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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Support for Faraday Technology FTPC100 PCI Controller
4  *
5  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
6  *
7  * Based on the out-of-tree OpenWRT patch for Cortina Gemini:
8  * Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
9  * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
10  * Based on SL2312 PCI controller code
11  * Storlink (C) 2003
12  */
13 
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/of_address.h>
19 #include <linux/of_device.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_pci.h>
22 #include <linux/pci.h>
23 #include <linux/platform_device.h>
24 #include <linux/slab.h>
25 #include <linux/irqdomain.h>
26 #include <linux/irqchip/chained_irq.h>
27 #include <linux/bitops.h>
28 #include <linux/irq.h>
29 #include <linux/clk.h>
30 
31 /*
32  * Special configuration registers directly in the first few words
33  * in I/O space.
34  */
35 #define PCI_IOSIZE	0x00
36 #define PCI_PROT	0x04 /* AHB protection */
37 #define PCI_CTRL	0x08 /* PCI control signal */
38 #define PCI_SOFTRST	0x10 /* Soft reset counter and response error enable */
39 #define PCI_CONFIG	0x28 /* PCI configuration command register */
40 #define PCI_DATA	0x2C
41 
42 #define FARADAY_PCI_STATUS_CMD		0x04 /* Status and command */
43 #define FARADAY_PCI_PMC			0x40 /* Power management control */
44 #define FARADAY_PCI_PMCSR		0x44 /* Power management status */
45 #define FARADAY_PCI_CTRL1		0x48 /* Control register 1 */
46 #define FARADAY_PCI_CTRL2		0x4C /* Control register 2 */
47 #define FARADAY_PCI_MEM1_BASE_SIZE	0x50 /* Memory base and size #1 */
48 #define FARADAY_PCI_MEM2_BASE_SIZE	0x54 /* Memory base and size #2 */
49 #define FARADAY_PCI_MEM3_BASE_SIZE	0x58 /* Memory base and size #3 */
50 
51 #define PCI_STATUS_66MHZ_CAPABLE	BIT(21)
52 
53 /* Bits 31..28 gives INTD..INTA status */
54 #define PCI_CTRL2_INTSTS_SHIFT		28
55 #define PCI_CTRL2_INTMASK_CMDERR	BIT(27)
56 #define PCI_CTRL2_INTMASK_PARERR	BIT(26)
57 /* Bits 25..22 masks INTD..INTA */
58 #define PCI_CTRL2_INTMASK_SHIFT		22
59 #define PCI_CTRL2_INTMASK_MABRT_RX	BIT(21)
60 #define PCI_CTRL2_INTMASK_TABRT_RX	BIT(20)
61 #define PCI_CTRL2_INTMASK_TABRT_TX	BIT(19)
62 #define PCI_CTRL2_INTMASK_RETRY4	BIT(18)
63 #define PCI_CTRL2_INTMASK_SERR_RX	BIT(17)
64 #define PCI_CTRL2_INTMASK_PERR_RX	BIT(16)
65 /* Bit 15 reserved */
66 #define PCI_CTRL2_MSTPRI_REQ6		BIT(14)
67 #define PCI_CTRL2_MSTPRI_REQ5		BIT(13)
68 #define PCI_CTRL2_MSTPRI_REQ4		BIT(12)
69 #define PCI_CTRL2_MSTPRI_REQ3		BIT(11)
70 #define PCI_CTRL2_MSTPRI_REQ2		BIT(10)
71 #define PCI_CTRL2_MSTPRI_REQ1		BIT(9)
72 #define PCI_CTRL2_MSTPRI_REQ0		BIT(8)
73 /* Bits 7..4 reserved */
74 /* Bits 3..0 TRDYW */
75 
76 /*
77  * Memory configs:
78  * Bit 31..20 defines the PCI side memory base
79  * Bit 19..16 (4 bits) defines the size per below
80  */
81 #define FARADAY_PCI_MEMBASE_MASK	0xfff00000
82 #define FARADAY_PCI_MEMSIZE_1MB		0x0
83 #define FARADAY_PCI_MEMSIZE_2MB		0x1
84 #define FARADAY_PCI_MEMSIZE_4MB		0x2
85 #define FARADAY_PCI_MEMSIZE_8MB		0x3
86 #define FARADAY_PCI_MEMSIZE_16MB	0x4
87 #define FARADAY_PCI_MEMSIZE_32MB	0x5
88 #define FARADAY_PCI_MEMSIZE_64MB	0x6
89 #define FARADAY_PCI_MEMSIZE_128MB	0x7
90 #define FARADAY_PCI_MEMSIZE_256MB	0x8
91 #define FARADAY_PCI_MEMSIZE_512MB	0x9
92 #define FARADAY_PCI_MEMSIZE_1GB		0xa
93 #define FARADAY_PCI_MEMSIZE_2GB		0xb
94 #define FARADAY_PCI_MEMSIZE_SHIFT	16
95 
96 /*
97  * The DMA base is set to 0x0 for all memory segments, it reflects the
98  * fact that the memory of the host system starts at 0x0.
