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1 /*
2  * Designware SPI core controller driver (refer pxa2xx_spi.c)
3  *
4  * Copyright (c) 2009, Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  */
15 
16 #include <linux/dma-mapping.h>
17 #include <linux/interrupt.h>
18 #include <linux/module.h>
19 #include <linux/highmem.h>
20 #include <linux/delay.h>
21 #include <linux/slab.h>
22 #include <linux/spi/spi.h>
23 #include <linux/gpio.h>
24 
25 #include "spi-dw.h"
26 
27 #ifdef CONFIG_DEBUG_FS
28 #include <linux/debugfs.h>
29 #endif
30 
31 #define START_STATE	((void *)0)
32 #define RUNNING_STATE	((void *)1)
33 #define DONE_STATE	((void *)2)
34 #define ERROR_STATE	((void *)-1)
35 
36 /* Slave spi_dev related */
37 struct chip_data {
38 	u16 cr0;
39 	u8 cs;			/* chip select pin */
40 	u8 n_bytes;		/* current is a 1/2/4 byte op */
41 	u8 tmode;		/* TR/TO/RO/EEPROM */
42 	u8 type;		/* SPI/SSP/MicroWire */
43 
44 	u8 poll_mode;		/* 1 means use poll mode */
45 
46 	u32 dma_width;
47 	u32 rx_threshold;
48 	u32 tx_threshold;
49 	u8 enable_dma;
50 	u8 bits_per_word;
51 	u16 clk_div;		/* baud rate divider */
52 	u32 speed_hz;		/* baud rate */
53 	void (*cs_control)(u32 command);
54 };
55 
56 #ifdef CONFIG_DEBUG_FS
57 #define SPI_REGS_BUFSIZE	1024
dw_spi_show_regs(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)58 static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
59 		size_t count, loff_t *ppos)
60 {
61 	struct dw_spi *dws = file->private_data;
62 	char *buf;
63 	u32 len = 0;
64 	ssize_t ret;
65 
66 	buf = kzalloc(SPI_REGS_BUFSIZE, GFP_KERNEL);
67 	if (!buf)
68 		return 0;
69 
70 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
71 			"%s registers:\n", dev_name(&dws->master->dev));
72 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
73 			"=================================\n");
74 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
75 			"CTRL0: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL0));
76 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
77 			"CTRL1: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL1));
78 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
79 			"SSIENR: \t0x%08x\n", dw_readl(dws, DW_SPI_SSIENR));
80 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
81 			"SER: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SER));
82 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
83 			"BAUDR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_BAUDR));
84 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
85 			"TXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_TXFLTR));
86 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
87 			"RXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_RXFLTR));
88 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
89 			"TXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_TXFLR));
90 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
91 			"RXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_RXFLR));
92 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
93 			"SR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SR));
94 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
95 			"IMR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_IMR));
96 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
97 			"ISR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_ISR));
98 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
