1 // SPDX-License-Identifier: GPL-2.0-only
2 //
3 // HiSilicon SPI Controller Driver for Kunpeng SoCs
4 //
5 // Copyright (c) 2021 HiSilicon Technologies Co., Ltd.
6 // Author: Jay Fang <f.fangjian@huawei.com>
7 //
8 // This code is based on spi-dw-core.c.
9
10 #include <linux/acpi.h>
11 #include <linux/bitfield.h>
12 #include <linux/debugfs.h>
13 #include <linux/delay.h>
14 #include <linux/err.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/property.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/spi/spi.h>
21
22 /* Register offsets */
23 #define HISI_SPI_CSCR 0x00 /* cs control register */
24 #define HISI_SPI_CR 0x04 /* spi common control register */
25 #define HISI_SPI_ENR 0x08 /* spi enable register */
26 #define HISI_SPI_FIFOC 0x0c /* fifo level control register */
27 #define HISI_SPI_IMR 0x10 /* interrupt mask register */
28 #define HISI_SPI_DIN 0x14 /* data in register */
29 #define HISI_SPI_DOUT 0x18 /* data out register */
30 #define HISI_SPI_SR 0x1c /* status register */
31 #define HISI_SPI_RISR 0x20 /* raw interrupt status register */
32 #define HISI_SPI_ISR 0x24 /* interrupt status register */
33 #define HISI_SPI_ICR 0x28 /* interrupt clear register */
34 #define HISI_SPI_VERSION 0xe0 /* version register */
35
36 /* Bit fields in HISI_SPI_CR */
37 #define CR_LOOP_MASK GENMASK(1, 1)
38 #define CR_CPOL_MASK GENMASK(2, 2)
39 #define CR_CPHA_MASK GENMASK(3, 3)
40 #define CR_DIV_PRE_MASK GENMASK(11, 4)
41 #define CR_DIV_POST_MASK GENMASK(19, 12)
42 #define CR_BPW_MASK GENMASK(24, 20)
43 #define CR_SPD_MODE_MASK GENMASK(25, 25)
44
45 /* Bit fields in HISI_SPI_FIFOC */
46 #define FIFOC_TX_MASK GENMASK(5, 3)
47 #define FIFOC_RX_MASK GENMASK(11, 9)
48
49 /* Bit fields in HISI_SPI_IMR, 4 bits */
50 #define IMR_RXOF BIT(0) /* Receive Overflow */
51 #define IMR_RXTO BIT(1) /* Receive Timeout */
52 #define IMR_RX BIT(2) /* Receive */
53 #define IMR_TX BIT(3) /* Transmit */
54 #define IMR_MASK (IMR_RXOF | IMR_RXTO | IMR_RX | IMR_TX)
55
56 /* Bit fields in HISI_SPI_SR, 5 bits */
57 #define SR_TXE BIT(0) /* Transmit FIFO empty */
58 #define SR_TXNF BIT(1) /* Transmit FIFO not full */
59 #define SR_RXNE BIT(2) /* Receive FIFO not empty */
60 #define SR_RXF BIT(3) /* Receive FIFO full */
61 #define SR_BUSY BIT(4) /* Busy Flag */
62
63 /* Bit fields in HISI_SPI_ISR, 4 bits */
64 #define ISR_RXOF BIT(0) /* Receive Overflow */
65 #define ISR_RXTO BIT(1) /* Receive Timeout */
66 #define ISR_RX BIT(2) /* Receive */
67 #define ISR_TX BIT(3) /* Transmit */
68 #define ISR_MASK (ISR_RXOF | ISR_RXTO | ISR_RX | ISR_TX)
69
70 /* Bit fields in HISI_SPI_ICR, 2 bits */
71 #define ICR_RXOF BIT(0) /* Receive Overflow */
72 #define ICR_RXTO BIT(1) /* Receive Timeout */
