xref: /openbmc/linux/drivers/spi/spi-mtk-nor.c (revision 82df5b73)
1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Mediatek SPI NOR controller driver
4 //
5 // Copyright (C) 2020 Chuanhong Guo <gch981213@gmail.com>
6 
7 #include <linux/bits.h>
8 #include <linux/clk.h>
9 #include <linux/completion.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of_device.h>
17 #include <linux/spi/spi.h>
18 #include <linux/spi/spi-mem.h>
19 #include <linux/string.h>
20 
21 #define DRIVER_NAME "mtk-spi-nor"
22 
23 #define MTK_NOR_REG_CMD			0x00
24 #define MTK_NOR_CMD_WRITE		BIT(4)
25 #define MTK_NOR_CMD_PROGRAM		BIT(2)
26 #define MTK_NOR_CMD_READ		BIT(0)
27 #define MTK_NOR_CMD_MASK		GENMASK(5, 0)
28 
29 #define MTK_NOR_REG_PRG_CNT		0x04
30 #define MTK_NOR_REG_RDATA		0x0c
31 
32 #define MTK_NOR_REG_RADR0		0x10
33 #define MTK_NOR_REG_RADR(n)		(MTK_NOR_REG_RADR0 + 4 * (n))
34 #define MTK_NOR_REG_RADR3		0xc8
35 
36 #define MTK_NOR_REG_WDATA		0x1c
37 
38 #define MTK_NOR_REG_PRGDATA0		0x20
39 #define MTK_NOR_REG_PRGDATA(n)		(MTK_NOR_REG_PRGDATA0 + 4 * (n))
40 #define MTK_NOR_REG_PRGDATA_MAX		5
41 
42 #define MTK_NOR_REG_SHIFT0		0x38
43 #define MTK_NOR_REG_SHIFT(n)		(MTK_NOR_REG_SHIFT0 + 4 * (n))
44 #define MTK_NOR_REG_SHIFT_MAX		9
45 
46 #define MTK_NOR_REG_CFG1		0x60
47 #define MTK_NOR_FAST_READ		BIT(0)
48 
49 #define MTK_NOR_REG_CFG2		0x64
50 #define MTK_NOR_WR_CUSTOM_OP_EN		BIT(4)
51 #define MTK_NOR_WR_BUF_EN		BIT(0)
52 
53 #define MTK_NOR_REG_PP_DATA		0x98
54 
55 #define MTK_NOR_REG_IRQ_STAT		0xa8
56 #define MTK_NOR_REG_IRQ_EN		0xac
57 #define MTK_NOR_IRQ_DMA			BIT(7)
58 #define MTK_NOR_IRQ_MASK		GENMASK(7, 0)
59 
60 #define MTK_NOR_REG_CFG3		0xb4
61 #define MTK_NOR_DISABLE_WREN		BIT(7)
62 #define MTK_NOR_DISABLE_SR_POLL		BIT(5)
63 
64 #define MTK_NOR_REG_WP			0xc4
65 #define MTK_NOR_ENABLE_SF_CMD		0x30
66 
67 #define MTK_NOR_REG_BUSCFG		0xcc
68 #define MTK_NOR_4B_ADDR			BIT(4)
69 #define MTK_NOR_QUAD_ADDR		BIT(3)
70 #define MTK_NOR_QUAD_READ		BIT(2)
71 #define MTK_NOR_DUAL_ADDR		BIT(1)
72 #define MTK_NOR_DUAL_READ		BIT(0)
73 #define MTK_NOR_BUS_MODE_MASK		GENMASK(4, 0)
74 
75 #define MTK_NOR_REG_DMA_CTL		0x718
76 #define MTK_NOR_DMA_START		BIT(0)
77 
78 #define MTK_NOR_REG_DMA_FADR		0x71c
79 #define MTK_NOR_REG_DMA_DADR		0x720
80 #define MTK_NOR_REG_DMA_END_DADR	0x724
81 
82 #define MTK_NOR_PRG_MAX_SIZE		6
83 // Reading DMA src/dst addresses have to be 16-byte aligned
84 #define MTK_NOR_DMA_ALIGN		16
85 #define MTK_NOR_DMA_ALIGN_MASK		(MTK_NOR_DMA_ALIGN - 1)
86 // and we allocate a bounce buffer if destination address isn't aligned.
