1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Omnitek Scatter-Gather DMA Controller
4 *
5 * Copyright 2012-2015 Cisco Systems, Inc. and/or its affiliates.
6 * All rights reserved.
7 */
8
9 #include <linux/string.h>
10 #include <linux/io.h>
11 #include <linux/pci_regs.h>
12 #include <linux/spinlock.h>
13
14 #include "cobalt-driver.h"
15 #include "cobalt-omnitek.h"
16
17 /* descriptor */
18 #define END_OF_CHAIN (1 << 1)
19 #define INTERRUPT_ENABLE (1 << 2)
20 #define WRITE_TO_PCI (1 << 3)
21 #define READ_FROM_PCI (0 << 3)
22 #define DESCRIPTOR_FLAG_MSK (END_OF_CHAIN | INTERRUPT_ENABLE | WRITE_TO_PCI)
23 #define NEXT_ADRS_MSK 0xffffffe0
24
25 /* control/status register */
26 #define ENABLE (1 << 0)
27 #define START (1 << 1)
28 #define ABORT (1 << 2)
29 #define DONE (1 << 4)
30 #define SG_INTERRUPT (1 << 5)
31 #define EVENT_INTERRUPT (1 << 6)
32 #define SCATTER_GATHER_MODE (1 << 8)
33 #define DISABLE_VIDEO_RESYNC (1 << 9)
34 #define EVENT_INTERRUPT_ENABLE (1 << 10)
35 #define DIRECTIONAL_MSK (3 << 16)
36 #define INPUT_ONLY (0 << 16)
37 #define OUTPUT_ONLY (1 << 16)
38 #define BIDIRECTIONAL (2 << 16)
39 #define DMA_TYPE_MEMORY (0 << 18)
40 #define DMA_TYPE_FIFO (1 << 18)
41
42 #define BASE (cobalt->bar0)
43 #define CAPABILITY_HEADER (BASE)
44 #define CAPABILITY_REGISTER (BASE + 0x04)
45 #define PCI_64BIT (1 << 8)
46 #define LOCAL_64BIT (1 << 9)
47 #define INTERRUPT_STATUS (BASE + 0x08)
48 #define PCI(c) (BASE + 0x40 + ((c) * 0x40))
49 #define SIZE(c) (BASE + 0x58 + ((c) * 0x40))
50 #define DESCRIPTOR(c) (BASE + 0x50 + ((c) * 0x40))
51 #define CS_REG(c) (BASE + 0x60 + ((c) * 0x40))
52 #define BYTES_TRANSFERRED(c) (BASE + 0x64 + ((c) * 0x40))
53
54
get_dma_direction(u32 status)55 static char *get_dma_direction(u32 status)
56 {
57 switch (status & DIRECTIONAL_MSK) {
58 case INPUT_ONLY: return "Input";
59 case OUTPUT_ONLY: return "Output";
60 case BIDIRECTIONAL: return "Bidirectional";
61 }
62 return "";
63 }
64
show_dma_capability(struct cobalt * cobalt)65 static void show_dma_capability(struct cobalt *cobalt)
66 {
67 u32 header = ioread32(CAPABILITY_HEADER);
68 u32 capa = ioread32(CAPABILITY_REGISTER);
69 u32 i;
70
71 cobalt_info("Omnitek DMA capability: ID 0x%02x Version 0x%02x Next 0x%x Size 0x%x\n",
72 header & 0xff, (header >> 8) & 0xff,
73 (header >> 16) & 0xffff, (capa >> 24) & 0xff);
74
75 switch ((capa >> 8) & 0x3) {
76 case 0:
77 cobalt_info("Omnitek DMA: 32 bits PCIe and Local\n");
78 break;
79 case 1:
80 cobalt_info("Omnitek DMA: 64 bits PCIe, 32 bits Local\n");
81 break;
82 case 3:
83 cobalt_info("Omnitek DMA: 64 bits PCIe and Local\n");
84 break;
85 }
86
87 for (i = 0; i < (capa & 0xf); i++) {
88 u32 status = ioread32(CS_REG(i));
89
90 cobalt_info("Omnitek DMA channel #%d: %s %s\n", i,
91 status & DMA_TYPE_FIFO ? "FIFO" : "MEMORY",
92 get_dma_direction(status));
93 }
94 }
95
omni_sg_dma_start(struct cobalt_stream * s,struct sg_dma_desc_info * desc)96 void omni_sg_dma_start(struct cobalt_stream *s, struct sg_dma_desc_info *desc)
97 {
98 struct cobalt *cobalt = s->cobalt;
99
100 iowrite32((u32)((u64)desc->bus >> 32), DESCRIPTOR(s->dma_channel) + 4);
101 iowrite32((u32)desc->bus & NEXT_ADRS_MSK, DESCRIPTOR(s->dma_channel));
102 iowrite32(ENABLE | SCATTER_GATHER_MODE | START, CS_REG(s->dma_channel));
103 }
104