99  */
100 #define FARADAY_PCI_DMA_MEM1_BASE	0x00000000
101 #define FARADAY_PCI_DMA_MEM2_BASE	0x00000000
102 #define FARADAY_PCI_DMA_MEM3_BASE	0x00000000
103 
104 /* Defines for PCI configuration command register */
105 #define PCI_CONF_ENABLE		BIT(31)
106 #define PCI_CONF_WHERE(r)	((r) & 0xFC)
107 #define PCI_CONF_BUS(b)		(((b) & 0xFF) << 16)
108 #define PCI_CONF_DEVICE(d)	(((d) & 0x1F) << 11)
109 #define PCI_CONF_FUNCTION(f)	(((f) & 0x07) << 8)
110 
111 /**
112  * struct faraday_pci_variant - encodes IP block differences
113  * @cascaded_irq: this host has cascaded IRQs from an interrupt controller
114  *	embedded in the host bridge.
115  */
116 struct faraday_pci_variant {
117 	bool cascaded_irq;
118 };
119 
120 struct faraday_pci {
121 	struct device *dev;
122 	void __iomem *base;
123 	struct irq_domain *irqdomain;
124 	struct pci_bus *bus;
125 	struct clk *bus_clk;
126 };
127 
faraday_res_to_memcfg(resource_size_t mem_base,resource_size_t mem_size,u32 * val)128 static int faraday_res_to_memcfg(resource_size_t mem_base,
129 				 resource_size_t mem_size, u32 *val)
130 {
131 	u32 outval;
132 
133 	switch (mem_size) {
134 	case SZ_1M:
135 		outval = FARADAY_PCI_MEMSIZE_1MB;
136 		break;
137 	case SZ_2M:
138 		outval = FARADAY_PCI_MEMSIZE_2MB;
139 		break;
140 	case SZ_4M:
141 		outval = FARADAY_PCI_MEMSIZE_4MB;
142 		break;
143 	case SZ_8M:
144 		outval = FARADAY_PCI_MEMSIZE_8MB;
145 		break;
146 	case SZ_16M:
147 		outval = FARADAY_PCI_MEMSIZE_16MB;
148 		break;
149 	case SZ_32M:
150 		outval = FARADAY_PCI_MEMSIZE_32MB;
151 		break;
152 	case SZ_64M:
153 		outval = FARADAY_PCI_MEMSIZE_64MB;
154 		break;
155 	case SZ_128M:
156 		outval = FARADAY_PCI_MEMSIZE_128MB;
157 		break;
158 	case SZ_256M:
159 		outval = FARADAY_PCI_MEMSIZE_256MB;
160 		break;
161 	case SZ_512M:
162 		outval = FARADAY_PCI_MEMSIZE_512MB;
163 		break;
164 	case SZ_1G:
165 		outval = FARADAY_PCI_MEMSIZE_1GB;
166 		break;
167 	case SZ_2G:
168 		outval = FARADAY_PCI_MEMSIZE_2GB;
169 		break;
170 	default:
171 		return -EINVAL;
172 	}
173 	outval <<= FARADAY_PCI_MEMSIZE_SHIFT;
174 
175 	/* This is probably not good */
176 	if (mem_base & ~(FARADAY_PCI_MEMBASE_MASK))
177 		pr_warn("truncated PCI memory base\n");
178 	/* Translate to bridge side address space */
179 	outval |= (mem_base & FARADAY_PCI_MEMBASE_MASK);
180 	pr_debug("Translated pci base @%pap, size %pap to config %08x\n",
181 		 &mem_base, &mem_size, outval);
182 
183 	*val = outval;
184 	return 0;
185 }
186 
faraday_raw_pci_read_config(struct faraday_pci * p,int bus_number,unsigned int fn,int config,int size,u32 * value)187 static int faraday_raw_pci_read_config(struct faraday_pci *p, int bus_number,
188 				       unsigned int fn, int config, int size,
189 				       u32 *value)
190 {
191 	writel(PCI_CONF_BUS(bus_number) |
192 			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
193 			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
194 			PCI_CONF_WHERE(config) |
195 			PCI_CONF_ENABLE,
196 			p->base + PCI_CONFIG);
197 
198 	*value = readl(p->base + PCI_DATA);
199 
200 	if (size == 1)
201 		*value = (*value >> (8 * (config & 3))) & 0xFF;
202 	else if (size == 2)
203 		*value = (*value >> (8 * (config & 3))) & 0xFFFF;
204 
205 	return PCIBIOS_SUCCESSFUL;
206 }
207 
