igbvf: do not modify tx_queue_len on link speed change
[linux-2.6.git] / drivers / spi / orion_spi.c
1 /*
2  * orion_spi.c -- Marvell Orion SPI controller driver
3  *
4  * Author: Shadi Ammouri <shadi@marvell.com>
5  * Copyright (C) 2007-2008 Marvell Ltd.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/delay.h>
15 #include <linux/platform_device.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/spi/spi.h>
19 #include <linux/spi/orion_spi.h>
20 #include <asm/unaligned.h>
21
22 #define DRIVER_NAME                     "orion_spi"
23
24 #define ORION_NUM_CHIPSELECTS           1 /* only one slave is supported*/
25 #define ORION_SPI_WAIT_RDY_MAX_LOOP     2000 /* in usec */
26
27 #define ORION_SPI_IF_CTRL_REG           0x00
28 #define ORION_SPI_IF_CONFIG_REG         0x04
29 #define ORION_SPI_DATA_OUT_REG          0x08
30 #define ORION_SPI_DATA_IN_REG           0x0c
31 #define ORION_SPI_INT_CAUSE_REG         0x10
32
33 #define ORION_SPI_IF_8_16_BIT_MODE      (1 << 5)
34 #define ORION_SPI_CLK_PRESCALE_MASK     0x1F
35
36 struct orion_spi {
37         struct work_struct      work;
38
39         /* Lock access to transfer list.        */
40         spinlock_t              lock;
41
42         struct list_head        msg_queue;
43         struct spi_master       *master;
44         void __iomem            *base;
45         unsigned int            max_speed;
46         unsigned int            min_speed;
47         struct orion_spi_info   *spi_info;
48 };
49
50 static struct workqueue_struct *orion_spi_wq;
51
52 static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
53 {
54         return orion_spi->base + reg;
55 }
56
57 static inline void
58 orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
59 {
60         void __iomem *reg_addr = spi_reg(orion_spi, reg);
61         u32 val;
62
63         val = readl(reg_addr);
64         val |= mask;
65         writel(val, reg_addr);
66 }
67
68 static inline void
69 orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
70 {
71         void __iomem *reg_addr = spi_reg(orion_spi, reg);
72         u32 val;
73
74         val = readl(reg_addr);
75         val &= ~mask;
76         writel(val, reg_addr);
77 }
78
79 static int orion_spi_set_transfer_size(struct orion_spi *orion_spi, int size)
80 {
81         if (size == 16) {
82                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
83                                   ORION_SPI_IF_8_16_BIT_MODE);
84         } else if (size == 8) {
85                 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
86                                   ORION_SPI_IF_8_16_BIT_MODE);
87         } else {
88                 pr_debug("Bad bits per word value %d (only 8 or 16 are "
89                          "allowed).\n", size);
90                 return -EINVAL;
91         }
92
93         return 0;
94 }
95
96 static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
97 {
98         u32 tclk_hz;
99         u32 rate;
100         u32 prescale;
101         u32 reg;
102         struct orion_spi *orion_spi;
103
104         orion_spi = spi_master_get_devdata(spi->master);
105
106         tclk_hz = orion_spi->spi_info->tclk;
107
108         /*
109          * the supported rates are: 4,6,8...30
110          * round up as we look for equal or less speed
111          */
112         rate = DIV_ROUND_UP(tclk_hz, speed);
113         rate = roundup(rate, 2);
114
115         /* check if requested speed is too small */
116         if (rate > 30)
117                 return -EINVAL;
118
119         if (rate < 4)
120                 rate = 4;
121
122         /* Convert the rate to SPI clock divisor value. */
123         prescale = 0x10 + rate/2;
124
125         reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
126         reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
127         writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
128
129         return 0;
130 }
131
132 /*
133  * called only when no transfer is active on the bus
134  */
135 static int
136 orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
137 {
138         struct orion_spi *orion_spi;
139         unsigned int speed = spi->max_speed_hz;
140         unsigned int bits_per_word = spi->bits_per_word;
141         int     rc;
142
143         orion_spi = spi_master_get_devdata(spi->master);
144
145         if ((t != NULL) && t->speed_hz)
146                 speed = t->speed_hz;
147
148         if ((t != NULL) && t->bits_per_word)
149                 bits_per_word = t->bits_per_word;
150
151         rc = orion_spi_baudrate_set(spi, speed);
152         if (rc)
153                 return rc;
154
155         return orion_spi_set_transfer_size(orion_spi, bits_per_word);
156 }
157
158 static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