is_dma_done(struct cobalt_stream * s)105 bool is_dma_done(struct cobalt_stream *s)
106 {
107 struct cobalt *cobalt = s->cobalt;
108
109 if (ioread32(CS_REG(s->dma_channel)) & DONE)
110 return true;
111
112 return false;
113 }
114
omni_sg_dma_abort_channel(struct cobalt_stream * s)115 void omni_sg_dma_abort_channel(struct cobalt_stream *s)
116 {
117 struct cobalt *cobalt = s->cobalt;
118
119 if (!is_dma_done(s))
120 iowrite32(ABORT, CS_REG(s->dma_channel));
121 }
122
omni_sg_dma_init(struct cobalt * cobalt)123 int omni_sg_dma_init(struct cobalt *cobalt)
124 {
125 u32 capa = ioread32(CAPABILITY_REGISTER);
126 int i;
127
128 cobalt->first_fifo_channel = 0;
129 cobalt->dma_channels = capa & 0xf;
130 if (capa & PCI_64BIT)
131 cobalt->pci_32_bit = false;
132 else
133 cobalt->pci_32_bit = true;
134
135 for (i = 0; i < cobalt->dma_channels; i++) {
136 u32 status = ioread32(CS_REG(i));
137 u32 ctrl = ioread32(CS_REG(i));
138
139 if (!(ctrl & DONE))
140 iowrite32(ABORT, CS_REG(i));
141
142 if (!(status & DMA_TYPE_FIFO))
143 cobalt->first_fifo_channel++;
144 }
145 show_dma_capability(cobalt);
146 return 0;
147 }
148
descriptor_list_create(struct cobalt * cobalt,struct scatterlist * scatter_list,bool to_pci,unsigned sglen,unsigned size,unsigned width,unsigned stride,struct sg_dma_desc_info * desc)149 int descriptor_list_create(struct cobalt *cobalt,
150 struct scatterlist *scatter_list, bool to_pci, unsigned sglen,
151 unsigned size, unsigned width, unsigned stride,
152 struct sg_dma_desc_info *desc)
153 {
154 struct sg_dma_descriptor *d = (struct sg_dma_descriptor *)desc->virt;
155 dma_addr_t next = desc->bus;
156 unsigned offset = 0;
157 unsigned copy_bytes = width;
158 unsigned copied = 0;
159 bool first = true;
160
161 /* Must be 4-byte aligned */
162 WARN_ON(sg_dma_address(scatter_list) & 3);
163 WARN_ON(size & 3);
164 WARN_ON(next & 3);
165 WARN_ON(stride & 3);
166 WARN_ON(stride < width);
167 if (width >= stride)
168 copy_bytes = stride = size;
169
170 while (size) {
171 dma_addr_t addr = sg_dma_address(scatter_list) + offset;
172 unsigned bytes;
173
174 if (addr == 0)
175 return -EFAULT;
176 if (cobalt->pci_32_bit) {
177 WARN_ON((u64)addr >> 32);
178 if ((u64)addr >> 32)
179 return -EFAULT;
180 }
181
182 /* PCIe address */
183 d->pci_l = addr & 0xffffffff;
184 /* If dma_addr_t is 32 bits, then addr >> 32 is actually the
185 equivalent of addr >> 0 in gcc. So must cast to u64. */
186 d->pci_h = (u64)addr >> 32;
187
188 /* Sync to start of streaming frame */
189 d->local = 0;
190 d->reserved0 = 0;
191
192 /* Transfer bytes */
193 bytes = min(sg_dma_len(scatter_list) - offset,
194 copy_bytes - copied);
195
196 if (first) {
197 if (to_pci)
198 d->local = 0x11111111;
199 first = false;
200 if (sglen == 1) {
201 /* Make sure there are always at least two
202 * descriptors */
203 d->bytes = (bytes / 2) & ~3;
204 d->reserved1 = 0;
205 size -= d->bytes;
206 copied += d->bytes;
207 offset += d->bytes;
208 addr += d->bytes;
209 next += sizeof(struct sg_dma_descriptor);
210 d->next_h = (u32)((u64)next >> 32);
211 d->next_l = (u32)next |
212 (to_pci ? WRITE_TO_PCI : 0);
213 bytes -= d->bytes;
214 d++;
215 /* PCIe address */
216 d->pci_l = addr & 0xffffffff;
217 /* If dma_addr_t is 32 bits, then addr >> 32
218 * is actually the equivalent of addr >> 0 in
219 * gcc. So must cast to u64. */
