objtool: Re-arrange validate_functions()
[linux-block.git] / drivers / spi / spi-meson-spicc.c
1 /*
2  * Driver for Amlogic Meson SPI communication controller (SPICC)
3  *
4  * Copyright (C) BayLibre, SAS
5  * Author: Neil Armstrong <narmstrong@baylibre.com>
6  *
7  * SPDX-License-Identifier: GPL-2.0+
8  */
9
10 #include <linux/bitfield.h>
11 #include <linux/clk.h>
12 #include <linux/device.h>
13 #include <linux/io.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 #include <linux/spi/spi.h>
19 #include <linux/types.h>
20 #include <linux/interrupt.h>
21 #include <linux/reset.h>
22
23 /*
24  * The Meson SPICC controller could support DMA based transfers, but is not
25  * implemented by the vendor code, and while having the registers documentation
26  * it has never worked on the GXL Hardware.
27  * The PIO mode is the only mode implemented, and due to badly designed HW :
28  * - all transfers are cutted in 16 words burst because the FIFO hangs on
29  *   TX underflow, and there is no TX "Half-Empty" interrupt, so we go by
30  *   FIFO max size chunk only
31  * - CS management is dumb, and goes UP between every burst, so is really a
32  *   "Data Valid" signal than a Chip Select, GPIO link should be used instead
33  *   to have a CS go down over the full transfer
34  */
35
36 #define SPICC_MAX_FREQ  30000000
37 #define SPICC_MAX_BURST 128
38
39 /* Register Map */
40 #define SPICC_RXDATA    0x00
41
42 #define SPICC_TXDATA    0x04
43
44 #define SPICC_CONREG    0x08
45 #define SPICC_ENABLE            BIT(0)
46 #define SPICC_MODE_MASTER       BIT(1)
47 #define SPICC_XCH               BIT(2)
48 #define SPICC_SMC               BIT(3)
49 #define SPICC_POL               BIT(4)
50 #define SPICC_PHA               BIT(5)
51 #define SPICC_SSCTL             BIT(6)
52 #define SPICC_SSPOL             BIT(7)
53 #define SPICC_DRCTL_MASK        GENMASK(9, 8)
54 #define SPICC_DRCTL_IGNORE      0
55 #define SPICC_DRCTL_FALLING     1
56 #define SPICC_DRCTL_LOWLEVEL    2
57 #define SPICC_CS_MASK           GENMASK(13, 12)
58 #define SPICC_DATARATE_MASK     GENMASK(18, 16)
59 #define SPICC_DATARATE_DIV4     0
60 #define SPICC_DATARATE_DIV8     1
61 #define SPICC_DATARATE_DIV16    2
62 #define SPICC_DATARATE_DIV32    3
63 #define SPICC_BITLENGTH_MASK    GENMASK(24, 19)
64 #define SPICC_BURSTLENGTH_MASK  GENMASK(31, 25)
65
66 #define SPICC_INTREG    0x0c
67 #define SPICC_TE_EN     BIT(0) /* TX FIFO Empty Interrupt */
68 #define SPICC_TH_EN     BIT(1) /* TX FIFO Half-Full Interrupt */
69 #define SPICC_TF_EN     BIT(2) /* TX FIFO Full Interrupt */
70 #define SPICC_RR_EN     BIT(3) /* RX FIFO Ready Interrupt */
71 #define SPICC_RH_EN     BIT(4) /* RX FIFO Half-Full Interrupt */
72 #define SPICC_RF_EN     BIT(5) /* RX FIFO Full Interrupt */
73 #define SPICC_RO_EN     BIT(6) /* RX FIFO Overflow Interrupt */
74 #define SPICC_TC_EN     BIT(7) /* Transfert Complete Interrupt */
75
76 #define SPICC_DMAREG    0x10
77 #define SPICC_DMA_ENABLE                BIT(0)
78 #define SPICC_TXFIFO_THRESHOLD_MASK     GENMASK(5, 1)
79 #define SPICC_RXFIFO_THRESHOLD_MASK     GENMASK(10, 6)
80 #define SPICC_READ_BURST_MASK           GENMASK(14, 11)
81 #define SPICC_WRITE_BURST_MASK          GENMASK(18, 15)
82 #define SPICC_DMA_URGENT                BIT(19)
83 #define SPICC_DMA_THREADID_MASK         GENMASK(25, 20)
84 #define SPICC_DMA_BURSTNUM_MASK         GENMASK(31, 26)
85
86 #define SPICC_STATREG   0x14
87 #define SPICC_TE        BIT(0) /* TX FIFO Empty Interrupt */
88 #define SPICC_TH        BIT(1) /* TX FIFO Half-Full Interrupt */
89 #define SPICC_TF        BIT(2) /* TX FIFO Full Interrupt */
90 #define SPICC_RR        BIT(3) /* RX FIFO Ready Interrupt */
