xref: /openbmc/linux/drivers/mtd/devices/spear_smi.c (revision 8a10bc9d)
1 /*
2  * SMI (Serial Memory Controller) device driver for Serial NOR Flash on
3  * SPEAr platform
4  * The serial nor interface is largely based on drivers/mtd/m25p80.c,
5  * however the SPI interface has been replaced by SMI.
6  *
7  * Copyright © 2010 STMicroelectronics.
8  * Ashish Priyadarshi
9  * Shiraz Hashim <shiraz.hashim@st.com>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2. This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15 
16 #include <linux/clk.h>
17 #include <linux/delay.h>
18 #include <linux/device.h>
19 #include <linux/err.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/io.h>
23 #include <linux/ioport.h>
24 #include <linux/jiffies.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/param.h>
28 #include <linux/platform_device.h>
29 #include <linux/pm.h>
30 #include <linux/mtd/mtd.h>
31 #include <linux/mtd/partitions.h>
32 #include <linux/mtd/spear_smi.h>
33 #include <linux/mutex.h>
34 #include <linux/sched.h>
35 #include <linux/slab.h>
36 #include <linux/wait.h>
37 #include <linux/of.h>
38 #include <linux/of_address.h>
39 
40 /* SMI clock rate */
41 #define SMI_MAX_CLOCK_FREQ	50000000 /* 50 MHz */
42 
43 /* MAX time out to safely come out of a erase or write busy conditions */
44 #define SMI_PROBE_TIMEOUT	(HZ / 10)
45 #define SMI_MAX_TIME_OUT	(3 * HZ)
46 
47 /* timeout for command completion */
48 #define SMI_CMD_TIMEOUT		(HZ / 10)
49 
50 /* registers of smi */
51 #define SMI_CR1		0x0	/* SMI control register 1 */
52 #define SMI_CR2		0x4	/* SMI control register 2 */
53 #define SMI_SR		0x8	/* SMI status register */
54 #define SMI_TR		0xC	/* SMI transmit register */
55 #define SMI_RR		0x10	/* SMI receive register */
56 
57 /* defines for control_reg 1 */
58 #define BANK_EN		(0xF << 0)	/* enables all banks */
59 #define DSEL_TIME	(0x6 << 4)	/* Deselect time 6 + 1 SMI_CK periods */
60 #define SW_MODE		(0x1 << 28)	/* enables SW Mode */
61 #define WB_MODE		(0x1 << 29)	/* Write Burst Mode */
62 #define FAST_MODE	(0x1 << 15)	/* Fast Mode */
63 #define HOLD1		(0x1 << 16)	/* Clock Hold period selection */
64 
65 /* defines for control_reg 2 */
66 #define SEND		(0x1 << 7)	/* Send data */
67 #define TFIE		(0x1 << 8)	/* Transmission Flag Interrupt Enable */
68 #define WCIE		(0x1 << 9)	/* Write Complete Interrupt Enable */
69 #define RD_STATUS_REG	(0x1 << 10)	/* reads status reg */
70 #define WE		(0x1 << 11)	/* Write Enable */
71 
72 #define TX_LEN_SHIFT	0
73 #define RX_LEN_SHIFT	4
74 #define BANK_SHIFT	12
75 
76 /* defines for status register */
77 #define SR_WIP		0x1	/* Write in progress */
78 #define SR_WEL		0x2	/* Write enable latch */
79 #define SR_BP0		0x4	/* Block protect 0 */
80 #define SR_BP1		0x8	/* Block protect 1 */
81 #define SR_BP2		0x10	/* Block protect 2 */
82 #define SR_SRWD		0x80	/* SR write protect */
83 #define TFF		0x100	/* Transfer Finished Flag */
84 #define WCF		0x200	/* Transfer Finished Flag */
85 #define ERF1		0x400	/* Forbidden Write Request */
86 #define ERF2		0x800	/* Forbidden Access */
87 
88 #define WM_SHIFT	12
89 
90 /* flash opcodes */
91 #define OPCODE_RDID	0x9f	/* Read JEDEC ID */
92 
93 /* Flash Device Ids maintenance section */
94 
95 /* data structure to maintain flash ids from different vendors */
96 struct flash_device {
97 	char *name;
98 	u8 erase_cmd;
99 	u32 device_id;
100 	u32 pagesize;
101 	unsigned long sectorsize;
102 	unsigned long size_in_bytes;
103 };
104 
105 #define FLASH_ID(n, es, id, psize, ssize, size)	\
106 {				\
107 	.name = n,		\
108 	.erase_cmd = es,	\
109 	.device_id = id,	\
110 	.pagesize = psize,	\
111 	.sectorsize = ssize,	\
112 	.size_in_bytes = size	\
113 }
114 
115 static struct flash_device flash_devices[] = {
116 	FLASH_ID("st m25p16"     , 0xd8, 0x00152020, 0x100, 0x10000, 0x200000),
117 	FLASH_ID("st m25p32"     , 0xd8, 0x00162020, 0x100, 0x10000, 0x400000),
