xref: /openbmc/linux/drivers/spi/spi-zynq-qspi.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2019 Xilinx, Inc.
4  *
5  * Author: Naga Sureshkumar Relli <nagasure@xilinx.com>
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/gpio.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/of_irq.h>
15 #include <linux/of_address.h>
16 #include <linux/platform_device.h>
17 #include <linux/spi/spi.h>
18 #include <linux/workqueue.h>
19 #include <linux/spi/spi-mem.h>
20 
21 /* Register offset definitions */
22 #define ZYNQ_QSPI_CONFIG_OFFSET		0x00 /* Configuration  Register, RW */
23 #define ZYNQ_QSPI_STATUS_OFFSET		0x04 /* Interrupt Status Register, RO */
24 #define ZYNQ_QSPI_IEN_OFFSET		0x08 /* Interrupt Enable Register, WO */
25 #define ZYNQ_QSPI_IDIS_OFFSET		0x0C /* Interrupt Disable Reg, WO */
26 #define ZYNQ_QSPI_IMASK_OFFSET		0x10 /* Interrupt Enabled Mask Reg,RO */
27 #define ZYNQ_QSPI_ENABLE_OFFSET		0x14 /* Enable/Disable Register, RW */
28 #define ZYNQ_QSPI_DELAY_OFFSET		0x18 /* Delay Register, RW */
29 #define ZYNQ_QSPI_TXD_00_00_OFFSET	0x1C /* Transmit 4-byte inst, WO */
30 #define ZYNQ_QSPI_TXD_00_01_OFFSET	0x80 /* Transmit 1-byte inst, WO */
31 #define ZYNQ_QSPI_TXD_00_10_OFFSET	0x84 /* Transmit 2-byte inst, WO */
32 #define ZYNQ_QSPI_TXD_00_11_OFFSET	0x88 /* Transmit 3-byte inst, WO */
33 #define ZYNQ_QSPI_RXD_OFFSET		0x20 /* Data Receive Register, RO */
34 #define ZYNQ_QSPI_SIC_OFFSET		0x24 /* Slave Idle Count Register, RW */
35 #define ZYNQ_QSPI_TX_THRESH_OFFSET	0x28 /* TX FIFO Watermark Reg, RW */
36 #define ZYNQ_QSPI_RX_THRESH_OFFSET	0x2C /* RX FIFO Watermark Reg, RW */
37 #define ZYNQ_QSPI_GPIO_OFFSET		0x30 /* GPIO Register, RW */
38 #define ZYNQ_QSPI_LINEAR_CFG_OFFSET	0xA0 /* Linear Adapter Config Ref, RW */
39 #define ZYNQ_QSPI_MOD_ID_OFFSET		0xFC /* Module ID Register, RO */
40 
41 /*
42  * QSPI Configuration Register bit Masks
43  *
44  * This register contains various control bits that effect the operation
45  * of the QSPI controller
46  */
47 #define ZYNQ_QSPI_CONFIG_IFMODE_MASK	BIT(31) /* Flash Memory Interface */
48 #define ZYNQ_QSPI_CONFIG_MANSRT_MASK	BIT(16) /* Manual TX Start */
49 #define ZYNQ_QSPI_CONFIG_MANSRTEN_MASK	BIT(15) /* Enable Manual TX Mode */
50 #define ZYNQ_QSPI_CONFIG_SSFORCE_MASK	BIT(14) /* Manual Chip Select */
51 #define ZYNQ_QSPI_CONFIG_BDRATE_MASK	GENMASK(5, 3) /* Baud Rate Mask */
52 #define ZYNQ_QSPI_CONFIG_CPHA_MASK	BIT(2) /* Clock Phase Control */
53 #define ZYNQ_QSPI_CONFIG_CPOL_MASK	BIT(1) /* Clock Polarity Control */
54 #define ZYNQ_QSPI_CONFIG_SSCTRL_MASK	BIT(10) /* Slave Select Mask */
55 #define ZYNQ_QSPI_CONFIG_FWIDTH_MASK	GENMASK(7, 6) /* FIFO width */
56 #define ZYNQ_QSPI_CONFIG_MSTREN_MASK	BIT(0) /* Master Mode */
57 
58 /*
59  * QSPI Configuration Register - Baud rate and slave select
60  *
61  * These are the values used in the calculation of baud rate divisor and
62  * setting the slave select.