91 #define SPICC_RH        BIT(4) /* RX FIFO Half-Full Interrupt */
92 #define SPICC_RF        BIT(5) /* RX FIFO Full Interrupt */
93 #define SPICC_RO        BIT(6) /* RX FIFO Overflow Interrupt */
94 #define SPICC_TC        BIT(7) /* Transfert Complete Interrupt */
95
96 #define SPICC_PERIODREG 0x18
97 #define SPICC_PERIOD    GENMASK(14, 0)  /* Wait cycles */
98
99 #define SPICC_TESTREG   0x1c
100 #define SPICC_TXCNT_MASK        GENMASK(4, 0)   /* TX FIFO Counter */
101 #define SPICC_RXCNT_MASK        GENMASK(9, 5)   /* RX FIFO Counter */
102 #define SPICC_SMSTATUS_MASK     GENMASK(12, 10) /* State Machine Status */
103 #define SPICC_LBC_RO            BIT(13) /* Loop Back Control Read-Only */
104 #define SPICC_LBC_W1            BIT(14) /* Loop Back Control Write-Only */
105 #define SPICC_SWAP_RO           BIT(14) /* RX FIFO Data Swap Read-Only */
106 #define SPICC_SWAP_W1           BIT(15) /* RX FIFO Data Swap Write-Only */
107 #define SPICC_DLYCTL_RO_MASK    GENMASK(20, 15) /* Delay Control Read-Only */
108 #define SPICC_DLYCTL_W1_MASK    GENMASK(21, 16) /* Delay Control Write-Only */
109 #define SPICC_FIFORST_RO_MASK   GENMASK(22, 21) /* FIFO Softreset Read-Only */
110 #define SPICC_FIFORST_W1_MASK   GENMASK(23, 22) /* FIFO Softreset Write-Only */
111
112 #define SPICC_DRADDR    0x20    /* Read Address of DMA */
113
114 #define SPICC_DWADDR    0x24    /* Write Address of DMA */
115
116 #define writel_bits_relaxed(mask, val, addr) \
117         writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr)
118
119 #define SPICC_BURST_MAX 16
120 #define SPICC_FIFO_HALF 10
121
122 struct meson_spicc_device {
123         struct spi_master               *master;
124         struct platform_device          *pdev;
125         void __iomem                    *base;
126         struct clk                      *core;
127         struct spi_message              *message;
128         struct spi_transfer             *xfer;
129         u8                              *tx_buf;
130         u8                              *rx_buf;
131         unsigned int                    bytes_per_word;
132         unsigned long                   tx_remain;
133         unsigned long                   txb_remain;
134         unsigned long                   rx_remain;
135         unsigned long                   rxb_remain;
136         unsigned long                   xfer_remain;
137         bool                            is_burst_end;
138         bool                            is_last_burst;
139 };
140
141 static inline bool meson_spicc_txfull(struct meson_spicc_device *spicc)
142 {
143         return !!FIELD_GET(SPICC_TF,
144                            readl_relaxed(spicc->base + SPICC_STATREG));
145 }
146
147 static inline bool meson_spicc_rxready(struct meson_spicc_device *spicc)
148 {
149         return FIELD_GET(SPICC_RH | SPICC_RR | SPICC_RF_EN,
150                          readl_relaxed(spicc->base + SPICC_STATREG));
151 }
152
153 static inline u32 meson_spicc_pull_data(struct meson_spicc_device *spicc)
154 {
155         unsigned int bytes = spicc->bytes_per_word;
156         unsigned int byte_shift = 0;
157         u32 data = 0;
158         u8 byte;
159
160         while (bytes--) {
161                 byte = *spicc->tx_buf++;
162                 data |= (byte & 0xff) << byte_shift;
163                 byte_shift += 8;
164         }
165
166         spicc->tx_remain--;
167         return data;
168 }
169
170 static inline void meson_spicc_push_data(struct meson_spicc_device *spicc,
171                                          u32 data)
172 {
173         unsigned int bytes = spicc->bytes_per_word;
174         unsigned int byte_shift = 0;
175         u8 byte;
176