73 #define ICR_MASK (ICR_RXOF | ICR_RXTO)
74
75 #define DIV_POST_MAX 0xFF
76 #define DIV_POST_MIN 0x00
77 #define DIV_PRE_MAX 0xFE
78 #define DIV_PRE_MIN 0x02
79 #define CLK_DIV_MAX ((1 + DIV_POST_MAX) * DIV_PRE_MAX)
80 #define CLK_DIV_MIN ((1 + DIV_POST_MIN) * DIV_PRE_MIN)
81
82 #define DEFAULT_NUM_CS 1
83
84 #define HISI_SPI_WAIT_TIMEOUT_MS 10UL
85
86 enum hisi_spi_rx_level_trig {
87 HISI_SPI_RX_1,
88 HISI_SPI_RX_4,
89 HISI_SPI_RX_8,
90 HISI_SPI_RX_16,
91 HISI_SPI_RX_32,
92 HISI_SPI_RX_64,
93 HISI_SPI_RX_128
94 };
95
96 enum hisi_spi_tx_level_trig {
97 HISI_SPI_TX_1_OR_LESS,
98 HISI_SPI_TX_4_OR_LESS,
99 HISI_SPI_TX_8_OR_LESS,
100 HISI_SPI_TX_16_OR_LESS,
101 HISI_SPI_TX_32_OR_LESS,
102 HISI_SPI_TX_64_OR_LESS,
103 HISI_SPI_TX_128_OR_LESS
104 };
105
106 enum hisi_spi_frame_n_bytes {
107 HISI_SPI_N_BYTES_NULL,
108 HISI_SPI_N_BYTES_U8,
109 HISI_SPI_N_BYTES_U16,
110 HISI_SPI_N_BYTES_U32 = 4
111 };
112
113 /* Slave spi_dev related */
114 struct hisi_chip_data {
115 u32 cr;
116 u32 speed_hz; /* baud rate */
117 u16 clk_div; /* baud rate divider */
118
119 /* clk_div = (1 + div_post) * div_pre */
120 u8 div_post; /* value from 0 to 255 */
121 u8 div_pre; /* value from 2 to 254 (even only!) */
122 };
123
124 struct hisi_spi {
125 struct device *dev;
126
127 void __iomem *regs;
128 int irq;
129 u32 fifo_len; /* depth of the FIFO buffer */
130
131 /* Current message transfer state info */
132 const void *tx;
133 unsigned int tx_len;
134 void *rx;
135 unsigned int rx_len;
136 u8 n_bytes; /* current is a 1/2/4 bytes op */
137
138 struct dentry *debugfs;
139 struct debugfs_regset32 regset;
140 };
141
142 #define HISI_SPI_DBGFS_REG(_name, _off) \
143 { \
144 .name = _name, \
145 .offset = _off, \
146 }
147
148 static const struct debugfs_reg32 hisi_spi_regs[] = {
149 HISI_SPI_DBGFS_REG("CSCR", HISI_SPI_CSCR),
150 HISI_SPI_DBGFS_REG("CR", HISI_SPI_CR),
151 HISI_SPI_DBGFS_REG("ENR", HISI_SPI_ENR),
152 HISI_SPI_DBGFS_REG("FIFOC", HISI_SPI_FIFOC),
153 HISI_SPI_DBGFS_REG("IMR", HISI_SPI_IMR),
154 HISI_SPI_DBGFS_REG("SR", HISI_SPI_SR),
155 HISI_SPI_DBGFS_REG("RISR", HISI_SPI_RISR),
156 HISI_SPI_DBGFS_REG("ISR", HISI_SPI_ISR),
157 HISI_SPI_DBGFS_REG("ICR", HISI_SPI_ICR),
158 HISI_SPI_DBGFS_REG("VERSION", HISI_SPI_VERSION),
159 };
160
hisi_spi_debugfs_init(struct hisi_spi * hs)161 static int hisi_spi_debugfs_init(struct hisi_spi *hs)
162 {
163 char name[32];
164
165 struct spi_controller *host;
166
167 host = container_of(hs->dev, struct spi_controller, dev);
168 snprintf(name, 32, "hisi_spi%d", host->bus_num);
169 hs->debugfs = debugfs_create_dir(name, NULL);
170 if (IS_ERR(hs->debugfs))
171 return -ENOMEM;
172
173 hs->regset.regs = hisi_spi_regs;