99 			"DMACR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_DMACR));
100 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
101 			"DMATDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMATDLR));
102 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
103 			"DMARDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMARDLR));
104 	len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
105 			"=================================\n");
106 
107 	ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
108 	kfree(buf);
109 	return ret;
110 }
111 
112 static const struct file_operations dw_spi_regs_ops = {
113 	.owner		= THIS_MODULE,
114 	.open		= simple_open,
115 	.read		= dw_spi_show_regs,
116 	.llseek		= default_llseek,
117 };
118 
dw_spi_debugfs_init(struct dw_spi * dws)119 static int dw_spi_debugfs_init(struct dw_spi *dws)
120 {
121 	char name[128];
122 
123 	snprintf(name, 128, "dw_spi-%s", dev_name(&dws->master->dev));
124 	dws->debugfs = debugfs_create_dir(name, NULL);
125 	if (!dws->debugfs)
126 		return -ENOMEM;
127 
128 	debugfs_create_file("registers", S_IFREG | S_IRUGO,
129 		dws->debugfs, (void *)dws, &dw_spi_regs_ops);
130 	return 0;
131 }
132 
dw_spi_debugfs_remove(struct dw_spi * dws)133 static void dw_spi_debugfs_remove(struct dw_spi *dws)
134 {
135 	debugfs_remove_recursive(dws->debugfs);
136 }
137 
138 #else
dw_spi_debugfs_init(struct dw_spi * dws)139 static inline int dw_spi_debugfs_init(struct dw_spi *dws)
140 {
141 	return 0;
142 }
143 
dw_spi_debugfs_remove(struct dw_spi * dws)144 static inline void dw_spi_debugfs_remove(struct dw_spi *dws)
145 {
146 }
147 #endif /* CONFIG_DEBUG_FS */
148 
149 /* Return the max entries we can fill into tx fifo */
tx_max(struct dw_spi * dws)150 static inline u32 tx_max(struct dw_spi *dws)
151 {
152 	u32 tx_left, tx_room, rxtx_gap;
153 
154 	tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
155 	tx_room = dws->fifo_len - dw_readw(dws, DW_SPI_TXFLR);
156 
157 	/*
158 	 * Another concern is about the tx/rx mismatch, we
159 	 * though to use (dws->fifo_len - rxflr - txflr) as
160 	 * one maximum value for tx, but it doesn't cover the
161 	 * data which is out of tx/rx fifo and inside the
162 	 * shift registers. So a control from sw point of
163 	 * view is taken.
164 	 */
165 	rxtx_gap =  ((dws->rx_end - dws->rx) - (dws->tx_end - dws->tx))
166 			/ dws->n_bytes;
167 
168 	return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
169 }
170 
171 /* Return the max entries we should read out of rx fifo */
rx_max(struct dw_spi * dws)172 static inline u32 rx_max(struct dw_spi *dws)
173 {
174 	u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
175 
176 	return min_t(u32, rx_left, dw_readw(dws, DW_SPI_RXFLR));
177 }
178 
dw_writer(struct dw_spi * dws)179 static void dw_writer(struct dw_spi *dws)
180 {
181 	u32 max = tx_max(dws);
182 	u16 txw = 0;
183 
184 	while (max--) {
185 		/* Set the tx word if the transfer's original "tx" is not null */
186 		if (dws->tx_end - dws->len) {
187 			if (dws->n_bytes == 1)
188 				txw = *(u8 *)(dws->tx);
189 			else
190 				txw = *(u16 *)(dws->tx);
191 		}
192 		dw_writew(dws, DW_SPI_DR, txw);
193 		dws->tx += dws->n_bytes;
194 	}
195 }
196 
dw_reader(struct dw_spi * dws)197 static void dw_reader(struct dw_spi *dws)
198 {
199 	u32 max = rx_max(dws);
200 	u16 rxw;
201 
202 	while (max--) {
203 		rxw = dw_readw(dws, DW_SPI_DR);
204 		/* Care rx only if the transfer's original "rx" is not null */
