1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * pci-j721e - PCIe controller driver for TI's J721E SoCs
4  *
5  * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com
6  * Author: Kishon Vijay Abraham I <kishon@ti.com>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/io.h>
13 #include <linux/irqchip/chained_irq.h>
14 #include <linux/irqdomain.h>
15 #include <linux/mfd/syscon.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/pci.h>
19 #include <linux/pm_runtime.h>
20 #include <linux/regmap.h>
21 
22 #include "../../pci.h"
23 #include "pcie-cadence.h"
24 
25 #define ENABLE_REG_SYS_2	0x108
26 #define STATUS_REG_SYS_2	0x508
27 #define STATUS_CLR_REG_SYS_2	0x708
28 #define LINK_DOWN		BIT(1)
29 #define J7200_LINK_DOWN		BIT(10)
30 
31 #define J721E_PCIE_USER_CMD_STATUS	0x4
32 #define LINK_TRAINING_ENABLE		BIT(0)
33 
34 #define J721E_PCIE_USER_LINKSTATUS	0x14
35 #define LINK_STATUS			GENMASK(1, 0)
36 
37 enum link_status {
38 	NO_RECEIVERS_DETECTED,
39 	LINK_TRAINING_IN_PROGRESS,
40 	LINK_UP_DL_IN_PROGRESS,
41 	LINK_UP_DL_COMPLETED,
42 };
43 
44 #define J721E_MODE_RC			BIT(7)
45 #define LANE_COUNT_MASK			BIT(8)
46 #define LANE_COUNT(n)			((n) << 8)
47 
48 #define GENERATION_SEL_MASK		GENMASK(1, 0)
49 
50 #define MAX_LANES			2
51 
52 struct j721e_pcie {
53 	struct cdns_pcie	*cdns_pcie;
54 	struct clk		*refclk;
55 	u32			mode;
56 	u32			num_lanes;
57 	void __iomem		*user_cfg_base;
58 	void __iomem		*intd_cfg_base;
59 	u32			linkdown_irq_regfield;
60 };
61 
62 enum j721e_pcie_mode {
63 	PCI_MODE_RC,
64 	PCI_MODE_EP,
65 };
66 
67 struct j721e_pcie_data {
68 	enum j721e_pcie_mode	mode;
69 	unsigned int		quirk_retrain_flag:1;
70 	unsigned int		quirk_detect_quiet_flag:1;
71 	unsigned int		quirk_disable_flr:1;
72 	u32			linkdown_irq_regfield;
73 	unsigned int		byte_access_allowed:1;
74 };
75 
76 static inline u32 j721e_pcie_user_readl(struct j721e_pcie *pcie, u32 offset)
77 {
78 	return readl(pcie->user_cfg_base + offset);
79 }
80 
81 static inline void j721e_pcie_user_writel(struct j721e_pcie *pcie, u32 offset,
82 					  u32 value)
83 {
84 	writel(value, pcie->user_cfg_base + offset);
85 }
86 
87 static inline u32 j721e_pcie_intd_readl(struct j721e_pcie *pcie, u32 offset)
88 {
89 	return readl(pcie->intd_cfg_base + offset);
90 }
91 
92 static inline void j721e_pcie_intd_writel(struct j721e_pcie *pcie, u32 offset,
93 					  u32 value)
94 {
95 	writel(value, pcie->intd_cfg_base + offset);
96 }
97 
98 static irqreturn_t j721e_pcie_link_irq_handler(int irq, void *priv)
99 {
100 	struct j721e_pcie *pcie = priv;
101 	struct device *dev = pcie->cdns_pcie->dev;
102 	u32 reg;
103 
104 	reg = j721e_pcie_intd_readl(pcie, STATUS_REG_SYS_2);
105 	if (!(reg & pcie->linkdown_irq_regfield))
106 		return IRQ_NONE;
107 
108 	dev_err(dev, "LINK DOWN!\n");
109 
110 	j721e_pcie_intd_writel(pcie, STATUS_CLR_REG_SYS_2, pcie->linkdown_irq_regfield);
111 	return IRQ_HANDLED;
112 }
113 
114 static void j721e_pcie_config_link_irq(struct j721e_pcie *pcie)
115 {
116 	u32 reg;
117 
118 	reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_2);
119 	reg |= pcie->linkdown_irq_regfield;