174 hs->regset.nregs = ARRAY_SIZE(hisi_spi_regs);
175 hs->regset.base = hs->regs;
176 debugfs_create_regset32("registers", 0400, hs->debugfs, &hs->regset);
177
178 return 0;
179 }
180
hisi_spi_busy(struct hisi_spi * hs)181 static u32 hisi_spi_busy(struct hisi_spi *hs)
182 {
183 return readl(hs->regs + HISI_SPI_SR) & SR_BUSY;
184 }
185
hisi_spi_rx_not_empty(struct hisi_spi * hs)186 static u32 hisi_spi_rx_not_empty(struct hisi_spi *hs)
187 {
188 return readl(hs->regs + HISI_SPI_SR) & SR_RXNE;
189 }
190
hisi_spi_tx_not_full(struct hisi_spi * hs)191 static u32 hisi_spi_tx_not_full(struct hisi_spi *hs)
192 {
193 return readl(hs->regs + HISI_SPI_SR) & SR_TXNF;
194 }
195
hisi_spi_flush_fifo(struct hisi_spi * hs)196 static void hisi_spi_flush_fifo(struct hisi_spi *hs)
197 {
198 unsigned long limit = loops_per_jiffy << 1;
199
200 do {
201 while (hisi_spi_rx_not_empty(hs))
202 readl(hs->regs + HISI_SPI_DOUT);
203 } while (hisi_spi_busy(hs) && limit--);
204 }
205
206 /* Disable the controller and all interrupts */
hisi_spi_disable(struct hisi_spi * hs)207 static void hisi_spi_disable(struct hisi_spi *hs)
208 {
209 writel(0, hs->regs + HISI_SPI_ENR);
210 writel(IMR_MASK, hs->regs + HISI_SPI_IMR);
211 writel(ICR_MASK, hs->regs + HISI_SPI_ICR);
212 }
213
hisi_spi_n_bytes(struct spi_transfer * transfer)214 static u8 hisi_spi_n_bytes(struct spi_transfer *transfer)
215 {
216 if (transfer->bits_per_word <= 8)
217 return HISI_SPI_N_BYTES_U8;
218 else if (transfer->bits_per_word <= 16)
219 return HISI_SPI_N_BYTES_U16;
220 else
221 return HISI_SPI_N_BYTES_U32;
222 }
223
hisi_spi_reader(struct hisi_spi * hs)224 static void hisi_spi_reader(struct hisi_spi *hs)
225 {
226 u32 max = min_t(u32, hs->rx_len, hs->fifo_len);
227 u32 rxw;
228
229 while (hisi_spi_rx_not_empty(hs) && max--) {
230 rxw = readl(hs->regs + HISI_SPI_DOUT);
231 /* Check the transfer's original "rx" is not null */
232 if (hs->rx) {
233 switch (hs->n_bytes) {
234 case HISI_SPI_N_BYTES_U8:
235 *(u8 *)(hs->rx) = rxw;
236 break;
237 case HISI_SPI_N_BYTES_U16:
238 *(u16 *)(hs->rx) = rxw;
239 break;
240 case HISI_SPI_N_BYTES_U32:
241 *(u32 *)(hs->rx) = rxw;
242 break;
243 }
244 hs->rx += hs->n_bytes;
245 }
246 --hs->rx_len;
247 }
248 }
249
hisi_spi_writer(struct hisi_spi * hs)250 static void hisi_spi_writer(struct hisi_spi *hs)
251 {
252 u32 max = min_t(u32, hs->tx_len, hs->fifo_len);
253 u32 txw = 0;
254
255 while (hisi_spi_tx_not_full(hs) && max--) {
256 /* Check the transfer's original "tx" is not null */
257 if (hs->tx) {
258 switch (hs->n_bytes) {
259 case HISI_SPI_N_BYTES_U8:
260 txw = *(u8 *)(hs->tx);
261 break;
262 case HISI_SPI_N_BYTES_U16:
263 txw = *(u16 *)(hs->tx);
264 break;
265 case HISI_SPI_N_BYTES_U32:
