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("DIN", HISI_SPI_DIN),
155 HISI_SPI_DBGFS_REG("DOUT", HISI_SPI_DOUT),
156 HISI_SPI_DBGFS_REG("SR", HISI_SPI_SR),
157 HISI_SPI_DBGFS_REG("RISR", HISI_SPI_RISR),
158 HISI_SPI_DBGFS_REG("ISR", HISI_SPI_ISR),
159 HISI_SPI_DBGFS_REG("ICR", HISI_SPI_ICR),
160 HISI_SPI_DBGFS_REG("VERSION", HISI_SPI_VERSION),
161 };
162
hisi_spi_debugfs_init(struct hisi_spi * hs)163 static int hisi_spi_debugfs_init(struct hisi_spi *hs)
164 {
165 char name[32];
166
167 struct spi_controller *host;
168
169 host = container_of(hs->dev, struct spi_controller, dev);
170 snprintf(name, 32, "hisi_spi%d", host->bus_num);
171 hs->debugfs = debugfs_create_dir(name, NULL);
172 if (IS_ERR(hs->debugfs))
173 return -ENOMEM;
174
175 hs->regset.regs = hisi_spi_regs;
176 hs->regset.nregs = ARRAY_SIZE(hisi_spi_regs);
177 hs->regset.base = hs->regs;
178 debugfs_create_regset32("registers", 0400, hs->debugfs, &hs->regset);
179
180 return 0;
181 }
182
hisi_spi_busy(struct hisi_spi * hs)183 static u32 hisi_spi_busy(struct hisi_spi *hs)
184 {
185 return readl(hs->regs + HISI_SPI_SR) & SR_BUSY;
186 }
187
hisi_spi_rx_not_empty(struct hisi_spi * hs)188 static u32 hisi_spi_rx_not_empty(struct hisi_spi *hs)
189 {
190 return readl(hs->regs + HISI_SPI_SR) & SR_RXNE;
191 }
192
hisi_spi_tx_not_full(struct hisi_spi * hs)193 static u32 hisi_spi_tx_not_full(struct hisi_spi *hs)
194 {
195 return readl(hs->regs + HISI_SPI_SR) & SR_TXNF;
196 }
197
hisi_spi_flush_fifo(struct hisi_spi * hs)198 static void hisi_spi_flush_fifo(struct hisi_spi *hs)
199 {
200 unsigned long limit = loops_per_jiffy << 1;
201
202 do {
203 while (hisi_spi_rx_not_empty(hs))
204 readl(hs->regs + HISI_SPI_DOUT);
205 } while (hisi_spi_busy(hs) && limit--);
206 }
207
208 /* Disable the controller and all interrupts */
hisi_spi_disable(struct hisi_spi * hs)209 static void hisi_spi_disable(struct hisi_spi *hs)
210 {
211 writel(0, hs->regs + HISI_SPI_ENR);
212 writel(IMR_MASK, hs->regs + HISI_SPI_IMR);
213 writel(ICR_MASK, hs->regs + HISI_SPI_ICR);
214 }
215
hisi_spi_n_bytes(struct spi_transfer * transfer)216 static u8 hisi_spi_n_bytes(struct spi_transfer *transfer)
217 {
218 if (transfer->bits_per_word <= 8)
219 return HISI_SPI_N_BYTES_U8;
220 else if (transfer->bits_per_word <= 16)
221 return HISI_SPI_N_BYTES_U16;
222 else
223 return HISI_SPI_N_BYTES_U32;
224 }
225
hisi_spi_reader(struct hisi_spi * hs)226 static void hisi_spi_reader(struct hisi_spi *hs)
227 {
228 u32 max = min_t(u32, hs->rx_len, hs->fifo_len);
229 u32 rxw;
230
231 while (hisi_spi_rx_not_empty(hs) && max--) {
232 rxw = readl(hs->regs + HISI_SPI_DOUT);
233 /* Check the transfer's original "rx" is not null */
234 if (hs->rx) {
235 switch (hs->n_bytes) {
236 case HISI_SPI_N_BYTES_U8:
237 *(u8 *)(hs->rx) = rxw;
238 break;
239 case HISI_SPI_N_BYTES_U16:
240 *(u16 *)(hs->rx) = rxw;
241 break;
242 case HISI_SPI_N_BYTES_U32:
243 *(u32 *)(hs->rx) = rxw;
244 break;
245 }
246 hs->rx += hs->n_bytes;
247 }
248 --hs->rx_len;
249 }
250 }
251
hisi_spi_writer(struct hisi_spi * hs)252 static void hisi_spi_writer(struct hisi_spi *hs)