120 	j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_2, reg);
121 }
122 
123 static int j721e_pcie_start_link(struct cdns_pcie *cdns_pcie)
124 {
125 	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
126 	u32 reg;
127 
128 	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
129 	reg |= LINK_TRAINING_ENABLE;
130 	j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
131 
132 	return 0;
133 }
134 
135 static void j721e_pcie_stop_link(struct cdns_pcie *cdns_pcie)
136 {
137 	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
138 	u32 reg;
139 
140 	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
141 	reg &= ~LINK_TRAINING_ENABLE;
142 	j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
143 }
144 
145 static bool j721e_pcie_link_up(struct cdns_pcie *cdns_pcie)
146 {
147 	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
148 	u32 reg;
149 
150 	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_LINKSTATUS);
151 	reg &= LINK_STATUS;
152 	if (reg == LINK_UP_DL_COMPLETED)
153 		return true;
154 
155 	return false;
156 }
157 
158 static const struct cdns_pcie_ops j721e_pcie_ops = {
159 	.start_link = j721e_pcie_start_link,
160 	.stop_link = j721e_pcie_stop_link,
161 	.link_up = j721e_pcie_link_up,
162 };
163 
164 static int j721e_pcie_set_mode(struct j721e_pcie *pcie, struct regmap *syscon,
165 			       unsigned int offset)
166 {
167 	struct device *dev = pcie->cdns_pcie->dev;
168 	u32 mask = J721E_MODE_RC;
169 	u32 mode = pcie->mode;
170 	u32 val = 0;
171 	int ret = 0;
172 
173 	if (mode == PCI_MODE_RC)
174 		val = J721E_MODE_RC;
175 
176 	ret = regmap_update_bits(syscon, offset, mask, val);
177 	if (ret)
178 		dev_err(dev, "failed to set pcie mode\n");
179 
180 	return ret;
181 }
182 
183 static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
184 				     struct regmap *syscon, unsigned int offset)
185 {
186 	struct device *dev = pcie->cdns_pcie->dev;
187 	struct device_node *np = dev->of_node;
188 	int link_speed;
189 	u32 val = 0;
190 	int ret;
191 
192 	link_speed = of_pci_get_max_link_speed(np);
193 	if (link_speed < 2)
194 		link_speed = 2;
195 
196 	val = link_speed - 1;
197 	ret = regmap_update_bits(syscon, offset, GENERATION_SEL_MASK, val);
198 	if (ret)
199 		dev_err(dev, "failed to set link speed\n");
200 
201 	return ret;
202 }
203 
204 static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
205 				     struct regmap *syscon, unsigned int offset)
206 {
207 	struct device *dev = pcie->cdns_pcie->dev;
208 	u32 lanes = pcie->num_lanes;
209 	u32 val = 0;
210 	int ret;
211 
212 	val = LANE_COUNT(lanes - 1);
213 	ret = regmap_update_bits(syscon, offset, LANE_COUNT_MASK, val);
214 	if (ret)
215 		dev_err(dev, "failed to set link count\n");
216 
217 	return ret;
218 }
219 
220 static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie)
221 {
222 	struct device *dev = pcie->cdns_pcie->dev;
223 	struct device_node *node = dev->of_node;
224 	struct of_phandle_args args;
225 	unsigned int offset = 0;
226 	struct regmap *syscon;
227 	int ret;
228 
229 	syscon = syscon_regmap_lookup_by_phandle(node, "ti,syscon-pcie-ctrl");
