summaryrefslogtreecommitdiff
path: root/drivers/spi/spi-hisi-kunpeng.c
blob: 3f986ba1c328c5d7a6679198b7ac704ac66d2c20 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
// SPDX-License-Identifier: GPL-2.0-only
//
// HiSilicon SPI Controller Driver for Kunpeng SoCs
//
// Copyright (c) 2021 HiSilicon Technologies Co., Ltd.
// Author: Jay Fang <f.fangjian@huawei.com>
//
// This code is based on spi-dw-core.c.

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>

/* Register offsets */
#define HISI_SPI_CSCR		0x00	/* cs control register */
#define HISI_SPI_CR		0x04	/* spi common control register */
#define HISI_SPI_ENR		0x08	/* spi enable register */
#define HISI_SPI_FIFOC		0x0c	/* fifo level control register */
#define HISI_SPI_IMR		0x10	/* interrupt mask register */
#define HISI_SPI_DIN		0x14	/* data in register */
#define HISI_SPI_DOUT		0x18	/* data out register */
#define HISI_SPI_SR		0x1c	/* status register */
#define HISI_SPI_RISR		0x20	/* raw interrupt status register */
#define HISI_SPI_ISR		0x24	/* interrupt status register */
#define HISI_SPI_ICR		0x28	/* interrupt clear register */
#define HISI_SPI_VERSION	0xe0	/* version register */

/* Bit fields in HISI_SPI_CR */
#define CR_LOOP_MASK		GENMASK(1, 1)
#define CR_CPOL_MASK		GENMASK(2, 2)
#define CR_CPHA_MASK		GENMASK(3, 3)
#define CR_DIV_PRE_MASK		GENMASK(11, 4)
#define CR_DIV_POST_MASK	GENMASK(19, 12)
#define CR_BPW_MASK		GENMASK(24, 20)
#define CR_SPD_MODE_MASK	GENMASK(25, 25)

/* Bit fields in HISI_SPI_FIFOC */
#define FIFOC_TX_MASK		GENMASK(5, 3)
#define FIFOC_RX_MASK		GENMASK(11, 9)

/* Bit fields in HISI_SPI_IMR, 4 bits */
#define IMR_RXOF		BIT(0)		/* Receive Overflow */
#define IMR_RXTO		BIT(1)		/* Receive Timeout */
#define IMR_RX			BIT(2)		/* Receive */
#define IMR_TX			BIT(3)		/* Transmit */
#define IMR_MASK		(IMR_RXOF | IMR_RXTO | IMR_RX | IMR_TX)

/* Bit fields in HISI_SPI_SR, 5 bits */
#define SR_TXE			BIT(0)		/* Transmit FIFO empty */
#define SR_TXNF			BIT(1)		/* Transmit FIFO not full */
#define SR_RXNE			BIT(2)		/* Receive FIFO not empty */
#define SR_RXF			BIT(3)		/* Receive FIFO full */
#define SR_BUSY			BIT(4)		/* Busy Flag */

/* Bit fields in HISI_SPI_ISR, 4 bits */
#define ISR_RXOF		BIT(0)		/* Receive Overflow */
#define ISR_RXTO		BIT(1)		/* Receive Timeout */
#define ISR_RX			BIT(2)		/* Receive */
#define ISR_TX			BIT(3)		/* Transmit */
#define ISR_MASK		(ISR_RXOF | ISR_RXTO | ISR_RX | ISR_TX)

/* Bit fields in HISI_SPI_ICR, 2 bits */
#define ICR_RXOF		BIT(0)		/* Receive Overflow */
#define ICR_RXTO		BIT(1)		/* Receive Timeout */
#define ICR_MASK		(ICR_RXOF | ICR_RXTO)

#define DIV_POST_MAX		0xFF
#define DIV_POST_MIN		0x00
#define DIV_PRE_MAX		0xFE
#define DIV_PRE_MIN		0x02
#define CLK_DIV_MAX		((1 + DIV_POST_MAX) * DIV_PRE_MAX)
#define CLK_DIV_MIN		((1 + DIV_POST_MIN) * DIV_PRE_MIN)