205 		if (dws->rx_end - dws->len) {
206 			if (dws->n_bytes == 1)
207 				*(u8 *)(dws->rx) = rxw;
208 			else
209 				*(u16 *)(dws->rx) = rxw;
210 		}
211 		dws->rx += dws->n_bytes;
212 	}
213 }
214 
next_transfer(struct dw_spi * dws)215 static void *next_transfer(struct dw_spi *dws)
216 {
217 	struct spi_message *msg = dws->cur_msg;
218 	struct spi_transfer *trans = dws->cur_transfer;
219 
220 	/* Move to next transfer */
221 	if (trans->transfer_list.next != &msg->transfers) {
222 		dws->cur_transfer =
223 			list_entry(trans->transfer_list.next,
224 					struct spi_transfer,
225 					transfer_list);
226 		return RUNNING_STATE;
227 	}
228 
229 	return DONE_STATE;
230 }
231 
232 /*
233  * Note: first step is the protocol driver prepares
234  * a dma-capable memory, and this func just need translate
235  * the virt addr to physical
236  */
map_dma_buffers(struct dw_spi * dws)237 static int map_dma_buffers(struct dw_spi *dws)
238 {
239 	if (!dws->cur_msg->is_dma_mapped
240 		|| !dws->dma_inited
241 		|| !dws->cur_chip->enable_dma
242 		|| !dws->dma_ops)
243 		return 0;
244 
245 	if (dws->cur_transfer->tx_dma)
246 		dws->tx_dma = dws->cur_transfer->tx_dma;
247 
248 	if (dws->cur_transfer->rx_dma)
249 		dws->rx_dma = dws->cur_transfer->rx_dma;
250 
251 	return 1;
252 }
253 
254 /* Caller already set message->status; dma and pio irqs are blocked */
giveback(struct dw_spi * dws)255 static void giveback(struct dw_spi *dws)
256 {
257 	struct spi_transfer *last_transfer;
258 	struct spi_message *msg;
259 
260 	msg = dws->cur_msg;
261 	dws->cur_msg = NULL;
262 	dws->cur_transfer = NULL;
263 	dws->prev_chip = dws->cur_chip;
264 	dws->cur_chip = NULL;
265 	dws->dma_mapped = 0;
266 
267 	last_transfer = list_last_entry(&msg->transfers, struct spi_transfer,
268 					transfer_list);
269 
270 	if (!last_transfer->cs_change)
271 		spi_chip_sel(dws, msg->spi, 0);
272 
273 	spi_finalize_current_message(dws->master);
274 }
275 
int_error_stop(struct dw_spi * dws,const char * msg)276 static void int_error_stop(struct dw_spi *dws, const char *msg)
277 {
278 	/* Stop the hw */
279 	spi_enable_chip(dws, 0);
280 
281 	dev_err(&dws->master->dev, "%s\n", msg);
282 	dws->cur_msg->state = ERROR_STATE;
283 	tasklet_schedule(&dws->pump_transfers);
284 }
285 
dw_spi_xfer_done(struct dw_spi * dws)286 void dw_spi_xfer_done(struct dw_spi *dws)
287 {
288 	/* Update total byte transferred return count actual bytes read */
289 	dws->cur_msg->actual_length += dws->len;
290 
291 	/* Move to next transfer */
292 	dws->cur_msg->state = next_transfer(dws);
293 
294 	/* Handle end of message */
295 	if (dws->cur_msg->state == DONE_STATE) {
296 		dws->cur_msg->status = 0;
297 		giveback(dws);
298 	} else
299 		tasklet_schedule(&dws->pump_transfers);
300 }
301 EXPORT_SYMBOL_GPL(dw_spi_xfer_done);
302 
interrupt_transfer(struct dw_spi * dws)303 static irqreturn_t interrupt_transfer(struct dw_spi *dws)
304 {
305 	u16 irq_status = dw_readw(dws, DW_SPI_ISR);
306 
307 	/* Error handling */
308 	if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
309 		dw_readw(dws, DW_SPI_TXOICR);
310 		dw_readw(dws, DW_SPI_RXOICR);
311 		dw_readw(dws, DW_SPI_RXUICR);
312 		int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
313 		return IRQ_HANDLED;
314 	}
315 
316 	dw_reader(dws);
317 	if (dws->rx_end == dws->rx) {
318 		spi_mask_intr(dws, SPI_INT_TXEI);
319 		dw_spi_xfer_done(dws);
320 		return IRQ_HANDLED;
321 	}
322 	if (irq_status & SPI_INT_TXEI) {
