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 		return PTR_ERR(al_pcie->dbi_base);
72 
73 	cfg->priv = al_pcie;
74 
75 	return 0;
76 }
77 
78 const struct pci_ecam_ops al_pcie_ops = {
79 	.init         =  al_pcie_init,
80 	.pci_ops      = {
81 		.map_bus    = al_pcie_map_bus,
82 		.read       = pci_generic_config_read,
83 		.write      = pci_generic_config_write,
84 	}
85 };
86 
87 #endif /* defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS) */
88 
89 #ifdef CONFIG_PCIE_AL
90 
91 #include <linux/of_pci.h>
92 #include "pcie-designware.h"
93 
94 #define AL_PCIE_REV_ID_2	2
95 #define AL_PCIE_REV_ID_3	3
96 #define AL_PCIE_REV_ID_4	4
97 
98 #define AXI_BASE_OFFSET		0x0
99 
100 #define DEVICE_ID_OFFSET	0x16c
101 
102 #define DEVICE_REV_ID			0x0
103 #define DEVICE_REV_ID_DEV_ID_MASK	GENMASK(31, 16)
104 
105 #define DEVICE_REV_ID_DEV_ID_X4		0
106 #define DEVICE_REV_ID_DEV_ID_X8		2
107 #define DEVICE_REV_ID_DEV_ID_X16	4
108 
109 #define OB_CTRL_REV1_2_OFFSET	0x0040
110 #define OB_CTRL_REV3_5_OFFSET	0x0030
111 
112 #define CFG_TARGET_BUS			0x0
113 #define CFG_TARGET_BUS_MASK_MASK	GENMASK(7, 0)
114 #define CFG_TARGET_BUS_BUSNUM_MASK	GENMASK(15, 8)
115 
116 #define CFG_CONTROL			0x4
117 #define CFG_CONTROL_SUBBUS_MASK		GENMASK(15, 8)
118 #define CFG_CONTROL_SEC_BUS_MASK	GENMASK(23, 16)
119 
120 struct al_pcie_reg_offsets {
121 	unsigned int ob_ctrl;
122 };
123 
124 struct al_pcie_target_bus_cfg {
125 	u8 reg_val;
126 	u8 reg_mask;
127 	u8 ecam_mask;
128 };
129 
130 struct al_pcie {
131 	struct dw_pcie *pci;
132 	void __iomem *controller_base; /* base of PCIe unit (not DW core) */
133 	struct device *dev;
134 	resource_size_t ecam_size;
135 	unsigned int controller_rev_id;
136 	struct al_pcie_reg_offsets reg_offsets;
137 	struct al_pcie_target_bus_cfg target_bus_cfg;
138 };
139 
140 #define to_al_pcie(x)		dev_get_drvdata((x)->dev)
141 
142 static inline u32 al_pcie_controller_readl(struct al_pcie *pcie, u32 offset)
143 {
144 	return readl_relaxed(pcie->controller_base + offset);
145 }
146 
147 static inline void al_pcie_controller_writel(struct al_pcie *pcie, u32 offset,
148 					     u32 val)
149 {
150 	writel_relaxed(val, pcie->controller_base + offset);
151 }
152 
153 static int al_pcie_rev_id_get(struct al_pcie *pcie, unsigned int *rev_id)
154 {
155 	u32 dev_rev_id_val;
156 	u32 dev_id_val;
157 
158 	dev_rev_id_val = al_pcie_controller_readl(pcie, AXI_BASE_OFFSET +
159 						  DEVICE_ID_OFFSET +
160 						  DEVICE_REV_ID);
161 	dev_id_val = FIELD_GET(DEVICE_REV_ID_DEV_ID_MASK, dev_rev_id_val);
162 
163 	switch (dev_id_val) {
164 	case DEVICE_REV_ID_DEV_ID_X4:
165 		*rev_id = AL_PCIE_REV_ID_2;
166 		break;
167 	case DEVICE_REV_ID_DEV_ID_X8:
168 		*rev_id = AL_PCIE_REV_ID_3;
169 		break;
170 	case DEVICE_REV_ID_DEV_ID_X16:
171 		*rev_id = AL_PCIE_REV_ID_4;
172 		break;
173 	default:
174 		dev_err(pcie->dev, "Unsupported dev_id_val (0x%x)\n",
175 			dev_id_val);
176 		return -EINVAL;
177 	}
178 
179 	dev_dbg(pcie->dev, "dev_id_val: 0x%x\n", dev_id_val);
180 
181 	return 0;
182 }
183 