faraday_pci_read_config(struct pci_bus * bus,unsigned int fn,int config,int size,u32 * value)208 static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
209 				   int config, int size, u32 *value)
210 {
211 	struct faraday_pci *p = bus->sysdata;
212 
213 	dev_dbg(&bus->dev,
214 		"[read]  slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
215 		PCI_SLOT(fn), PCI_FUNC(fn), config, size, *value);
216 
217 	return faraday_raw_pci_read_config(p, bus->number, fn, config, size, value);
218 }
219 
faraday_raw_pci_write_config(struct faraday_pci * p,int bus_number,unsigned int fn,int config,int size,u32 value)220 static int faraday_raw_pci_write_config(struct faraday_pci *p, int bus_number,
221 					 unsigned int fn, int config, int size,
222 					 u32 value)
223 {
224 	int ret = PCIBIOS_SUCCESSFUL;
225 
226 	writel(PCI_CONF_BUS(bus_number) |
227 			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
228 			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
229 			PCI_CONF_WHERE(config) |
230 			PCI_CONF_ENABLE,
231 			p->base + PCI_CONFIG);
232 
233 	switch (size) {
234 	case 4:
235 		writel(value, p->base + PCI_DATA);
236 		break;
237 	case 2:
238 		writew(value, p->base + PCI_DATA + (config & 3));
239 		break;
240 	case 1:
241 		writeb(value, p->base + PCI_DATA + (config & 3));
242 		break;
243 	default:
244 		ret = PCIBIOS_BAD_REGISTER_NUMBER;
245 	}
246 
247 	return ret;
248 }
249 
faraday_pci_write_config(struct pci_bus * bus,unsigned int fn,int config,int size,u32 value)250 static int faraday_pci_write_config(struct pci_bus *bus, unsigned int fn,
251 				    int config, int size, u32 value)
252 {
253 	struct faraday_pci *p = bus->sysdata;
254 
255 	dev_dbg(&bus->dev,
256 		"[write] slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
257 		PCI_SLOT(fn), PCI_FUNC(fn), config, size, value);
258 
259 	return faraday_raw_pci_write_config(p, bus->number, fn, config, size,
260 					    value);
261 }
262 
263 static struct pci_ops faraday_pci_ops = {
264 	.read	= faraday_pci_read_config,
265 	.write	= faraday_pci_write_config,
266 };
267 
faraday_pci_ack_irq(struct irq_data * d)268 static void faraday_pci_ack_irq(struct irq_data *d)
269 {
270 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
271 	unsigned int reg;
272 
273 	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
274 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
275 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTSTS_SHIFT);
276 	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
277 }
278 
faraday_pci_mask_irq(struct irq_data * d)279 static void faraday_pci_mask_irq(struct irq_data *d)
280 {
281 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
282 	unsigned int reg;
283 
284 	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
285 	reg &= ~((0xF << PCI_CTRL2_INTSTS_SHIFT)
286 		 | BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT));
287 	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
288 }
289 
faraday_pci_unmask_irq(struct irq_data * d)290 static void faraday_pci_unmask_irq(struct irq_data *d)
291 {
292 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
293 	unsigned int reg;
294 
295 	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
296 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
297 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT);