220 d->pci_h = (u64)addr >> 32;
221
222 /* Sync to start of streaming frame */
223 d->local = 0;
224 d->reserved0 = 0;
225 }
226 }
227
228 d->bytes = bytes;
229 d->reserved1 = 0;
230 size -= bytes;
231 copied += bytes;
232 offset += bytes;
233
234 if (copied == copy_bytes) {
235 while (copied < stride) {
236 bytes = min(sg_dma_len(scatter_list) - offset,
237 stride - copied);
238 copied += bytes;
239 offset += bytes;
240 size -= bytes;
241 if (sg_dma_len(scatter_list) == offset) {
242 offset = 0;
243 scatter_list = sg_next(scatter_list);
244 }
245 }
246 copied = 0;
247 } else {
248 offset = 0;
249 scatter_list = sg_next(scatter_list);
250 }
251
252 /* Next descriptor + control bits */
253 next += sizeof(struct sg_dma_descriptor);
254 if (size == 0) {
255 /* Loopback to the first descriptor */
256 d->next_h = (u32)((u64)desc->bus >> 32);
257 d->next_l = (u32)desc->bus |
258 (to_pci ? WRITE_TO_PCI : 0) | INTERRUPT_ENABLE;
259 if (!to_pci)
260 d->local = 0x22222222;
261 desc->last_desc_virt = d;
262 } else {
263 d->next_h = (u32)((u64)next >> 32);
264 d->next_l = (u32)next | (to_pci ? WRITE_TO_PCI : 0);
265 }
266 d++;
267 }
268 return 0;
269 }
270
descriptor_list_chain(struct sg_dma_desc_info * this,struct sg_dma_desc_info * next)271 void descriptor_list_chain(struct sg_dma_desc_info *this,
272 struct sg_dma_desc_info *next)
273 {
274 struct sg_dma_descriptor *d = this->last_desc_virt;
275 u32 direction = d->next_l & WRITE_TO_PCI;
276
277 if (next == NULL) {
278 d->next_h = 0;
279 d->next_l = direction | INTERRUPT_ENABLE | END_OF_CHAIN;
280 } else {
281 d->next_h = (u32)((u64)next->bus >> 32);
282 d->next_l = (u32)next->bus | direction | INTERRUPT_ENABLE;
283 }
284 }
285
descriptor_list_allocate(struct sg_dma_desc_info * desc,size_t bytes)286 void *descriptor_list_allocate(struct sg_dma_desc_info *desc, size_t bytes)
287 {
288 desc->size = bytes;
289 desc->virt = dma_alloc_coherent(desc->dev, bytes,
290 &desc->bus, GFP_KERNEL);
291 return desc->virt;
292 }
293
descriptor_list_free(struct sg_dma_desc_info * desc)294 void descriptor_list_free(struct sg_dma_desc_info *desc)
295 {
296 if (desc->virt)
297 dma_free_coherent(desc->dev, desc->size,
298 desc->virt, desc->bus);
299 desc->virt = NULL;
300 }
301
descriptor_list_interrupt_enable(struct sg_dma_desc_info * desc)302 void descriptor_list_interrupt_enable(struct sg_dma_desc_info *desc)
303 {
304 struct sg_dma_descriptor *d = desc->last_desc_virt;
305
306 d->next_l |= INTERRUPT_ENABLE;
307 }
308
descriptor_list_interrupt_disable(struct sg_dma_desc_info * desc)309 void descriptor_list_interrupt_disable(struct sg_dma_desc_info *desc)
310 {
311 struct sg_dma_descriptor *d = desc->last_desc_virt;
312
313 d->next_l &= ~INTERRUPT_ENABLE;
314 }
315
descriptor_list_loopback(struct sg_dma_desc_info * desc)316 void descriptor_list_loopback(struct sg_dma_desc_info *desc)
317 {
318 struct sg_dma_descriptor *d = desc->last_desc_virt;
319
320 d->next_h = (u32)((u64)desc->bus >> 32);
321 d->next_l = (u32)desc->bus | (d->next_l & DESCRIPTOR_FLAG_MSK);
322 }
323
descriptor_list_end_of_chain(struct sg_dma_desc_info * desc)324 void descriptor_list_end_of_chain(struct sg_dma_desc_info *desc)
325 {
326 struct sg_dma_descriptor *d = desc->last_desc_virt;
327
328 d->next_l |= END_OF_CHAIN;
329 }
330