87 #define MTK_NOR_BOUNCE_BUF_SIZE		PAGE_SIZE
88 
89 // Buffered page program can do one 128-byte transfer
90 #define MTK_NOR_PP_SIZE			128
91 
92 #define CLK_TO_US(sp, clkcnt)		((clkcnt) * 1000000 / sp->spi_freq)
93 
94 struct mtk_nor {
95 	struct spi_controller *ctlr;
96 	struct device *dev;
97 	void __iomem *base;
98 	u8 *buffer;
99 	struct clk *spi_clk;
100 	struct clk *ctlr_clk;
101 	unsigned int spi_freq;
102 	bool wbuf_en;
103 	bool has_irq;
104 	struct completion op_done;
105 };
106 
107 static inline void mtk_nor_rmw(struct mtk_nor *sp, u32 reg, u32 set, u32 clr)
108 {
109 	u32 val = readl(sp->base + reg);
110 
111 	val &= ~clr;
112 	val |= set;
113 	writel(val, sp->base + reg);
114 }
115 
116 static inline int mtk_nor_cmd_exec(struct mtk_nor *sp, u32 cmd, ulong clk)
117 {
118 	ulong delay = CLK_TO_US(sp, clk);
119 	u32 reg;
120 	int ret;
121 
122 	writel(cmd, sp->base + MTK_NOR_REG_CMD);
123 	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CMD, reg, !(reg & cmd),
124 				 delay / 3, (delay + 1) * 200);
125 	if (ret < 0)
126 		dev_err(sp->dev, "command %u timeout.\n", cmd);
127 	return ret;
128 }
129 
130 static void mtk_nor_set_addr(struct mtk_nor *sp, const struct spi_mem_op *op)
131 {
132 	u32 addr = op->addr.val;
133 	int i;
134 
135 	for (i = 0; i < 3; i++) {
136 		writeb(addr & 0xff, sp->base + MTK_NOR_REG_RADR(i));
137 		addr >>= 8;
138 	}
139 	if (op->addr.nbytes == 4) {
140 		writeb(addr & 0xff, sp->base + MTK_NOR_REG_RADR3);
141 		mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, MTK_NOR_4B_ADDR, 0);
142 	} else {
143 		mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, 0, MTK_NOR_4B_ADDR);
144 	}
145 }
146 
147 static bool mtk_nor_match_read(const struct spi_mem_op *op)
148 {
149 	int dummy = 0;
150 
151 	if (op->dummy.buswidth)
152 		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
153 
154 	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
155 		if (op->addr.buswidth == 1)
156 			return dummy == 8;
157 		else if (op->addr.buswidth == 2)
158 			return dummy == 4;
159 		else if (op->addr.buswidth == 4)
160 			return dummy == 6;
161 	} else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
162 		if (op->cmd.opcode == 0x03)
163 			return dummy == 0;
164 		else if (op->cmd.opcode == 0x0b)
165 			return dummy == 8;
166 	}
167 	return false;
168 }
169 
170 static int mtk_nor_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
171 {
172 	size_t len;
173 
174 	if (!op->data.nbytes)
175 		return 0;
176 
177 	if ((op->addr.nbytes == 3) || (op->addr.nbytes == 4)) {
178 		if ((op->data.dir == SPI_MEM_DATA_IN) &&
179 		    mtk_nor_match_read(op)) {
180 			if ((op->addr.val & MTK_NOR_DMA_ALIGN_MASK) ||
181 			    (op->data.nbytes < MTK_NOR_DMA_ALIGN))
182 				op->data.nbytes = 1;
183 			else if (!((ulong)(op->data.buf.in) &
184 				   MTK_NOR_DMA_ALIGN_MASK))
185 				op->data.nbytes &= ~MTK_NOR_DMA_ALIGN_MASK;
