summaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/pasemi/dma_lib.c
blob: c529d8dff395bdd5a6f3cfb316dbaafcb674ab1a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Common functions for DMA access on PA Semi PWRficient
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/of.h>

#include <asm/pasemi_dma.h>

#define MAX_TXCH 64
#define MAX_RXCH 64

static struct pasdma_status *dma_status;

static void __iomem *iob_regs;
static void __iomem *mac_regs[6];
static void __iomem *dma_regs;

static int base_hw_irq;

static int num_txch, num_rxch;

static struct pci_dev *dma_pdev;

/* Bitmaps to handle allocation of channels */

static DECLARE_BITMAP(txch_free, MAX_TXCH);
static DECLARE_BITMAP(rxch_free, MAX_RXCH);

/* pasemi_read_iob_reg - read IOB register
 * @reg: Register to read (offset into PCI CFG space)
 */
unsigned int pasemi_read_iob_reg(unsigned int reg)
{
	return in_le32(iob_regs+reg);
}
EXPORT_SYMBOL(pasemi_read_iob_reg);

/* pasemi_write_iob_reg - write IOB register
 * @reg: Register to write to (offset into PCI CFG space)
 * @val: Value to write
 */
void pasemi_write_iob_reg(unsigned int reg, unsigned int val)
{
	out_le32(iob_regs+reg, val);
}
EXPORT_SYMBOL(pasemi_write_iob_reg);

/* pasemi_read_mac_reg - read MAC register
 * @intf: MAC interface
 * @reg: Register to read (offset into PCI CFG space)
 */
unsigned int pasemi_read_mac_reg(int intf, unsigned int reg)
{
	return in_le32(mac_regs[intf]+reg);
}
EXPORT_SYMBOL(pasemi_read_mac_reg);

/* pasemi_write_mac_reg - write MAC register
 * @intf: MAC interface
 * @reg: Register to write to (offset into PCI CFG space)
 * @val: Value to write
 */
void pasemi_write_mac_reg(int intf, unsigned int reg, unsigned int val)
{
	out_le32(mac_regs[intf]+reg, val);
}
EXPORT_SYMBOL(pasemi_write_mac_reg);

/* pasemi_read_dma_reg - read DMA register
 * @reg: Register to read (offset into PCI CFG space)
 */
unsigned int pasemi_read_dma_reg(unsigned int reg)
{
	return in_le32(dma_regs+reg);
}
EXPORT_SYMBOL(pasemi_read_dma_reg);

/* pasemi_write_dma_reg - write DMA register
 * @reg: Register to write to (offset into PCI CFG space)
 * @val: Value to write
 */
void pasemi_write_dma_reg(unsigned int reg, unsigned int val)
{
	out_le32(dma_regs+reg, val);
}
EXPORT_SYMBOL(pasemi_write_dma_reg);

static int pasemi_alloc_tx_chan(enum pasemi_dmachan_type type)
{
	int bit;
	int start, limit;

	switch (type & (TXCHAN_EVT0|TXCHAN_EVT1)) {
	case TXCHAN_EVT0:
		start = 0;
		limit = 10;
		break;
	case TXCHAN_EVT1:
		start = 10;
		limit = MAX_TXCH;
		break;
	default:
		start = 0;
		limit = MAX_TXCH;
		break;
	}
retry:
	bit = find_next_bit(txch_free, MAX_TXCH, start);
	if (bit >= limit)
		return -ENOSPC;
	if (!test_and_clear_bit(bit, txch_free))
		goto retry;

	return bit;
}

static void pasemi_free_tx_chan(int chan)
{
	BUG_ON(test_bit(chan, txch_free));
	set_bit(chan, txch_free);
}

static int pasemi_alloc_rx_chan(void)
{
	int bit;
retry:
	bit = find_first_bit(rxch_free, MAX_RXCH);
	if (bit >= MAX_TXCH)
		return -ENOSPC;
	if (!test_and_clear_bit(bit, rxch_free))
		goto retry;

	return bit;
}

static void pasemi_free_rx_chan(int chan)
{
	BUG_ON(test_bit(chan, rxch_free));
	set_bit(chan, rxch_free);
}

/* pasemi_dma_alloc_chan - Allocate a DMA channel
 * @type: Type of channel to allocate
 * @total_size: Total size of structure to allocate (to allow for more
 *		room behind the structure to be used by the client)
 * @offset: Offset in bytes from start of the total structure to the beginning
 *	    of struct pasemi_dmachan. Needed when struct pasemi_dmachan is
 *	    not the first member of the client structure.
 *
 * pasemi_dma_alloc_chan allocates a DMA channel for use by a client. The
 * type argument specifies whether it's a RX or TX channel, and in the case
 * of TX channels which group it needs to belong to (if any).
 *
 * Returns a pointer to the total structure allocated on success, NULL
 * on failure.
 */
void *pasemi_dma_alloc_chan(enum pasemi_dmachan_type type,
			    int total_size, int offset)
{
	void *buf;
	struct pasemi_dmachan *chan;
	int chno;