#define DEFAULT_NUM_CS		1

#define HISI_SPI_WAIT_TIMEOUT_MS	10UL

enum hisi_spi_rx_level_trig {
	HISI_SPI_RX_1,
	HISI_SPI_RX_4,
	HISI_SPI_RX_8,
	HISI_SPI_RX_16,
	HISI_SPI_RX_32,
	HISI_SPI_RX_64,
	HISI_SPI_RX_128
};

enum hisi_spi_tx_level_trig {
	HISI_SPI_TX_1_OR_LESS,
	HISI_SPI_TX_4_OR_LESS,
	HISI_SPI_TX_8_OR_LESS,
	HISI_SPI_TX_16_OR_LESS,
	HISI_SPI_TX_32_OR_LESS,
	HISI_SPI_TX_64_OR_LESS,
	HISI_SPI_TX_128_OR_LESS
};

enum hisi_spi_frame_n_bytes {
	HISI_SPI_N_BYTES_NULL,
	HISI_SPI_N_BYTES_U8,
	HISI_SPI_N_BYTES_U16,
	HISI_SPI_N_BYTES_U32 = 4
};

/* Slave spi_dev related */
struct hisi_chip_data {
	u32 cr;
	u32 speed_hz;	/* baud rate */
	u16 clk_div;	/* baud rate divider */

	/* clk_div = (1 + div_post) * div_pre */
	u8 div_post;	/* value from 0 to 255 */
	u8 div_pre;	/* value from 2 to 254 (even only!) */
};

struct hisi_spi {
	struct device		*dev;

	void __iomem		*regs;
	int			irq;
	u32			fifo_len; /* depth of the FIFO buffer */

	/* Current message transfer state info */
	const void		*tx;
	unsigned int		tx_len;
	void			*rx;
	unsigned int		rx_len;
	u8			n_bytes; /* current is a 1/2/4 bytes op */
};

static u32 hisi_spi_busy(struct hisi_spi *hs)
{
	return readl(hs->regs + HISI_SPI_SR) & SR_BUSY;
}

static u32 hisi_spi_rx_not_empty(struct hisi_spi *hs)
{
	return readl(hs->regs + HISI_SPI_SR) & SR_RXNE;
}

static u32 hisi_spi_tx_not_full(struct hisi_spi *hs)
{
	return readl(hs->regs + HISI_SPI_SR) & SR_TXNF;
}

static void hisi_spi_flush_fifo(struct hisi_spi *hs)
{
	unsigned long limit = loops_per_jiffy << 1;

	do {
		while (hisi_spi_rx_not_empty(hs))
			readl(hs->regs + HISI_SPI_DOUT);
	} while (hisi_spi_busy(hs) && limit--);
}

/* Disable the controller and all interrupts */
static void hisi_spi_disable(struct hisi_spi *hs)
{
	writel(0, hs->regs + HISI_SPI_ENR);
	writel(IMR_MASK, hs->regs + HISI_SPI_IMR);
	writel(ICR_MASK, hs->regs + HISI_SPI_ICR);
}

static u8 hisi_spi_n_bytes(struct spi_transfer *transfer)
{
	if (transfer->bits_per_word <= 8)
		return HISI_SPI_N_BYTES_U8;
	else if (transfer->bits_per_word <= 16)
		return HISI_SPI_N_BYTES_U16;
	else
		return HISI_SPI_N_BYTES_U32;
}

static void hisi_spi_reader(struct hisi_spi *hs)
{
	u32 max = min_t(u32, hs->rx_len, hs->fifo_len);
	u32 rxw;

	while (hisi_spi_rx_not_empty(hs) && max--) {
		rxw = readl(hs->regs + HISI_SPI_DOUT);
		/* Check the transfer's original "rx" is not null */
		if (hs->rx) {
			switch (hs->n_bytes) {
			case HISI_SPI_N_BYTES_U8:
				*(u8 *)(hs->rx) = rxw;
				break;
			case HISI_SPI_N_BYTES_U16:
				*(u16 *)(hs->rx) = rxw;
				break;
			case HISI_SPI_N_BYTES_U32:
				*(u32 *)(hs->rx) = rxw;
				break;
			}
			hs->rx += hs->n_bytes;
		}
		--hs->rx_len;
	}
}

static void hisi_spi_writer(struct hisi_spi *hs)
{
	u32 max = min_t(u32, hs->tx_len, hs->fifo_len);
	u32 txw = 0;

	while (hisi_spi_tx_not_full(hs) && max--) {
		/* Check the transfer's original "tx" is not null */
		if (hs->tx) {
			switch (hs->n_bytes) {
			case HISI_SPI_N_BYTES_U8:
				txw = *(u8 *)(hs->tx);
				break;
			case HISI_SPI_N_BYTES_U16:
				txw = *(u16 *)(hs->tx);
				break;
			case HISI_SPI_N_BYTES_U32:
				txw = *(u32 *)(hs->tx);
				break;
			}
			hs->tx += hs->n_bytes;
		}
		writel(txw, hs->regs + HISI_SPI_DIN);
		--hs->tx_len;
	}
}