253 {
254 u32 max = min_t(u32, hs->tx_len, hs->fifo_len);
255 u32 txw = 0;
256
257 while (hisi_spi_tx_not_full(hs) && max--) {
258 /* Check the transfer's original "tx" is not null */
259 if (hs->tx) {
260 switch (hs->n_bytes) {
261 case HISI_SPI_N_BYTES_U8:
262 txw = *(u8 *)(hs->tx);
263 break;
264 case HISI_SPI_N_BYTES_U16:
265 txw = *(u16 *)(hs->tx);
266 break;
267 case HISI_SPI_N_BYTES_U32:
268 txw = *(u32 *)(hs->tx);
269 break;
270 }
271 hs->tx += hs->n_bytes;
272 }
273 writel(txw, hs->regs + HISI_SPI_DIN);
274 --hs->tx_len;
275 }
276 }
277
__hisi_calc_div_reg(struct hisi_chip_data * chip)278 static void __hisi_calc_div_reg(struct hisi_chip_data *chip)
279 {
280 chip->div_pre = DIV_PRE_MAX;
281 while (chip->div_pre >= DIV_PRE_MIN) {
282 if (chip->clk_div % chip->div_pre == 0)
283 break;
284
285 chip->div_pre -= 2;
286 }
287
288 if (chip->div_pre > chip->clk_div)
289 chip->div_pre = chip->clk_div;
290
291 chip->div_post = (chip->clk_div / chip->div_pre) - 1;
292 }
293
hisi_calc_effective_speed(struct spi_controller * host,struct hisi_chip_data * chip,u32 speed_hz)294 static u32 hisi_calc_effective_speed(struct spi_controller *host,
295 struct hisi_chip_data *chip, u32 speed_hz)
296 {
297 u32 effective_speed;
298
299 /* Note clock divider doesn't support odd numbers */
300 chip->clk_div = DIV_ROUND_UP(host->max_speed_hz, speed_hz) + 1;
301 chip->clk_div &= 0xfffe;
302 if (chip->clk_div > CLK_DIV_MAX)
303 chip->clk_div = CLK_DIV_MAX;
304
305 effective_speed = host->max_speed_hz / chip->clk_div;
306 if (chip->speed_hz != effective_speed) {
307 __hisi_calc_div_reg(chip);
308 chip->speed_hz = effective_speed;
309 }
310
311 return effective_speed;
312 }
313
hisi_spi_prepare_cr(struct spi_device * spi)314 static u32 hisi_spi_prepare_cr(struct spi_device *spi)
315 {
316 u32 cr = FIELD_PREP(CR_SPD_MODE_MASK, 1);
317
318 cr |= FIELD_PREP(CR_CPHA_MASK, (spi->mode & SPI_CPHA) ? 1 : 0);
319 cr |= FIELD_PREP(CR_CPOL_MASK, (spi->mode & SPI_CPOL) ? 1 : 0);
320 cr |= FIELD_PREP(CR_LOOP_MASK, (spi->mode & SPI_LOOP) ? 1 : 0);
321
322 return cr;
323 }
324
hisi_spi_hw_init(struct hisi_spi * hs)325 static void hisi_spi_hw_init(struct hisi_spi *hs)
326 {
327 hisi_spi_disable(hs);
328
329 /* FIFO default config */
330 writel(FIELD_PREP(FIFOC_TX_MASK, HISI_SPI_TX_64_OR_LESS) |
331 FIELD_PREP(FIFOC_RX_MASK, HISI_SPI_RX_16),
332 hs->regs + HISI_SPI_FIFOC);
333
334 hs->fifo_len = 256;
335 }
336
hisi_spi_irq(int irq,void * dev_id)337 static irqreturn_t hisi_spi_irq(int irq, void *dev_id)
338 {
339 struct spi_controller *host = dev_id;
340 struct hisi_spi *hs = spi_controller_get_devdata(host);
341 u32 irq_status = readl(hs->regs + HISI_SPI_ISR) & ISR_MASK;
342
343 if (!irq_status)
344 return IRQ_NONE;
345
346 if (!host->cur_msg)
347 return IRQ_HANDLED;
348
349 /* Error handling */
350 if (irq_status & ISR_RXOF) {
351 dev_err(hs->dev, "interrupt_transfer: fifo overflow\n");
352 host->cur_msg->status = -EIO;
353 goto finalize_transfer;
354 }
355
356 /*
357 * Read data from the Rx FIFO every time. If there is
358 * nothing left to receive, finalize the transfer.