118 	FLASH_ID("st m25p64"     , 0xd8, 0x00172020, 0x100, 0x10000, 0x800000),
119 	FLASH_ID("st m25p128"    , 0xd8, 0x00182020, 0x100, 0x40000, 0x1000000),
120 	FLASH_ID("st m25p05"     , 0xd8, 0x00102020, 0x80 , 0x8000 , 0x10000),
121 	FLASH_ID("st m25p10"     , 0xd8, 0x00112020, 0x80 , 0x8000 , 0x20000),
122 	FLASH_ID("st m25p20"     , 0xd8, 0x00122020, 0x100, 0x10000, 0x40000),
123 	FLASH_ID("st m25p40"     , 0xd8, 0x00132020, 0x100, 0x10000, 0x80000),
124 	FLASH_ID("st m25p80"     , 0xd8, 0x00142020, 0x100, 0x10000, 0x100000),
125 	FLASH_ID("st m45pe10"    , 0xd8, 0x00114020, 0x100, 0x10000, 0x20000),
126 	FLASH_ID("st m45pe20"    , 0xd8, 0x00124020, 0x100, 0x10000, 0x40000),
127 	FLASH_ID("st m45pe40"    , 0xd8, 0x00134020, 0x100, 0x10000, 0x80000),
128 	FLASH_ID("st m45pe80"    , 0xd8, 0x00144020, 0x100, 0x10000, 0x100000),
129 	FLASH_ID("sp s25fl004"   , 0xd8, 0x00120201, 0x100, 0x10000, 0x80000),
130 	FLASH_ID("sp s25fl008"   , 0xd8, 0x00130201, 0x100, 0x10000, 0x100000),
131 	FLASH_ID("sp s25fl016"   , 0xd8, 0x00140201, 0x100, 0x10000, 0x200000),
132 	FLASH_ID("sp s25fl032"   , 0xd8, 0x00150201, 0x100, 0x10000, 0x400000),
133 	FLASH_ID("sp s25fl064"   , 0xd8, 0x00160201, 0x100, 0x10000, 0x800000),
134 	FLASH_ID("atmel 25f512"  , 0x52, 0x0065001F, 0x80 , 0x8000 , 0x10000),
135 	FLASH_ID("atmel 25f1024" , 0x52, 0x0060001F, 0x100, 0x8000 , 0x20000),
136 	FLASH_ID("atmel 25f2048" , 0x52, 0x0063001F, 0x100, 0x10000, 0x40000),
137 	FLASH_ID("atmel 25f4096" , 0x52, 0x0064001F, 0x100, 0x10000, 0x80000),
138 	FLASH_ID("atmel 25fs040" , 0xd7, 0x0004661F, 0x100, 0x10000, 0x80000),
139 	FLASH_ID("mac 25l512"    , 0xd8, 0x001020C2, 0x010, 0x10000, 0x10000),
140 	FLASH_ID("mac 25l1005"   , 0xd8, 0x001120C2, 0x010, 0x10000, 0x20000),
141 	FLASH_ID("mac 25l2005"   , 0xd8, 0x001220C2, 0x010, 0x10000, 0x40000),
142 	FLASH_ID("mac 25l4005"   , 0xd8, 0x001320C2, 0x010, 0x10000, 0x80000),
143 	FLASH_ID("mac 25l4005a"  , 0xd8, 0x001320C2, 0x010, 0x10000, 0x80000),
144 	FLASH_ID("mac 25l8005"   , 0xd8, 0x001420C2, 0x010, 0x10000, 0x100000),
145 	FLASH_ID("mac 25l1605"   , 0xd8, 0x001520C2, 0x100, 0x10000, 0x200000),
146 	FLASH_ID("mac 25l1605a"  , 0xd8, 0x001520C2, 0x010, 0x10000, 0x200000),
147 	FLASH_ID("mac 25l3205"   , 0xd8, 0x001620C2, 0x100, 0x10000, 0x400000),
148 	FLASH_ID("mac 25l3205a"  , 0xd8, 0x001620C2, 0x100, 0x10000, 0x400000),
149 	FLASH_ID("mac 25l6405"   , 0xd8, 0x001720C2, 0x100, 0x10000, 0x800000),
150 };
151 
152 /* Define spear specific structures */
153 
154 struct spear_snor_flash;
155 
156 /**
157  * struct spear_smi - Structure for SMI Device
158  *
159  * @clk: functional clock
160  * @status: current status register of SMI.
161  * @clk_rate: functional clock rate of SMI (default: SMI_MAX_CLOCK_FREQ)
162  * @lock: lock to prevent parallel access of SMI.
163  * @io_base: base address for registers of SMI.
164  * @pdev: platform device
165  * @cmd_complete: queue to wait for command completion of NOR-flash.
166  * @num_flashes: number of flashes actually present on board.
167  * @flash: separate structure for each Serial NOR-flash attached to SMI.
168  */
169 struct spear_smi {
170 	struct clk *clk;
171 	u32 status;
172 	unsigned long clk_rate;
173 	struct mutex lock;
174 	void __iomem *io_base;
175 	struct platform_device *pdev;
176 	wait_queue_head_t cmd_complete;
177 	u32 num_flashes;
178 	struct spear_snor_flash *flash[MAX_NUM_FLASH_CHIP];
179 };
180 
181 /**
182  * struct spear_snor_flash - Structure for Serial NOR Flash
183  *
184  * @bank: Bank number(0, 1, 2, 3) for each NOR-flash.
185  * @dev_id: Device ID of NOR-flash.
186  * @lock: lock to manage flash read, write and erase operations
187  * @mtd: MTD info for each NOR-flash.
188  * @num_parts: Total number of partition in each bank of NOR-flash.
189  * @parts: Partition info for each bank of NOR-flash.
