1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PCIe host controller driver for Amazon's Annapurna Labs IP (used in chips
4  * such as Graviton and Alpine)
5  *
6  * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
7  *
8  * Author: Jonathan Chocron <jonnyc@amazon.com>
9  */
10 
11 #include <linux/pci.h>
12 #include <linux/pci-ecam.h>
13 #include <linux/pci-acpi.h>
14 #include "../../pci.h"
15 
16 #if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
17 
18 struct al_pcie_acpi  {
19 	void __iomem *dbi_base;
20 };
21 
22 static void __iomem *al_pcie_map_bus(struct pci_bus *bus, unsigned int devfn,
23 				     int where)
24 {
25 	struct pci_config_window *cfg = bus->sysdata;
26 	struct al_pcie_acpi *pcie = cfg->priv;
27 	void __iomem *dbi_base = pcie->dbi_base;
28 
29 	if (bus->number == cfg->busr.start) {
30 		/*
31 		 * The DW PCIe core doesn't filter out transactions to other
32 		 * devices/functions on the root bus num, so we do this here.
33 		 */
34 		if (PCI_SLOT(devfn) > 0)
35 			return NULL;
36 		else
37 			return dbi_base + where;
38 	}
39 
40 	return pci_ecam_map_bus(bus, devfn, where);
41 }
42 
43 static int al_pcie_init(struct pci_config_window *cfg)
44 {
45 	struct device *dev = cfg->parent;
46 	struct acpi_device *adev = to_acpi_device(dev);
47 	struct acpi_pci_root *root = acpi_driver_data(adev);
48 	struct al_pcie_acpi *al_pcie;
49 	struct resource *res;
50 	int ret;
51 
52 	al_pcie = devm_kzalloc(dev, sizeof(*al_pcie), GFP_KERNEL);
53 	if (!al_pcie)
54 		return -ENOMEM;
55 
56 	res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
57 	if (!res)
58 		return -ENOMEM;
59 
60 	ret = acpi_get_rc_resources(dev, "AMZN0001", root->segment, res);
61 	if (ret) {
62 		dev_err(dev, "can't get rc dbi base address for SEG %d\n",
63 			root->segment);
64 		return ret;
65 	}
66 
67 	dev_dbg(dev, "Root port dbi res: %pR\n", res);
68 
69 	al_pcie->dbi_base = devm_pci_remap_cfg_resource(dev, res);
70 	if (IS_ERR(al_pcie->dbi_base)) {
71 		long err = PTR_ERR(al_pcie->dbi_base);
72 
73 		dev_err(dev, "couldn't remap dbi base %pR (err:%ld)\n",
74 			res, err);
75 		return err;
76 	}
77 
78 	cfg->priv = al_pcie;
79 
80 	return 0;
81 }
82 
83 const struct pci_ecam_ops al_pcie_ops = {
84 	.bus_shift    = 20,
85 	.init         =  al_pcie_init,
86 	.pci_ops      = {
87 		.map_bus    = al_pcie_map_bus,
88 		.read       = pci_generic_config_read,
89 		.write      = pci_generic_config_write,
90 	}
91 };
92 
93 #endif /* defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS) */
94 
95 #ifdef CONFIG_PCIE_AL
96 
97 #include <linux/of_pci.h>
98 #include "pcie-designware.h"
99 
100 #define AL_PCIE_REV_ID_2	2
101 #define AL_PCIE_REV_ID_3	3
102 #define AL_PCIE_REV_ID_4	4
103 
104 #define AXI_BASE_OFFSET		0x0
105 
106 #define DEVICE_ID_OFFSET	0x16c
107 
108 #define DEVICE_REV_ID			0x0
109 #define DEVICE_REV_ID_DEV_ID_MASK	GENMASK(31, 16)
110 
111 #define DEVICE_REV_ID_DEV_ID_X4		0
112 #define DEVICE_REV_ID_DEV_ID_X8		2
113 #define DEVICE_REV_ID_DEV_ID_X16	4
114 
115 #define OB_CTRL_REV1_2_OFFSET	0x0040
116 #define OB_CTRL_REV3_5_OFFSET	0x0030
117 
118 #define CFG_TARGET_BUS			0x0
119 #define CFG_TARGET_BUS_MASK_MASK	GENMASK(7, 0)
120 #define CFG_TARGET_BUS_BUSNUM_MASK	GENMASK(15, 8)
121 
122 #define CFG_CONTROL			0x4
123 #define CFG_CONTROL_SUBBUS_MASK		GENMASK(15, 8)
