1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MUSB OTG driver - support for Mentor's DMA controller
4  *
5  * Copyright 2005 Mentor Graphics Corporation
6  * Copyright (C) 2005-2007 by Texas Instruments
7  */
8 #include <linux/device.h>
9 #include <linux/interrupt.h>
10 #include <linux/platform_device.h>
11 #include <linux/slab.h>
12 #include "musb_core.h"
13 #include "musb_dma.h"
14 
15 #define MUSB_HSDMA_CHANNEL_OFFSET(_bchannel, _offset)		\
16 		(MUSB_HSDMA_BASE + (_bchannel << 4) + _offset)
17 
18 #define musb_read_hsdma_addr(mbase, bchannel)	\
19 	musb_readl(mbase,	\
20 		   MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_ADDRESS))
21 
22 #define musb_write_hsdma_addr(mbase, bchannel, addr) \
23 	musb_writel(mbase, \
24 		    MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_ADDRESS), \
25 		    addr)
26 
27 #define musb_read_hsdma_count(mbase, bchannel)	\
28 	musb_readl(mbase,	\
29 		   MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_COUNT))
30 
31 #define musb_write_hsdma_count(mbase, bchannel, len) \
32 	musb_writel(mbase, \
33 		    MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_COUNT), \
34 		    len)
35 /* control register (16-bit): */
36 #define MUSB_HSDMA_ENABLE_SHIFT		0
37 #define MUSB_HSDMA_TRANSMIT_SHIFT	1
38 #define MUSB_HSDMA_MODE1_SHIFT		2
39 #define MUSB_HSDMA_IRQENABLE_SHIFT	3
40 #define MUSB_HSDMA_ENDPOINT_SHIFT	4
41 #define MUSB_HSDMA_BUSERROR_SHIFT	8
42 #define MUSB_HSDMA_BURSTMODE_SHIFT	9
43 #define MUSB_HSDMA_BURSTMODE		(3 << MUSB_HSDMA_BURSTMODE_SHIFT)
44 #define MUSB_HSDMA_BURSTMODE_UNSPEC	0
45 #define MUSB_HSDMA_BURSTMODE_INCR4	1
46 #define MUSB_HSDMA_BURSTMODE_INCR8	2
47 #define MUSB_HSDMA_BURSTMODE_INCR16	3
48 
49 #define MUSB_HSDMA_CHANNELS		8
50 
51 struct musb_dma_controller;
52 
53 struct musb_dma_channel {
54 	struct dma_channel		channel;
55 	struct musb_dma_controller	*controller;
56 	u32				start_addr;
57 	u32				len;
58 	u16				max_packet_sz;
59 	u8				idx;
60 	u8				epnum;
61 	u8				transmit;
62 };
63 
64 struct musb_dma_controller {
65 	struct dma_controller		controller;
66 	struct musb_dma_channel		channel[MUSB_HSDMA_CHANNELS];
67 	void				*private_data;
68 	void __iomem			*base;
69 	u8				channel_count;
70 	u8				used_channels;
71 	int				irq;
72 };
73 
74 static void dma_channel_release(struct dma_channel *channel);
75 
dma_controller_stop(struct musb_dma_controller * controller)76 static void dma_controller_stop(struct musb_dma_controller *controller)
77 {
78 	struct musb *musb = controller->private_data;
79 	struct dma_channel *channel;
80 	u8 bit;
81 
82 	if (controller->used_channels != 0) {
83 		dev_err(musb->controller,
84 			"Stopping DMA controller while channel active\n");
85 
86 		for (bit = 0; bit < MUSB_HSDMA_CHANNELS; bit++) {
87 			if (controller->used_channels & (1 << bit)) {
88 				channel = &controller->channel[bit].channel;
89 				dma_channel_release(channel);
90 
91 				if (!controller->used_channels)
92 					break;
93 			}
94 		}
95 	}
96 }
97 
dma_channel_allocate(struct dma_controller * c,struct musb_hw_ep * hw_ep,u8 transmit)98 static struct dma_channel *dma_channel_allocate(struct dma_controller *c,
99 				struct musb_hw_ep *hw_ep, u8 transmit)
100 {
101 	struct musb_dma_controller *controller = container_of(c,
102 			struct musb_dma_controller, controller);
103 	struct musb_dma_channel *musb_channel = NULL;
104 	struct dma_channel *channel = NULL;
105 	u8 bit;
106 
107 	for (bit = 0; bit < MUSB_HSDMA_CHANNELS; bit++) {