	BUG_ON(total_size < sizeof(struct pasemi_dmachan));

	buf = kzalloc(total_size, GFP_KERNEL);

	if (!buf)
		return NULL;
	chan = buf + offset;

	chan->priv = buf;

	switch (type & (TXCHAN|RXCHAN)) {
	case RXCHAN:
		chno = pasemi_alloc_rx_chan();
		chan->chno = chno;
		chan->irq = irq_create_mapping(NULL,
					       base_hw_irq + num_txch + chno);
		chan->status = &dma_status->rx_sta[chno];
		break;
	case TXCHAN:
		chno = pasemi_alloc_tx_chan(type);
		chan->chno = chno;
		chan->irq = irq_create_mapping(NULL, base_hw_irq + chno);
		chan->status = &dma_status->tx_sta[chno];
		break;
	}

	chan->chan_type = type;

	return chan;
}
EXPORT_SYMBOL(pasemi_dma_alloc_chan);

/* pasemi_dma_free_chan - Free a previously allocated channel
 * @chan: Channel to free
 *
 * Frees a previously allocated channel. It will also deallocate any
 * descriptor ring associated with the channel, if allocated.
 */
void pasemi_dma_free_chan(struct pasemi_dmachan *chan)
{
	if (chan->ring_virt)
		pasemi_dma_free_ring(chan);

	switch (chan->chan_type & (RXCHAN|TXCHAN)) {
	case RXCHAN:
		pasemi_free_rx_chan(chan->chno);
		break;
	case TXCHAN:
		pasemi_free_tx_chan(chan->chno);
		break;
	}

	kfree(chan->priv);
}
EXPORT_SYMBOL(pasemi_dma_free_chan);

/* pasemi_dma_alloc_ring - Allocate descriptor ring for a channel
 * @chan: Channel for which to allocate
 * @ring_size: Ring size in 64-bit (8-byte) words
 *
 * Allocate a descriptor ring for a channel. Returns 0 on success, errno
 * on failure. The passed in struct pasemi_dmachan is updated with the
 * virtual and DMA addresses of the ring.
 */
int pasemi_dma_alloc_ring(struct pasemi_dmachan *chan, int ring_size)
{
	BUG_ON(chan->ring_virt);

	chan->ring_size = ring_size;

	chan->ring_virt = dma_alloc_coherent(&dma_pdev->dev,
					     ring_size * sizeof(u64),
					     &chan->ring_dma, GFP_KERNEL);

	if (!chan->ring_virt)
		return -ENOMEM;

	memset(chan->ring_virt, 0, ring_size * sizeof(u64));

	return 0;
}
EXPORT_SYMBOL(pasemi_dma_alloc_ring);

/* pasemi_dma_free_ring - Free an allocated descriptor ring for a channel
 * @chan: Channel for which to free the descriptor ring
 *
 * Frees a previously allocated descriptor ring for a channel.
 */
void pasemi_dma_free_ring(struct pasemi_dmachan *chan)
{
	BUG_ON(!chan->ring_virt);

	dma_free_coherent(&dma_pdev->dev, chan->ring_size * sizeof(u64),
			  chan->ring_virt, chan->ring_dma);
	chan->ring_virt = NULL;
	chan->ring_size = 0;
	chan->ring_dma = 0;
}
EXPORT_SYMBOL(pasemi_dma_free_ring);

/* pasemi_dma_start_chan - Start a DMA channel
 * @chan: Channel to start
 * @cmdsta: Additional CCMDSTA/TCMDSTA bits to write
 *
 * Enables (starts) a DMA channel with optional additional arguments.
 */
void pasemi_dma_start_chan(const struct pasemi_dmachan *chan, const u32 cmdsta)
{
	if (chan->chan_type == RXCHAN)
		pasemi_write_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(chan->chno),
				     cmdsta | PAS_DMA_RXCHAN_CCMDSTA_EN);
	else
		pasemi_write_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(chan->chno),
				     cmdsta | PAS_DMA_TXCHAN_TCMDSTA_EN);
}
EXPORT_SYMBOL(pasemi_dma_start_chan);

/* pasemi_dma_stop_chan - Stop a DMA channel
 * @chan: Channel to stop
 *
 * Stops (disables) a DMA channel. This is done by setting the ST bit in the
 * CMDSTA register and waiting on the ACT (active) bit to clear, then
 * finally disabling the whole channel.
 *
 * This function will only try for a short while for the channel to stop, if
 * it doesn't it will return failure.
 *
 * Returns 1 on success, 0 on failure.
 */
#define MAX_RETRIES 5000
int pasemi_dma_stop_chan(const struct pasemi_dmachan *chan)
{
	int reg, retries;
	u32 sta;

	if (chan->chan_type == RXCHAN) {
		reg = PAS_DMA_RXCHAN_CCMDSTA(chan->chno);
		pasemi_write_dma_reg(reg, PAS_DMA_RXCHAN_CCMDSTA_ST);
		for (retries = 0; retries < MAX_RETRIES; retries++) {
			sta = pasemi_read_dma_reg(reg);
			if (!(sta & PAS_DMA_RXCHAN_CCMDSTA_ACT)) {
				pasemi_write_dma_reg(reg, 0);
				return 1;
			}
			cond_resched();
		}
	} else {
		reg = PAS_DMA_TXCHAN_TCMDSTA(chan->chno);
		pasemi_write_dma_reg(reg, PAS_DMA_TXCHAN_TCMDSTA_ST);
		for (retries = 0; retries < MAX_RETRIES; retries++) {
			sta = pasemi_read_dma_reg(reg);
			if (!(sta & PAS_DMA_TXCHAN_TCMDSTA_ACT)) {
				pasemi_write_dma_reg(reg, 0);
				return 1;
			}
			cond_resched();
		}
	}

	return 0;
}
EXPORT_SYMBOL(pasemi_dma_stop_chan);