323 		spi_mask_intr(dws, SPI_INT_TXEI);
324 		dw_writer(dws);
325 		/* Enable TX irq always, it will be disabled when RX finished */
326 		spi_umask_intr(dws, SPI_INT_TXEI);
327 	}
328 
329 	return IRQ_HANDLED;
330 }
331 
dw_spi_irq(int irq,void * dev_id)332 static irqreturn_t dw_spi_irq(int irq, void *dev_id)
333 {
334 	struct dw_spi *dws = dev_id;
335 	u16 irq_status = dw_readw(dws, DW_SPI_ISR) & 0x3f;
336 
337 	if (!irq_status)
338 		return IRQ_NONE;
339 
340 	if (!dws->cur_msg) {
341 		spi_mask_intr(dws, SPI_INT_TXEI);
342 		return IRQ_HANDLED;
343 	}
344 
345 	return dws->transfer_handler(dws);
346 }
347 
348 /* Must be called inside pump_transfers() */
poll_transfer(struct dw_spi * dws)349 static void poll_transfer(struct dw_spi *dws)
350 {
351 	do {
352 		dw_writer(dws);
353 		dw_reader(dws);
354 		cpu_relax();
355 	} while (dws->rx_end > dws->rx);
356 
357 	dw_spi_xfer_done(dws);
358 }
359 
pump_transfers(unsigned long data)360 static void pump_transfers(unsigned long data)
361 {
362 	struct dw_spi *dws = (struct dw_spi *)data;
363 	struct spi_message *message = NULL;
364 	struct spi_transfer *transfer = NULL;
365 	struct spi_transfer *previous = NULL;
366 	struct spi_device *spi = NULL;
367 	struct chip_data *chip = NULL;
368 	u8 bits = 0;
369 	u8 imask = 0;
370 	u8 cs_change = 0;
371 	u16 txint_level = 0;
372 	u16 clk_div = 0;
373 	u32 speed = 0;
374 	u32 cr0 = 0;
375 
376 	/* Get current state information */
377 	message = dws->cur_msg;
378 	transfer = dws->cur_transfer;
379 	chip = dws->cur_chip;
380 	spi = message->spi;
381 
382 	if (message->state == ERROR_STATE) {
383 		message->status = -EIO;
384 		goto early_exit;
385 	}
386 
387 	/* Handle end of message */
388 	if (message->state == DONE_STATE) {
389 		message->status = 0;
390 		goto early_exit;
391 	}
392 
393 	/* Delay if requested at end of transfer */
394 	if (message->state == RUNNING_STATE) {
395 		previous = list_entry(transfer->transfer_list.prev,
396 					struct spi_transfer,
397 					transfer_list);
398 		if (previous->delay_usecs)
399 			udelay(previous->delay_usecs);
400 	}
401 
402 	dws->n_bytes = chip->n_bytes;
403 	dws->dma_width = chip->dma_width;
404 	dws->cs_control = chip->cs_control;
405 
406 	dws->rx_dma = transfer->rx_dma;
407 	dws->tx_dma = transfer->tx_dma;
408 	dws->tx = (void *)transfer->tx_buf;
409 	dws->tx_end = dws->tx + transfer->len;
410 	dws->rx = transfer->rx_buf;
411 	dws->rx_end = dws->rx + transfer->len;
412 	dws->len = dws->cur_transfer->len;
413 	if (chip != dws->prev_chip)
414 		cs_change = 1;
415 
416 	cr0 = chip->cr0;
417 
418 	/* Handle per transfer options for bpw and speed */
419 	if (transfer->speed_hz) {
420 		speed = chip->speed_hz;
421 
422 		if ((transfer->speed_hz != speed) || (!chip->clk_div)) {
423 			speed = transfer->speed_hz;
424 
425 			/* clk_div doesn't support odd number */
426 			clk_div = dws->max_freq / speed;
427 			clk_div = (clk_div + 1) & 0xfffe;
428 
429 			chip->speed_hz = speed;
430 			chip->clk_div = clk_div;
431 		}
432 	}
433 	if (transfer->bits_per_word) {
434 		bits = transfer->bits_per_word;
435 		dws->n_bytes = dws->dma_width = bits >> 3;
436 		cr0 = (bits - 1)
437 			| (chip->type << SPI_FRF_OFFSET)
438 			| (spi->mode << SPI_MODE_OFFSET)
439 			| (chip->tmode << SPI_TMOD_OFFSET);
440 	}
441 	message->state = RUNNING_STATE;
442 
443 	/*
444 	 * Adjust transfer mode if necessary. Requires platform dependent
445 	 * chipselect mechanism.
