
145
146 return 0;
147 }
148
g2_get_residue(struct dma_channel * chan)149 static int g2_get_residue(struct dma_channel *chan)
150 {
151 return g2_bytes_remaining(chan->chan);
152 }
153
154 static struct dma_ops g2_dma_ops = {
155 .xfer = g2_xfer_dma,
156 .get_residue = g2_get_residue,
157 };
158
159 static struct dma_info g2_dma_info = {
160 .name = "g2_dmac",
161 .nr_channels = 4,
162 .ops = &g2_dma_ops,
163 .flags = DMAC_CHANNELS_TEI_CAPABLE,
164 };
165
g2_dma_init(void)166 static int __init g2_dma_init(void)
167 {
168 int ret;
169
170 ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, 0,
171 "g2 DMA handler", &g2_dma_info);
172 if (unlikely(ret))
173 return -EINVAL;
174
175 /* Magic */
176 g2_dma->wait_state = 27;
177 g2_dma->magic = 0x4659404f;
178
179 ret = register_dmac(&g2_dma_info);
180 if (unlikely(ret != 0))
181 free_irq(HW_EVENT_G2_DMA, &g2_dma_info);
182
183 return ret;
184 }
185
g2_dma_exit(void)186 static void __exit g2_dma_exit(void)
187 {
188 free_irq(HW_EVENT_G2_DMA, &g2_dma_info);
189 unregister_dmac(&g2_dma_info);
190 }
191
192 subsys_initcall(g2_dma_init);
193 module_exit(g2_dma_exit);
194
195 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
196 MODULE_DESCRIPTION("G2 bus DMA driver");
197 MODULE_LICENSE("GPL v2");
198