186 			else if (op->data.nbytes > MTK_NOR_BOUNCE_BUF_SIZE)
187 				op->data.nbytes = MTK_NOR_BOUNCE_BUF_SIZE;
188 			return 0;
189 		} else if (op->data.dir == SPI_MEM_DATA_OUT) {
190 			if (op->data.nbytes >= MTK_NOR_PP_SIZE)
191 				op->data.nbytes = MTK_NOR_PP_SIZE;
192 			else
193 				op->data.nbytes = 1;
194 			return 0;
195 		}
196 	}
197 
198 	len = MTK_NOR_PRG_MAX_SIZE - sizeof(op->cmd.opcode) - op->addr.nbytes -
199 	      op->dummy.nbytes;
200 	if (op->data.nbytes > len)
201 		op->data.nbytes = len;
202 
203 	return 0;
204 }
205 
206 static bool mtk_nor_supports_op(struct spi_mem *mem,
207 				const struct spi_mem_op *op)
208 {
209 	size_t len;
210 
211 	if (op->cmd.buswidth != 1)
212 		return false;
213 
214 	if ((op->addr.nbytes == 3) || (op->addr.nbytes == 4)) {
215 		if ((op->data.dir == SPI_MEM_DATA_IN) && mtk_nor_match_read(op))
216 			return true;
217 		else if (op->data.dir == SPI_MEM_DATA_OUT)
218 			return (op->addr.buswidth == 1) &&
219 			       (op->dummy.buswidth == 0) &&
220 			       (op->data.buswidth == 1);
221 	}
222 	len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
223 	if ((len > MTK_NOR_PRG_MAX_SIZE) ||
224 	    ((op->data.nbytes) && (len == MTK_NOR_PRG_MAX_SIZE)))
225 		return false;
226 	return true;
227 }
228 
229 static void mtk_nor_setup_bus(struct mtk_nor *sp, const struct spi_mem_op *op)
230 {
231 	u32 reg = 0;
232 
233 	if (op->addr.nbytes == 4)
234 		reg |= MTK_NOR_4B_ADDR;
235 
236 	if (op->data.buswidth == 4) {
237 		reg |= MTK_NOR_QUAD_READ;
238 		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA(4));
239 		if (op->addr.buswidth == 4)
240 			reg |= MTK_NOR_QUAD_ADDR;
241 	} else if (op->data.buswidth == 2) {
242 		reg |= MTK_NOR_DUAL_READ;
243 		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA(3));
244 		if (op->addr.buswidth == 2)
245 			reg |= MTK_NOR_DUAL_ADDR;
246 	} else {
247 		if (op->cmd.opcode == 0x0b)
248 			mtk_nor_rmw(sp, MTK_NOR_REG_CFG1, MTK_NOR_FAST_READ, 0);
249 		else
250 			mtk_nor_rmw(sp, MTK_NOR_REG_CFG1, 0, MTK_NOR_FAST_READ);
251 	}
252 	mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, reg, MTK_NOR_BUS_MODE_MASK);
253 }
254 
255 static int mtk_nor_read_dma(struct mtk_nor *sp, u32 from, unsigned int length,
256 			    u8 *buffer)
257 {
258 	int ret = 0;
259 	ulong delay;
260 	u32 reg;
261 	dma_addr_t dma_addr;
262 
263 	dma_addr = dma_map_single(sp->dev, buffer, length, DMA_FROM_DEVICE);
264 	if (dma_mapping_error(sp->dev, dma_addr)) {
265 		dev_err(sp->dev, "failed to map dma buffer.\n");
266 		return -EINVAL;
267 	}
268 
269 	writel(from, sp->base + MTK_NOR_REG_DMA_FADR);
270 	writel(dma_addr, sp->base + MTK_NOR_REG_DMA_DADR);
271 	writel(dma_addr + length, sp->base + MTK_NOR_REG_DMA_END_DADR);
272 
273 	if (sp->has_irq) {
274 		reinit_completion(&sp->op_done);
275 		mtk_nor_rmw(sp, MTK_NOR_REG_IRQ_EN, MTK_NOR_IRQ_DMA, 0);