124 #define CFG_CONTROL_SEC_BUS_MASK	GENMASK(23, 16)
125 
126 struct al_pcie_reg_offsets {
127 	unsigned int ob_ctrl;
128 };
129 
130 struct al_pcie_target_bus_cfg {
131 	u8 reg_val;
132 	u8 reg_mask;
133 	u8 ecam_mask;
134 };
135 
136 struct al_pcie {
137 	struct dw_pcie *pci;
138 	void __iomem *controller_base; /* base of PCIe unit (not DW core) */
139 	struct device *dev;
140 	resource_size_t ecam_size;
141 	unsigned int controller_rev_id;
142 	struct al_pcie_reg_offsets reg_offsets;
143 	struct al_pcie_target_bus_cfg target_bus_cfg;
144 };
145 
146 #define PCIE_ECAM_DEVFN(x)		(((x) & 0xff) << 12)
147 
148 #define to_al_pcie(x)		dev_get_drvdata((x)->dev)
149 
150 static inline u32 al_pcie_controller_readl(struct al_pcie *pcie, u32 offset)
151 {
152 	return readl_relaxed(pcie->controller_base + offset);
153 }
154 
155 static inline void al_pcie_controller_writel(struct al_pcie *pcie, u32 offset,
156 					     u32 val)
157 {
158 	writel_relaxed(val, pcie->controller_base + offset);
159 }
160 
161 static int al_pcie_rev_id_get(struct al_pcie *pcie, unsigned int *rev_id)
162 {
163 	u32 dev_rev_id_val;
164 	u32 dev_id_val;
165 
166 	dev_rev_id_val = al_pcie_controller_readl(pcie, AXI_BASE_OFFSET +
167 						  DEVICE_ID_OFFSET +
168 						  DEVICE_REV_ID);
169 	dev_id_val = FIELD_GET(DEVICE_REV_ID_DEV_ID_MASK, dev_rev_id_val);
170 
171 	switch (dev_id_val) {
172 	case DEVICE_REV_ID_DEV_ID_X4:
173 		*rev_id = AL_PCIE_REV_ID_2;
174 		break;
175 	case DEVICE_REV_ID_DEV_ID_X8:
176 		*rev_id = AL_PCIE_REV_ID_3;
177 		break;
178 	case DEVICE_REV_ID_DEV_ID_X16:
179 		*rev_id = AL_PCIE_REV_ID_4;
180 		break;
181 	default:
182 		dev_err(pcie->dev, "Unsupported dev_id_val (0x%x)\n",
183 			dev_id_val);
184 		return -EINVAL;
185 	}
186 
187 	dev_dbg(pcie->dev, "dev_id_val: 0x%x\n", dev_id_val);
188 
189 	return 0;
190 }
191 
192 static int al_pcie_reg_offsets_set(struct al_pcie *pcie)
193 {
194 	switch (pcie->controller_rev_id) {
195 	case AL_PCIE_REV_ID_2:
196 		pcie->reg_offsets.ob_ctrl = OB_CTRL_REV1_2_OFFSET;
197 		break;
198 	case AL_PCIE_REV_ID_3:
199 	case AL_PCIE_REV_ID_4:
200 		pcie->reg_offsets.ob_ctrl = OB_CTRL_REV3_5_OFFSET;
201 		break;
202 	default:
203 		dev_err(pcie->dev, "Unsupported controller rev_id: 0x%x\n",
204 			pcie->controller_rev_id);
205 		return -EINVAL;
206 	}
207 
208 	return 0;
209 }
210 
211 static inline void al_pcie_target_bus_set(struct al_pcie *pcie,
212 					  u8 target_bus,
213 					  u8 mask_target_bus)
214 {
215 	u32 reg;
216 
217 	reg = FIELD_PREP(CFG_TARGET_BUS_MASK_MASK, mask_target_bus) |
218 	      FIELD_PREP(CFG_TARGET_BUS_BUSNUM_MASK, target_bus);
219 
220 	al_pcie_controller_writel(pcie, AXI_BASE_OFFSET +
221 				  pcie->reg_offsets.ob_ctrl + CFG_TARGET_BUS,
222 				  reg);
223 }
224 
225 static void __iomem *al_pcie_conf_addr_map(struct al_pcie *pcie,
226 					   unsigned int busnr,
227 					   unsigned int devfn)
228 {
229 	struct al_pcie_target_bus_cfg *target_bus_cfg = &pcie->target_bus_cfg;
230 	unsigned int busnr_ecam = busnr & target_bus_cfg->ecam_mask;
231 	unsigned int busnr_reg = busnr & target_bus_cfg->reg_mask;
232 	struct pcie_port *pp = &pcie->pci->pp;
233 	void __iomem *pci_base_addr;
234 
235 	pci_base_addr = (void __iomem *)((uintptr_t)pp->va_cfg0_base +
236 					 (busnr_ecam << 20) +
237 					 PCIE_ECAM_DEVFN(devfn));
238 