190  * @page_size: Page size of NOR-flash.
191  * @base_addr: Base address of NOR-flash.
192  * @erase_cmd: erase command may vary on different flash types
193  * @fast_mode: flash supports read in fast mode
194  */
195 struct spear_snor_flash {
196 	u32 bank;
197 	u32 dev_id;
198 	struct mutex lock;
199 	struct mtd_info mtd;
200 	u32 num_parts;
201 	struct mtd_partition *parts;
202 	u32 page_size;
203 	void __iomem *base_addr;
204 	u8 erase_cmd;
205 	u8 fast_mode;
206 };
207 
208 static inline struct spear_snor_flash *get_flash_data(struct mtd_info *mtd)
209 {
210 	return container_of(mtd, struct spear_snor_flash, mtd);
211 }
212 
213 /**
214  * spear_smi_read_sr - Read status register of flash through SMI
215  * @dev: structure of SMI information.
216  * @bank: bank to which flash is connected
217  *
218  * This routine will return the status register of the flash chip present at the
219  * given bank.
220  */
221 static int spear_smi_read_sr(struct spear_smi *dev, u32 bank)
222 {
223 	int ret;
224 	u32 ctrlreg1;
225 
226 	mutex_lock(&dev->lock);
227 	dev->status = 0; /* Will be set in interrupt handler */
228 
229 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
230 	/* program smi in hw mode */
231 	writel(ctrlreg1 & ~(SW_MODE | WB_MODE), dev->io_base + SMI_CR1);
232 
233 	/* performing a rsr instruction in hw mode */
234 	writel((bank << BANK_SHIFT) | RD_STATUS_REG | TFIE,
235 			dev->io_base + SMI_CR2);
236 
237 	/* wait for tff */
238 	ret = wait_event_interruptible_timeout(dev->cmd_complete,
239 			dev->status & TFF, SMI_CMD_TIMEOUT);
240 
241 	/* copy dev->status (lower 16 bits) in order to release lock */
242 	if (ret > 0)
243 		ret = dev->status & 0xffff;
244 	else if (ret == 0)
245 		ret = -ETIMEDOUT;
246 
247 	/* restore the ctrl regs state */
248 	writel(ctrlreg1, dev->io_base + SMI_CR1);
249 	writel(0, dev->io_base + SMI_CR2);
250 	mutex_unlock(&dev->lock);
251 
252 	return ret;
253 }
254 
255 /**
256  * spear_smi_wait_till_ready - wait till flash is ready
257  * @dev: structure of SMI information.
258  * @bank: flash corresponding to this bank
259  * @timeout: timeout for busy wait condition
260  *
261  * This routine checks for WIP (write in progress) bit in Status register
262  * If successful the routine returns 0 else -EBUSY
263  */
264 static int spear_smi_wait_till_ready(struct spear_smi *dev, u32 bank,
265 		unsigned long timeout)
266 {
267 	unsigned long finish;
268 	int status;
269 
270 	finish = jiffies + timeout;
271 	do {
272 		status = spear_smi_read_sr(dev, bank);
273 		if (status < 0) {
274 			if (status == -ETIMEDOUT)
275 				continue; /* try till finish */
276 			return status;
277 		} else if (!(status & SR_WIP)) {
278 			return 0;
279 		}
280 
281 		cond_resched();
282 	} while (!time_after_eq(jiffies, finish));
283 
284 	dev_err(&dev->pdev->dev, "smi controller is busy, timeout\n");
285 	return -EBUSY;
286 }
287 
288 /**
289  * spear_smi_int_handler - SMI Interrupt Handler.
290  * @irq: irq number
291  * @dev_id: structure of SMI device, embedded in dev_id.
292  *
293  * The handler clears all interrupt conditions and records the status in
294  * dev->status which is used by the driver later.
295  */
296 static irqreturn_t spear_smi_int_handler(int irq, void *dev_id)
297 {
298 	u32 status = 0;
299 	struct spear_smi *dev = dev_id;
300 
301 	status = readl(dev->io_base + SMI_SR);
302 
303 	if (unlikely(!status))
304 		return IRQ_NONE;
305 
306 	/* clear all interrupt conditions */
307 	writel(0, dev->io_base + SMI_SR);
308 
309 	/* copy the status register in dev->status */
310 	dev->status |= status;
311 
312 	/* send the completion */
313 	wake_up_interruptible(&dev->cmd_complete);
314 
315 	return IRQ_HANDLED;
316 }
317 
318 /**
319  * spear_smi_hw_init - initializes the smi controller.
320  * @dev: structure of smi device
321  *
322  * this routine initializes the smi controller wit the default values
323  */
324 static void spear_smi_hw_init(struct spear_smi *dev)
325 {
326 	unsigned long rate = 0;
327 	u32 prescale = 0;
328 	u32 val;
329 
330 	rate = clk_get_rate(dev->clk);
331 
332 	/* functional clock of smi */
333 	prescale = DIV_ROUND_UP(rate, dev->clk_rate);
334 
335 	/*
336 	 * setting the standard values, fast mode, prescaler for
337 	 * SMI_MAX_CLOCK_FREQ (50MHz) operation and bank enable
338 	 */
339 	val = HOLD1 | BANK_EN | DSEL_TIME | (prescale << 8);
340 
341 	mutex_lock(&dev->lock);
342 	/* clear all interrupt conditions */
343 	writel(0, dev->io_base + SMI_SR);
344 
345 	writel(val, dev->io_base + SMI_CR1);
346 	mutex_unlock(&dev->lock);
347 }
348 
349 /**
350  * get_flash_index - match chip id from a flash list.