177         while (bytes--) {
178                 byte = (data >> byte_shift) & 0xff;
179                 *spicc->rx_buf++ = byte;
180                 byte_shift += 8;
181         }
182
183         spicc->rx_remain--;
184 }
185
186 static inline void meson_spicc_rx(struct meson_spicc_device *spicc)
187 {
188         /* Empty RX FIFO */
189         while (spicc->rx_remain &&
190                meson_spicc_rxready(spicc))
191                 meson_spicc_push_data(spicc,
192                                 readl_relaxed(spicc->base + SPICC_RXDATA));
193 }
194
195 static inline void meson_spicc_tx(struct meson_spicc_device *spicc)
196 {
197         /* Fill Up TX FIFO */
198         while (spicc->tx_remain &&
199                !meson_spicc_txfull(spicc))
200                 writel_relaxed(meson_spicc_pull_data(spicc),
201                                spicc->base + SPICC_TXDATA);
202 }
203
204 static inline u32 meson_spicc_setup_rx_irq(struct meson_spicc_device *spicc,
205                                            u32 irq_ctrl)
206 {
207         if (spicc->rx_remain > SPICC_FIFO_HALF)
208                 irq_ctrl |= SPICC_RH_EN;
209         else
210                 irq_ctrl |= SPICC_RR_EN;
211
212         return irq_ctrl;
213 }
214
215 static inline void meson_spicc_setup_burst(struct meson_spicc_device *spicc,
216                                            unsigned int burst_len)
217 {
218         /* Setup Xfer variables */
219         spicc->tx_remain = burst_len;
220         spicc->rx_remain = burst_len;
221         spicc->xfer_remain -= burst_len * spicc->bytes_per_word;
222         spicc->is_burst_end = false;
223         if (burst_len < SPICC_BURST_MAX || !spicc->xfer_remain)
224                 spicc->is_last_burst = true;
225         else
226                 spicc->is_last_burst = false;
227
228         /* Setup burst length */
229         writel_bits_relaxed(SPICC_BURSTLENGTH_MASK,
230                         FIELD_PREP(SPICC_BURSTLENGTH_MASK,
231                                 burst_len),
232                         spicc->base + SPICC_CONREG);
233
234         /* Fill TX FIFO */
235         meson_spicc_tx(spicc);
236 }
237
238 static irqreturn_t meson_spicc_irq(int irq, void *data)
239 {
240         struct meson_spicc_device *spicc = (void *) data;
241         u32 ctrl = readl_relaxed(spicc->base + SPICC_INTREG);
242         u32 stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl;
243
244         ctrl &= ~(SPICC_RH_EN | SPICC_RR_EN);
245
246         /* Empty RX FIFO */
247         meson_spicc_rx(spicc);
248
249         /* Enable TC interrupt since we transferred everything */
250         if (!spicc->tx_remain && !spicc->rx_remain) {
251                 spicc->is_burst_end = true;
252
253                 /* Enable TC interrupt */
254                 ctrl |= SPICC_TC_EN;
255
256                 /* Reload IRQ status */
257                 stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl;
258         }
259
260         /* Check transfer complete */
261         if ((stat & SPICC_TC) && spicc->is_burst_end) {
262                 unsigned int burst_len;
263
264                 /* Clear TC bit */
265                 writel_relaxed(SPICC_TC, spicc->base + SPICC_STATREG);
266
267                 /* Disable TC interrupt */
268                 ctrl &= ~SPICC_TC_EN;
269
270                 if (spicc->is_last_burst) {
271                         /* Disable all IRQs */
272                         writel(0, spicc->base + SPICC_INTREG);
273
274                         spi_finalize_current_transfer(spicc->master);
275
276                         return IRQ_HANDLED;
277                 }
278
279                 burst_len = min_t(unsigned int,