298 	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
299 }
300 
faraday_pci_irq_handler(struct irq_desc * desc)301 static void faraday_pci_irq_handler(struct irq_desc *desc)
302 {
303 	struct faraday_pci *p = irq_desc_get_handler_data(desc);
304 	struct irq_chip *irqchip = irq_desc_get_chip(desc);
305 	unsigned int irq_stat, reg, i;
306 
307 	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
308 	irq_stat = reg >> PCI_CTRL2_INTSTS_SHIFT;
309 
310 	chained_irq_enter(irqchip, desc);
311 
312 	for (i = 0; i < 4; i++) {
313 		if ((irq_stat & BIT(i)) == 0)
314 			continue;
315 		generic_handle_irq(irq_find_mapping(p->irqdomain, i));
316 	}
317 
318 	chained_irq_exit(irqchip, desc);
319 }
320 
321 static struct irq_chip faraday_pci_irq_chip = {
322 	.name = "PCI",
323 	.irq_ack = faraday_pci_ack_irq,
324 	.irq_mask = faraday_pci_mask_irq,
325 	.irq_unmask = faraday_pci_unmask_irq,
326 };
327 
faraday_pci_irq_map(struct irq_domain * domain,unsigned int irq,irq_hw_number_t hwirq)328 static int faraday_pci_irq_map(struct irq_domain *domain, unsigned int irq,
329 			       irq_hw_number_t hwirq)
330 {
331 	irq_set_chip_and_handler(irq, &faraday_pci_irq_chip, handle_level_irq);
332 	irq_set_chip_data(irq, domain->host_data);
333 
334 	return 0;
335 }
336 
337 static const struct irq_domain_ops faraday_pci_irqdomain_ops = {
338 	.map = faraday_pci_irq_map,
339 };
340 
faraday_pci_setup_cascaded_irq(struct faraday_pci * p)341 static int faraday_pci_setup_cascaded_irq(struct faraday_pci *p)
342 {
343 	struct device_node *intc = of_get_next_child(p->dev->of_node, NULL);
344 	int irq;
345 	int i;
346 
347 	if (!intc) {
348 		dev_err(p->dev, "missing child interrupt-controller node\n");
349 		return -EINVAL;
350 	}
351 
352 	/* All PCI IRQs cascade off this one */
353 	irq = of_irq_get(intc, 0);
354 	if (irq <= 0) {
355 		dev_err(p->dev, "failed to get parent IRQ\n");
356 		of_node_put(intc);
357 		return irq ?: -EINVAL;
358 	}
359 
360 	p->irqdomain = irq_domain_add_linear(intc, PCI_NUM_INTX,
361 					     &faraday_pci_irqdomain_ops, p);
362 	of_node_put(intc);
363 	if (!p->irqdomain) {
364 		dev_err(p->dev, "failed to create Gemini PCI IRQ domain\n");
365 		return -EINVAL;
366 	}
367 
368 	irq_set_chained_handler_and_data(irq, faraday_pci_irq_handler, p);
369 
370 	for (i = 0; i < 4; i++)
371 		irq_create_mapping(p->irqdomain, i);
372 
373 	return 0;
374 }
375 
pci_dma_range_parser_init(struct of_pci_range_parser * parser,struct device_node * node)376 static int pci_dma_range_parser_init(struct of_pci_range_parser *parser,
377 				     struct device_node *node)
378 {
379 	const int na = 3, ns = 2;
380 	int rlen;
381 
382 	parser->node = node;
383 	parser->pna = of_n_addr_cells(node);
384 	parser->np = parser->pna + na + ns;
385 
386 	parser->range = of_get_property(node, "dma-ranges", &rlen);
387 	if (!parser->range)
388 		return -ENOENT;
389 	parser->end = parser->range + rlen / sizeof(__be32);
390 
391 	return 0;
392 }
393 
faraday_pci_parse_map_dma_ranges(struct faraday_pci * p,struct device_node * np)394 static int faraday_pci_parse_map_dma_ranges(struct faraday_pci *p,
395 					    struct device_node *np)
396 {
397 	struct of_pci_range range;
398 	struct of_pci_range_parser parser;
399 	struct device *dev = p->dev;
400 	u32 confreg[3] = {
401 		FARADAY_PCI_MEM1_BASE_SIZE,