239 	if (busnr_reg != target_bus_cfg->reg_val) {
240 		dev_dbg(pcie->pci->dev, "Changing target bus busnum val from 0x%x to 0x%x\n",
241 			target_bus_cfg->reg_val, busnr_reg);
242 		target_bus_cfg->reg_val = busnr_reg;
243 		al_pcie_target_bus_set(pcie,
244 				       target_bus_cfg->reg_val,
245 				       target_bus_cfg->reg_mask);
246 	}
247 
248 	return pci_base_addr;
249 }
250 
251 static int al_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
252 				 unsigned int devfn, int where, int size,
253 				 u32 *val)
254 {
255 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
256 	struct al_pcie *pcie = to_al_pcie(pci);
257 	unsigned int busnr = bus->number;
258 	void __iomem *pci_addr;
259 	int rc;
260 
261 	pci_addr = al_pcie_conf_addr_map(pcie, busnr, devfn);
262 
263 	rc = dw_pcie_read(pci_addr + where, size, val);
264 
265 	dev_dbg(pci->dev, "%d-byte config read from %04x:%02x:%02x.%d offset 0x%x (pci_addr: 0x%px) - val:0x%x\n",
266 		size, pci_domain_nr(bus), bus->number,
267 		PCI_SLOT(devfn), PCI_FUNC(devfn), where,
268 		(pci_addr + where), *val);
269 
270 	return rc;
271 }
272 
273 static int al_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
274 				 unsigned int devfn, int where, int size,
275 				 u32 val)
276 {
277 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
278 	struct al_pcie *pcie = to_al_pcie(pci);
279 	unsigned int busnr = bus->number;
280 	void __iomem *pci_addr;
281 	int rc;
282 
283 	pci_addr = al_pcie_conf_addr_map(pcie, busnr, devfn);
284 
285 	rc = dw_pcie_write(pci_addr + where, size, val);
286 
287 	dev_dbg(pci->dev, "%d-byte config write to %04x:%02x:%02x.%d offset 0x%x (pci_addr: 0x%px) - val:0x%x\n",
288 		size, pci_domain_nr(bus), bus->number,
289 		PCI_SLOT(devfn), PCI_FUNC(devfn), where,
290 		(pci_addr + where), val);
291 
292 	return rc;
293 }
294 
295 static void al_pcie_config_prepare(struct al_pcie *pcie)
296 {
297 	struct al_pcie_target_bus_cfg *target_bus_cfg;
298 	struct pcie_port *pp = &pcie->pci->pp;
299 	unsigned int ecam_bus_mask;
300 	u32 cfg_control_offset;
301 	u8 subordinate_bus;
302 	u8 secondary_bus;
303 	u32 cfg_control;
304 	u32 reg;
305 
306 	target_bus_cfg = &pcie->target_bus_cfg;
307 
308 	ecam_bus_mask = (pcie->ecam_size >> 20) - 1;
309 	if (ecam_bus_mask > 255) {
310 		dev_warn(pcie->dev, "ECAM window size is larger than 256MB. Cutting off at 256\n");
311 		ecam_bus_mask = 255;
312 	}
313 
314 	/* This portion is taken from the transaction address */
315 	target_bus_cfg->ecam_mask = ecam_bus_mask;
316 	/* This portion is taken from the cfg_target_bus reg */
317 	target_bus_cfg->reg_mask = ~target_bus_cfg->ecam_mask;
318 	target_bus_cfg->reg_val = pp->busn->start & target_bus_cfg->reg_mask;
319 
320 	al_pcie_target_bus_set(pcie, target_bus_cfg->reg_val,
321 			       target_bus_cfg->reg_mask);
322 
323 	secondary_bus = pp->busn->start + 1;
324 	subordinate_bus = pp->busn->end;
325 
326 	/* Set the valid values of secondary and subordinate buses */
327 	cfg_control_offset = AXI_BASE_OFFSET + pcie->reg_offsets.ob_ctrl +
328 			     CFG_CONTROL;
329 
330 	cfg_control = al_pcie_controller_readl(pcie, cfg_control_offset);
331 
332 	reg = cfg_control &
333 	      ~(CFG_CONTROL_SEC_BUS_MASK | CFG_CONTROL_SUBBUS_MASK);
334 
335 	reg |= FIELD_PREP(CFG_CONTROL_SUBBUS_MASK, subordinate_bus) |