351  * @flash_id: a valid nor flash chip id obtained from board.
352  *
353  * try to validate the chip id by matching from a list, if not found then simply
354  * returns negative. In case of success returns index in to the flash devices
355  * array.
356  */
357 static int get_flash_index(u32 flash_id)
358 {
359 	int index;
360 
361 	/* Matches chip-id to entire list of 'serial-nor flash' ids */
362 	for (index = 0; index < ARRAY_SIZE(flash_devices); index++) {
363 		if (flash_devices[index].device_id == flash_id)
364 			return index;
365 	}
366 
367 	/* Memory chip is not listed and not supported */
368 	return -ENODEV;
369 }
370 
371 /**
372  * spear_smi_write_enable - Enable the flash to do write operation
373  * @dev: structure of SMI device
374  * @bank: enable write for flash connected to this bank
375  *
376  * Set write enable latch with Write Enable command.
377  * Returns 0 on success.
378  */
379 static int spear_smi_write_enable(struct spear_smi *dev, u32 bank)
380 {
381 	int ret;
382 	u32 ctrlreg1;
383 
384 	mutex_lock(&dev->lock);
385 	dev->status = 0; /* Will be set in interrupt handler */
386 
387 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
388 	/* program smi in h/w mode */
389 	writel(ctrlreg1 & ~SW_MODE, dev->io_base + SMI_CR1);
390 
391 	/* give the flash, write enable command */
392 	writel((bank << BANK_SHIFT) | WE | TFIE, dev->io_base + SMI_CR2);
393 
394 	ret = wait_event_interruptible_timeout(dev->cmd_complete,
395 			dev->status & TFF, SMI_CMD_TIMEOUT);
396 
397 	/* restore the ctrl regs state */
398 	writel(ctrlreg1, dev->io_base + SMI_CR1);
399 	writel(0, dev->io_base + SMI_CR2);
400 
401 	if (ret == 0) {
402 		ret = -EIO;
403 		dev_err(&dev->pdev->dev,
404 			"smi controller failed on write enable\n");
405 	} else if (ret > 0) {
406 		/* check whether write mode status is set for required bank */
407 		if (dev->status & (1 << (bank + WM_SHIFT)))
408 			ret = 0;
409 		else {
410 			dev_err(&dev->pdev->dev, "couldn't enable write\n");
411 			ret = -EIO;
412 		}
413 	}
414 
415 	mutex_unlock(&dev->lock);
416 	return ret;
417 }
418 
419 static inline u32
420 get_sector_erase_cmd(struct spear_snor_flash *flash, u32 offset)
421 {
422 	u32 cmd;
423 	u8 *x = (u8 *)&cmd;
424 
425 	x[0] = flash->erase_cmd;
426 	x[1] = offset >> 16;
427 	x[2] = offset >> 8;
428 	x[3] = offset;
429 
430 	return cmd;
431 }
432 
433 /**
434  * spear_smi_erase_sector - erase one sector of flash
435  * @dev: structure of SMI information
436  * @command: erase command to be send
437  * @bank: bank to which this command needs to be send
438  * @bytes: size of command
439  *
440  * Erase one sector of flash memory at offset ``offset'' which is any
441  * address within the sector which should be erased.
442  * Returns 0 if successful, non-zero otherwise.
443  */
444 static int spear_smi_erase_sector(struct spear_smi *dev,
445 		u32 bank, u32 command, u32 bytes)
446 {
447 	u32 ctrlreg1 = 0;
448 	int ret;
449 
450 	ret = spear_smi_wait_till_ready(dev, bank, SMI_MAX_TIME_OUT);
451 	if (ret)
452 		return ret;
453 
454 	ret = spear_smi_write_enable(dev, bank);
455 	if (ret)
456 		return ret;
457 
458 	mutex_lock(&dev->lock);
459 
460 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
461 	writel((ctrlreg1 | SW_MODE) & ~WB_MODE, dev->io_base + SMI_CR1);
462 
463 	/* send command in sw mode */
464 	writel(command, dev->io_base + SMI_TR);
465 
466 	writel((bank << BANK_SHIFT) | SEND | TFIE | (bytes << TX_LEN_SHIFT),
467 			dev->io_base + SMI_CR2);
468 
469 	ret = wait_event_interruptible_timeout(dev->cmd_complete,
470 			dev->status & TFF, SMI_CMD_TIMEOUT);
471 
472 	if (ret == 0) {
473 		ret = -EIO;
474 		dev_err(&dev->pdev->dev, "sector erase failed\n");
475 	} else if (ret > 0)
476 		ret = 0; /* success */
477 
478 	/* restore ctrl regs */
479 	writel(ctrlreg1, dev->io_base + SMI_CR1);
480 	writel(0, dev->io_base + SMI_CR2);
481 
482 	mutex_unlock(&dev->lock);
483 	return ret;
484 }
485 
486 /**
487  * spear_mtd_erase - perform flash erase operation as requested by user
488  * @mtd: Provides the memory characteristics
489  * @e_info: Provides the erase information
490  *
491  * Erase an address range on the flash chip. The address range may extend
492  * one or more erase sectors. Return an error is there is a problem erasing.