402 		FARADAY_PCI_MEM2_BASE_SIZE,
403 		FARADAY_PCI_MEM3_BASE_SIZE,
404 	};
405 	int i = 0;
406 	u32 val;
407 
408 	if (pci_dma_range_parser_init(&parser, np)) {
409 		dev_err(dev, "missing dma-ranges property\n");
410 		return -EINVAL;
411 	}
412 
413 	/*
414 	 * Get the dma-ranges from the device tree
415 	 */
416 	for_each_of_pci_range(&parser, &range) {
417 		u64 end = range.pci_addr + range.size - 1;
418 		int ret;
419 
420 		ret = faraday_res_to_memcfg(range.pci_addr, range.size, &val);
421 		if (ret) {
422 			dev_err(dev,
423 				"DMA range %d: illegal MEM resource size\n", i);
424 			return -EINVAL;
425 		}
426 
427 		dev_info(dev, "DMA MEM%d BASE: 0x%016llx -> 0x%016llx config %08x\n",
428 			 i + 1, range.pci_addr, end, val);
429 		if (i <= 2) {
430 			faraday_raw_pci_write_config(p, 0, 0, confreg[i],
431 						     4, val);
432 		} else {
433 			dev_err(dev, "ignore extraneous dma-range %d\n", i);
434 			break;
435 		}
436 
437 		i++;
438 	}
439 
440 	return 0;
441 }
442 
faraday_pci_probe(struct platform_device * pdev)443 static int faraday_pci_probe(struct platform_device *pdev)
444 {
445 	struct device *dev = &pdev->dev;
446 	const struct faraday_pci_variant *variant =
447 		of_device_get_match_data(dev);
448 	struct resource *regs;
449 	resource_size_t io_base;
450 	struct resource_entry *win;
451 	struct faraday_pci *p;
452 	struct resource *mem;
453 	struct resource *io;
454 	struct pci_host_bridge *host;
455 	struct clk *clk;
456 	unsigned char max_bus_speed = PCI_SPEED_33MHz;
457 	unsigned char cur_bus_speed = PCI_SPEED_33MHz;
458 	int ret;
459 	u32 val;
460 	LIST_HEAD(res);
461 
462 	host = devm_pci_alloc_host_bridge(dev, sizeof(*p));
463 	if (!host)
464 		return -ENOMEM;
465 
466 	host->dev.parent = dev;
467 	host->ops = &faraday_pci_ops;
468 	host->busnr = 0;
469 	host->msi = NULL;
470 	host->map_irq = of_irq_parse_and_map_pci;
471 	host->swizzle_irq = pci_common_swizzle;
472 	p = pci_host_bridge_priv(host);
473 	host->sysdata = p;
474 	p->dev = dev;
475 
476 	/* Retrieve and enable optional clocks */
477 	clk = devm_clk_get(dev, "PCLK");
478 	if (IS_ERR(clk))
479 		return PTR_ERR(clk);
480 	ret = clk_prepare_enable(clk);
481 	if (ret) {
482 		dev_err(dev, "could not prepare PCLK\n");
483 		return ret;
484 	}
485 	p->bus_clk = devm_clk_get(dev, "PCICLK");
486 	if (IS_ERR(p->bus_clk))
487 		return PTR_ERR(clk);
488 	ret = clk_prepare_enable(p->bus_clk);
489 	if (ret) {
490 		dev_err(dev, "could not prepare PCICLK\n");
491 		return ret;
492 	}
493 
494 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
495 	p->base = devm_ioremap_resource(dev, regs);
496 	if (IS_ERR(p->base))
497 		return PTR_ERR(p->base);
498 
499 	ret = of_pci_get_host_bridge_resources(dev->of_node, 0, 0xff,
500 					       &res, &io_base);
501 	if (ret)
502 		return ret;
503 
504 	ret = devm_request_pci_bus_resources(dev, &res);
505 	if (ret)
506 		return ret;
507 
508 	/* Get the I/O and memory ranges from DT */
509 	resource_list_for_each_entry(win, &res) {
510 		switch (resource_type(win->res)) {
511 		case IORESOURCE_IO:
512 			io = win->res;
513 			io->name = "Gemini PCI I/O";
514 			if (!faraday_res_to_memcfg(io->start - win->offset,
515 						   resource_size(io), &val)) {
516 				/* setup I/O space size */
517 				writel(val, p->base + PCI_IOSIZE);
518 			} else {