63  */
64 #define ZYNQ_QSPI_BAUD_DIV_MAX		GENMASK(2, 0) /* Baud rate maximum */
65 #define ZYNQ_QSPI_BAUD_DIV_SHIFT	3 /* Baud rate divisor shift in CR */
66 #define ZYNQ_QSPI_SS_SHIFT		10 /* Slave Select field shift in CR */
67 
68 /*
69  * QSPI Interrupt Registers bit Masks
70  *
71  * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
72  * bit definitions.
73  */
74 #define ZYNQ_QSPI_IXR_RX_OVERFLOW_MASK	BIT(0) /* QSPI RX FIFO Overflow */
75 #define ZYNQ_QSPI_IXR_TXNFULL_MASK	BIT(2) /* QSPI TX FIFO Overflow */
76 #define ZYNQ_QSPI_IXR_TXFULL_MASK	BIT(3) /* QSPI TX FIFO is full */
77 #define ZYNQ_QSPI_IXR_RXNEMTY_MASK	BIT(4) /* QSPI RX FIFO Not Empty */
78 #define ZYNQ_QSPI_IXR_RXF_FULL_MASK	BIT(5) /* QSPI RX FIFO is full */
79 #define ZYNQ_QSPI_IXR_TXF_UNDRFLOW_MASK	BIT(6) /* QSPI TX FIFO Underflow */
80 #define ZYNQ_QSPI_IXR_ALL_MASK		(ZYNQ_QSPI_IXR_RX_OVERFLOW_MASK | \
81 					ZYNQ_QSPI_IXR_TXNFULL_MASK | \
82 					ZYNQ_QSPI_IXR_TXFULL_MASK | \
83 					ZYNQ_QSPI_IXR_RXNEMTY_MASK | \
84 					ZYNQ_QSPI_IXR_RXF_FULL_MASK | \
85 					ZYNQ_QSPI_IXR_TXF_UNDRFLOW_MASK)
86 #define ZYNQ_QSPI_IXR_RXTX_MASK		(ZYNQ_QSPI_IXR_TXNFULL_MASK | \
87 					ZYNQ_QSPI_IXR_RXNEMTY_MASK)
88 
89 /*
90  * QSPI Enable Register bit Masks
91  *
92  * This register is used to enable or disable the QSPI controller
93  */
94 #define ZYNQ_QSPI_ENABLE_ENABLE_MASK	BIT(0) /* QSPI Enable Bit Mask */
95 
96 /*
97  * QSPI Linear Configuration Register
98  *
99  * It is named Linear Configuration but it controls other modes when not in
100  * linear mode also.
101  */
102 #define ZYNQ_QSPI_LCFG_TWO_MEM_MASK	BIT(30) /* LQSPI Two memories Mask */
103 #define ZYNQ_QSPI_LCFG_SEP_BUS_MASK	BIT(29) /* LQSPI Separate bus Mask */
104 #define ZYNQ_QSPI_LCFG_U_PAGE_MASK	BIT(28) /* LQSPI Upper Page Mask */
105 
106 #define ZYNQ_QSPI_LCFG_DUMMY_SHIFT	8
107 
108 #define ZYNQ_QSPI_FAST_READ_QOUT_CODE	0x6B /* read instruction code */
109 #define ZYNQ_QSPI_FIFO_DEPTH		63 /* FIFO depth in words */
110 #define ZYNQ_QSPI_RX_THRESHOLD		32 /* Rx FIFO threshold level */
111 #define ZYNQ_QSPI_TX_THRESHOLD		1 /* Tx FIFO threshold level */
112 
113 /*
114  * The modebits configurable by the driver to make the SPI support different
115  * data formats
116  */
117 #define ZYNQ_QSPI_MODEBITS			(SPI_CPOL | SPI_CPHA)
118 
119 /* Default number of chip selects */
120 #define ZYNQ_QSPI_DEFAULT_NUM_CS	1
121 
122 /**
123  * struct zynq_qspi - Defines qspi driver instance
124  * @regs:		Virtual address of the QSPI controller registers
125  * @refclk:		Pointer to the peripheral clock
126  * @pclk:		Pointer to the APB clock
127  * @irq:		IRQ number
128  * @txbuf:		Pointer to the TX buffer
129  * @rxbuf:		Pointer to the RX buffer
130  * @tx_bytes:		Number of bytes left to transfer
131  * @rx_bytes:		Number of bytes left to receive
132  * @data_completion:	completion structure
133  */
134 struct zynq_qspi {
135 	struct device *dev;
136 	void __iomem *regs;
137 	struct clk *refclk;
138 	struct clk *pclk;
139 	int irq;
140 	u8 *txbuf;
141 	u8 *rxbuf;