493  */
494 static int spear_mtd_erase(struct mtd_info *mtd, struct erase_info *e_info)
495 {
496 	struct spear_snor_flash *flash = get_flash_data(mtd);
497 	struct spear_smi *dev = mtd->priv;
498 	u32 addr, command, bank;
499 	int len, ret;
500 
501 	if (!flash || !dev)
502 		return -ENODEV;
503 
504 	bank = flash->bank;
505 	if (bank > dev->num_flashes - 1) {
506 		dev_err(&dev->pdev->dev, "Invalid Bank Num");
507 		return -EINVAL;
508 	}
509 
510 	addr = e_info->addr;
511 	len = e_info->len;
512 
513 	mutex_lock(&flash->lock);
514 
515 	/* now erase sectors in loop */
516 	while (len) {
517 		command = get_sector_erase_cmd(flash, addr);
518 		/* preparing the command for flash */
519 		ret = spear_smi_erase_sector(dev, bank, command, 4);
520 		if (ret) {
521 			e_info->state = MTD_ERASE_FAILED;
522 			mutex_unlock(&flash->lock);
523 			return ret;
524 		}
525 		addr += mtd->erasesize;
526 		len -= mtd->erasesize;
527 	}
528 
529 	mutex_unlock(&flash->lock);
530 	e_info->state = MTD_ERASE_DONE;
531 	mtd_erase_callback(e_info);
532 
533 	return 0;
534 }
535 
536 /**
537  * spear_mtd_read - performs flash read operation as requested by the user
538  * @mtd: MTD information of the memory bank
539  * @from: Address from which to start read
540  * @len: Number of bytes to be read
541  * @retlen: Fills the Number of bytes actually read
542  * @buf: Fills this after reading
543  *
544  * Read an address range from the flash chip. The address range
545  * may be any size provided it is within the physical boundaries.
546  * Returns 0 on success, non zero otherwise
547  */
548 static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
549 		size_t *retlen, u8 *buf)
550 {
551 	struct spear_snor_flash *flash = get_flash_data(mtd);
552 	struct spear_smi *dev = mtd->priv;
553 	void __iomem *src;
554 	u32 ctrlreg1, val;
555 	int ret;
556 
557 	if (!flash || !dev)
558 		return -ENODEV;
559 
560 	if (flash->bank > dev->num_flashes - 1) {
561 		dev_err(&dev->pdev->dev, "Invalid Bank Num");
562 		return -EINVAL;
563 	}
564 
565 	/* select address as per bank number */
566 	src = flash->base_addr + from;
567 
568 	mutex_lock(&flash->lock);
569 
570 	/* wait till previous write/erase is done. */
571 	ret = spear_smi_wait_till_ready(dev, flash->bank, SMI_MAX_TIME_OUT);
572 	if (ret) {
573 		mutex_unlock(&flash->lock);
574 		return ret;
575 	}
576 
577 	mutex_lock(&dev->lock);
578 	/* put smi in hw mode not wbt mode */
579 	ctrlreg1 = val = readl(dev->io_base + SMI_CR1);
580 	val &= ~(SW_MODE | WB_MODE);
581 	if (flash->fast_mode)
582 		val |= FAST_MODE;
583 
584 	writel(val, dev->io_base + SMI_CR1);
585 
586 	memcpy_fromio(buf, src, len);
587 
588 	/* restore ctrl reg1 */
589 	writel(ctrlreg1, dev->io_base + SMI_CR1);
590 	mutex_unlock(&dev->lock);
591 
592 	*retlen = len;
593 	mutex_unlock(&flash->lock);
594 
595 	return 0;
596 }
597 
598 static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
599 		void __iomem *dest, const void *src, size_t len)
600 {
601 	int ret;
602 	u32 ctrlreg1;
603 
604 	/* wait until finished previous write command. */
605 	ret = spear_smi_wait_till_ready(dev, bank, SMI_MAX_TIME_OUT);
606 	if (ret)
607 		return ret;
608 
609 	/* put smi in write enable */
610 	ret = spear_smi_write_enable(dev, bank);
611 	if (ret)
612 		return ret;
613 
614 	/* put smi in hw, write burst mode */
615 	mutex_lock(&dev->lock);
616 
617 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
618 	writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1);
619 
620 	memcpy_toio(dest, src, len);
621 
622 	writel(ctrlreg1, dev->io_base + SMI_CR1);
623 
624 	mutex_unlock(&dev->lock);
625 	return 0;
626 }
627 
628 /**
629  * spear_mtd_write - performs write operation as requested by the user.
630  * @mtd: MTD information of the memory bank.
631  * @to:	Address to write.
632  * @len: Number of bytes to be written.
633  * @retlen: Number of bytes actually wrote.
634  * @buf: Buffer from which the data to be taken.
635  *
636  * Write an address range to the flash chip. Data must be written in
637  * flash_page_size chunks. The address range may be any size provided
638  * it is within the physical boundaries.