446 	 */
447 	if (dws->cs_control) {
448 		if (dws->rx && dws->tx)
449 			chip->tmode = SPI_TMOD_TR;
450 		else if (dws->rx)
451 			chip->tmode = SPI_TMOD_RO;
452 		else
453 			chip->tmode = SPI_TMOD_TO;
454 
455 		cr0 &= ~SPI_TMOD_MASK;
456 		cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
457 	}
458 
459 	/* Check if current transfer is a DMA transaction */
460 	dws->dma_mapped = map_dma_buffers(dws);
461 
462 	/*
463 	 * Interrupt mode
464 	 * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
465 	 */
466 	if (!dws->dma_mapped && !chip->poll_mode) {
467 		int templen = dws->len / dws->n_bytes;
468 
469 		txint_level = dws->fifo_len / 2;
470 		txint_level = (templen > txint_level) ? txint_level : templen;
471 
472 		imask |= SPI_INT_TXEI | SPI_INT_TXOI |
473 			 SPI_INT_RXUI | SPI_INT_RXOI;
474 		dws->transfer_handler = interrupt_transfer;
475 	}
476 
477 	/*
478 	 * Reprogram registers only if
479 	 *	1. chip select changes
480 	 *	2. clk_div is changed
481 	 *	3. control value changes
482 	 */
483 	if (dw_readw(dws, DW_SPI_CTRL0) != cr0 || cs_change || clk_div || imask) {
484 		spi_enable_chip(dws, 0);
485 
486 		if (dw_readw(dws, DW_SPI_CTRL0) != cr0)
487 			dw_writew(dws, DW_SPI_CTRL0, cr0);
488 
489 		spi_set_clk(dws, clk_div ? clk_div : chip->clk_div);
490 		spi_chip_sel(dws, spi, 1);
491 
492 		/* Set the interrupt mask, for poll mode just disable all int */
493 		spi_mask_intr(dws, 0xff);
494 		if (imask)
495 			spi_umask_intr(dws, imask);
496 		if (txint_level)
497 			dw_writew(dws, DW_SPI_TXFLTR, txint_level);
498 
499 		spi_enable_chip(dws, 1);
500 		if (cs_change)
501 			dws->prev_chip = chip;
502 	}
503 
504 	if (dws->dma_mapped)
505 		dws->dma_ops->dma_transfer(dws, cs_change);
506 
507 	if (chip->poll_mode)
508 		poll_transfer(dws);
509 
510 	return;
511 
512 early_exit:
513 	giveback(dws);
514 }
515 
dw_spi_transfer_one_message(struct spi_master * master,struct spi_message * msg)516 static int dw_spi_transfer_one_message(struct spi_master *master,
517 		struct spi_message *msg)
518 {
519 	struct dw_spi *dws = spi_master_get_devdata(master);
520 
521 	dws->cur_msg = msg;
522 	/* Initial message state */
523 	dws->cur_msg->state = START_STATE;
524 	dws->cur_transfer = list_entry(dws->cur_msg->transfers.next,
525 						struct spi_transfer,
526 						transfer_list);
527 	dws->cur_chip = spi_get_ctldata(dws->cur_msg->spi);
528 
529 	/* Launch transfers */
530 	tasklet_schedule(&dws->pump_transfers);
531 
532 	return 0;
533 }
534 
535 /* This may be called twice for each spi dev */
dw_spi_setup(struct spi_device * spi)536 static int dw_spi_setup(struct spi_device *spi)
537 {
538 	struct dw_spi_chip *chip_info = NULL;
539 	struct chip_data *chip;
540 	int ret;
541 
542 	/* Only alloc on first setup */
543 	chip = spi_get_ctldata(spi);
544 	if (!chip) {
545 		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
546 		if (!chip)
547 			return -ENOMEM;
548 		spi_set_ctldata(spi, chip);
549 	}
550 
551 	/*
552 	 * Protocol drivers may change the chip settings, so...