276 	}
277 
278 	mtk_nor_rmw(sp, MTK_NOR_REG_DMA_CTL, MTK_NOR_DMA_START, 0);
279 
280 	delay = CLK_TO_US(sp, (length + 5) * BITS_PER_BYTE);
281 
282 	if (sp->has_irq) {
283 		if (!wait_for_completion_timeout(&sp->op_done,
284 						 (delay + 1) * 100))
285 			ret = -ETIMEDOUT;
286 	} else {
287 		ret = readl_poll_timeout(sp->base + MTK_NOR_REG_DMA_CTL, reg,
288 					 !(reg & MTK_NOR_DMA_START), delay / 3,
289 					 (delay + 1) * 100);
290 	}
291 
292 	dma_unmap_single(sp->dev, dma_addr, length, DMA_FROM_DEVICE);
293 	if (ret < 0)
294 		dev_err(sp->dev, "dma read timeout.\n");
295 
296 	return ret;
297 }
298 
299 static int mtk_nor_read_bounce(struct mtk_nor *sp, u32 from,
300 			       unsigned int length, u8 *buffer)
301 {
302 	unsigned int rdlen;
303 	int ret;
304 
305 	if (length & MTK_NOR_DMA_ALIGN_MASK)
306 		rdlen = (length + MTK_NOR_DMA_ALIGN) & ~MTK_NOR_DMA_ALIGN_MASK;
307 	else
308 		rdlen = length;
309 
310 	ret = mtk_nor_read_dma(sp, from, rdlen, sp->buffer);
311 	if (ret)
312 		return ret;
313 
314 	memcpy(buffer, sp->buffer, length);
315 	return 0;
316 }
317 
318 static int mtk_nor_read_pio(struct mtk_nor *sp, const struct spi_mem_op *op)
319 {
320 	u8 *buf = op->data.buf.in;
321 	int ret;
322 
323 	ret = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_READ, 6 * BITS_PER_BYTE);
324 	if (!ret)
325 		buf[0] = readb(sp->base + MTK_NOR_REG_RDATA);
326 	return ret;
327 }
328 
329 static int mtk_nor_write_buffer_enable(struct mtk_nor *sp)
330 {
331 	int ret;
332 	u32 val;
333 
334 	if (sp->wbuf_en)
335 		return 0;
336 
337 	val = readl(sp->base + MTK_NOR_REG_CFG2);
338 	writel(val | MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
339 	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
340 				 val & MTK_NOR_WR_BUF_EN, 0, 10000);
341 	if (!ret)
342 		sp->wbuf_en = true;
343 	return ret;
344 }
345 
346 static int mtk_nor_write_buffer_disable(struct mtk_nor *sp)
347 {
348 	int ret;
349 	u32 val;
350 
351 	if (!sp->wbuf_en)
352 		return 0;
353 	val = readl(sp->base + MTK_NOR_REG_CFG2);
354 	writel(val & ~MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
355 	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
356 				 !(val & MTK_NOR_WR_BUF_EN), 0, 10000);
357 	if (!ret)
358 		sp->wbuf_en = false;
359 	return ret;
360 }
361 
362 static int mtk_nor_pp_buffered(struct mtk_nor *sp, const struct spi_mem_op *op)
363 {
364 	const u8 *buf = op->data.buf.out;
365 	u32 val;
366 	int ret, i;
367 
368 	ret = mtk_nor_write_buffer_enable(sp);
369 	if (ret < 0)
370 		return ret;
371 
372 	for (i = 0; i < op->data.nbytes; i += 4) {
373 		val = buf[i + 3] << 24 | buf[i + 2] << 16 | buf[i + 1] << 8 |
374 		      buf[i];
375 		writel(val, sp->base + MTK_NOR_REG_PP_DATA);
376 	}
377 	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE,
378 				(op->data.nbytes + 5) * BITS_PER_BYTE);
379 }
380 