266 txw = *(u32 *)(hs->tx);
267 break;
268 }
269 hs->tx += hs->n_bytes;
270 }
271 writel(txw, hs->regs + HISI_SPI_DIN);
272 --hs->tx_len;
273 }
274 }
275
__hisi_calc_div_reg(struct hisi_chip_data * chip)276 static void __hisi_calc_div_reg(struct hisi_chip_data *chip)
277 {
278 chip->div_pre = DIV_PRE_MAX;
279 while (chip->div_pre >= DIV_PRE_MIN) {
280 if (chip->clk_div % chip->div_pre == 0)
281 break;
282
283 chip->div_pre -= 2;
284 }
285
286 if (chip->div_pre > chip->clk_div)
287 chip->div_pre = chip->clk_div;
288
289 chip->div_post = (chip->clk_div / chip->div_pre) - 1;
290 }
291
hisi_calc_effective_speed(struct spi_controller * host,struct hisi_chip_data * chip,u32 speed_hz)292 static u32 hisi_calc_effective_speed(struct spi_controller *host,
293 struct hisi_chip_data *chip, u32 speed_hz)
294 {
295 u32 effective_speed;
296
297 /* Note clock divider doesn't support odd numbers */
298 chip->clk_div = DIV_ROUND_UP(host->max_speed_hz, speed_hz) + 1;
299 chip->clk_div &= 0xfffe;
300 if (chip->clk_div > CLK_DIV_MAX)
301 chip->clk_div = CLK_DIV_MAX;
302
303 effective_speed = host->max_speed_hz / chip->clk_div;
304 if (chip->speed_hz != effective_speed) {
305 __hisi_calc_div_reg(chip);
306 chip->speed_hz = effective_speed;
307 }
308
309 return effective_speed;
310 }
311
hisi_spi_prepare_cr(struct spi_device * spi)312 static u32 hisi_spi_prepare_cr(struct spi_device *spi)
313 {
314 u32 cr = FIELD_PREP(CR_SPD_MODE_MASK, 1);
315
316 cr |= FIELD_PREP(CR_CPHA_MASK, (spi->mode & SPI_CPHA) ? 1 : 0);
317 cr |= FIELD_PREP(CR_CPOL_MASK, (spi->mode & SPI_CPOL) ? 1 : 0);
318 cr |= FIELD_PREP(CR_LOOP_MASK, (spi->mode & SPI_LOOP) ? 1 : 0);
319
320 return cr;
321 }
322
hisi_spi_hw_init(struct hisi_spi * hs)323 static void hisi_spi_hw_init(struct hisi_spi *hs)
324 {
325 hisi_spi_disable(hs);
326
327 /* FIFO default config */
328 writel(FIELD_PREP(FIFOC_TX_MASK, HISI_SPI_TX_64_OR_LESS) |
329 FIELD_PREP(FIFOC_RX_MASK, HISI_SPI_RX_16),
330 hs->regs + HISI_SPI_FIFOC);
331
332 hs->fifo_len = 256;
333 }
334
hisi_spi_irq(int irq,void * dev_id)335 static irqreturn_t hisi_spi_irq(int irq, void *dev_id)
336 {
337 struct spi_controller *host = dev_id;
338 struct hisi_spi *hs = spi_controller_get_devdata(host);
339 u32 irq_status = readl(hs->regs + HISI_SPI_ISR) & ISR_MASK;
340
341 if (!irq_status)
342 return IRQ_NONE;
343
344 if (!host->cur_msg)
345 return IRQ_HANDLED;
346
347 /* Error handling */
348 if (irq_status & ISR_RXOF) {
349 dev_err(hs->dev, "interrupt_transfer: fifo overflow\n");
350 host->cur_msg->status = -EIO;
351 goto finalize_transfer;
352 }
353
354 /*
355 * Read data from the Rx FIFO every time. If there is
356 * nothing left to receive, finalize the transfer.