280                                   spicc->xfer_remain / spicc->bytes_per_word,
281                                   SPICC_BURST_MAX);
282
283                 /* Setup burst */
284                 meson_spicc_setup_burst(spicc, burst_len);
285
286                 /* Restart burst */
287                 writel_bits_relaxed(SPICC_XCH, SPICC_XCH,
288                                     spicc->base + SPICC_CONREG);
289         }
290
291         /* Setup RX interrupt trigger */
292         ctrl = meson_spicc_setup_rx_irq(spicc, ctrl);
293
294         /* Reconfigure interrupts */
295         writel(ctrl, spicc->base + SPICC_INTREG);
296
297         return IRQ_HANDLED;
298 }
299
300 static u32 meson_spicc_setup_speed(struct meson_spicc_device *spicc, u32 conf,
301                                    u32 speed)
302 {
303         unsigned long parent, value;
304         unsigned int i, div;
305
306         parent = clk_get_rate(spicc->core);
307
308         /* Find closest inferior/equal possible speed */
309         for (i = 0 ; i < 7 ; ++i) {
310                 /* 2^(data_rate+2) */
311                 value = parent >> (i + 2);
312
313                 if (value <= speed)
314                         break;
315         }
316
317         /* If provided speed it lower than max divider, use max divider */
318         if (i > 7) {
319                 div = 7;
320                 dev_warn_once(&spicc->pdev->dev, "unable to get close to speed %u\n",
321                               speed);
322         } else
323                 div = i;
324
325         dev_dbg(&spicc->pdev->dev, "parent %lu, speed %u -> %lu (%u)\n",
326                 parent, speed, value, div);
327
328         conf &= ~SPICC_DATARATE_MASK;
329         conf |= FIELD_PREP(SPICC_DATARATE_MASK, div);
330
331         return conf;
332 }
333
334 static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
335                                    struct spi_transfer *xfer)
336 {
337         u32 conf, conf_orig;
338
339         /* Read original configuration */
340         conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG);
341
342         /* Select closest divider */
343         conf = meson_spicc_setup_speed(spicc, conf, xfer->speed_hz);
344
345         /* Setup word width */
346         conf &= ~SPICC_BITLENGTH_MASK;
347         conf |= FIELD_PREP(SPICC_BITLENGTH_MASK,
348                            (spicc->bytes_per_word << 3) - 1);
349
350         /* Ignore if unchanged */
351         if (conf != conf_orig)
352                 writel_relaxed(conf, spicc->base + SPICC_CONREG);
353 }
354
355 static int meson_spicc_transfer_one(struct spi_master *master,
356                                     struct spi_device *spi,
357                                     struct spi_transfer *xfer)
358 {
359         struct meson_spicc_device *spicc = spi_master_get_devdata(master);
360         unsigned int burst_len;
361         u32 irq = 0;
362
363         /* Store current transfer */
364         spicc->xfer = xfer;
365
366         /* Setup transfer parameters */
367         spicc->tx_buf = (u8 *)xfer->tx_buf;
368         spicc->rx_buf = (u8 *)xfer->rx_buf;
369         spicc->xfer_remain = xfer->len;
370
371         /* Pre-calculate word size */
372         spicc->bytes_per_word =
373            DIV_ROUND_UP(spicc->xfer->bits_per_word, 8);
374
375         /* Setup transfer parameters */
376         meson_spicc_setup_xfer(spicc, xfer);
377
378         burst_len = min_t(unsigned int,
379                           spicc->xfer_remain / spicc->bytes_per_word,
380                           SPICC_BURST_MAX);
381
382         meson_spicc_setup_burst(spicc, burst_len);
383