142 	int tx_bytes;
143 	int rx_bytes;
144 	struct completion data_completion;
145 };
146 
147 /*
148  * Inline functions for the QSPI controller read/write
149  */
150 static inline u32 zynq_qspi_read(struct zynq_qspi *xqspi, u32 offset)
151 {
152 	return readl_relaxed(xqspi->regs + offset);
153 }
154 
155 static inline void zynq_qspi_write(struct zynq_qspi *xqspi, u32 offset,
156 				   u32 val)
157 {
158 	writel_relaxed(val, xqspi->regs + offset);
159 }
160 
161 /**
162  * zynq_qspi_init_hw - Initialize the hardware
163  * @xqspi:	Pointer to the zynq_qspi structure
164  *
165  * The default settings of the QSPI controller's configurable parameters on
166  * reset are
167  *	- Master mode
168  *	- Baud rate divisor is set to 2
169  *	- Tx threshold set to 1l Rx threshold set to 32
170  *	- Flash memory interface mode enabled
171  *	- Size of the word to be transferred as 8 bit
172  * This function performs the following actions
173  *	- Disable and clear all the interrupts
174  *	- Enable manual slave select
175  *	- Enable manual start
176  *	- Deselect all the chip select lines
177  *	- Set the size of the word to be transferred as 32 bit
178  *	- Set the little endian mode of TX FIFO and
179  *	- Enable the QSPI controller
180  */
181 static void zynq_qspi_init_hw(struct zynq_qspi *xqspi)
182 {
183 	u32 config_reg;
184 
185 	zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET, 0);
186 	zynq_qspi_write(xqspi, ZYNQ_QSPI_IDIS_OFFSET, ZYNQ_QSPI_IXR_ALL_MASK);
187 
188 	/* Disable linear mode as the boot loader may have used it */
189 	zynq_qspi_write(xqspi, ZYNQ_QSPI_LINEAR_CFG_OFFSET, 0);
190 
191 	/* Clear the RX FIFO */
192 	while (zynq_qspi_read(xqspi, ZYNQ_QSPI_STATUS_OFFSET) &
193 			      ZYNQ_QSPI_IXR_RXNEMTY_MASK)
194 		zynq_qspi_read(xqspi, ZYNQ_QSPI_RXD_OFFSET);
195 
196 	zynq_qspi_write(xqspi, ZYNQ_QSPI_STATUS_OFFSET, ZYNQ_QSPI_IXR_ALL_MASK);
197 	config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
198 	config_reg &= ~(ZYNQ_QSPI_CONFIG_MSTREN_MASK |
199 			ZYNQ_QSPI_CONFIG_CPOL_MASK |
200 			ZYNQ_QSPI_CONFIG_CPHA_MASK |
201 			ZYNQ_QSPI_CONFIG_BDRATE_MASK |
202 			ZYNQ_QSPI_CONFIG_SSFORCE_MASK |
203 			ZYNQ_QSPI_CONFIG_MANSRTEN_MASK |
204 			ZYNQ_QSPI_CONFIG_MANSRT_MASK);
205 	config_reg |= (ZYNQ_QSPI_CONFIG_MSTREN_MASK |
206 		       ZYNQ_QSPI_CONFIG_SSFORCE_MASK |
207 		       ZYNQ_QSPI_CONFIG_FWIDTH_MASK |
208 		       ZYNQ_QSPI_CONFIG_IFMODE_MASK);
209 	zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
210 
211 	zynq_qspi_write(xqspi, ZYNQ_QSPI_RX_THRESH_OFFSET,
212 			ZYNQ_QSPI_RX_THRESHOLD);
213 	zynq_qspi_write(xqspi, ZYNQ_QSPI_TX_THRESH_OFFSET,
214 			ZYNQ_QSPI_TX_THRESHOLD);
215 
216 	zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET,
217 			ZYNQ_QSPI_ENABLE_ENABLE_MASK);
218 }
219 
220 static bool zynq_qspi_supports_op(struct spi_mem *mem,
221 				  const struct spi_mem_op *op)
222 {
223 	if (!spi_mem_default_supports_op(mem, op))
224 		return false;
225 
226 	/*
227 	 * The number of address bytes should be equal to or less than 3 bytes.