381 static int mtk_nor_pp_unbuffered(struct mtk_nor *sp,
382 				 const struct spi_mem_op *op)
383 {
384 	const u8 *buf = op->data.buf.out;
385 	int ret;
386 
387 	ret = mtk_nor_write_buffer_disable(sp);
388 	if (ret < 0)
389 		return ret;
390 	writeb(buf[0], sp->base + MTK_NOR_REG_WDATA);
391 	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE, 6 * BITS_PER_BYTE);
392 }
393 
394 static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
395 {
396 	struct mtk_nor *sp = spi_controller_get_devdata(mem->spi->master);
397 	int ret;
398 
399 	if ((op->data.nbytes == 0) ||
400 	    ((op->addr.nbytes != 3) && (op->addr.nbytes != 4)))
401 		return -ENOTSUPP;
402 
403 	if (op->data.dir == SPI_MEM_DATA_OUT) {
404 		mtk_nor_set_addr(sp, op);
405 		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA0);
406 		if (op->data.nbytes == MTK_NOR_PP_SIZE)
407 			return mtk_nor_pp_buffered(sp, op);
408 		return mtk_nor_pp_unbuffered(sp, op);
409 	}
410 
411 	if ((op->data.dir == SPI_MEM_DATA_IN) && mtk_nor_match_read(op)) {
412 		ret = mtk_nor_write_buffer_disable(sp);
413 		if (ret < 0)
414 			return ret;
415 		mtk_nor_setup_bus(sp, op);
416 		if (op->data.nbytes == 1) {
417 			mtk_nor_set_addr(sp, op);
418 			return mtk_nor_read_pio(sp, op);
419 		} else if (((ulong)(op->data.buf.in) &
420 			    MTK_NOR_DMA_ALIGN_MASK)) {
421 			return mtk_nor_read_bounce(sp, op->addr.val,
422 						   op->data.nbytes,
423 						   op->data.buf.in);
424 		} else {
425 			return mtk_nor_read_dma(sp, op->addr.val,
426 						op->data.nbytes,
427 						op->data.buf.in);
428 		}
429 	}
430 
431 	return -ENOTSUPP;
432 }
433 
434 static int mtk_nor_setup(struct spi_device *spi)
435 {
436 	struct mtk_nor *sp = spi_controller_get_devdata(spi->master);
437 
438 	if (spi->max_speed_hz && (spi->max_speed_hz < sp->spi_freq)) {
439 		dev_err(&spi->dev, "spi clock should be %u Hz.\n",
440 			sp->spi_freq);
441 		return -EINVAL;
442 	}
443 	spi->max_speed_hz = sp->spi_freq;
444 
445 	return 0;
446 }
447 
448 static int mtk_nor_transfer_one_message(struct spi_controller *master,
449 					struct spi_message *m)
450 {
451 	struct mtk_nor *sp = spi_controller_get_devdata(master);
452 	struct spi_transfer *t = NULL;
453 	unsigned long trx_len = 0;
454 	int stat = 0;
455 	int reg_offset = MTK_NOR_REG_PRGDATA_MAX;
456 	void __iomem *reg;
457 	const u8 *txbuf;
458 	u8 *rxbuf;
459 	int i;
460 
461 	list_for_each_entry(t, &m->transfers, transfer_list) {
462 		txbuf = t->tx_buf;
463 		for (i = 0; i < t->len; i++, reg_offset--) {
464 			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
465 			if (txbuf)
466 				writeb(txbuf[i], reg);
467 			else
468 				writeb(0, reg);
469 		}
470 		trx_len += t->len;
471 	}
472 
473 	writel(trx_len * BITS_PER_BYTE, sp->base + MTK_NOR_REG_PRG_CNT);
474 
475 	stat = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_PROGRAM,