static void __hisi_calc_div_reg(struct hisi_chip_data *chip)
{
	chip->div_pre = DIV_PRE_MAX;
	while (chip->div_pre >= DIV_PRE_MIN) {
		if (chip->clk_div % chip->div_pre == 0)
			break;

		chip->div_pre -= 2;
	}

	if (chip->div_pre > chip->clk_div)
		chip->div_pre = chip->clk_div;

	chip->div_post = (chip->clk_div / chip->div_pre) - 1;
}

static u32 hisi_calc_effective_speed(struct spi_controller *master,
			struct hisi_chip_data *chip, u32 speed_hz)
{
	u32 effective_speed;

	/* Note clock divider doesn't support odd numbers */
	chip->clk_div = DIV_ROUND_UP(master->max_speed_hz, speed_hz) + 1;
	chip->clk_div &= 0xfffe;
	if (chip->clk_div > CLK_DIV_MAX)
		chip->clk_div = CLK_DIV_MAX;

	effective_speed = master->max_speed_hz / chip->clk_div;
	if (chip->speed_hz != effective_speed) {
		__hisi_calc_div_reg(chip);
		chip->speed_hz = effective_speed;
	}

	return effective_speed;
}

static u32 hisi_spi_prepare_cr(struct spi_device *spi)
{
	u32 cr = FIELD_PREP(CR_SPD_MODE_MASK, 1);

	cr |= FIELD_PREP(CR_CPHA_MASK, (spi->mode & SPI_CPHA) ? 1 : 0);
	cr |= FIELD_PREP(CR_CPOL_MASK, (spi->mode & SPI_CPOL) ? 1 : 0);
	cr |= FIELD_PREP(CR_LOOP_MASK, (spi->mode & SPI_LOOP) ? 1 : 0);

	return cr;
}

static void hisi_spi_hw_init(struct hisi_spi *hs)
{
	hisi_spi_disable(hs);

	/* FIFO default config */
	writel(FIELD_PREP(FIFOC_TX_MASK, HISI_SPI_TX_64_OR_LESS) |
		FIELD_PREP(FIFOC_RX_MASK, HISI_SPI_RX_16),
		hs->regs + HISI_SPI_FIFOC);

	hs->fifo_len = 256;
}

static irqreturn_t hisi_spi_irq(int irq, void *dev_id)
{
	struct spi_controller *master = dev_id;
	struct hisi_spi *hs = spi_controller_get_devdata(master);
	u32 irq_status = readl(hs->regs + HISI_SPI_ISR) & ISR_MASK;

	if (!irq_status)
		return IRQ_NONE;

	if (!master->cur_msg)
		return IRQ_HANDLED;

	/* Error handling */
	if (irq_status & ISR_RXOF) {
		dev_err(hs->dev, "interrupt_transfer: fifo overflow\n");
		master->cur_msg->status = -EIO;
		goto finalize_transfer;
	}

	/*
	 * Read data from the Rx FIFO every time. If there is
	 * nothing left to receive, finalize the transfer.
	 */
	hisi_spi_reader(hs);
	if (!hs->rx_len)
		goto finalize_transfer;

	/* Send data out when Tx FIFO IRQ triggered */
	if (irq_status & ISR_TX)
		hisi_spi_writer(hs);

	return IRQ_HANDLED;

finalize_transfer:
	hisi_spi_disable(hs);
	spi_finalize_current_transfer(master);
	return IRQ_HANDLED;
}

static int hisi_spi_transfer_one(struct spi_controller *master,
		struct spi_device *spi, struct spi_transfer *transfer)
{
	struct hisi_spi *hs = spi_controller_get_devdata(master);
	struct hisi_chip_data *chip = spi_get_ctldata(spi);
	u32 cr = chip->cr;

	/* Update per transfer options for speed and bpw */
	transfer->effective_speed_hz =
		hisi_calc_effective_speed(master, chip, transfer->speed_hz);
	cr |= FIELD_PREP(CR_DIV_PRE_MASK, chip->div_pre);
	cr |= FIELD_PREP(CR_DIV_POST_MASK, chip->div_post);
	cr |= FIELD_PREP(CR_BPW_MASK, transfer->bits_per_word - 1);
	writel(cr, hs->regs + HISI_SPI_CR);

	hisi_spi_flush_fifo(hs);

	hs->n_bytes = hisi_spi_n_bytes(transfer);
	hs->tx = transfer->tx_buf;
	hs->tx_len = transfer->len / hs->n_bytes;
	hs->rx = transfer->rx_buf;
	hs->rx_len = hs->tx_len;

