1 // SPDX-License-Identifier: GPL-2.0
2 /* ebus.c: EBUS DMA library code.
3 *
4 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
5 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
6 */
7
8 #include <linux/export.h>
9 #include <linux/kernel.h>
10 #include <linux/types.h>
11 #include <linux/interrupt.h>
12 #include <linux/delay.h>
13
14 #include <asm/ebus_dma.h>
15 #include <asm/io.h>
16
17 #define EBDMA_CSR 0x00UL /* Control/Status */
18 #define EBDMA_ADDR 0x04UL /* DMA Address */
19 #define EBDMA_COUNT 0x08UL /* DMA Count */
20
21 #define EBDMA_CSR_INT_PEND 0x00000001
22 #define EBDMA_CSR_ERR_PEND 0x00000002
23 #define EBDMA_CSR_DRAIN 0x00000004
24 #define EBDMA_CSR_INT_EN 0x00000010
25 #define EBDMA_CSR_RESET 0x00000080
26 #define EBDMA_CSR_WRITE 0x00000100
27 #define EBDMA_CSR_EN_DMA 0x00000200
28 #define EBDMA_CSR_CYC_PEND 0x00000400
29 #define EBDMA_CSR_DIAG_RD_DONE 0x00000800
30 #define EBDMA_CSR_DIAG_WR_DONE 0x00001000
31 #define EBDMA_CSR_EN_CNT 0x00002000
32 #define EBDMA_CSR_TC 0x00004000
33 #define EBDMA_CSR_DIS_CSR_DRN 0x00010000
34 #define EBDMA_CSR_BURST_SZ_MASK 0x000c0000
35 #define EBDMA_CSR_BURST_SZ_1 0x00080000
36 #define EBDMA_CSR_BURST_SZ_4 0x00000000
37 #define EBDMA_CSR_BURST_SZ_8 0x00040000
38 #define EBDMA_CSR_BURST_SZ_16 0x000c0000
39 #define EBDMA_CSR_DIAG_EN 0x00100000
40 #define EBDMA_CSR_DIS_ERR_PEND 0x00400000
41 #define EBDMA_CSR_TCI_DIS 0x00800000
42 #define EBDMA_CSR_EN_NEXT 0x01000000
43 #define EBDMA_CSR_DMA_ON 0x02000000
44 #define EBDMA_CSR_A_LOADED 0x04000000
45 #define EBDMA_CSR_NA_LOADED 0x08000000
46 #define EBDMA_CSR_DEV_ID_MASK 0xf0000000
47
48 #define EBUS_DMA_RESET_TIMEOUT 10000
49
50 static void __ebus_dma_reset(struct ebus_dma_info *p, int no_drain)
51 {
52 int i;
53 u32 val = 0;
54
55 writel(EBDMA_CSR_RESET, p->regs + EBDMA_CSR);
56 udelay(1);
57
58 if (no_drain)
59 return;
60
61 for (i = EBUS_DMA_RESET_TIMEOUT; i > 0; i--) {
62 val = readl(p->regs + EBDMA_CSR);
63
64 if (!(val & (EBDMA_CSR_DRAIN | EBDMA_CSR_CYC_PEND)))
65 break;
66 udelay(10);
67 }
68 }
69
70 static irqreturn_t ebus_dma_irq(int irq, void *dev_id)
71 {
72 struct ebus_dma_info *p = dev_id;
73 unsigned long flags;
74 u32 csr = 0;
75
76 spin_lock_irqsave(&p->lock, flags);
77 csr = readl(p->regs + EBDMA_CSR);
78 writel(csr, p->regs + EBDMA_CSR);
79 spin_unlock_irqrestore(&p->lock, flags);
80
81 if (csr & EBDMA_CSR_ERR_PEND) {
82 printk(KERN_CRIT "ebus_dma(%s): DMA error!\n", p->name);
83 p->callback(p, EBUS_DMA_EVENT_ERROR, p->client_cookie);
84 return IRQ_HANDLED;
85 } else if (csr & EBDMA_CSR_INT_PEND) {
86 p->callback(p,
87 (csr & EBDMA_CSR_TC) ?