553 	 * if chip_info exists, use it
554 	 */
555 	chip_info = spi->controller_data;
556 
557 	/* chip_info doesn't always exist */
558 	if (chip_info) {
559 		if (chip_info->cs_control)
560 			chip->cs_control = chip_info->cs_control;
561 
562 		chip->poll_mode = chip_info->poll_mode;
563 		chip->type = chip_info->type;
564 
565 		chip->rx_threshold = 0;
566 		chip->tx_threshold = 0;
567 
568 		chip->enable_dma = chip_info->enable_dma;
569 	}
570 
571 	if (spi->bits_per_word == 8) {
572 		chip->n_bytes = 1;
573 		chip->dma_width = 1;
574 	} else if (spi->bits_per_word == 16) {
575 		chip->n_bytes = 2;
576 		chip->dma_width = 2;
577 	}
578 	chip->bits_per_word = spi->bits_per_word;
579 
580 	if (!spi->max_speed_hz) {
581 		dev_err(&spi->dev, "No max speed HZ parameter\n");
582 		return -EINVAL;
583 	}
584 
585 	chip->tmode = 0; /* Tx & Rx */
586 	/* Default SPI mode is SCPOL = 0, SCPH = 0 */
587 	chip->cr0 = (chip->bits_per_word - 1)
588 			| (chip->type << SPI_FRF_OFFSET)
589 			| (spi->mode  << SPI_MODE_OFFSET)
590 			| (chip->tmode << SPI_TMOD_OFFSET);
591 
592 	if (spi->mode & SPI_LOOP)
593 		chip->cr0 |= 1 << SPI_SRL_OFFSET;
594 
595 	if (gpio_is_valid(spi->cs_gpio)) {
596 		ret = gpio_direction_output(spi->cs_gpio,
597 				!(spi->mode & SPI_CS_HIGH));
598 		if (ret)
599 			return ret;
600 	}
601 
602 	return 0;
603 }
604 
dw_spi_cleanup(struct spi_device * spi)605 static void dw_spi_cleanup(struct spi_device *spi)
606 {
607 	struct chip_data *chip = spi_get_ctldata(spi);
608 
609 	kfree(chip);
610 	spi_set_ctldata(spi, NULL);
611 }
612 
613 /* Restart the controller, disable all interrupts, clean rx fifo */
spi_hw_init(struct dw_spi * dws)614 static void spi_hw_init(struct dw_spi *dws)
615 {
616 	spi_enable_chip(dws, 0);
617 	spi_mask_intr(dws, 0xff);
618 	spi_enable_chip(dws, 1);
619 
620 	/*
621 	 * Try to detect the FIFO depth if not set by interface driver,
622 	 * the depth could be from 2 to 256 from HW spec
623 	 */
624 	if (!dws->fifo_len) {
625 		u32 fifo;
626 
627 		for (fifo = 2; fifo <= 256; fifo++) {
628 			dw_writew(dws, DW_SPI_TXFLTR, fifo);
629 			if (fifo != dw_readw(dws, DW_SPI_TXFLTR))
630 				break;
631 		}
632 
633 		dws->fifo_len = (fifo == 2) ? 0 : fifo - 1;
634 		dw_writew(dws, DW_SPI_TXFLTR, 0);
635 	}
636 }
637 
dw_spi_add_host(struct device * dev,struct dw_spi * dws)638 int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
639 {
640 	struct spi_master *master;
641 	int ret;
642 
643 	BUG_ON(dws == NULL);
644 
645 	master = spi_alloc_master(dev, 0);
646 	if (!master)
647 		return -ENOMEM;
648 
649 	dws->master = master;
650 	dws->type = SSI_MOTO_SPI;
651 	dws->prev_chip = NULL;
652 	dws->dma_inited = 0;
653 	dws->dma_addr = (dma_addr_t)(dws->paddr + 0x60);