336 	       FIELD_PREP(CFG_CONTROL_SEC_BUS_MASK, secondary_bus);
337 
338 	al_pcie_controller_writel(pcie, cfg_control_offset, reg);
339 }
340 
341 static int al_pcie_host_init(struct pcie_port *pp)
342 {
343 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
344 	struct al_pcie *pcie = to_al_pcie(pci);
345 	int rc;
346 
347 	rc = al_pcie_rev_id_get(pcie, &pcie->controller_rev_id);
348 	if (rc)
349 		return rc;
350 
351 	rc = al_pcie_reg_offsets_set(pcie);
352 	if (rc)
353 		return rc;
354 
355 	al_pcie_config_prepare(pcie);
356 
357 	return 0;
358 }
359 
360 static const struct dw_pcie_host_ops al_pcie_host_ops = {
361 	.rd_other_conf = al_pcie_rd_other_conf,
362 	.wr_other_conf = al_pcie_wr_other_conf,
363 	.host_init = al_pcie_host_init,
364 };
365 
366 static int al_add_pcie_port(struct pcie_port *pp,
367 			    struct platform_device *pdev)
368 {
369 	struct device *dev = &pdev->dev;
370 	int ret;
371 
372 	pp->ops = &al_pcie_host_ops;
373 
374 	ret = dw_pcie_host_init(pp);
375 	if (ret) {
376 		dev_err(dev, "failed to initialize host\n");
377 		return ret;
378 	}
379 
380 	return 0;
381 }
382 
383 static const struct dw_pcie_ops dw_pcie_ops = {
384 };
385 
386 static int al_pcie_probe(struct platform_device *pdev)
387 {
388 	struct device *dev = &pdev->dev;
389 	struct resource *controller_res;
390 	struct resource *ecam_res;
391 	struct resource *dbi_res;
392 	struct al_pcie *al_pcie;
393 	struct dw_pcie *pci;
394 
395 	al_pcie = devm_kzalloc(dev, sizeof(*al_pcie), GFP_KERNEL);
396 	if (!al_pcie)
397 		return -ENOMEM;
398 
399 	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
400 	if (!pci)
401 		return -ENOMEM;
402 
403 	pci->dev = dev;
404 	pci->ops = &dw_pcie_ops;
405 
406 	al_pcie->pci = pci;
407 	al_pcie->dev = dev;
408 
409 	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
410 	pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_res);
411 	if (IS_ERR(pci->dbi_base)) {
412 		dev_err(dev, "couldn't remap dbi base %pR\n", dbi_res);
413 		return PTR_ERR(pci->dbi_base);
414 	}
415 
416 	ecam_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
417 	if (!ecam_res) {
418 		dev_err(dev, "couldn't find 'config' reg in DT\n");
419 		return -ENOENT;
420 	}
421 	al_pcie->ecam_size = resource_size(ecam_res);
422 
423 	controller_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
424 						      "controller");
425 	al_pcie->controller_base = devm_ioremap_resource(dev, controller_res);
426 	if (IS_ERR(al_pcie->controller_base)) {
427 		dev_err(dev, "couldn't remap controller base %pR\n",
428 			controller_res);
429 		return PTR_ERR(al_pcie->controller_base);
430 	}
431 
432 	dev_dbg(dev, "From DT: dbi_base: %pR, controller_base: %pR\n",
433 		dbi_res, controller_res);
434 
435 	platform_set_drvdata(pdev, al_pcie);
436 
437 	return al_add_pcie_port(&pci->pp, pdev);
438 }
439 
440 static const struct of_device_id al_pcie_of_match[] = {
441 	{ .compatible = "amazon,al-alpine-v2-pcie",
442 	},
443 	{ .compatible = "amazon,al-alpine-v3-pcie",
444 	},
445 	{},
446 };
447 
448 static struct platform_driver al_pcie_driver = {
449 	.driver = {
450 		.name	= "al-pcie",
451 		.of_match_table = al_pcie_of_match,
452 		.suppress_bind_attrs = true,
453 	},
454 	.probe = al_pcie_probe,
455 };
456 builtin_platform_driver(al_pcie_driver);
457 
458 #endif /* CONFIG_PCIE_AL*/
459