228 	 */
229 	if (op->addr.nbytes > 3)
230 		return false;
231 
232 	return true;
233 }
234 
235 /**
236  * zynq_qspi_rxfifo_op - Read 1..4 bytes from RxFIFO to RX buffer
237  * @xqspi:	Pointer to the zynq_qspi structure
238  * @size:	Number of bytes to be read (1..4)
239  */
240 static void zynq_qspi_rxfifo_op(struct zynq_qspi *xqspi, unsigned int size)
241 {
242 	u32 data;
243 
244 	data = zynq_qspi_read(xqspi, ZYNQ_QSPI_RXD_OFFSET);
245 
246 	if (xqspi->rxbuf) {
247 		memcpy(xqspi->rxbuf, ((u8 *)&data) + 4 - size, size);
248 		xqspi->rxbuf += size;
249 	}
250 
251 	xqspi->rx_bytes -= size;
252 	if (xqspi->rx_bytes < 0)
253 		xqspi->rx_bytes = 0;
254 }
255 
256 /**
257  * zynq_qspi_txfifo_op - Write 1..4 bytes from TX buffer to TxFIFO
258  * @xqspi:	Pointer to the zynq_qspi structure
259  * @size:	Number of bytes to be written (1..4)
260  */
261 static void zynq_qspi_txfifo_op(struct zynq_qspi *xqspi, unsigned int size)
262 {
263 	static const unsigned int offset[4] = {
264 		ZYNQ_QSPI_TXD_00_01_OFFSET, ZYNQ_QSPI_TXD_00_10_OFFSET,
265 		ZYNQ_QSPI_TXD_00_11_OFFSET, ZYNQ_QSPI_TXD_00_00_OFFSET };
266 	u32 data;
267 
268 	if (xqspi->txbuf) {
269 		data = 0xffffffff;
270 		memcpy(&data, xqspi->txbuf, size);
271 		xqspi->txbuf += size;
272 	} else {
273 		data = 0;
274 	}
275 
276 	xqspi->tx_bytes -= size;
277 	zynq_qspi_write(xqspi, offset[size - 1], data);
278 }
279 
280 /**
281  * zynq_qspi_chipselect - Select or deselect the chip select line
282  * @spi:	Pointer to the spi_device structure
283  * @assert:	1 for select or 0 for deselect the chip select line
284  */
285 static void zynq_qspi_chipselect(struct spi_device *spi, bool assert)
286 {
287 	struct spi_controller *ctrl = spi->master;
288 	struct zynq_qspi *xqspi = spi_controller_get_devdata(ctrl);
289 	u32 config_reg;
290 
291 	config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
292 	if (assert) {
293 		/* Select the slave */
294 		config_reg &= ~ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
295 		config_reg |= (((~(BIT(spi->chip_select))) <<
296 				ZYNQ_QSPI_SS_SHIFT) &
297 				ZYNQ_QSPI_CONFIG_SSCTRL_MASK);
298 	} else {
299 		config_reg |= ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
300 	}
301 
302 	zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
303 }
304 
305 /**
306  * zynq_qspi_config_op - Configure QSPI controller for specified transfer
307  * @xqspi:	Pointer to the zynq_qspi structure
308  * @qspi:	Pointer to the spi_device structure
309  *
310  * Sets the operational mode of QSPI controller for the next QSPI transfer and
311  * sets the requested clock frequency.
312  *
313  * Return:	0 on success and -EINVAL on invalid input parameter
314  *
315  * Note: If the requested frequency is not an exact match with what can be
316  * obtained using the prescalar value, the driver sets the clock frequency which
317  * is lower than the requested frequency (maximum lower) for the transfer. If
318  * the requested frequency is higher or lower than that is supported by the QSPI
319  * controller the driver will set the highest or lowest frequency supported by
320  * controller.