108 		if (!(controller->used_channels & (1 << bit))) {
109 			controller->used_channels |= (1 << bit);
110 			musb_channel = &(controller->channel[bit]);
111 			musb_channel->controller = controller;
112 			musb_channel->idx = bit;
113 			musb_channel->epnum = hw_ep->epnum;
114 			musb_channel->transmit = transmit;
115 			channel = &(musb_channel->channel);
116 			channel->private_data = musb_channel;
117 			channel->status = MUSB_DMA_STATUS_FREE;
118 			channel->max_len = 0x100000;
119 			/* Tx => mode 1; Rx => mode 0 */
120 			channel->desired_mode = transmit;
121 			channel->actual_len = 0;
122 			break;
123 		}
124 	}
125 
126 	return channel;
127 }
128 
dma_channel_release(struct dma_channel * channel)129 static void dma_channel_release(struct dma_channel *channel)
130 {
131 	struct musb_dma_channel *musb_channel = channel->private_data;
132 
133 	channel->actual_len = 0;
134 	musb_channel->start_addr = 0;
135 	musb_channel->len = 0;
136 
137 	musb_channel->controller->used_channels &=
138 		~(1 << musb_channel->idx);
139 
140 	channel->status = MUSB_DMA_STATUS_UNKNOWN;
141 }
142 
configure_channel(struct dma_channel * channel,u16 packet_sz,u8 mode,dma_addr_t dma_addr,u32 len)143 static void configure_channel(struct dma_channel *channel,
144 				u16 packet_sz, u8 mode,
145 				dma_addr_t dma_addr, u32 len)
146 {
147 	struct musb_dma_channel *musb_channel = channel->private_data;
148 	struct musb_dma_controller *controller = musb_channel->controller;
149 	struct musb *musb = controller->private_data;
150 	void __iomem *mbase = controller->base;
151 	u8 bchannel = musb_channel->idx;
152 	u16 csr = 0;
153 
154 	musb_dbg(musb, "%p, pkt_sz %d, addr %pad, len %d, mode %d",
155 			channel, packet_sz, &dma_addr, len, mode);
156 
157 	if (mode) {
158 		csr |= 1 << MUSB_HSDMA_MODE1_SHIFT;
159 		BUG_ON(len < packet_sz);
160 	}
161 	csr |= MUSB_HSDMA_BURSTMODE_INCR16
162 				<< MUSB_HSDMA_BURSTMODE_SHIFT;
163 
164 	csr |= (musb_channel->epnum << MUSB_HSDMA_ENDPOINT_SHIFT)
165 		| (1 << MUSB_HSDMA_ENABLE_SHIFT)
166 		| (1 << MUSB_HSDMA_IRQENABLE_SHIFT)
167 		| (musb_channel->transmit
168 				? (1 << MUSB_HSDMA_TRANSMIT_SHIFT)
169 				: 0);
170 
171 	/* address/count */
172 	musb_write_hsdma_addr(mbase, bchannel, dma_addr);
173 	musb_write_hsdma_count(mbase, bchannel, len);
174 
175 	/* control (this should start things) */
176 	musb_writew(mbase,
177 		MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_CONTROL),
178 		csr);
179 }
180 
dma_channel_program(struct dma_channel * channel,u16 packet_sz,u8 mode,dma_addr_t dma_addr,u32 len)181 static int dma_channel_program(struct dma_channel *channel,
182 				u16 packet_sz, u8 mode,
183 				dma_addr_t dma_addr, u32 len)
184 {
185 	struct musb_dma_channel *musb_channel = channel->private_data;
186 	struct musb_dma_controller *controller = musb_channel->controller;
187 	struct musb *musb = controller->private_data;
188 
189 	musb_dbg(musb, "ep%d-%s pkt_sz %d, dma_addr %pad length %d, mode %d",
190 		musb_channel->epnum,
191 		musb_channel->transmit ? "Tx" : "Rx",
192 		packet_sz, &dma_addr, len, mode);
193 
194 	BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
195 		channel->status == MUSB_DMA_STATUS_BUSY);
196 
197 	/*
198 	 * The DMA engine in RTL1.8 and above cannot handle
199 	 * DMA addresses that are not aligned to a 4 byte boundary.
200 	 * It ends up masking the last two bits of the address
201 	 * programmed in DMA_ADDR.