88 EBUS_DMA_EVENT_DMA : EBUS_DMA_EVENT_DEVICE,
89 p->client_cookie);
90 return IRQ_HANDLED;
91 }
92
93 return IRQ_NONE;
94
95 }
96
97 int ebus_dma_register(struct ebus_dma_info *p)
98 {
99 u32 csr;
100
101 if (!p->regs)
102 return -EINVAL;
103 if (p->flags & ~(EBUS_DMA_FLAG_USE_EBDMA_HANDLER |
104 EBUS_DMA_FLAG_TCI_DISABLE))
105 return -EINVAL;
106 if ((p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) && !p->callback)
107 return -EINVAL;
108 if (!strlen(p->name))
109 return -EINVAL;
110
111 __ebus_dma_reset(p, 1);
112
113 csr = EBDMA_CSR_BURST_SZ_16 | EBDMA_CSR_EN_CNT;
114
115 if (p->flags & EBUS_DMA_FLAG_TCI_DISABLE)
116 csr |= EBDMA_CSR_TCI_DIS;
117
118 writel(csr, p->regs + EBDMA_CSR);
119
120 return 0;
121 }
122 EXPORT_SYMBOL(ebus_dma_register);
123
124 int ebus_dma_irq_enable(struct ebus_dma_info *p, int on)
125 {
126 unsigned long flags;
127 u32 csr;
128
129 if (on) {
130 if (p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) {
131 if (request_irq(p->irq, ebus_dma_irq, IRQF_SHARED, p->name, p))
132 return -EBUSY;
133 }
134
135 spin_lock_irqsave(&p->lock, flags);
136 csr = readl(p->regs + EBDMA_CSR);
137 csr |= EBDMA_CSR_INT_EN;
138 writel(csr, p->regs + EBDMA_CSR);
139 spin_unlock_irqrestore(&p->lock, flags);
140 } else {
141 spin_lock_irqsave(&p->lock, flags);
142 csr = readl(p->regs + EBDMA_CSR);
143 csr &= ~EBDMA_CSR_INT_EN;
144 writel(csr, p->regs + EBDMA_CSR);
145 spin_unlock_irqrestore(&p->lock, flags);
146
147 if (p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) {
148 free_irq(p->irq, p);
149 }
150 }
151
152 return 0;
153 }
154 EXPORT_SYMBOL(ebus_dma_irq_enable);
155
156 void ebus_dma_unregister(struct ebus_dma_info *p)
157 {
158 unsigned long flags;
159 u32 csr;
160 int irq_on = 0;
161
162 spin_lock_irqsave(&p->lock, flags);
163 csr = readl(p->regs + EBDMA_CSR);
164 if (csr & EBDMA_CSR_INT_EN) {
165 csr &= ~EBDMA_CSR_INT_EN;
166 writel(csr, p->regs + EBDMA_CSR);
167 irq_on = 1;
168 }
169 spin_unlock_irqrestore(&p->lock, flags);
170
171 if (irq_on)
172 free_irq(p->irq, p);
173 }
174 EXPORT_SYMBOL(ebus_dma_unregister);
175
176 int ebus_dma_request(struct ebus_dma_info *p, dma_addr_t bus_addr, size_t len)
177 {
178 unsigned long flags;
179 u32 csr;
180 int err;
181
182 if (len >= (1 << 24))
183 return -EINVAL;
184
185 spin_lock_irqsave(&p->lock, flags);
186 csr = readl(p->regs + EBDMA_CSR);
187 err = -EINVAL;
188 if (!(csr & EBDMA_CSR_EN_DMA))
189 goto out;
190 err = -EBUSY;
191 if (csr & EBDMA_CSR_NA_LOADED)
192 goto out;
193
194 writel(len, p->regs + EBDMA_COUNT);
195 writel(bus_addr, p->regs + EBDMA_ADDR);
196 err = 0;
197
198 out:
199 spin_unlock_irqrestore(&p->lock, flags);
200
201 return err;
202 }
203 EXPORT_SYMBOL(ebus_dma_request);
204
205 void ebus_dma_prepare(struct ebus_dma_info *p, int write)
206 {
207 unsigned long flags;
208 u32 csr;
209
210 spin_lock_irqsave(&p->lock, flags);
211 __ebus_dma_reset(p, 0);
212
213 csr = (EBDMA_CSR_INT_EN |
214 EBDMA_CSR_EN_CNT |
215 EBDMA_CSR_BURST_SZ_16 |
216 EBDMA_CSR_EN_NEXT);
217
218 if (write)
219 csr |= EBDMA_CSR_WRITE;
220 if (p->flags & EBUS_DMA_FLAG_TCI_DISABLE)
221 csr |= EBDMA_CSR_TCI_DIS;
222
223 writel(csr, p->regs + EBDMA_CSR);
224
225 spin_unlock_irqrestore(&p->lock, flags);
226 }
227 EXPORT_SYMBOL(ebus_dma_prepare);
228
229 unsigned int ebus_dma_residue(struct ebus_dma_info *p)
230 {
231 return readl(p->regs + EBDMA_COUNT);
232 }
233 EXPORT_SYMBOL(ebus_dma_residue);
234
235 unsigned int ebus_dma_addr(struct ebus_dma_info *p)
236 {
237 return readl(p->regs + EBDMA_ADDR);
238 }
239 EXPORT_SYMBOL(ebus_dma_addr);
240
241 void ebus_dma_enable(struct ebus_dma_info *p, int on)
242 {
243 unsigned long flags;
244 u32 orig_csr, csr;
245
246 spin_lock_irqsave(&p->lock, flags);
247 orig_csr = csr = readl(p->regs + EBDMA_CSR);
248 if (on)
249 csr |= EBDMA_CSR_EN_DMA;
250 else
251 csr &= ~EBDMA_CSR_EN_DMA;
252 if ((orig_csr & EBDMA_CSR_EN_DMA) !=
253 (csr & EBDMA_CSR_EN_DMA))
254 writel(csr, p->regs + EBDMA_CSR);
255 spin_unlock_irqrestore(&p->lock, flags);
256 }
257 EXPORT_SYMBOL(ebus_dma_enable);
258
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