159 {
160         if (enable)
161                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
162         else
163                 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
164 }
165
166 static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
167 {
168         int i;
169
170         for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
171                 if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
172                         return 1;
173                 else
174                         udelay(1);
175         }
176
177         return -1;
178 }
179
180 static inline int
181 orion_spi_write_read_8bit(struct spi_device *spi,
182                           const u8 **tx_buf, u8 **rx_buf)
183 {
184         void __iomem *tx_reg, *rx_reg, *int_reg;
185         struct orion_spi *orion_spi;
186
187         orion_spi = spi_master_get_devdata(spi->master);
188         tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
189         rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
190         int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
191
192         /* clear the interrupt cause register */
193         writel(0x0, int_reg);
194
195         if (tx_buf && *tx_buf)
196                 writel(*(*tx_buf)++, tx_reg);
197         else
198                 writel(0, tx_reg);
199
200         if (orion_spi_wait_till_ready(orion_spi) < 0) {
201                 dev_err(&spi->dev, "TXS timed out\n");
202                 return -1;
203         }
204
205         if (rx_buf && *rx_buf)
206                 *(*rx_buf)++ = readl(rx_reg);
207
208         return 1;
209 }
210
211 static inline int
212 orion_spi_write_read_16bit(struct spi_device *spi,
213                            const u16 **tx_buf, u16 **rx_buf)
214 {
215         void __iomem *tx_reg, *rx_reg, *int_reg;
216         struct orion_spi *orion_spi;
217
218         orion_spi = spi_master_get_devdata(spi->master);
219         tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
220         rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
221         int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
222
223         /* clear the interrupt cause register */
224         writel(0x0, int_reg);
225
226         if (tx_buf && *tx_buf)
227                 writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
228         else
229                 writel(0, tx_reg);
230
231         if (orion_spi_wait_till_ready(orion_spi) < 0) {
232                 dev_err(&spi->dev, "TXS timed out\n");
233                 return -1;
234         }
235
236         if (rx_buf && *rx_buf)
237                 put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
238
239         return 1;
240 }
241
242 static unsigned int
243 orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
244 {
245         struct orion_spi *orion_spi;
246         unsigned int count;
247         int word_len;
248
249         orion_spi = spi_master_get_devdata(spi->master);
250         word_len = spi->bits_per_word;
251         count = xfer->len;
252
253         if (word_len == 8) {
254                 const u8 *tx = xfer->tx_buf;
255                 u8 *rx = xfer->rx_buf;
256
257                 do {
258                         if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
259                                 goto out;
260                         count--;
261                 } while (count);
262         } else if (word_len == 16) {
263                 const u16 *tx = xfer->tx_buf;
264                 u16 *rx = xfer->rx_buf;
265
266                 do {
267                         if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
268                                 goto out;
269                         count -= 2;
270                 } while (count);
271         }
272
273 out:
274         return xfer->len - count;
275 }
276
277
278 static void orion_spi_work(struct work_struct *work)
279 {
280         struct orion_spi *orion_spi =
281                 container_of(work, struct orion_spi, work);
282
283         spin_lock_irq(&orion_spi->lock);
284         while (!list_empty(&orion_spi->msg_queue)) {
285                 struct spi_message *m;
286                 struct spi_device *spi;
287                 struct spi_transfer *t = NULL;
288                 int par_override = 0;
289                 int status = 0;
290                 int cs_active = 0;
291
292                 m = container_of(orion_spi->msg_queue.next, struct spi_message,
293                                  queue);
294
295                 list_del_init(&m->queue);
296                 spin_unlock_irq(&orion_spi->lock);
297
298                 spi = m->spi;
299
300                 /* Load defaults */
301                 status = orion_spi_setup_transfer(spi, NULL);