359 */
360 hisi_spi_reader(hs);
361 if (!hs->rx_len)
362 goto finalize_transfer;
363
364 /* Send data out when Tx FIFO IRQ triggered */
365 if (irq_status & ISR_TX)
366 hisi_spi_writer(hs);
367
368 return IRQ_HANDLED;
369
370 finalize_transfer:
371 hisi_spi_disable(hs);
372 spi_finalize_current_transfer(host);
373 return IRQ_HANDLED;
374 }
375
hisi_spi_transfer_one(struct spi_controller * host,struct spi_device * spi,struct spi_transfer * transfer)376 static int hisi_spi_transfer_one(struct spi_controller *host,
377 struct spi_device *spi, struct spi_transfer *transfer)
378 {
379 struct hisi_spi *hs = spi_controller_get_devdata(host);
380 struct hisi_chip_data *chip = spi_get_ctldata(spi);
381 u32 cr = chip->cr;
382
383 /* Update per transfer options for speed and bpw */
384 transfer->effective_speed_hz =
385 hisi_calc_effective_speed(host, chip, transfer->speed_hz);
386 cr |= FIELD_PREP(CR_DIV_PRE_MASK, chip->div_pre);
387 cr |= FIELD_PREP(CR_DIV_POST_MASK, chip->div_post);
388 cr |= FIELD_PREP(CR_BPW_MASK, transfer->bits_per_word - 1);
389 writel(cr, hs->regs + HISI_SPI_CR);
390
391 hisi_spi_flush_fifo(hs);
392
393 hs->n_bytes = hisi_spi_n_bytes(transfer);
394 hs->tx = transfer->tx_buf;
395 hs->tx_len = transfer->len / hs->n_bytes;
396 hs->rx = transfer->rx_buf;
397 hs->rx_len = hs->tx_len;
398
399 /*
400 * Ensure that the transfer data above has been updated
401 * before the interrupt to start.
402 */
403 smp_mb();
404
405 /* Enable all interrupts and the controller */
406 writel(~(u32)IMR_MASK, hs->regs + HISI_SPI_IMR);
407 writel(1, hs->regs + HISI_SPI_ENR);
408
409 return 1;
410 }
411
hisi_spi_handle_err(struct spi_controller * host,struct spi_message * msg)412 static void hisi_spi_handle_err(struct spi_controller *host,
413 struct spi_message *msg)
414 {
415 struct hisi_spi *hs = spi_controller_get_devdata(host);
416
417 hisi_spi_disable(hs);
418
419 /*
420 * Wait for interrupt handler that is
421 * already in timeout to complete.