321  */
322 static int zynq_qspi_config_op(struct zynq_qspi *xqspi, struct spi_device *spi)
323 {
324 	u32 config_reg, baud_rate_val = 0;
325 
326 	/*
327 	 * Set the clock frequency
328 	 * The baud rate divisor is not a direct mapping to the value written
329 	 * into the configuration register (config_reg[5:3])
330 	 * i.e. 000 - divide by 2
331 	 *      001 - divide by 4
332 	 *      ----------------
333 	 *      111 - divide by 256
334 	 */
335 	while ((baud_rate_val < ZYNQ_QSPI_BAUD_DIV_MAX)  &&
336 	       (clk_get_rate(xqspi->refclk) / (2 << baud_rate_val)) >
337 		spi->max_speed_hz)
338 		baud_rate_val++;
339 
340 	config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
341 
342 	/* Set the QSPI clock phase and clock polarity */
343 	config_reg &= (~ZYNQ_QSPI_CONFIG_CPHA_MASK) &
344 		      (~ZYNQ_QSPI_CONFIG_CPOL_MASK);
345 	if (spi->mode & SPI_CPHA)
346 		config_reg |= ZYNQ_QSPI_CONFIG_CPHA_MASK;
347 	if (spi->mode & SPI_CPOL)
348 		config_reg |= ZYNQ_QSPI_CONFIG_CPOL_MASK;
349 
350 	config_reg &= ~ZYNQ_QSPI_CONFIG_BDRATE_MASK;
351 	config_reg |= (baud_rate_val << ZYNQ_QSPI_BAUD_DIV_SHIFT);
352 	zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
353 
354 	return 0;
355 }
356 
357 /**
358  * zynq_qspi_setup - Configure the QSPI controller
359  * @spi:	Pointer to the spi_device structure
360  *
361  * Sets the operational mode of QSPI controller for the next QSPI transfer, baud
362  * rate and divisor value to setup the requested qspi clock.
363  *
364  * Return:	0 on success and error value on failure
365  */
366 static int zynq_qspi_setup_op(struct spi_device *spi)
367 {
368 	struct spi_controller *ctrl = spi->master;
369 	struct zynq_qspi *qspi = spi_controller_get_devdata(ctrl);
370 
371 	if (ctrl->busy)
372 		return -EBUSY;
373 
374 	clk_enable(qspi->refclk);
375 	clk_enable(qspi->pclk);
376 	zynq_qspi_write(qspi, ZYNQ_QSPI_ENABLE_OFFSET,
377 			ZYNQ_QSPI_ENABLE_ENABLE_MASK);
378 
379 	return 0;
380 }
381 
382 /**
383  * zynq_qspi_write_op - Fills the TX FIFO with as many bytes as possible
384  * @xqspi:	Pointer to the zynq_qspi structure
385  * @txcount:	Maximum number of words to write
386  * @txempty:	Indicates that TxFIFO is empty
387  */
388 static void zynq_qspi_write_op(struct zynq_qspi *xqspi, int txcount,
389 			       bool txempty)
390 {
391 	int count, len, k;
392 
393 	len = xqspi->tx_bytes;
394 	if (len && len < 4) {
395 		/*
396 		 * We must empty the TxFIFO between accesses to TXD0,
397 		 * TXD1, TXD2, TXD3.
398 		 */
399 		if (txempty)
400 			zynq_qspi_txfifo_op(xqspi, len);
401 
402 		return;
403 	}
404 
405 	count = len / 4;
406 	if (count > txcount)
407 		count = txcount;
408 
409 	if (xqspi->txbuf) {
410 		iowrite32_rep(xqspi->regs + ZYNQ_QSPI_TXD_00_00_OFFSET,
411 			      xqspi->txbuf, count);
412 		xqspi->txbuf += count * 4;
413 	} else {
414 		for (k = 0; k < count; k++)
415 			writel_relaxed(0, xqspi->regs +
416 					  ZYNQ_QSPI_TXD_00_00_OFFSET);
417 	}
418 
419 	xqspi->tx_bytes -= count * 4;
420 }
421 
422 /**
423  * zynq_qspi_read_op - Drains the RX FIFO by as many bytes as possible
424  * @xqspi:	Pointer to the zynq_qspi structure
425  * @rxcount:	Maximum number of words to read
426  */
427 static void zynq_qspi_read_op(struct zynq_qspi *xqspi, int rxcount)
428 {
429 	int count, len, k;
430 
431 	len = xqspi->rx_bytes - xqspi->tx_bytes;
432 	count = len / 4;
433 	if (count > rxcount)
434 		count = rxcount;
435 	if (xqspi->rxbuf) {
436 		ioread32_rep(xqspi->regs + ZYNQ_QSPI_RXD_OFFSET,
437 			     xqspi->rxbuf, count);
438 		xqspi->rxbuf += count * 4;
439 	} else {
440 		for (k = 0; k < count; k++)
441 			readl_relaxed(xqspi->regs + ZYNQ_QSPI_RXD_OFFSET);
442 	}
443 	xqspi->rx_bytes -= count * 4;
444 	len -= count * 4;
445 
446 	if (len && len < 4 && count < rxcount)
447 		zynq_qspi_rxfifo_op(xqspi, len);
448 }
449 
450 /**
451  * zynq_qspi_irq - Interrupt service routine of the QSPI controller
452  * @irq:	IRQ number
453  * @dev_id:	Pointer to the xqspi structure
454  *
455  * This function handles TX empty only.