476 				trx_len * BITS_PER_BYTE);
477 	if (stat < 0)
478 		goto msg_done;
479 
480 	reg_offset = trx_len - 1;
481 	list_for_each_entry(t, &m->transfers, transfer_list) {
482 		rxbuf = t->rx_buf;
483 		for (i = 0; i < t->len; i++, reg_offset--) {
484 			reg = sp->base + MTK_NOR_REG_SHIFT(reg_offset);
485 			if (rxbuf)
486 				rxbuf[i] = readb(reg);
487 		}
488 	}
489 
490 	m->actual_length = trx_len;
491 msg_done:
492 	m->status = stat;
493 	spi_finalize_current_message(master);
494 
495 	return 0;
496 }
497 
498 static void mtk_nor_disable_clk(struct mtk_nor *sp)
499 {
500 	clk_disable_unprepare(sp->spi_clk);
501 	clk_disable_unprepare(sp->ctlr_clk);
502 }
503 
504 static int mtk_nor_enable_clk(struct mtk_nor *sp)
505 {
506 	int ret;
507 
508 	ret = clk_prepare_enable(sp->spi_clk);
509 	if (ret)
510 		return ret;
511 
512 	ret = clk_prepare_enable(sp->ctlr_clk);
513 	if (ret) {
514 		clk_disable_unprepare(sp->spi_clk);
515 		return ret;
516 	}
517 
518 	return 0;
519 }
520 
521 static int mtk_nor_init(struct mtk_nor *sp)
522 {
523 	int ret;
524 
525 	ret = mtk_nor_enable_clk(sp);
526 	if (ret)
527 		return ret;
528 
529 	sp->spi_freq = clk_get_rate(sp->spi_clk);
530 
531 	writel(MTK_NOR_ENABLE_SF_CMD, sp->base + MTK_NOR_REG_WP);
532 	mtk_nor_rmw(sp, MTK_NOR_REG_CFG2, MTK_NOR_WR_CUSTOM_OP_EN, 0);
533 	mtk_nor_rmw(sp, MTK_NOR_REG_CFG3,
534 		    MTK_NOR_DISABLE_WREN | MTK_NOR_DISABLE_SR_POLL, 0);
535 
536 	return ret;
537 }
538 
539 static irqreturn_t mtk_nor_irq_handler(int irq, void *data)
540 {
541 	struct mtk_nor *sp = data;
542 	u32 irq_status, irq_enabled;
543 
544 	irq_status = readl(sp->base + MTK_NOR_REG_IRQ_STAT);
545 	irq_enabled = readl(sp->base + MTK_NOR_REG_IRQ_EN);
546 	// write status back to clear interrupt
547 	writel(irq_status, sp->base + MTK_NOR_REG_IRQ_STAT);
548 
549 	if (!(irq_status & irq_enabled))
550 		return IRQ_NONE;
551 
552 	if (irq_status & MTK_NOR_IRQ_DMA) {
553 		complete(&sp->op_done);
554 		writel(0, sp->base + MTK_NOR_REG_IRQ_EN);
555 	}
556 
557 	return IRQ_HANDLED;
558 }
559 
560 static size_t mtk_max_msg_size(struct spi_device *spi)
561 {
562 	return MTK_NOR_PRG_MAX_SIZE;
563 }
564 
565 static const struct spi_controller_mem_ops mtk_nor_mem_ops = {
566 	.adjust_op_size = mtk_nor_adjust_op_size,
567 	.supports_op = mtk_nor_supports_op,
568 	.exec_op = mtk_nor_exec_op
569 };
570 
571 static const struct of_device_id mtk_nor_match[] = {
572 	{ .compatible = "mediatek,mt8173-nor" },
573 	{ /* sentinel */ }
574 };
575 MODULE_DEVICE_TABLE(of, mtk_nor_match);
576 
577 static int mtk_nor_probe(struct platform_device *pdev)
578 {
579 	struct spi_controller *ctlr;
580 	struct mtk_nor *sp;
581 	void __iomem *base;
582 	u8 *buffer;
583 	struct clk *spi_clk, *ctlr_clk;
584 	int ret, irq;
585 
586 	base = devm_platform_ioremap_resource(pdev, 0);
587 	if (IS_ERR(base))
588 		return PTR_ERR(base);
589 