202 	 *
203 	 * Fail such DMA transfers, so that the backup PIO mode
204 	 * can carry out the transfer
205 	 */
206 	if ((musb->hwvers >= MUSB_HWVERS_1800) && (dma_addr % 4))
207 		return false;
208 
209 	channel->actual_len = 0;
210 	musb_channel->start_addr = dma_addr;
211 	musb_channel->len = len;
212 	musb_channel->max_packet_sz = packet_sz;
213 	channel->status = MUSB_DMA_STATUS_BUSY;
214 
215 	configure_channel(channel, packet_sz, mode, dma_addr, len);
216 
217 	return true;
218 }
219 
dma_channel_abort(struct dma_channel * channel)220 static int dma_channel_abort(struct dma_channel *channel)
221 {
222 	struct musb_dma_channel *musb_channel = channel->private_data;
223 	void __iomem *mbase = musb_channel->controller->base;
224 	struct musb *musb = musb_channel->controller->private_data;
225 
226 	u8 bchannel = musb_channel->idx;
227 	int offset;
228 	u16 csr;
229 
230 	if (channel->status == MUSB_DMA_STATUS_BUSY) {
231 		if (musb_channel->transmit) {
232 			offset = musb->io.ep_offset(musb_channel->epnum,
233 						MUSB_TXCSR);
234 
235 			/*
236 			 * The programming guide says that we must clear
237 			 * the DMAENAB bit before the DMAMODE bit...
238 			 */
239 			csr = musb_readw(mbase, offset);
240 			csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
241 			musb_writew(mbase, offset, csr);
242 			csr &= ~MUSB_TXCSR_DMAMODE;
243 			musb_writew(mbase, offset, csr);
244 		} else {
245 			offset = musb->io.ep_offset(musb_channel->epnum,
246 						MUSB_RXCSR);
247 
248 			csr = musb_readw(mbase, offset);
249 			csr &= ~(MUSB_RXCSR_AUTOCLEAR |
250 				 MUSB_RXCSR_DMAENAB |
251 				 MUSB_RXCSR_DMAMODE);
252 			musb_writew(mbase, offset, csr);
253 		}
254 
255 		musb_writew(mbase,
256 			MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_CONTROL),
257 			0);
258 		musb_write_hsdma_addr(mbase, bchannel, 0);
259 		musb_write_hsdma_count(mbase, bchannel, 0);
260 		channel->status = MUSB_DMA_STATUS_FREE;
261 	}
262 
263 	return 0;
264 }
265 
dma_controller_irq(int irq,void * private_data)266 irqreturn_t dma_controller_irq(int irq, void *private_data)
267 {
268 	struct musb_dma_controller *controller = private_data;
269 	struct musb *musb = controller->private_data;
270 	struct musb_dma_channel *musb_channel;
271 	struct dma_channel *channel;
272 
273 	void __iomem *mbase = controller->base;
274 
275 	irqreturn_t retval = IRQ_NONE;
276 
277 	unsigned long flags;
278 
279 	u8 bchannel;
280 	u8 int_hsdma;
281 
282 	u32 addr, count;
283 	u16 csr;
284 
285 	spin_lock_irqsave(&musb->lock, flags);
286 
287 	int_hsdma = musb_clearb(mbase, MUSB_HSDMA_INTR);
288 
289 	if (!int_hsdma) {
290 		musb_dbg(musb, "spurious DMA irq");
291 
292 		for (bchannel = 0; bchannel < MUSB_HSDMA_CHANNELS; bchannel++) {
293 			musb_channel = (struct musb_dma_channel *)
294 					&(controller->channel[bchannel]);
295 			channel = &musb_channel->channel;
296 			if (channel->status == MUSB_DMA_STATUS_BUSY) {
297 				count = musb_read_hsdma_count(mbase, bchannel);
298 
299 				if (count == 0)
300 					int_hsdma |= (1 << bchannel);
301 			}
302 		}
303 
304 		musb_dbg(musb, "int_hsdma = 0x%x", int_hsdma);
305 
306 		if (!int_hsdma)
307 			goto done;
308 	}
309 
310 	for (bchannel = 0; bchannel < MUSB_HSDMA_CHANNELS; bchannel++) {
311 		if (int_hsdma & (1 << bchannel)) {
312 			musb_channel = (struct musb_dma_channel *)
313 					&(controller->channel[bchannel]);
314 			channel = &musb_channel->channel;
315 
316 			csr = musb_readw(mbase,
317 					MUSB_HSDMA_CHANNEL_OFFSET(bchannel,
318 							MUSB_HSDMA_CONTROL));
319 
320 			if (csr & (1 << MUSB_HSDMA_BUSERROR_SHIFT)) {
321 				musb_channel->channel.status =
322 					MUSB_DMA_STATUS_BUS_ABORT;
323 			} else {
324 				addr = musb_read_hsdma_addr(mbase,
325 						bchannel);
326 				channel->actual_len = addr
327 					- musb_channel->start_addr;
328 
329 				musb_dbg(musb, "ch %p, 0x%x -> 0x%x (%zu / %d) %s",
330 					channel, musb_channel->start_addr,
331 					addr, channel->actual_len,
332 					musb_channel->len,
333 					(channel->actual_len
334 						< musb_channel->len) ?