357 */
358 hisi_spi_reader(hs);
359 if (!hs->rx_len)
360 goto finalize_transfer;
361
362 /* Send data out when Tx FIFO IRQ triggered */
363 if (irq_status & ISR_TX)
364 hisi_spi_writer(hs);
365
366 return IRQ_HANDLED;
367
368 finalize_transfer:
369 hisi_spi_disable(hs);
370 spi_finalize_current_transfer(host);
371 return IRQ_HANDLED;
372 }
373
hisi_spi_transfer_one(struct spi_controller * host,struct spi_device * spi,struct spi_transfer * transfer)374 static int hisi_spi_transfer_one(struct spi_controller *host,
375 struct spi_device *spi, struct spi_transfer *transfer)
376 {
377 struct hisi_spi *hs = spi_controller_get_devdata(host);
378 struct hisi_chip_data *chip = spi_get_ctldata(spi);
379 u32 cr = chip->cr;
380
381 /* Update per transfer options for speed and bpw */
382 transfer->effective_speed_hz =
383 hisi_calc_effective_speed(host, chip, transfer->speed_hz);
384 cr |= FIELD_PREP(CR_DIV_PRE_MASK, chip->div_pre);
385 cr |= FIELD_PREP(CR_DIV_POST_MASK, chip->div_post);
386 cr |= FIELD_PREP(CR_BPW_MASK, transfer->bits_per_word - 1);
387 writel(cr, hs->regs + HISI_SPI_CR);
388
389 hisi_spi_flush_fifo(hs);
390
391 hs->n_bytes = hisi_spi_n_bytes(transfer);
392 hs->tx = transfer->tx_buf;
393 hs->tx_len = transfer->len / hs->n_bytes;
394 hs->rx = transfer->rx_buf;
395 hs->rx_len = hs->tx_len;
396
397 /*
398 * Ensure that the transfer data above has been updated
399 * before the interrupt to start.
400 */
401 smp_mb();
402
403 /* Enable all interrupts and the controller */
404 writel(~(u32)IMR_MASK, hs->regs + HISI_SPI_IMR);
405 writel(1, hs->regs + HISI_SPI_ENR);
406
407 return 1;
408 }
409
hisi_spi_handle_err(struct spi_controller * host,struct spi_message * msg)410 static void hisi_spi_handle_err(struct spi_controller *host,
411 struct spi_message *msg)
412 {
413 struct hisi_spi *hs = spi_controller_get_devdata(host);
414
415 hisi_spi_disable(hs);
416
417 /*
418 * Wait for interrupt handler that is
419 * already in timeout to complete.