654 	snprintf(dws->name, sizeof(dws->name), "dw_spi%d", dws->bus_num);
655 
656 	ret = devm_request_irq(dev, dws->irq, dw_spi_irq, IRQF_SHARED,
657 			dws->name, dws);
658 	if (ret < 0) {
659 		dev_err(&master->dev, "can not get IRQ\n");
660 		goto err_free_master;
661 	}
662 
663 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
664 	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
665 	master->bus_num = dws->bus_num;
666 	master->num_chipselect = dws->num_cs;
667 	master->setup = dw_spi_setup;
668 	master->cleanup = dw_spi_cleanup;
669 	master->transfer_one_message = dw_spi_transfer_one_message;
670 	master->max_speed_hz = dws->max_freq;
671 	master->dev.of_node = dev->of_node;
672 
673 	/* Basic HW init */
674 	spi_hw_init(dws);
675 
676 	if (dws->dma_ops && dws->dma_ops->dma_init) {
677 		ret = dws->dma_ops->dma_init(dws);
678 		if (ret) {
679 			dev_warn(&master->dev, "DMA init failed\n");
680 			dws->dma_inited = 0;
681 		}
682 	}
683 
684 	tasklet_init(&dws->pump_transfers, pump_transfers, (unsigned long)dws);
685 
686 	spi_master_set_devdata(master, dws);
687 	ret = devm_spi_register_master(dev, master);
688 	if (ret) {
689 		dev_err(&master->dev, "problem registering spi master\n");
690 		goto err_dma_exit;
691 	}
692 
693 	dw_spi_debugfs_init(dws);
694 	return 0;
695 
696 err_dma_exit:
697 	if (dws->dma_ops && dws->dma_ops->dma_exit)
698 		dws->dma_ops->dma_exit(dws);
699 	spi_enable_chip(dws, 0);
700 err_free_master:
701 	spi_master_put(master);
702 	return ret;
703 }
704 EXPORT_SYMBOL_GPL(dw_spi_add_host);
705 
dw_spi_remove_host(struct dw_spi * dws)706 void dw_spi_remove_host(struct dw_spi *dws)
707 {
708 	if (!dws)
709 		return;
710 	dw_spi_debugfs_remove(dws);
711 
712 	if (dws->dma_ops && dws->dma_ops->dma_exit)
713 		dws->dma_ops->dma_exit(dws);
714 	spi_enable_chip(dws, 0);
715 	/* Disable clk */
716 	spi_set_clk(dws, 0);
717 }
718 EXPORT_SYMBOL_GPL(dw_spi_remove_host);
719 
dw_spi_suspend_host(struct dw_spi * dws)720 int dw_spi_suspend_host(struct dw_spi *dws)
721 {
722 	int ret = 0;
723 
724 	ret = spi_master_suspend(dws->master);
725 	if (ret)
726 		return ret;
727 	spi_enable_chip(dws, 0);
728 	spi_set_clk(dws, 0);
729 	return ret;
730 }
731 EXPORT_SYMBOL_GPL(dw_spi_suspend_host);
732 
dw_spi_resume_host(struct dw_spi * dws)733 int dw_spi_resume_host(struct dw_spi *dws)
734 {
735 	int ret;
736 
737 	spi_hw_init(dws);
738 	ret = spi_master_resume(dws->master);
739 	if (ret)
740 		dev_err(&dws->master->dev, "fail to start queue (%d)\n", ret);
741 	return ret;
742 }
743 EXPORT_SYMBOL_GPL(dw_spi_resume_host);
744 
745 MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
746 MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
747 MODULE_LICENSE("GPL v2");
748