639  * Returns 0 on success, non zero otherwise
640  */
641 static int spear_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
642 		size_t *retlen, const u8 *buf)
643 {
644 	struct spear_snor_flash *flash = get_flash_data(mtd);
645 	struct spear_smi *dev = mtd->priv;
646 	void __iomem *dest;
647 	u32 page_offset, page_size;
648 	int ret;
649 
650 	if (!flash || !dev)
651 		return -ENODEV;
652 
653 	if (flash->bank > dev->num_flashes - 1) {
654 		dev_err(&dev->pdev->dev, "Invalid Bank Num");
655 		return -EINVAL;
656 	}
657 
658 	/* select address as per bank number */
659 	dest = flash->base_addr + to;
660 	mutex_lock(&flash->lock);
661 
662 	page_offset = (u32)to % flash->page_size;
663 
664 	/* do if all the bytes fit onto one page */
665 	if (page_offset + len <= flash->page_size) {
666 		ret = spear_smi_cpy_toio(dev, flash->bank, dest, buf, len);
667 		if (!ret)
668 			*retlen += len;
669 	} else {
670 		u32 i;
671 
672 		/* the size of data remaining on the first page */
673 		page_size = flash->page_size - page_offset;
674 
675 		ret = spear_smi_cpy_toio(dev, flash->bank, dest, buf,
676 				page_size);
677 		if (ret)
678 			goto err_write;
679 		else
680 			*retlen += page_size;
681 
682 		/* write everything in pagesize chunks */
683 		for (i = page_size; i < len; i += page_size) {
684 			page_size = len - i;
685 			if (page_size > flash->page_size)
686 				page_size = flash->page_size;
687 
688 			ret = spear_smi_cpy_toio(dev, flash->bank, dest + i,
689 					buf + i, page_size);
690 			if (ret)
691 				break;
692 			else
693 				*retlen += page_size;
694 		}
695 	}
696 
697 err_write:
698 	mutex_unlock(&flash->lock);
699 
700 	return ret;
701 }
702 
703 /**
704  * spear_smi_probe_flash - Detects the NOR Flash chip.
705  * @dev: structure of SMI information.
706  * @bank: bank on which flash must be probed
707  *
708  * This routine will check whether there exists a flash chip on a given memory
709  * bank ID.
710  * Return index of the probed flash in flash devices structure
711  */
712 static int spear_smi_probe_flash(struct spear_smi *dev, u32 bank)
713 {
714 	int ret;
715 	u32 val = 0;
716 
717 	ret = spear_smi_wait_till_ready(dev, bank, SMI_PROBE_TIMEOUT);
718 	if (ret)
719 		return ret;
720 
721 	mutex_lock(&dev->lock);
722 
723 	dev->status = 0; /* Will be set in interrupt handler */
724 	/* put smi in sw mode */
725 	val = readl(dev->io_base + SMI_CR1);
726 	writel(val | SW_MODE, dev->io_base + SMI_CR1);
727 
728 	/* send readid command in sw mode */
729 	writel(OPCODE_RDID, dev->io_base + SMI_TR);
730 
731 	val = (bank << BANK_SHIFT) | SEND | (1 << TX_LEN_SHIFT) |
732 		(3 << RX_LEN_SHIFT) | TFIE;
733 	writel(val, dev->io_base + SMI_CR2);
734 
735 	/* wait for TFF */
736 	ret = wait_event_interruptible_timeout(dev->cmd_complete,
737 			dev->status & TFF, SMI_CMD_TIMEOUT);
738 	if (ret <= 0) {
739 		ret = -ENODEV;
740 		goto err_probe;
741 	}
742 
743 	/* get memory chip id */
744 	val = readl(dev->io_base + SMI_RR);
745 	val &= 0x00ffffff;
746 	ret = get_flash_index(val);
747 
748 err_probe:
749 	/* clear sw mode */
750 	val = readl(dev->io_base + SMI_CR1);
751 	writel(val & ~SW_MODE, dev->io_base + SMI_CR1);
752 
753 	mutex_unlock(&dev->lock);
754 	return ret;
755 }
756 
757 
758 #ifdef CONFIG_OF
759 static int spear_smi_probe_config_dt(struct platform_device *pdev,
760 				     struct device_node *np)
761 {
762 	struct spear_smi_plat_data *pdata = dev_get_platdata(&pdev->dev);
763 	struct device_node *pp = NULL;
764 	const __be32 *addr;
765 	u32 val;
766 	int len;
767 	int i = 0;
768 
769 	if (!np)
770 		return -ENODEV;
771 
772 	of_property_read_u32(np, "clock-rate", &val);
773 	pdata->clk_rate = val;
774 
775 	pdata->board_flash_info = devm_kzalloc(&pdev->dev,
776 					       sizeof(*pdata->board_flash_info),
777 					       GFP_KERNEL);
778 
779 	/* Fill structs for each subnode (flash device) */