230 	if (IS_ERR(syscon)) {
231 		dev_err(dev, "Unable to get ti,syscon-pcie-ctrl regmap\n");
232 		return PTR_ERR(syscon);
233 	}
234 
235 	/* Do not error out to maintain old DT compatibility */
236 	ret = of_parse_phandle_with_fixed_args(node, "ti,syscon-pcie-ctrl", 1,
237 					       0, &args);
238 	if (!ret)
239 		offset = args.args[0];
240 
241 	ret = j721e_pcie_set_mode(pcie, syscon, offset);
242 	if (ret < 0) {
243 		dev_err(dev, "Failed to set pci mode\n");
244 		return ret;
245 	}
246 
247 	ret = j721e_pcie_set_link_speed(pcie, syscon, offset);
248 	if (ret < 0) {
249 		dev_err(dev, "Failed to set link speed\n");
250 		return ret;
251 	}
252 
253 	ret = j721e_pcie_set_lane_count(pcie, syscon, offset);
254 	if (ret < 0) {
255 		dev_err(dev, "Failed to set num-lanes\n");
256 		return ret;
257 	}
258 
259 	return 0;
260 }
261 
262 static int cdns_ti_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
263 				    int where, int size, u32 *value)
264 {
265 	if (pci_is_root_bus(bus))
266 		return pci_generic_config_read32(bus, devfn, where, size,
267 						 value);
268 
269 	return pci_generic_config_read(bus, devfn, where, size, value);
270 }
271 
272 static int cdns_ti_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
273 				     int where, int size, u32 value)
274 {
275 	if (pci_is_root_bus(bus))
276 		return pci_generic_config_write32(bus, devfn, where, size,
277 						  value);
278 
279 	return pci_generic_config_write(bus, devfn, where, size, value);
280 }
281 
282 static struct pci_ops cdns_ti_pcie_host_ops = {
283 	.map_bus	= cdns_pci_map_bus,
284 	.read		= cdns_ti_pcie_config_read,
285 	.write		= cdns_ti_pcie_config_write,
286 };
287 
288 static const struct j721e_pcie_data j721e_pcie_rc_data = {
289 	.mode = PCI_MODE_RC,
290 	.quirk_retrain_flag = true,
291 	.byte_access_allowed = false,
292 	.linkdown_irq_regfield = LINK_DOWN,
293 };
294 
295 static const struct j721e_pcie_data j721e_pcie_ep_data = {
296 	.mode = PCI_MODE_EP,
297 	.linkdown_irq_regfield = LINK_DOWN,
298 };
299 
300 static const struct j721e_pcie_data j7200_pcie_rc_data = {
301 	.mode = PCI_MODE_RC,
302 	.quirk_detect_quiet_flag = true,
303 	.linkdown_irq_regfield = J7200_LINK_DOWN,
304 	.byte_access_allowed = true,
305 };
306 
307 static const struct j721e_pcie_data j7200_pcie_ep_data = {
308 	.mode = PCI_MODE_EP,
309 	.quirk_detect_quiet_flag = true,
310 	.quirk_disable_flr = true,
311 };
312 
313 static const struct j721e_pcie_data am64_pcie_rc_data = {
314 	.mode = PCI_MODE_RC,
315 	.linkdown_irq_regfield = J7200_LINK_DOWN,
316 	.byte_access_allowed = true,
317 };
318 
319 static const struct j721e_pcie_data am64_pcie_ep_data = {
320 	.mode = PCI_MODE_EP,
321 	.linkdown_irq_regfield = J7200_LINK_DOWN,
322 };
323 
324 static const struct of_device_id of_j721e_pcie_match[] = {
325 	{
326 		.compatible = "ti,j721e-pcie-host",
327 		.data = &j721e_pcie_rc_data,
328 	},
329 	{
330 		.compatible = "ti,j721e-pcie-ep",
331 		.data = &j721e_pcie_ep_data,
332 	},
333 	{
334 		.compatible = "ti,j7200-pcie-host",
335 		.data = &j7200_pcie_rc_data,
336 	},
337 	{
338 		.compatible = "ti,j7200-pcie-ep",