184 static int al_pcie_reg_offsets_set(struct al_pcie *pcie)
185 {
186 	switch (pcie->controller_rev_id) {
187 	case AL_PCIE_REV_ID_2:
188 		pcie->reg_offsets.ob_ctrl = OB_CTRL_REV1_2_OFFSET;
189 		break;
190 	case AL_PCIE_REV_ID_3:
191 	case AL_PCIE_REV_ID_4:
192 		pcie->reg_offsets.ob_ctrl = OB_CTRL_REV3_5_OFFSET;
193 		break;
194 	default:
195 		dev_err(pcie->dev, "Unsupported controller rev_id: 0x%x\n",
196 			pcie->controller_rev_id);
197 		return -EINVAL;
198 	}
199 
200 	return 0;
201 }
202 
203 static inline void al_pcie_target_bus_set(struct al_pcie *pcie,
204 					  u8 target_bus,
205 					  u8 mask_target_bus)
206 {
207 	u32 reg;
208 
209 	reg = FIELD_PREP(CFG_TARGET_BUS_MASK_MASK, mask_target_bus) |
210 	      FIELD_PREP(CFG_TARGET_BUS_BUSNUM_MASK, target_bus);
211 
212 	al_pcie_controller_writel(pcie, AXI_BASE_OFFSET +
213 				  pcie->reg_offsets.ob_ctrl + CFG_TARGET_BUS,
214 				  reg);
215 }
216 
217 static void __iomem *al_pcie_conf_addr_map_bus(struct pci_bus *bus,
218 					       unsigned int devfn, int where)
219 {
220 	struct pcie_port *pp = bus->sysdata;
221 	struct al_pcie *pcie = to_al_pcie(to_dw_pcie_from_pp(pp));
222 	unsigned int busnr = bus->number;
223 	struct al_pcie_target_bus_cfg *target_bus_cfg = &pcie->target_bus_cfg;
224 	unsigned int busnr_ecam = busnr & target_bus_cfg->ecam_mask;
225 	unsigned int busnr_reg = busnr & target_bus_cfg->reg_mask;
226 
227 	if (busnr_reg != target_bus_cfg->reg_val) {
228 		dev_dbg(pcie->pci->dev, "Changing target bus busnum val from 0x%x to 0x%x\n",
229 			target_bus_cfg->reg_val, busnr_reg);
230 		target_bus_cfg->reg_val = busnr_reg;
231 		al_pcie_target_bus_set(pcie,
232 				       target_bus_cfg->reg_val,
233 				       target_bus_cfg->reg_mask);
234 	}
235 
236 	return pp->va_cfg0_base + PCIE_ECAM_OFFSET(busnr_ecam, devfn, where);
237 }
238 
239 static struct pci_ops al_child_pci_ops = {
240 	.map_bus = al_pcie_conf_addr_map_bus,
241 	.read = pci_generic_config_read,
242 	.write = pci_generic_config_write,
243 };
244 
245 static void al_pcie_config_prepare(struct al_pcie *pcie)
246 {
247 	struct al_pcie_target_bus_cfg *target_bus_cfg;
248 	struct pcie_port *pp = &pcie->pci->pp;
249 	unsigned int ecam_bus_mask;
250 	u32 cfg_control_offset;
251 	u8 subordinate_bus;
252 	u8 secondary_bus;
253 	u32 cfg_control;
254 	u32 reg;
255 	struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
256 
257 	target_bus_cfg = &pcie->target_bus_cfg;
258 
259 	ecam_bus_mask = (pcie->ecam_size >> PCIE_ECAM_BUS_SHIFT) - 1;
260 	if (ecam_bus_mask > 255) {
261 		dev_warn(pcie->dev, "ECAM window size is larger than 256MB. Cutting off at 256\n");
262 		ecam_bus_mask = 255;
263 	}
264 
265 	/* This portion is taken from the transaction address */
266 	target_bus_cfg->ecam_mask = ecam_bus_mask;
267 	/* This portion is taken from the cfg_target_bus reg */
268 	target_bus_cfg->reg_mask = ~target_bus_cfg->ecam_mask;
269 	target_bus_cfg->reg_val = bus->start & target_bus_cfg->reg_mask;
270 
271 	al_pcie_target_bus_set(pcie, target_bus_cfg->reg_val,
272 			       target_bus_cfg->reg_mask);