519 				dev_err(dev, "illegal IO mem size\n");
520 				return -EINVAL;
521 			}
522 			ret = pci_remap_iospace(io, io_base);
523 			if (ret) {
524 				dev_warn(dev, "error %d: failed to map resource %pR\n",
525 					 ret, io);
526 				continue;
527 			}
528 			break;
529 		case IORESOURCE_MEM:
530 			mem = win->res;
531 			mem->name = "Gemini PCI MEM";
532 			break;
533 		case IORESOURCE_BUS:
534 			break;
535 		default:
536 			break;
537 		}
538 	}
539 
540 	/* Setup hostbridge */
541 	val = readl(p->base + PCI_CTRL);
542 	val |= PCI_COMMAND_IO;
543 	val |= PCI_COMMAND_MEMORY;
544 	val |= PCI_COMMAND_MASTER;
545 	writel(val, p->base + PCI_CTRL);
546 	/* Mask and clear all interrupts */
547 	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2 + 2, 2, 0xF000);
548 	if (variant->cascaded_irq) {
549 		ret = faraday_pci_setup_cascaded_irq(p);
550 		if (ret) {
551 			dev_err(dev, "failed to setup cascaded IRQ\n");
552 			return ret;
553 		}
554 	}
555 
556 	/* Check bus clock if we can gear up to 66 MHz */
557 	if (!IS_ERR(p->bus_clk)) {
558 		unsigned long rate;
559 		u32 val;
560 
561 		faraday_raw_pci_read_config(p, 0, 0,
562 					    FARADAY_PCI_STATUS_CMD, 4, &val);
563 		rate = clk_get_rate(p->bus_clk);
564 
565 		if ((rate == 33000000) && (val & PCI_STATUS_66MHZ_CAPABLE)) {
566 			dev_info(dev, "33MHz bus is 66MHz capable\n");
567 			max_bus_speed = PCI_SPEED_66MHz;
568 			ret = clk_set_rate(p->bus_clk, 66000000);
569 			if (ret)
570 				dev_err(dev, "failed to set bus clock\n");
571 		} else {
572 			dev_info(dev, "33MHz only bus\n");
573 			max_bus_speed = PCI_SPEED_33MHz;
574 		}
575 
576 		/* Bumping the clock may fail so read back the rate */
577 		rate = clk_get_rate(p->bus_clk);
578 		if (rate == 33000000)
579 			cur_bus_speed = PCI_SPEED_33MHz;
580 		if (rate == 66000000)
581 			cur_bus_speed = PCI_SPEED_66MHz;
582 	}
583 
584 	ret = faraday_pci_parse_map_dma_ranges(p, dev->of_node);
585 	if (ret)
586 		return ret;
587 
588 	list_splice_init(&res, &host->windows);
589 	ret = pci_scan_root_bus_bridge(host);
590 	if (ret) {
591 		dev_err(dev, "failed to scan host: %d\n", ret);
592 		return ret;
593 	}
594 	p->bus = host->bus;
595 	p->bus->max_bus_speed = max_bus_speed;
596 	p->bus->cur_bus_speed = cur_bus_speed;
597 
598 	pci_bus_assign_resources(p->bus);
599 	pci_bus_add_devices(p->bus);
600 	pci_free_resource_list(&res);
601 
602 	return 0;
603 }
604 
605 /*
606  * We encode bridge variants here, we have at least two so it doesn't
607  * hurt to have infrastructure to encompass future variants as well.
608  */
609 const struct faraday_pci_variant faraday_regular = {
610 	.cascaded_irq = true,
611 };
612 
613 const struct faraday_pci_variant faraday_dual = {
614 	.cascaded_irq = false,
615 };
616 
617 static const struct of_device_id faraday_pci_of_match[] = {
618 	{
619 		.compatible = "faraday,ftpci100",
620 		.data = &faraday_regular,
621 	},
622 	{
623 		.compatible = "faraday,ftpci100-dual",
624 		.data = &faraday_dual,
625 	},
626 	{},
627 };
628 
629 static struct platform_driver faraday_pci_driver = {
630 	.driver = {
631 		.name = "ftpci100",
632 		.of_match_table = of_match_ptr(faraday_pci_of_match),
633 		.suppress_bind_attrs = true,
634 	},
635 	.probe  = faraday_pci_probe,
636 };
637 builtin_platform_driver(faraday_pci_driver);
638