339 		.data = &j7200_pcie_ep_data,
340 	},
341 	{
342 		.compatible = "ti,am64-pcie-host",
343 		.data = &am64_pcie_rc_data,
344 	},
345 	{
346 		.compatible = "ti,am64-pcie-ep",
347 		.data = &am64_pcie_ep_data,
348 	},
349 	{},
350 };
351 
352 static int j721e_pcie_probe(struct platform_device *pdev)
353 {
354 	struct device *dev = &pdev->dev;
355 	struct device_node *node = dev->of_node;
356 	struct pci_host_bridge *bridge;
357 	const struct j721e_pcie_data *data;
358 	struct cdns_pcie *cdns_pcie;
359 	struct j721e_pcie *pcie;
360 	struct cdns_pcie_rc *rc = NULL;
361 	struct cdns_pcie_ep *ep = NULL;
362 	struct gpio_desc *gpiod;
363 	void __iomem *base;
364 	struct clk *clk;
365 	u32 num_lanes;
366 	u32 mode;
367 	int ret;
368 	int irq;
369 
370 	data = of_device_get_match_data(dev);
371 	if (!data)
372 		return -EINVAL;
373 
374 	mode = (u32)data->mode;
375 
376 	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
377 	if (!pcie)
378 		return -ENOMEM;
379 
380 	switch (mode) {
381 	case PCI_MODE_RC:
382 		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST))
383 			return -ENODEV;
384 
385 		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
386 		if (!bridge)
387 			return -ENOMEM;
388 
389 		if (!data->byte_access_allowed)
390 			bridge->ops = &cdns_ti_pcie_host_ops;
391 		rc = pci_host_bridge_priv(bridge);
392 		rc->quirk_retrain_flag = data->quirk_retrain_flag;
393 		rc->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
394 
395 		cdns_pcie = &rc->pcie;
396 		cdns_pcie->dev = dev;
397 		cdns_pcie->ops = &j721e_pcie_ops;
398 		pcie->cdns_pcie = cdns_pcie;
399 		break;
400 	case PCI_MODE_EP:
401 		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP))
402 			return -ENODEV;
403 
404 		ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
405 		if (!ep)
406 			return -ENOMEM;
407 
408 		ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
409 		ep->quirk_disable_flr = data->quirk_disable_flr;
410 
411 		cdns_pcie = &ep->pcie;
412 		cdns_pcie->dev = dev;
413 		cdns_pcie->ops = &j721e_pcie_ops;
414 		pcie->cdns_pcie = cdns_pcie;
415 		break;
416 	default:
417 		dev_err(dev, "INVALID device type %d\n", mode);
418 		return 0;
419 	}
420 
421 	pcie->mode = mode;
422 	pcie->linkdown_irq_regfield = data->linkdown_irq_regfield;
423 
424 	base = devm_platform_ioremap_resource_byname(pdev, "intd_cfg");
425 	if (IS_ERR(base))
426 		return PTR_ERR(base);
427 	pcie->intd_cfg_base = base;
428 
429 	base = devm_platform_ioremap_resource_byname(pdev, "user_cfg");
430 	if (IS_ERR(base))
431 		return PTR_ERR(base);
432 	pcie->user_cfg_base = base;
433 
434 	ret = of_property_read_u32(node, "num-lanes", &num_lanes);
435 	if (ret || num_lanes > MAX_LANES)
436 		num_lanes = 1;
437 	pcie->num_lanes = num_lanes;
438 
439 	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48)))
440 		return -EINVAL;
441 
442 	irq = platform_get_irq_byname(pdev, "link_state");
443 	if (irq < 0)
444 		return irq;
445 
446 	dev_set_drvdata(dev, pcie);
447 	pm_runtime_enable(dev);
448 	ret = pm_runtime_get_sync(dev);
449 	if (ret < 0) {
450 		dev_err(dev, "pm_runtime_get_sync failed\n");