273 
274 	secondary_bus = bus->start + 1;
275 	subordinate_bus = bus->end;
276 
277 	/* Set the valid values of secondary and subordinate buses */
278 	cfg_control_offset = AXI_BASE_OFFSET + pcie->reg_offsets.ob_ctrl +
279 			     CFG_CONTROL;
280 
281 	cfg_control = al_pcie_controller_readl(pcie, cfg_control_offset);
282 
283 	reg = cfg_control &
284 	      ~(CFG_CONTROL_SEC_BUS_MASK | CFG_CONTROL_SUBBUS_MASK);
285 
286 	reg |= FIELD_PREP(CFG_CONTROL_SUBBUS_MASK, subordinate_bus) |
287 	       FIELD_PREP(CFG_CONTROL_SEC_BUS_MASK, secondary_bus);
288 
289 	al_pcie_controller_writel(pcie, cfg_control_offset, reg);
290 }
291 
292 static int al_pcie_host_init(struct pcie_port *pp)
293 {
294 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
295 	struct al_pcie *pcie = to_al_pcie(pci);
296 	int rc;
297 
298 	pp->bridge->child_ops = &al_child_pci_ops;
299 
300 	rc = al_pcie_rev_id_get(pcie, &pcie->controller_rev_id);
301 	if (rc)
302 		return rc;
303 
304 	rc = al_pcie_reg_offsets_set(pcie);
305 	if (rc)
306 		return rc;
307 
308 	al_pcie_config_prepare(pcie);
309 
310 	return 0;
311 }
312 
313 static const struct dw_pcie_host_ops al_pcie_host_ops = {
314 	.host_init = al_pcie_host_init,
315 };
316 
317 static int al_pcie_probe(struct platform_device *pdev)
318 {
319 	struct device *dev = &pdev->dev;
320 	struct resource *controller_res;
321 	struct resource *ecam_res;
322 	struct al_pcie *al_pcie;
323 	struct dw_pcie *pci;
324 
325 	al_pcie = devm_kzalloc(dev, sizeof(*al_pcie), GFP_KERNEL);
326 	if (!al_pcie)
327 		return -ENOMEM;
328 
329 	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
330 	if (!pci)
331 		return -ENOMEM;
332 
333 	pci->dev = dev;
334 	pci->pp.ops = &al_pcie_host_ops;
335 
336 	al_pcie->pci = pci;
337 	al_pcie->dev = dev;
338 
339 	ecam_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
340 	if (!ecam_res) {
341 		dev_err(dev, "couldn't find 'config' reg in DT\n");
342 		return -ENOENT;
343 	}
344 	al_pcie->ecam_size = resource_size(ecam_res);
345 
346 	controller_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
347 						      "controller");
348 	al_pcie->controller_base = devm_ioremap_resource(dev, controller_res);
349 	if (IS_ERR(al_pcie->controller_base)) {
350 		dev_err(dev, "couldn't remap controller base %pR\n",
351 			controller_res);
352 		return PTR_ERR(al_pcie->controller_base);
353 	}
354 
355 	dev_dbg(dev, "From DT: controller_base: %pR\n", controller_res);
356 
357 	platform_set_drvdata(pdev, al_pcie);
358 
359 	return dw_pcie_host_init(&pci->pp);
360 }
361 
362 static const struct of_device_id al_pcie_of_match[] = {
363 	{ .compatible = "amazon,al-alpine-v2-pcie",
364 	},
365 	{ .compatible = "amazon,al-alpine-v3-pcie",
366 	},
367 	{},
368 };
369 
370 static struct platform_driver al_pcie_driver = {
371 	.driver = {
372 		.name	= "al-pcie",
373 		.of_match_table = al_pcie_of_match,
374 		.suppress_bind_attrs = true,
375 	},
376 	.probe = al_pcie_probe,
377 };
378 builtin_platform_driver(al_pcie_driver);
379 
380 #endif /* CONFIG_PCIE_AL*/
381