	/*
	 * Ensure that the transfer data above has been updated
	 * before the interrupt to start.
	 */
	smp_mb();

	/* Enable all interrupts and the controller */
	writel(~(u32)IMR_MASK, hs->regs + HISI_SPI_IMR);
	writel(1, hs->regs + HISI_SPI_ENR);

	return 1;
}

static void hisi_spi_handle_err(struct spi_controller *master,
		struct spi_message *msg)
{
	struct hisi_spi *hs = spi_controller_get_devdata(master);

	hisi_spi_disable(hs);

	/*
	 * Wait for interrupt handler that is
	 * already in timeout to complete.
	 */
	msleep(HISI_SPI_WAIT_TIMEOUT_MS);
}

static int hisi_spi_setup(struct spi_device *spi)
{
	struct hisi_chip_data *chip;

	/* Only alloc on first setup */
	chip = spi_get_ctldata(spi);
	if (!chip) {
		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
		if (!chip)
			return -ENOMEM;
		spi_set_ctldata(spi, chip);
	}

	chip->cr = hisi_spi_prepare_cr(spi);

	return 0;
}

static void hisi_spi_cleanup(struct spi_device *spi)
{
	struct hisi_chip_data *chip = spi_get_ctldata(spi);

	kfree(chip);
	spi_set_ctldata(spi, NULL);
}

static int hisi_spi_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct spi_controller *master;
	struct hisi_spi *hs;
	int ret, irq;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	master = devm_spi_alloc_master(dev, sizeof(*hs));
	if (!master)
		return -ENOMEM;

	platform_set_drvdata(pdev, master);

	hs = spi_controller_get_devdata(master);
	hs->dev = dev;
	hs->irq = irq;

	hs->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(hs->regs))
		return PTR_ERR(hs->regs);

	/* Specify maximum SPI clocking speed (master only) by firmware */
	ret = device_property_read_u32(dev, "spi-max-frequency",
					&master->max_speed_hz);
	if (ret) {
		dev_err(dev, "failed to get max SPI clocking speed, ret=%d\n",
			ret);
		return -EINVAL;
	}

	ret = device_property_read_u16(dev, "num-cs",
					&master->num_chipselect);
	if (ret)
		master->num_chipselect = DEFAULT_NUM_CS;

	master->use_gpio_descriptors = true;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
	master->bus_num = pdev->id;
	master->setup = hisi_spi_setup;
	master->cleanup = hisi_spi_cleanup;
	master->transfer_one = hisi_spi_transfer_one;
	master->handle_err = hisi_spi_handle_err;
	master->dev.fwnode = dev->fwnode;

	hisi_spi_hw_init(hs);

	ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, 0, dev_name(dev),
			master);
	if (ret < 0) {
		dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret);
		return ret;
	}

	ret = spi_register_controller(master);
	if (ret) {
		dev_err(dev, "failed to register spi master, ret=%d\n", ret);
		return ret;
	}

	dev_info(dev, "hw version:0x%x max-freq:%u kHz\n",
		readl(hs->regs + HISI_SPI_VERSION),
		master->max_speed_hz / 1000);

	return 0;
}

static int hisi_spi_remove(struct platform_device *pdev)
{
	struct spi_controller *master = platform_get_drvdata(pdev);

	spi_unregister_controller(master);

	return 0;
}

static const struct acpi_device_id hisi_spi_acpi_match[] = {
	{"HISI03E1", 0},
	{}
};
MODULE_DEVICE_TABLE(acpi, hisi_spi_acpi_match);

static struct platform_driver hisi_spi_driver = {
	.probe		= hisi_spi_probe,
	.remove		= hisi_spi_remove,
	.driver		= {
		.name	= "hisi-kunpeng-spi",
		.acpi_match_table = hisi_spi_acpi_match,
	},
};
module_platform_driver(hisi_spi_driver);

MODULE_AUTHOR("Jay Fang <f.fangjian@huawei.com>");
MODULE_DESCRIPTION("HiSilicon SPI Controller Driver for Kunpeng SoCs");
MODULE_LICENSE("GPL v2");