420 */
421 msleep(HISI_SPI_WAIT_TIMEOUT_MS);
422 }
423
hisi_spi_setup(struct spi_device * spi)424 static int hisi_spi_setup(struct spi_device *spi)
425 {
426 struct hisi_chip_data *chip;
427
428 /* Only alloc on first setup */
429 chip = spi_get_ctldata(spi);
430 if (!chip) {
431 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
432 if (!chip)
433 return -ENOMEM;
434 spi_set_ctldata(spi, chip);
435 }
436
437 chip->cr = hisi_spi_prepare_cr(spi);
438
439 return 0;
440 }
441
hisi_spi_cleanup(struct spi_device * spi)442 static void hisi_spi_cleanup(struct spi_device *spi)
443 {
444 struct hisi_chip_data *chip = spi_get_ctldata(spi);
445
446 kfree(chip);
447 spi_set_ctldata(spi, NULL);
448 }
449
hisi_spi_probe(struct platform_device * pdev)450 static int hisi_spi_probe(struct platform_device *pdev)
451 {
452 struct device *dev = &pdev->dev;
453 struct spi_controller *host;
454 struct hisi_spi *hs;
455 int ret, irq;
456
457 irq = platform_get_irq(pdev, 0);
458 if (irq < 0)
459 return irq;
460
461 host = devm_spi_alloc_host(dev, sizeof(*hs));
462 if (!host)
463 return -ENOMEM;
464
465 platform_set_drvdata(pdev, host);
466
467 hs = spi_controller_get_devdata(host);
468 hs->dev = dev;
469 hs->irq = irq;
470
471 hs->regs = devm_platform_ioremap_resource(pdev, 0);
472 if (IS_ERR(hs->regs))
473 return PTR_ERR(hs->regs);
474
475 /* Specify maximum SPI clocking speed (host only) by firmware */
476 ret = device_property_read_u32(dev, "spi-max-frequency",
477 &host->max_speed_hz);
478 if (ret) {
479 dev_err(dev, "failed to get max SPI clocking speed, ret=%d\n",
480 ret);
481 return -EINVAL;
482 }
483
484 ret = device_property_read_u16(dev, "num-cs",
485 &host->num_chipselect);
486 if (ret)
487 host->num_chipselect = DEFAULT_NUM_CS;
488
489 host->use_gpio_descriptors = true;
490 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
491 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
492 host->bus_num = pdev->id;
493 host->setup = hisi_spi_setup;
494 host->cleanup = hisi_spi_cleanup;
495 host->transfer_one = hisi_spi_transfer_one;
496 host->handle_err = hisi_spi_handle_err;
497 host->dev.fwnode = dev->fwnode;
498
499 hisi_spi_hw_init(hs);
500
501 ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, 0, dev_name(dev),
502 host);
503 if (ret < 0) {
504 dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret);
505 return ret;
506 }
507
508 ret = spi_register_controller(host);
509 if (ret) {
510 dev_err(dev, "failed to register spi host, ret=%d\n", ret);
511 return ret;
512 }
513
514 if (hisi_spi_debugfs_init(hs))
515 dev_info(dev, "failed to create debugfs dir\n");
516
517 dev_info(dev, "hw version:0x%x max-freq:%u kHz\n",
518 readl(hs->regs + HISI_SPI_VERSION),
519 host->max_speed_hz / 1000);
520
521 return 0;
522 }
523
hisi_spi_remove(struct platform_device * pdev)524 static void hisi_spi_remove(struct platform_device *pdev)
525 {
526 struct spi_controller *host = platform_get_drvdata(pdev);
527 struct hisi_spi *hs = spi_controller_get_devdata(host);
528
529 debugfs_remove_recursive(hs->debugfs);
530 spi_unregister_controller(host);
531 }
532
533 static const struct acpi_device_id hisi_spi_acpi_match[] = {
534 {"HISI03E1", 0},
535 {}
536 };
537 MODULE_DEVICE_TABLE(acpi, hisi_spi_acpi_match);
538
539 static struct platform_driver hisi_spi_driver = {
540 .probe = hisi_spi_probe,
541 .remove_new = hisi_spi_remove,
542 .driver = {
543 .name = "hisi-kunpeng-spi",
544 .acpi_match_table = hisi_spi_acpi_match,
545 },
546 };
547 module_platform_driver(hisi_spi_driver);
548
549 MODULE_AUTHOR("Jay Fang <f.fangjian@huawei.com>");
550 MODULE_DESCRIPTION("HiSilicon SPI Controller Driver for Kunpeng SoCs");
551 MODULE_LICENSE("GPL v2");
552