780 	while ((pp = of_get_next_child(np, pp))) {
781 		struct spear_smi_flash_info *flash_info;
782 
783 		flash_info = &pdata->board_flash_info[i];
784 		pdata->np[i] = pp;
785 
786 		/* Read base-addr and size from DT */
787 		addr = of_get_property(pp, "reg", &len);
788 		pdata->board_flash_info->mem_base = be32_to_cpup(&addr[0]);
789 		pdata->board_flash_info->size = be32_to_cpup(&addr[1]);
790 
791 		if (of_get_property(pp, "st,smi-fast-mode", NULL))
792 			pdata->board_flash_info->fast_mode = 1;
793 
794 		i++;
795 	}
796 
797 	pdata->num_flashes = i;
798 
799 	return 0;
800 }
801 #else
802 static int spear_smi_probe_config_dt(struct platform_device *pdev,
803 				     struct device_node *np)
804 {
805 	return -ENOSYS;
806 }
807 #endif
808 
809 static int spear_smi_setup_banks(struct platform_device *pdev,
810 				 u32 bank, struct device_node *np)
811 {
812 	struct spear_smi *dev = platform_get_drvdata(pdev);
813 	struct mtd_part_parser_data ppdata = {};
814 	struct spear_smi_flash_info *flash_info;
815 	struct spear_smi_plat_data *pdata;
816 	struct spear_snor_flash *flash;
817 	struct mtd_partition *parts = NULL;
818 	int count = 0;
819 	int flash_index;
820 	int ret = 0;
821 
822 	pdata = dev_get_platdata(&pdev->dev);
823 	if (bank > pdata->num_flashes - 1)
824 		return -EINVAL;
825 
826 	flash_info = &pdata->board_flash_info[bank];
827 	if (!flash_info)
828 		return -ENODEV;
829 
830 	flash = devm_kzalloc(&pdev->dev, sizeof(*flash), GFP_ATOMIC);
831 	if (!flash)
832 		return -ENOMEM;
833 	flash->bank = bank;
834 	flash->fast_mode = flash_info->fast_mode ? 1 : 0;
835 	mutex_init(&flash->lock);
836 
837 	/* verify whether nor flash is really present on board */
838 	flash_index = spear_smi_probe_flash(dev, bank);
839 	if (flash_index < 0) {
840 		dev_info(&dev->pdev->dev, "smi-nor%d not found\n", bank);
841 		return flash_index;
842 	}
843 	/* map the memory for nor flash chip */
844 	flash->base_addr = devm_ioremap(&pdev->dev, flash_info->mem_base,
845 					flash_info->size);
846 	if (!flash->base_addr)
847 		return -EIO;
848 
849 	dev->flash[bank] = flash;
850 	flash->mtd.priv = dev;
851 
852 	if (flash_info->name)
853 		flash->mtd.name = flash_info->name;
854 	else
855 		flash->mtd.name = flash_devices[flash_index].name;
856 
857 	flash->mtd.type = MTD_NORFLASH;
858 	flash->mtd.writesize = 1;
859 	flash->mtd.flags = MTD_CAP_NORFLASH;
860 	flash->mtd.size = flash_info->size;
861 	flash->mtd.erasesize = flash_devices[flash_index].sectorsize;
862 	flash->page_size = flash_devices[flash_index].pagesize;
863 	flash->mtd.writebufsize = flash->page_size;
864 	flash->erase_cmd = flash_devices[flash_index].erase_cmd;
865 	flash->mtd._erase = spear_mtd_erase;
866 	flash->mtd._read = spear_mtd_read;
867 	flash->mtd._write = spear_mtd_write;
868 	flash->dev_id = flash_devices[flash_index].device_id;
869 
870 	dev_info(&dev->pdev->dev, "mtd .name=%s .size=%llx(%lluM)\n",
871 			flash->mtd.name, flash->mtd.size,
872 			flash->mtd.size / (1024 * 1024));
873 
874 	dev_info(&dev->pdev->dev, ".erasesize = 0x%x(%uK)\n",
875 			flash->mtd.erasesize, flash->mtd.erasesize / 1024);
876 
877 #ifndef CONFIG_OF
878 	if (flash_info->partitions) {
879 		parts = flash_info->partitions;
880 		count = flash_info->nr_partitions;
881 	}
882 #endif
883 	ppdata.of_node = np;
884 
885 	ret = mtd_device_parse_register(&flash->mtd, NULL, &ppdata, parts,
886 					count);
887 	if (ret) {
888 		dev_err(&dev->pdev->dev, "Err MTD partition=%d\n", ret);
889 		return ret;
890 	}
891 
892 	return 0;
893 }
894 
895 /**
896  * spear_smi_probe - Entry routine
897  * @pdev: platform device structure
898  *
899  * This is the first routine which gets invoked during booting and does all
900  * initialization/allocation work. The routine looks for available memory banks,
901  * and do proper init for any found one.