302
303                 if (status < 0)
304                         goto msg_done;
305
306                 list_for_each_entry(t, &m->transfers, transfer_list) {
307                         if (par_override || t->speed_hz || t->bits_per_word) {
308                                 par_override = 1;
309                                 status = orion_spi_setup_transfer(spi, t);
310                                 if (status < 0)
311                                         break;
312                                 if (!t->speed_hz && !t->bits_per_word)
313                                         par_override = 0;
314                         }
315
316                         if (!cs_active) {
317                                 orion_spi_set_cs(orion_spi, 1);
318                                 cs_active = 1;
319                         }
320
321                         if (t->len)
322                                 m->actual_length +=
323                                         orion_spi_write_read(spi, t);
324
325                         if (t->delay_usecs)
326                                 udelay(t->delay_usecs);
327
328                         if (t->cs_change) {
329                                 orion_spi_set_cs(orion_spi, 0);
330                                 cs_active = 0;
331                         }
332                 }
333
334 msg_done:
335                 if (cs_active)
336                         orion_spi_set_cs(orion_spi, 0);
337
338                 m->status = status;
339                 m->complete(m->context);
340
341                 spin_lock_irq(&orion_spi->lock);
342         }
343
344         spin_unlock_irq(&orion_spi->lock);
345 }
346
347 static int __init orion_spi_reset(struct orion_spi *orion_spi)
348 {
349         /* Verify that the CS is deasserted */
350         orion_spi_set_cs(orion_spi, 0);
351
352         return 0;
353 }
354
355 static int orion_spi_setup(struct spi_device *spi)
356 {
357         struct orion_spi *orion_spi;
358
359         orion_spi = spi_master_get_devdata(spi->master);
360
361         /* Fix ac timing if required.   */
362         if (orion_spi->spi_info->enable_clock_fix)
363                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
364                                   (1 << 14));
365
366         if ((spi->max_speed_hz == 0)
367                         || (spi->max_speed_hz > orion_spi->max_speed))
368                 spi->max_speed_hz = orion_spi->max_speed;
369
370         if (spi->max_speed_hz < orion_spi->min_speed) {
371                 dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
372                         spi->max_speed_hz);
373                 return -EINVAL;
374         }
375
376         /*
377          * baudrate & width will be set orion_spi_setup_transfer
378          */
379         return 0;
380 }
381
382 static int orion_spi_transfer(struct spi_device *spi, struct spi_message *m)
383 {
384         struct orion_spi *orion_spi;
385         struct spi_transfer *t = NULL;
386         unsigned long flags;
387
388         m->actual_length = 0;
389         m->status = 0;
390
391         /* reject invalid messages and transfers */
392         if (list_empty(&m->transfers) || !m->complete)
393                 return -EINVAL;
394
395         orion_spi = spi_master_get_devdata(spi->master);
396
397         list_for_each_entry(t, &m->transfers, transfer_list) {
398                 unsigned int bits_per_word = spi->bits_per_word;
399
400                 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
401                         dev_err(&spi->dev,
402                                 "message rejected : "
403                                 "invalid transfer data buffers\n");
404                         goto msg_rejected;
405                 }
406
407                 if ((t != NULL) && t->bits_per_word)
408                         bits_per_word = t->bits_per_word;
409
410                 if ((bits_per_word != 8) && (bits_per_word != 16)) {
411                         dev_err(&spi->dev,
412                                 "message rejected : "
413                                 "invalid transfer bits_per_word (%d bits)\n",
414                                 bits_per_word);
415                         goto msg_rejected;
416                 }
417                 /*make sure buffer length is even when working in 16 bit mode*/
418                 if ((t != NULL) && (t->bits_per_word == 16) && (t->len & 1)) {
419                         dev_err(&spi->dev,
420                                 "message rejected : "
421                                 "odd data length (%d) while in 16 bit mode\n",
422                                 t->len);
423                         goto msg_rejected;