422 */
423 msleep(HISI_SPI_WAIT_TIMEOUT_MS);
424 }
425
hisi_spi_setup(struct spi_device * spi)426 static int hisi_spi_setup(struct spi_device *spi)
427 {
428 struct hisi_chip_data *chip;
429
430 /* Only alloc on first setup */
431 chip = spi_get_ctldata(spi);
432 if (!chip) {
433 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
434 if (!chip)
435 return -ENOMEM;
436 spi_set_ctldata(spi, chip);
437 }
438
439 chip->cr = hisi_spi_prepare_cr(spi);
440
441 return 0;
442 }
443
hisi_spi_cleanup(struct spi_device * spi)444 static void hisi_spi_cleanup(struct spi_device *spi)
445 {
446 struct hisi_chip_data *chip = spi_get_ctldata(spi);
447
448 kfree(chip);
449 spi_set_ctldata(spi, NULL);
450 }
451
hisi_spi_probe(struct platform_device * pdev)452 static int hisi_spi_probe(struct platform_device *pdev)
453 {
454 struct device *dev = &pdev->dev;
455 struct spi_controller *host;
456 struct hisi_spi *hs;
457 int ret, irq;
458
459 irq = platform_get_irq(pdev, 0);
460 if (irq < 0)
461 return irq;
462
463 host = devm_spi_alloc_host(dev, sizeof(*hs));
464 if (!host)
465 return -ENOMEM;
466
467 platform_set_drvdata(pdev, host);
468
469 hs = spi_controller_get_devdata(host);
470 hs->dev = dev;
471 hs->irq = irq;
472
473 hs->regs = devm_platform_ioremap_resource(pdev, 0);
474 if (IS_ERR(hs->regs))
475 return PTR_ERR(hs->regs);
476
477 /* Specify maximum SPI clocking speed (host only) by firmware */
478 ret = device_property_read_u32(dev, "spi-max-frequency",
479 &host->max_speed_hz);
480 if (ret) {
481 dev_err(dev, "failed to get max SPI clocking speed, ret=%d\n",
482 ret);
483 return -EINVAL;
484 }
485
486 ret = device_property_read_u16(dev, "num-cs",
487 &host->num_chipselect);
488 if (ret)
489 host->num_chipselect = DEFAULT_NUM_CS;
490
491 host->use_gpio_descriptors = true;
492 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
493 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
494 host->bus_num = pdev->id;
495 host->setup = hisi_spi_setup;
496 host->cleanup = hisi_spi_cleanup;
497 host->transfer_one = hisi_spi_transfer_one;
498 host->handle_err = hisi_spi_handle_err;
499 host->dev.fwnode = dev->fwnode;
500
501 hisi_spi_hw_init(hs);
502
503 ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, 0, dev_name(dev),
504 host);
505 if (ret < 0) {
506 dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret);
507 return ret;
508 }
509
510 ret = spi_register_controller(host);
511 if (ret) {
512 dev_err(dev, "failed to register spi host, ret=%d\n", ret);
513 return ret;
514 }
515
516 if (hisi_spi_debugfs_init(hs))
517 dev_info(dev, "failed to create debugfs dir\n");
518
519 dev_info(dev, "hw version:0x%x max-freq:%u kHz\n",
520 readl(hs->regs + HISI_SPI_VERSION),
521 host->max_speed_hz / 1000);
522
523 return 0;
524 }
525
hisi_spi_remove(struct platform_device * pdev)526 static void hisi_spi_remove(struct platform_device *pdev)
527 {
528 struct spi_controller *host = platform_get_drvdata(pdev);
529 struct hisi_spi *hs = spi_controller_get_devdata(host);
530
531 debugfs_remove_recursive(hs->debugfs);
532 spi_unregister_controller(host);
533 }
534
535 static const struct acpi_device_id hisi_spi_acpi_match[] = {
536 {"HISI03E1", 0},
537 {}
538 };
539 MODULE_DEVICE_TABLE(acpi, hisi_spi_acpi_match);
540
541 static struct platform_driver hisi_spi_driver = {
542 .probe = hisi_spi_probe,
543 .remove_new = hisi_spi_remove,
544 .driver = {
545 .name = "hisi-kunpeng-spi",
546 .acpi_match_table = hisi_spi_acpi_match,
547 },
548 };
549 module_platform_driver(hisi_spi_driver);
550
551 MODULE_AUTHOR("Jay Fang <f.fangjian@huawei.com>");
552 MODULE_DESCRIPTION("HiSilicon SPI Controller Driver for Kunpeng SoCs");
553 MODULE_LICENSE("GPL v2");
554