456  * On TX empty interrupt this function reads the received data from RX FIFO and
457  * fills the TX FIFO if there is any data remaining to be transferred.
458  *
459  * Return:	IRQ_HANDLED when interrupt is handled; IRQ_NONE otherwise.
460  */
461 static irqreturn_t zynq_qspi_irq(int irq, void *dev_id)
462 {
463 	u32 intr_status;
464 	bool txempty;
465 	struct zynq_qspi *xqspi = (struct zynq_qspi *)dev_id;
466 
467 	intr_status = zynq_qspi_read(xqspi, ZYNQ_QSPI_STATUS_OFFSET);
468 	zynq_qspi_write(xqspi, ZYNQ_QSPI_STATUS_OFFSET, intr_status);
469 
470 	if ((intr_status & ZYNQ_QSPI_IXR_TXNFULL_MASK) ||
471 	    (intr_status & ZYNQ_QSPI_IXR_RXNEMTY_MASK)) {
472 		/*
473 		 * This bit is set when Tx FIFO has < THRESHOLD entries.
474 		 * We have the THRESHOLD value set to 1,
475 		 * so this bit indicates Tx FIFO is empty.
476 		 */
477 		txempty = !!(intr_status & ZYNQ_QSPI_IXR_TXNFULL_MASK);
478 		/* Read out the data from the RX FIFO */
479 		zynq_qspi_read_op(xqspi, ZYNQ_QSPI_RX_THRESHOLD);
480 		if (xqspi->tx_bytes) {
481 			/* There is more data to send */
482 			zynq_qspi_write_op(xqspi, ZYNQ_QSPI_RX_THRESHOLD,
483 					   txempty);
484 		} else {
485 			/*
486 			 * If transfer and receive is completed then only send
487 			 * complete signal.
488 			 */
489 			if (!xqspi->rx_bytes) {
490 				zynq_qspi_write(xqspi,
491 						ZYNQ_QSPI_IDIS_OFFSET,
492 						ZYNQ_QSPI_IXR_RXTX_MASK);
493 				complete(&xqspi->data_completion);
494 			}
495 		}
496 		return IRQ_HANDLED;
497 	}
498 
499 	return IRQ_NONE;
500 }
501 
502 /**
503  * zynq_qspi_exec_mem_op() - Initiates the QSPI transfer
504  * @mem: the SPI memory
505  * @op: the memory operation to execute
506  *
507  * Executes a memory operation.
508  *
509  * This function first selects the chip and starts the memory operation.
510  *
511  * Return: 0 in case of success, a negative error code otherwise.