590 	spi_clk = devm_clk_get(&pdev->dev, "spi");
591 	if (IS_ERR(spi_clk))
592 		return PTR_ERR(spi_clk);
593 
594 	ctlr_clk = devm_clk_get(&pdev->dev, "sf");
595 	if (IS_ERR(ctlr_clk))
596 		return PTR_ERR(ctlr_clk);
597 
598 	buffer = devm_kmalloc(&pdev->dev,
599 			      MTK_NOR_BOUNCE_BUF_SIZE + MTK_NOR_DMA_ALIGN,
600 			      GFP_KERNEL);
601 	if (!buffer)
602 		return -ENOMEM;
603 
604 	if ((ulong)buffer & MTK_NOR_DMA_ALIGN_MASK)
605 		buffer = (u8 *)(((ulong)buffer + MTK_NOR_DMA_ALIGN) &
606 				~MTK_NOR_DMA_ALIGN_MASK);
607 
608 	ctlr = spi_alloc_master(&pdev->dev, sizeof(*sp));
609 	if (!ctlr) {
610 		dev_err(&pdev->dev, "failed to allocate spi controller\n");
611 		return -ENOMEM;
612 	}
613 
614 	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
615 	ctlr->dev.of_node = pdev->dev.of_node;
616 	ctlr->max_message_size = mtk_max_msg_size;
617 	ctlr->mem_ops = &mtk_nor_mem_ops;
618 	ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD;
619 	ctlr->num_chipselect = 1;
620 	ctlr->setup = mtk_nor_setup;
621 	ctlr->transfer_one_message = mtk_nor_transfer_one_message;
622 
623 	dev_set_drvdata(&pdev->dev, ctlr);
624 
625 	sp = spi_controller_get_devdata(ctlr);
626 	sp->base = base;
627 	sp->buffer = buffer;
628 	sp->has_irq = false;
629 	sp->wbuf_en = false;
630 	sp->ctlr = ctlr;
631 	sp->dev = &pdev->dev;
632 	sp->spi_clk = spi_clk;
633 	sp->ctlr_clk = ctlr_clk;
634 
635 	irq = platform_get_irq_optional(pdev, 0);
636 	if (irq < 0) {
637 		dev_warn(sp->dev, "IRQ not available.");
638 	} else {
639 		writel(MTK_NOR_IRQ_MASK, base + MTK_NOR_REG_IRQ_STAT);
640 		writel(0, base + MTK_NOR_REG_IRQ_EN);
641 		ret = devm_request_irq(sp->dev, irq, mtk_nor_irq_handler, 0,
642 				       pdev->name, sp);
643 		if (ret < 0) {
644 			dev_warn(sp->dev, "failed to request IRQ.");
645 		} else {
646 			init_completion(&sp->op_done);
647 			sp->has_irq = true;
648 		}
649 	}
650 
651 	ret = mtk_nor_init(sp);
652 	if (ret < 0) {
653 		kfree(ctlr);
654 		return ret;
655 	}
656 
657 	dev_info(&pdev->dev, "spi frequency: %d Hz\n", sp->spi_freq);
658 
659 	return devm_spi_register_controller(&pdev->dev, ctlr);
660 }
661 
662 static int mtk_nor_remove(struct platform_device *pdev)
663 {
664 	struct spi_controller *ctlr;
665 	struct mtk_nor *sp;
666 
667 	ctlr = dev_get_drvdata(&pdev->dev);
668 	sp = spi_controller_get_devdata(ctlr);
669 
670 	mtk_nor_disable_clk(sp);
671 
672 	return 0;
673 }
674 
675 static struct platform_driver mtk_nor_driver = {
676 	.driver = {
677 		.name = DRIVER_NAME,
678 		.of_match_table = mtk_nor_match,
679 	},
680 	.probe = mtk_nor_probe,
681 	.remove = mtk_nor_remove,
682 };
683 
684 module_platform_driver(mtk_nor_driver);
685 
686 MODULE_DESCRIPTION("Mediatek SPI NOR controller driver");
687 MODULE_AUTHOR("Chuanhong Guo <gch981213@gmail.com>");
688 MODULE_LICENSE("GPL v2");
689 MODULE_ALIAS("platform:" DRIVER_NAME);
690