/* pasemi_dma_alloc_buf - Allocate a buffer to use for DMA
 * @chan: Channel to allocate for
 * @size: Size of buffer in bytes
 * @handle: DMA handle
 *
 * Allocate a buffer to be used by the DMA engine for read/write,
 * similar to dma_alloc_coherent().
 *
 * Returns the virtual address of the buffer, or NULL in case of failure.
 */
void *pasemi_dma_alloc_buf(struct pasemi_dmachan *chan, int size,
			   dma_addr_t *handle)
{
	return dma_alloc_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
}
EXPORT_SYMBOL(pasemi_dma_alloc_buf);

/* pasemi_dma_free_buf - Free a buffer used for DMA
 * @chan: Channel the buffer was allocated for
 * @size: Size of buffer in bytes
 * @handle: DMA handle
 *
 * Frees a previously allocated buffer.
 */
void pasemi_dma_free_buf(struct pasemi_dmachan *chan, int size,
			 dma_addr_t *handle)
{
	dma_free_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
}
EXPORT_SYMBOL(pasemi_dma_free_buf);

static void *map_onedev(struct pci_dev *p, int index)
{
	struct device_node *dn;
	void __iomem *ret;

	dn = pci_device_to_OF_node(p);
	if (!dn)
		goto fallback;

	ret = of_iomap(dn, index);
	if (!ret)
		goto fallback;

	return ret;
fallback:
	/* This is hardcoded and ugly, but we have some firmware versions
	 * that don't provide the register space in the device tree. Luckily
	 * they are at well-known locations so we can just do the math here.
	 */
	return ioremap(0xe0000000 + (p->devfn << 12), 0x2000);
}

/* pasemi_dma_init - Initialize the PA Semi DMA library
 *
 * This function initializes the DMA library. It must be called before
 * any other function in the library.
 *
 * Returns 0 on success, errno on failure.
 */
int pasemi_dma_init(void)
{
	static spinlock_t init_lock = SPIN_LOCK_UNLOCKED;
	struct pci_dev *iob_pdev;
	struct pci_dev *pdev;
	struct resource res;
	struct device_node *dn;
	int i, intf, err = 0;
	u32 tmp;

	if (!machine_is(pasemi))
		return -ENODEV;

	spin_lock(&init_lock);

	/* Make sure we haven't already initialized */
	if (dma_pdev)
		goto out;

	iob_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa001, NULL);
	if (!iob_pdev) {
		BUG();
		printk(KERN_WARNING "Can't find I/O Bridge\n");
		err = -ENODEV;
		goto out;
	}
	iob_regs = map_onedev(iob_pdev, 0);

	dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
	if (!dma_pdev) {
		BUG();
		printk(KERN_WARNING "Can't find DMA controller\n");
		err = -ENODEV;
		goto out;
	}
	dma_regs = map_onedev(dma_pdev, 0);
	base_hw_irq = virq_to_hw(dma_pdev->irq);

	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_TXCH, &tmp);
	num_txch = (tmp & PAS_DMA_CAP_TXCH_TCHN_M) >> PAS_DMA_CAP_TXCH_TCHN_S;

	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_RXCH, &tmp);
	num_rxch = (tmp & PAS_DMA_CAP_RXCH_RCHN_M) >> PAS_DMA_CAP_RXCH_RCHN_S;

	intf = 0;
	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, NULL);
	     pdev;
	     pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, pdev))
		mac_regs[intf++] = map_onedev(pdev, 0);

	pci_dev_put(pdev);

	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, NULL);
	     pdev;
	     pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, pdev))
		mac_regs[intf++] = map_onedev(pdev, 0);

	pci_dev_put(pdev);

	dn = pci_device_to_OF_node(iob_pdev);
	if (dn)
		err = of_address_to_resource(dn, 1, &res);
	if (!dn || err) {
		/* Fallback for old firmware */
		res.start = 0xfd800000;
		res.end = res.start + 0x1000;
	}
	dma_status = __ioremap(res.start, res.end-res.start, 0);
	pci_dev_put(iob_pdev);

	for (i = 0; i < MAX_TXCH; i++)
		__set_bit(i, txch_free);

	for (i = 0; i < MAX_RXCH; i++)
		__set_bit(i, rxch_free);

	printk(KERN_INFO "PA Semi PWRficient DMA library initialized "
		"(%d tx, %d rx channels)\n", num_txch, num_rxch);

out:
	spin_unlock(&init_lock);
	return err;
}
EXPORT_SYMBOL(pasemi_dma_init);