512  */
513 static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
514 				 const struct spi_mem_op *op)
515 {
516 	struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
517 	int err = 0, i;
518 	u8 *tmpbuf;
519 
520 	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
521 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
522 		op->dummy.buswidth, op->data.buswidth);
523 
524 	zynq_qspi_chipselect(mem->spi, true);
525 	zynq_qspi_config_op(xqspi, mem->spi);
526 
527 	if (op->cmd.opcode) {
528 		reinit_completion(&xqspi->data_completion);
529 		xqspi->txbuf = (u8 *)&op->cmd.opcode;
530 		xqspi->rxbuf = NULL;
531 		xqspi->tx_bytes = sizeof(op->cmd.opcode);
532 		xqspi->rx_bytes = sizeof(op->cmd.opcode);
533 		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
534 		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
535 				ZYNQ_QSPI_IXR_RXTX_MASK);
536 		if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
537 							       msecs_to_jiffies(1000)))
538 			err = -ETIMEDOUT;
539 	}
540 
541 	if (op->addr.nbytes) {
542 		for (i = 0; i < op->addr.nbytes; i++) {
543 			xqspi->txbuf[i] = op->addr.val >>
544 					(8 * (op->addr.nbytes - i - 1));
545 		}
546 
547 		reinit_completion(&xqspi->data_completion);
548 		xqspi->rxbuf = NULL;
549 		xqspi->tx_bytes = op->addr.nbytes;
550 		xqspi->rx_bytes = op->addr.nbytes;
551 		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
552 		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
553 				ZYNQ_QSPI_IXR_RXTX_MASK);
554 		if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
555 							       msecs_to_jiffies(1000)))
556 			err = -ETIMEDOUT;
557 	}
558 
559 	if (op->dummy.nbytes) {
560 		tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
561 		memset(tmpbuf, 0xff, op->dummy.nbytes);
562 		reinit_completion(&xqspi->data_completion);
563 		xqspi->txbuf = tmpbuf;
564 		xqspi->rxbuf = NULL;
565 		xqspi->tx_bytes = op->dummy.nbytes;
566 		xqspi->rx_bytes = op->dummy.nbytes;
567 		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
568 		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
569 				ZYNQ_QSPI_IXR_RXTX_MASK);
570 		if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
571 							       msecs_to_jiffies(1000)))
572 			err = -ETIMEDOUT;
573 
574 		kfree(tmpbuf);
575 	}
576 
577 	if (op->data.nbytes) {
578 		reinit_completion(&xqspi->data_completion);
579 		if (op->data.dir == SPI_MEM_DATA_OUT) {
580 			xqspi->txbuf = (u8 *)op->data.buf.out;
581 			xqspi->tx_bytes = op->data.nbytes;
582 			xqspi->rxbuf = NULL;
583 			xqspi->rx_bytes = op->data.nbytes;
584 		} else {
585 			xqspi->txbuf = NULL;
586 			xqspi->rxbuf = (u8 *)op->data.buf.in;
587 			xqspi->rx_bytes = op->data.nbytes;
588 			xqspi->tx_bytes = op->data.nbytes;
589 		}
590 
591 		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
592 		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
593 				ZYNQ_QSPI_IXR_RXTX_MASK);
594 		if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
595 							       msecs_to_jiffies(1000)))
596 			err = -ETIMEDOUT;
597 	}
598 	zynq_qspi_chipselect(mem->spi, false);
599 
600 	return err;
601 }
602 
603 static const struct spi_controller_mem_ops zynq_qspi_mem_ops = {
604 	.supports_op = zynq_qspi_supports_op,
605 	.exec_op = zynq_qspi_exec_mem_op,
606 };
607 
608 /**
609  * zynq_qspi_probe - Probe method for the QSPI driver
610  * @pdev:	Pointer to the platform_device structure
611  *
612  * This function initializes the driver data structures and the hardware.
613  *
614  * Return:	0 on success and error value on failure
615  */
616 static int zynq_qspi_probe(struct platform_device *pdev)
617 {
618 	int ret = 0;
619 	struct spi_controller *ctlr;
620 	struct device *dev = &pdev->dev;
621 	struct device_node *np = dev->of_node;
622 	struct zynq_qspi *xqspi;
623 	struct resource *res;
624 	u32 num_cs;
625 
626 	ctlr = spi_alloc_master(&pdev->dev, sizeof(*xqspi));