384         irq = meson_spicc_setup_rx_irq(spicc, irq);
385
386         /* Start burst */
387         writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
388
389         /* Enable interrupts */
390         writel_relaxed(irq, spicc->base + SPICC_INTREG);
391
392         return 1;
393 }
394
395 static int meson_spicc_prepare_message(struct spi_master *master,
396                                        struct spi_message *message)
397 {
398         struct meson_spicc_device *spicc = spi_master_get_devdata(master);
399         struct spi_device *spi = message->spi;
400         u32 conf = 0;
401
402         /* Store current message */
403         spicc->message = message;
404
405         /* Enable Master */
406         conf |= SPICC_ENABLE;
407         conf |= SPICC_MODE_MASTER;
408
409         /* SMC = 0 */
410
411         /* Setup transfer mode */
412         if (spi->mode & SPI_CPOL)
413                 conf |= SPICC_POL;
414         else
415                 conf &= ~SPICC_POL;
416
417         if (spi->mode & SPI_CPHA)
418                 conf |= SPICC_PHA;
419         else
420                 conf &= ~SPICC_PHA;
421
422         /* SSCTL = 0 */
423
424         if (spi->mode & SPI_CS_HIGH)
425                 conf |= SPICC_SSPOL;
426         else
427                 conf &= ~SPICC_SSPOL;
428
429         if (spi->mode & SPI_READY)
430                 conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_LOWLEVEL);
431         else
432                 conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_IGNORE);
433
434         /* Select CS */
435         conf |= FIELD_PREP(SPICC_CS_MASK, spi->chip_select);
436
437         /* Default Clock rate core/4 */
438
439         /* Default 8bit word */
440         conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, 8 - 1);
441
442         writel_relaxed(conf, spicc->base + SPICC_CONREG);
443
444         /* Setup no wait cycles by default */
445         writel_relaxed(0, spicc->base + SPICC_PERIODREG);
446
447         writel_bits_relaxed(BIT(24), BIT(24), spicc->base + SPICC_TESTREG);
448
449         return 0;
450 }
451
452 static int meson_spicc_unprepare_transfer(struct spi_master *master)
453 {
454         struct meson_spicc_device *spicc = spi_master_get_devdata(master);
455
456         /* Disable all IRQs */
457         writel(0, spicc->base + SPICC_INTREG);
458
459         /* Disable controller */
460         writel_bits_relaxed(SPICC_ENABLE, 0, spicc->base + SPICC_CONREG);
461
462         device_reset_optional(&spicc->pdev->dev);
463
464         return 0;
465 }
466
467 static int meson_spicc_setup(struct spi_device *spi)
468 {
469         if (!spi->controller_state)
470                 spi->controller_state = spi_master_get_devdata(spi->master);
471
472         return 0;
473 }
474
475 static void meson_spicc_cleanup(struct spi_device *spi)
476 {
477         spi->controller_state = NULL;
478 }
479
480 static int meson_spicc_probe(struct platform_device *pdev)
481 {
482         struct spi_master *master;
483         struct meson_spicc_device *spicc;
484         int ret, irq, rate;
485
486         master = spi_alloc_master(&pdev->dev, sizeof(*spicc));
487         if (!master) {
488                 dev_err(&pdev->dev, "master allocation failed\n");
489                 return -ENOMEM;
490         }
491         spicc = spi_master_get_devdata(master);
492         spicc->master = master;
493
494         spicc->pdev = pdev;
495         platform_set_drvdata(pdev, spicc);
496
497         spicc->base = devm_platform_ioremap_resource(pdev, 0);
498         if (IS_ERR(spicc->base)) {
499                 dev_err(&pdev->dev, "io resource mapping failed\n");