902  * Returns 0 on success, non zero otherwise
903  */
904 static int spear_smi_probe(struct platform_device *pdev)
905 {
906 	struct device_node *np = pdev->dev.of_node;
907 	struct spear_smi_plat_data *pdata = NULL;
908 	struct spear_smi *dev;
909 	struct resource *smi_base;
910 	int irq, ret = 0;
911 	int i;
912 
913 	if (np) {
914 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
915 		if (!pdata) {
916 			pr_err("%s: ERROR: no memory", __func__);
917 			ret = -ENOMEM;
918 			goto err;
919 		}
920 		pdev->dev.platform_data = pdata;
921 		ret = spear_smi_probe_config_dt(pdev, np);
922 		if (ret) {
923 			ret = -ENODEV;
924 			dev_err(&pdev->dev, "no platform data\n");
925 			goto err;
926 		}
927 	} else {
928 		pdata = dev_get_platdata(&pdev->dev);
929 		if (!pdata) {
930 			ret = -ENODEV;
931 			dev_err(&pdev->dev, "no platform data\n");
932 			goto err;
933 		}
934 	}
935 
936 	irq = platform_get_irq(pdev, 0);
937 	if (irq < 0) {
938 		ret = -ENODEV;
939 		dev_err(&pdev->dev, "invalid smi irq\n");
940 		goto err;
941 	}
942 
943 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_ATOMIC);
944 	if (!dev) {
945 		ret = -ENOMEM;
946 		dev_err(&pdev->dev, "mem alloc fail\n");
947 		goto err;
948 	}
949 
950 	smi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
951 
952 	dev->io_base = devm_ioremap_resource(&pdev->dev, smi_base);
953 	if (IS_ERR(dev->io_base)) {
954 		ret = PTR_ERR(dev->io_base);
955 		goto err;
956 	}
957 
958 	dev->pdev = pdev;
959 	dev->clk_rate = pdata->clk_rate;
960 
961 	if (dev->clk_rate > SMI_MAX_CLOCK_FREQ)
962 		dev->clk_rate = SMI_MAX_CLOCK_FREQ;
963 
964 	dev->num_flashes = pdata->num_flashes;
965 
966 	if (dev->num_flashes > MAX_NUM_FLASH_CHIP) {
967 		dev_err(&pdev->dev, "exceeding max number of flashes\n");
968 		dev->num_flashes = MAX_NUM_FLASH_CHIP;
969 	}
970 
971 	dev->clk = devm_clk_get(&pdev->dev, NULL);
972 	if (IS_ERR(dev->clk)) {
973 		ret = PTR_ERR(dev->clk);
974 		goto err;
975 	}
976 
977 	ret = clk_prepare_enable(dev->clk);
978 	if (ret)
979 		goto err;
980 
981 	ret = devm_request_irq(&pdev->dev, irq, spear_smi_int_handler, 0,
982 			       pdev->name, dev);
983 	if (ret) {
984 		dev_err(&dev->pdev->dev, "SMI IRQ allocation failed\n");
985 		goto err_irq;
986 	}
987 
988 	mutex_init(&dev->lock);
989 	init_waitqueue_head(&dev->cmd_complete);
990 	spear_smi_hw_init(dev);
991 	platform_set_drvdata(pdev, dev);
992 
993 	/* loop for each serial nor-flash which is connected to smi */
994 	for (i = 0; i < dev->num_flashes; i++) {
995 		ret = spear_smi_setup_banks(pdev, i, pdata->np[i]);
996 		if (ret) {
997 			dev_err(&dev->pdev->dev, "bank setup failed\n");
998 			goto err_irq;
999 		}
1000 	}
1001 
1002 	return 0;
1003 
1004 err_irq:
1005 	clk_disable_unprepare(dev->clk);
1006 err:
1007 	return ret;
1008 }
1009 
1010 /**
1011  * spear_smi_remove - Exit routine
1012  * @pdev: platform device structure
1013  *
1014  * free all allocations and delete the partitions.
1015  */
1016 static int spear_smi_remove(struct platform_device *pdev)
1017 {
1018 	struct spear_smi *dev;
1019 	struct spear_snor_flash *flash;
1020 	int ret, i;
1021 
1022 	dev = platform_get_drvdata(pdev);
1023 	if (!dev) {
1024 		dev_err(&pdev->dev, "dev is null\n");
1025 		return -ENODEV;
1026 	}
1027 
1028 	/* clean up for all nor flash */
1029 	for (i = 0; i < dev->num_flashes; i++) {
1030 		flash = dev->flash[i];
1031 		if (!flash)
1032 			continue;
1033 
1034 		/* clean up mtd stuff */
1035 		ret = mtd_device_unregister(&flash->mtd);
1036 		if (ret)
1037 			dev_err(&pdev->dev, "error removing mtd\n");
1038 	}
1039 
1040 	clk_disable_unprepare(dev->clk);
1041 
1042 	return 0;
1043 }
1044 
1045 #ifdef CONFIG_PM_SLEEP
1046 static int spear_smi_suspend(struct device *dev)
1047 {
1048 	struct spear_smi *sdev = dev_get_drvdata(dev);
1049 
1050 	if (sdev && sdev->clk)
1051 		clk_disable_unprepare(sdev->clk);
1052 
1053 	return 0;
1054 }
1055 
1056 static int spear_smi_resume(struct device *dev)
1057 {
1058 	struct spear_smi *sdev = dev_get_drvdata(dev);
1059 	int ret = -EPERM;
1060 
1061 	if (sdev && sdev->clk)
1062 		ret = clk_prepare_enable(sdev->clk);
1063 
1064 	if (!ret)
1065 		spear_smi_hw_init(sdev);
1066 	return ret;
1067 }
1068 #endif
1069 
1070 static SIMPLE_DEV_PM_OPS(spear_smi_pm_ops, spear_smi_suspend, spear_smi_resume);
1071 
1072 #ifdef CONFIG_OF
1073 static const struct of_device_id spear_smi_id_table[] = {
1074 	{ .compatible = "st,spear600-smi" },
1075 	{}
1076 };
1077 MODULE_DEVICE_TABLE(of, spear_smi_id_table);
1078 #endif
1079 
1080 static struct platform_driver spear_smi_driver = {
1081 	.driver = {
1082 		.name = "smi",
1083 		.bus = &platform_bus_type,
1084 		.owner = THIS_MODULE,
1085 		.of_match_table = of_match_ptr(spear_smi_id_table),
1086 		.pm = &spear_smi_pm_ops,
1087 	},
1088 	.probe = spear_smi_probe,
1089 	.remove = spear_smi_remove,
1090 };
1091 module_platform_driver(spear_smi_driver);
1092 
1093 MODULE_LICENSE("GPL");
1094 MODULE_AUTHOR("Ashish Priyadarshi, Shiraz Hashim <shiraz.hashim@st.com>");
1095 MODULE_DESCRIPTION("MTD SMI driver for serial nor flash chips");
1096