451 		goto err_get_sync;
452 	}
453 
454 	ret = j721e_pcie_ctrl_init(pcie);
455 	if (ret < 0) {
456 		dev_err(dev, "pm_runtime_get_sync failed\n");
457 		goto err_get_sync;
458 	}
459 
460 	ret = devm_request_irq(dev, irq, j721e_pcie_link_irq_handler, 0,
461 			       "j721e-pcie-link-down-irq", pcie);
462 	if (ret < 0) {
463 		dev_err(dev, "failed to request link state IRQ %d\n", irq);
464 		goto err_get_sync;
465 	}
466 
467 	j721e_pcie_config_link_irq(pcie);
468 
469 	switch (mode) {
470 	case PCI_MODE_RC:
471 		gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
472 		if (IS_ERR(gpiod)) {
473 			ret = PTR_ERR(gpiod);
474 			if (ret != -EPROBE_DEFER)
475 				dev_err(dev, "Failed to get reset GPIO\n");
476 			goto err_get_sync;
477 		}
478 
479 		ret = cdns_pcie_init_phy(dev, cdns_pcie);
480 		if (ret) {
481 			dev_err(dev, "Failed to init phy\n");
482 			goto err_get_sync;
483 		}
484 
485 		clk = devm_clk_get_optional(dev, "pcie_refclk");
486 		if (IS_ERR(clk)) {
487 			ret = PTR_ERR(clk);
488 			dev_err(dev, "failed to get pcie_refclk\n");
489 			goto err_pcie_setup;
490 		}
491 
492 		ret = clk_prepare_enable(clk);
493 		if (ret) {
494 			dev_err(dev, "failed to enable pcie_refclk\n");
495 			goto err_pcie_setup;
496 		}
497 		pcie->refclk = clk;
498 
499 		/*
500 		 * "Power Sequencing and Reset Signal Timings" table in
501 		 * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0
502 		 * indicates PERST# should be deasserted after minimum of 100us
503 		 * once REFCLK is stable. The REFCLK to the connector in RC
504 		 * mode is selected while enabling the PHY. So deassert PERST#
505 		 * after 100 us.
506 		 */
507 		if (gpiod) {
508 			usleep_range(100, 200);
509 			gpiod_set_value_cansleep(gpiod, 1);
510 		}
511 
512 		ret = cdns_pcie_host_setup(rc);
513 		if (ret < 0) {
514 			clk_disable_unprepare(pcie->refclk);
515 			goto err_pcie_setup;
516 		}
517 
518 		break;
519 	case PCI_MODE_EP:
520 		ret = cdns_pcie_init_phy(dev, cdns_pcie);
521 		if (ret) {
522 			dev_err(dev, "Failed to init phy\n");
523 			goto err_get_sync;
524 		}
525 
526 		ret = cdns_pcie_ep_setup(ep);
527 		if (ret < 0)
528 			goto err_pcie_setup;
529 
530 		break;
531 	}
532 
533 	return 0;
534 
535 err_pcie_setup:
536 	cdns_pcie_disable_phy(cdns_pcie);
537 
538 err_get_sync:
539 	pm_runtime_put(dev);
540 	pm_runtime_disable(dev);
541 
542 	return ret;
543 }
544 
545 static void j721e_pcie_remove(struct platform_device *pdev)
546 {
547 	struct j721e_pcie *pcie = platform_get_drvdata(pdev);
548 	struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
549 	struct device *dev = &pdev->dev;
550 
551 	clk_disable_unprepare(pcie->refclk);
552 	cdns_pcie_disable_phy(cdns_pcie);
553 	pm_runtime_put(dev);
554 	pm_runtime_disable(dev);
555 }
556 
557 static struct platform_driver j721e_pcie_driver = {
558 	.probe  = j721e_pcie_probe,
559 	.remove_new = j721e_pcie_remove,
560 	.driver = {
561 		.name	= "j721e-pcie",
562 		.of_match_table = of_j721e_pcie_match,
563 		.suppress_bind_attrs = true,
564 	},
565 };
566 builtin_platform_driver(j721e_pcie_driver);
567