627 	if (!ctlr)
628 		return -ENOMEM;
629 
630 	xqspi = spi_controller_get_devdata(ctlr);
631 	xqspi->dev = dev;
632 	platform_set_drvdata(pdev, xqspi);
633 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
634 	xqspi->regs = devm_ioremap_resource(&pdev->dev, res);
635 	if (IS_ERR(xqspi->regs)) {
636 		ret = PTR_ERR(xqspi->regs);
637 		goto remove_master;
638 	}
639 
640 	xqspi->pclk = devm_clk_get(&pdev->dev, "pclk");
641 	if (IS_ERR(xqspi->pclk)) {
642 		dev_err(&pdev->dev, "pclk clock not found.\n");
643 		ret = PTR_ERR(xqspi->pclk);
644 		goto remove_master;
645 	}
646 
647 	init_completion(&xqspi->data_completion);
648 
649 	xqspi->refclk = devm_clk_get(&pdev->dev, "ref_clk");
650 	if (IS_ERR(xqspi->refclk)) {
651 		dev_err(&pdev->dev, "ref_clk clock not found.\n");
652 		ret = PTR_ERR(xqspi->refclk);
653 		goto remove_master;
654 	}
655 
656 	ret = clk_prepare_enable(xqspi->pclk);
657 	if (ret) {
658 		dev_err(&pdev->dev, "Unable to enable APB clock.\n");
659 		goto remove_master;
660 	}
661 
662 	ret = clk_prepare_enable(xqspi->refclk);
663 	if (ret) {
664 		dev_err(&pdev->dev, "Unable to enable device clock.\n");
665 		goto clk_dis_pclk;
666 	}
667 
668 	/* QSPI controller initializations */
669 	zynq_qspi_init_hw(xqspi);
670 
671 	xqspi->irq = platform_get_irq(pdev, 0);
672 	if (xqspi->irq <= 0) {
673 		ret = -ENXIO;
674 		dev_err(&pdev->dev, "irq resource not found\n");
675 		goto remove_master;
676 	}
677 	ret = devm_request_irq(&pdev->dev, xqspi->irq, zynq_qspi_irq,
678 			       0, pdev->name, xqspi);
679 	if (ret != 0) {
680 		ret = -ENXIO;
681 		dev_err(&pdev->dev, "request_irq failed\n");
682 		goto remove_master;
683 	}
684 
685 	ret = of_property_read_u32(np, "num-cs",
686 				   &num_cs);
687 	if (ret < 0)
688 		ctlr->num_chipselect = ZYNQ_QSPI_DEFAULT_NUM_CS;
689 	else
690 		ctlr->num_chipselect = num_cs;
691 
692 	ctlr->mode_bits =  SPI_RX_DUAL | SPI_RX_QUAD |
693 			    SPI_TX_DUAL | SPI_TX_QUAD;
694 	ctlr->mem_ops = &zynq_qspi_mem_ops;
695 	ctlr->setup = zynq_qspi_setup_op;
696 	ctlr->max_speed_hz = clk_get_rate(xqspi->refclk) / 2;
697 	ctlr->dev.of_node = np;
698 	ret = spi_register_controller(ctlr);
699 	if (ret) {
700 		dev_err(&pdev->dev, "spi_register_master failed\n");
701 		goto clk_dis_all;
702 	}
703 
704 	return ret;
705 
706 clk_dis_all:
707 	clk_disable_unprepare(xqspi->refclk);
708 clk_dis_pclk:
709 	clk_disable_unprepare(xqspi->pclk);
710 remove_master:
711 	spi_controller_put(ctlr);
712 
713 	return ret;
714 }
715 
716 /**
717  * zynq_qspi_remove - Remove method for the QSPI driver
718  * @pdev:	Pointer to the platform_device structure
719  *
720  * This function is called if a device is physically removed from the system or
721  * if the driver module is being unloaded. It frees all resources allocated to
722  * the device.
723  *
724  * Return:	0 on success and error value on failure
725  */
726 static int zynq_qspi_remove(struct platform_device *pdev)
727 {
728 	struct zynq_qspi *xqspi = platform_get_drvdata(pdev);
729 
730 	zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET, 0);
731 
732 	clk_disable_unprepare(xqspi->refclk);
733 	clk_disable_unprepare(xqspi->pclk);
734 
735 	return 0;
736 }
737 
738 static const struct of_device_id zynq_qspi_of_match[] = {
739 	{ .compatible = "xlnx,zynq-qspi-1.0", },
740 	{ /* end of table */ }
741 };
742 
743 MODULE_DEVICE_TABLE(of, zynq_qspi_of_match);
744 
745 /*
746  * zynq_qspi_driver - This structure defines the QSPI platform driver
747  */
748 static struct platform_driver zynq_qspi_driver = {
749 	.probe = zynq_qspi_probe,
750 	.remove = zynq_qspi_remove,
751 	.driver = {
752 		.name = "zynq-qspi",
753 		.of_match_table = zynq_qspi_of_match,
754 	},
755 };
756 
757 module_platform_driver(zynq_qspi_driver);
758 
759 MODULE_AUTHOR("Xilinx, Inc.");
760 MODULE_DESCRIPTION("Xilinx Zynq QSPI driver");
761 MODULE_LICENSE("GPL");
762