335 					"=> reconfig 0" : "=> complete");
336 
337 				channel->status = MUSB_DMA_STATUS_FREE;
338 
339 				/* completed */
340 				if (musb_channel->transmit &&
341 					(!channel->desired_mode ||
342 					(channel->actual_len %
343 					    musb_channel->max_packet_sz))) {
344 					u8  epnum  = musb_channel->epnum;
345 					int offset = musb->io.ep_offset(epnum,
346 								    MUSB_TXCSR);
347 					u16 txcsr;
348 
349 					/*
350 					 * The programming guide says that we
351 					 * must clear DMAENAB before DMAMODE.
352 					 */
353 					musb_ep_select(mbase, epnum);
354 					txcsr = musb_readw(mbase, offset);
355 					if (channel->desired_mode == 1) {
356 						txcsr &= ~(MUSB_TXCSR_DMAENAB
357 							| MUSB_TXCSR_AUTOSET);
358 						musb_writew(mbase, offset, txcsr);
359 						/* Send out the packet */
360 						txcsr &= ~MUSB_TXCSR_DMAMODE;
361 						txcsr |= MUSB_TXCSR_DMAENAB;
362 					}
363 					txcsr |=  MUSB_TXCSR_TXPKTRDY;
364 					musb_writew(mbase, offset, txcsr);
365 				}
366 				musb_dma_completion(musb, musb_channel->epnum,
367 						    musb_channel->transmit);
368 			}
369 		}
370 	}
371 
372 	retval = IRQ_HANDLED;
373 done:
374 	spin_unlock_irqrestore(&musb->lock, flags);
375 	return retval;
376 }
377 EXPORT_SYMBOL_GPL(dma_controller_irq);
378 
musbhs_dma_controller_destroy(struct dma_controller * c)379 void musbhs_dma_controller_destroy(struct dma_controller *c)
380 {
381 	struct musb_dma_controller *controller = container_of(c,
382 			struct musb_dma_controller, controller);
383 
384 	dma_controller_stop(controller);
385 
386 	if (controller->irq)
387 		free_irq(controller->irq, c);
388 
389 	kfree(controller);
390 }
391 EXPORT_SYMBOL_GPL(musbhs_dma_controller_destroy);
392 
393 static struct musb_dma_controller *
dma_controller_alloc(struct musb * musb,void __iomem * base)394 dma_controller_alloc(struct musb *musb, void __iomem *base)
395 {
396 	struct musb_dma_controller *controller;
397 
398 	controller = kzalloc(sizeof(*controller), GFP_KERNEL);
399 	if (!controller)
400 		return NULL;
401 
402 	controller->channel_count = MUSB_HSDMA_CHANNELS;
403 	controller->private_data = musb;
404 	controller->base = base;
405 
406 	controller->controller.channel_alloc = dma_channel_allocate;
407 	controller->controller.channel_release = dma_channel_release;
408 	controller->controller.channel_program = dma_channel_program;
409 	controller->controller.channel_abort = dma_channel_abort;
410 	return controller;
411 }
412 
413 struct dma_controller *
musbhs_dma_controller_create(struct musb * musb,void __iomem * base)414 musbhs_dma_controller_create(struct musb *musb, void __iomem *base)
415 {
416 	struct musb_dma_controller *controller;
417 	struct device *dev = musb->controller;
418 	struct platform_device *pdev = to_platform_device(dev);
419 	int irq = platform_get_irq_byname(pdev, "dma");
420 
421 	if (irq <= 0) {
422 		dev_err(dev, "No DMA interrupt line!\n");
423 		return NULL;
424 	}
425 
426 	controller = dma_controller_alloc(musb, base);
427 	if (!controller)
428 		return NULL;
429 
430 	if (request_irq(irq, dma_controller_irq, 0,
431 			dev_name(musb->controller), controller)) {
432 		dev_err(dev, "request_irq %d failed!\n", irq);
433 		musb_dma_controller_destroy(&controller->controller);
434 
435 		return NULL;
436 	}
437 
438 	controller->irq = irq;
439 
440 	return &controller->controller;
441 }
442 EXPORT_SYMBOL_GPL(musbhs_dma_controller_create);
443 
444 struct dma_controller *
musbhs_dma_controller_create_noirq(struct musb * musb,void __iomem * base)445 musbhs_dma_controller_create_noirq(struct musb *musb, void __iomem *base)
446 {
447 	struct musb_dma_controller *controller;
448 
449 	controller = dma_controller_alloc(musb, base);
450 	if (!controller)
451 		return NULL;
452 
453 	return &controller->controller;
454 }
455 EXPORT_SYMBOL_GPL(musbhs_dma_controller_create_noirq);
456