424                 }
425
426                 if (t->speed_hz && t->speed_hz < orion_spi->min_speed) {
427                         dev_err(&spi->dev,
428                                 "message rejected : "
429                                 "device min speed (%d Hz) exceeds "
430                                 "required transfer speed (%d Hz)\n",
431                                 orion_spi->min_speed, t->speed_hz);
432                         goto msg_rejected;
433                 }
434         }
435
436
437         spin_lock_irqsave(&orion_spi->lock, flags);
438         list_add_tail(&m->queue, &orion_spi->msg_queue);
439         queue_work(orion_spi_wq, &orion_spi->work);
440         spin_unlock_irqrestore(&orion_spi->lock, flags);
441
442         return 0;
443 msg_rejected:
444         /* Message rejected and not queued */
445         m->status = -EINVAL;
446         if (m->complete)
447                 m->complete(m->context);
448         return -EINVAL;
449 }
450
451 static int __init orion_spi_probe(struct platform_device *pdev)
452 {
453         struct spi_master *master;
454         struct orion_spi *spi;
455         struct resource *r;
456         struct orion_spi_info *spi_info;
457         int status = 0;
458
459         spi_info = pdev->dev.platform_data;
460
461         master = spi_alloc_master(&pdev->dev, sizeof *spi);
462         if (master == NULL) {
463                 dev_dbg(&pdev->dev, "master allocation failed\n");
464                 return -ENOMEM;
465         }
466
467         if (pdev->id != -1)
468                 master->bus_num = pdev->id;
469
470         /* we support only mode 0, and no options */
471         master->mode_bits = 0;
472
473         master->setup = orion_spi_setup;
474         master->transfer = orion_spi_transfer;
475         master->num_chipselect = ORION_NUM_CHIPSELECTS;
476
477         dev_set_drvdata(&pdev->dev, master);
478
479         spi = spi_master_get_devdata(master);
480         spi->master = master;
481         spi->spi_info = spi_info;
482
483         spi->max_speed = DIV_ROUND_UP(spi_info->tclk, 4);
484         spi->min_speed = DIV_ROUND_UP(spi_info->tclk, 30);
485
486         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
487         if (r == NULL) {
488                 status = -ENODEV;
489                 goto out;
490         }
491
492         if (!request_mem_region(r->start, (r->end - r->start) + 1,
493                                 dev_name(&pdev->dev))) {
494                 status = -EBUSY;
495                 goto out;
496         }
497         spi->base = ioremap(r->start, SZ_1K);
498
499         INIT_WORK(&spi->work, orion_spi_work);
500
501         spin_lock_init(&spi->lock);
502         INIT_LIST_HEAD(&spi->msg_queue);
503
504         if (orion_spi_reset(spi) < 0)
505                 goto out_rel_mem;
506
507         status = spi_register_master(master);
508         if (status < 0)
509                 goto out_rel_mem;
510
511         return status;
512
513 out_rel_mem:
514         release_mem_region(r->start, (r->end - r->start) + 1);
515
516 out:
517         spi_master_put(master);
518         return status;
519 }
520
521
522 static int __exit orion_spi_remove(struct platform_device *pdev)
523 {
524         struct spi_master *master;
525         struct orion_spi *spi;
526         struct resource *r;
527
528         master = dev_get_drvdata(&pdev->dev);
529         spi = spi_master_get_devdata(master);
530
531         cancel_work_sync(&spi->work);
532
533         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
534         release_mem_region(r->start, (r->end - r->start) + 1);
535
536         spi_unregister_master(master);
537
538         return 0;
539 }
540
541 MODULE_ALIAS("platform:" DRIVER_NAME);
542
543 static struct platform_driver orion_spi_driver = {
544         .driver = {
545                 .name   = DRIVER_NAME,
546                 .owner  = THIS_MODULE,
547         },
548         .remove         = __exit_p(orion_spi_remove),
549 };
550
551 static int __init orion_spi_init(void)
552 {
553         orion_spi_wq = create_singlethread_workqueue(
554                                 orion_spi_driver.driver.name);
555         if (orion_spi_wq == NULL)
556                 return -ENOMEM;
557
558         return platform_driver_probe(&orion_spi_driver, orion_spi_probe);
559 }
560 module_init(orion_spi_init);
561
562 static void __exit orion_spi_exit(void)
563 {
564         flush_workqueue(orion_spi_wq);
565         platform_driver_unregister(&orion_spi_driver);
566
567         destroy_workqueue(orion_spi_wq);
568 }
569 module_exit(orion_spi_exit);
570
571 MODULE_DESCRIPTION("Orion SPI driver");
572 MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
573 MODULE_LICENSE("GPL");