500                 ret = PTR_ERR(spicc->base);
501                 goto out_master;
502         }
503
504         /* Disable all IRQs */
505         writel_relaxed(0, spicc->base + SPICC_INTREG);
506
507         irq = platform_get_irq(pdev, 0);
508         ret = devm_request_irq(&pdev->dev, irq, meson_spicc_irq,
509                                0, NULL, spicc);
510         if (ret) {
511                 dev_err(&pdev->dev, "irq request failed\n");
512                 goto out_master;
513         }
514
515         spicc->core = devm_clk_get(&pdev->dev, "core");
516         if (IS_ERR(spicc->core)) {
517                 dev_err(&pdev->dev, "core clock request failed\n");
518                 ret = PTR_ERR(spicc->core);
519                 goto out_master;
520         }
521
522         ret = clk_prepare_enable(spicc->core);
523         if (ret) {
524                 dev_err(&pdev->dev, "core clock enable failed\n");
525                 goto out_master;
526         }
527         rate = clk_get_rate(spicc->core);
528
529         device_reset_optional(&pdev->dev);
530
531         master->num_chipselect = 4;
532         master->dev.of_node = pdev->dev.of_node;
533         master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
534         master->bits_per_word_mask = SPI_BPW_MASK(32) |
535                                      SPI_BPW_MASK(24) |
536                                      SPI_BPW_MASK(16) |
537                                      SPI_BPW_MASK(8);
538         master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
539         master->min_speed_hz = rate >> 9;
540         master->setup = meson_spicc_setup;
541         master->cleanup = meson_spicc_cleanup;
542         master->prepare_message = meson_spicc_prepare_message;
543         master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer;
544         master->transfer_one = meson_spicc_transfer_one;
545         master->use_gpio_descriptors = true;
546
547         /* Setup max rate according to the Meson GX datasheet */
548         if ((rate >> 2) > SPICC_MAX_FREQ)
549                 master->max_speed_hz = SPICC_MAX_FREQ;
550         else
551                 master->max_speed_hz = rate >> 2;
552
553         ret = devm_spi_register_master(&pdev->dev, master);
554         if (ret) {
555                 dev_err(&pdev->dev, "spi master registration failed\n");
556                 goto out_clk;
557         }
558
559         return 0;
560
561 out_clk:
562         clk_disable_unprepare(spicc->core);
563
564 out_master:
565         spi_master_put(master);
566
567         return ret;
568 }
569
570 static int meson_spicc_remove(struct platform_device *pdev)
571 {
572         struct meson_spicc_device *spicc = platform_get_drvdata(pdev);
573
574         /* Disable SPI */
575         writel(0, spicc->base + SPICC_CONREG);
576
577         clk_disable_unprepare(spicc->core);
578
579         return 0;
580 }
581
582 static const struct of_device_id meson_spicc_of_match[] = {
583         { .compatible = "amlogic,meson-gx-spicc", },
584         { .compatible = "amlogic,meson-axg-spicc", },
585         { /* sentinel */ }
586 };
587 MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
588
589 static struct platform_driver meson_spicc_driver = {
590         .probe   = meson_spicc_probe,
591         .remove  = meson_spicc_remove,
592         .driver  = {
593                 .name = "meson-spicc",
594                 .of_match_table = of_match_ptr(meson_spicc_of_match),
595         },
596 };
597
598 module_platform_driver(meson_spicc_driver);
599
600 MODULE_DESCRIPTION("Meson SPI Communication Controller driver");
601 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
602 MODULE_LICENSE("GPL");