xref: /linux/drivers/pci/controller/pci-ixp4xx.c (revision 09a8e5f01dfb30667a8f05e35c1cc073cb4fd134)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Support for Intel IXP4xx PCI host controller
4  *
5  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
6  *
7  * Based on the IXP4xx arch/arm/mach-ixp4xx/common-pci.c driver
8  * Copyright (C) 2002 Intel Corporation
9  * Copyright (C) 2003 Greg Ungerer <gerg@linux-m68k.org>
10  * Copyright (C) 2003-2004 MontaVista Software, Inc.
11  * Copyright (C) 2005 Deepak Saxena <dsaxena@plexity.net>
12  * Copyright (C) 2005 Alessandro Zummo <a.zummo@towertech.it>
13  *
14  * TODO:
15  * - Test IO-space access
16  * - DMA support
17  */
18 
19 #include <linux/init.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/of_address.h>
23 #include <linux/of_device.h>
24 #include <linux/of_pci.h>
25 #include <linux/pci.h>
26 #include <linux/platform_device.h>
27 #include <linux/slab.h>
28 #include <linux/bits.h>
29 #include "../pci.h"
30 
31 /* Register offsets */
32 #define IXP4XX_PCI_NP_AD		0x00
33 #define IXP4XX_PCI_NP_CBE		0x04
34 #define IXP4XX_PCI_NP_WDATA		0x08
35 #define IXP4XX_PCI_NP_RDATA		0x0c
36 #define IXP4XX_PCI_CRP_AD_CBE		0x10
37 #define IXP4XX_PCI_CRP_WDATA		0x14
38 #define IXP4XX_PCI_CRP_RDATA		0x18
39 #define IXP4XX_PCI_CSR			0x1c
40 #define IXP4XX_PCI_ISR			0x20
41 #define IXP4XX_PCI_INTEN		0x24
42 #define IXP4XX_PCI_DMACTRL		0x28
43 #define IXP4XX_PCI_AHBMEMBASE		0x2c
44 #define IXP4XX_PCI_AHBIOBASE		0x30
45 #define IXP4XX_PCI_PCIMEMBASE		0x34
46 #define IXP4XX_PCI_AHBDOORBELL		0x38
47 #define IXP4XX_PCI_PCIDOORBELL		0x3c
48 #define IXP4XX_PCI_ATPDMA0_AHBADDR	0x40
49 #define IXP4XX_PCI_ATPDMA0_PCIADDR	0x44
50 #define IXP4XX_PCI_ATPDMA0_LENADDR	0x48
51 #define IXP4XX_PCI_ATPDMA1_AHBADDR	0x4c
52 #define IXP4XX_PCI_ATPDMA1_PCIADDR	0x50
53 #define IXP4XX_PCI_ATPDMA1_LENADDR	0x54
54 
55 /* CSR bit definitions */
56 #define IXP4XX_PCI_CSR_HOST		BIT(0)
57 #define IXP4XX_PCI_CSR_ARBEN		BIT(1)
58 #define IXP4XX_PCI_CSR_ADS		BIT(2)
59 #define IXP4XX_PCI_CSR_PDS		BIT(3)
60 #define IXP4XX_PCI_CSR_ABE		BIT(4)
61 #define IXP4XX_PCI_CSR_DBT		BIT(5)
62 #define IXP4XX_PCI_CSR_ASE		BIT(8)
63 #define IXP4XX_PCI_CSR_IC		BIT(15)
64 #define IXP4XX_PCI_CSR_PRST		BIT(16)
65 
66 /* ISR (Interrupt status) Register bit definitions */
67 #define IXP4XX_PCI_ISR_PSE		BIT(0)
68 #define IXP4XX_PCI_ISR_PFE		BIT(1)
69 #define IXP4XX_PCI_ISR_PPE		BIT(2)
70 #define IXP4XX_PCI_ISR_AHBE		BIT(3)
71 #define IXP4XX_PCI_ISR_APDC		BIT(4)
72 #define IXP4XX_PCI_ISR_PADC		BIT(5)
73 #define IXP4XX_PCI_ISR_ADB		BIT(6)
74 #define IXP4XX_PCI_ISR_PDB		BIT(7)
75 
76 /* INTEN (Interrupt Enable) Register bit definitions */
77 #define IXP4XX_PCI_INTEN_PSE		BIT(0)
78 #define IXP4XX_PCI_INTEN_PFE		BIT(1)
79 #define IXP4XX_PCI_INTEN_PPE		BIT(2)
80 #define IXP4XX_PCI_INTEN_AHBE		BIT(3)
81 #define IXP4XX_PCI_INTEN_APDC		BIT(4)
82 #define IXP4XX_PCI_INTEN_PADC		BIT(5)
83 #define IXP4XX_PCI_INTEN_ADB		BIT(6)
84 #define IXP4XX_PCI_INTEN_PDB		BIT(7)
85 
86 /* Shift value for byte enable on NP cmd/byte enable register */
87 #define IXP4XX_PCI_NP_CBE_BESL		4
88 
89 /* PCI commands supported by NP access unit */
90 #define NP_CMD_IOREAD			0x2
91 #define NP_CMD_IOWRITE			0x3
92 #define NP_CMD_CONFIGREAD		0xa
93 #define NP_CMD_CONFIGWRITE		0xb
94 #define NP_CMD_MEMREAD			0x6
95 #define	NP_CMD_MEMWRITE			0x7
96 
97 /* Constants for CRP access into local config space */
98 #define CRP_AD_CBE_BESL         20
99 #define CRP_AD_CBE_WRITE	0x00010000
100 
101 /* Special PCI configuration space registers for this controller */
102 #define IXP4XX_PCI_RTOTTO		0x40
103 
104 struct ixp4xx_pci {
105 	struct device *dev;
106 	void __iomem *base;
107 	bool errata_hammer;
108 	bool host_mode;
109 };
110 
111 /*
112  * The IXP4xx has a peculiar address bus that will change the
113  * byte order on SoC peripherals depending on whether the device
114  * operates in big-endian or little-endian mode. That means that
115  * readl() and writel() that always use little-endian access
116  * will not work for SoC peripherals such as the PCI controller
117  * when used in big-endian mode. The accesses to the individual
118  * PCI devices on the other hand, are always little-endian and
119  * can use readl() and writel().
120  *
121  * For local AHB bus access we need to use __raw_[readl|writel]()
122  * to make sure that we access the SoC devices in the CPU native
123  * endianness.
124  */
125 static inline u32 ixp4xx_readl(struct ixp4xx_pci *p, u32 reg)
126 {
127 	return __raw_readl(p->base + reg);
128 }
129 
130 static inline void ixp4xx_writel(struct ixp4xx_pci *p, u32 reg, u32 val)
131 {
132 	__raw_writel(val, p->base + reg);
133 }
134 
135 static int ixp4xx_pci_check_master_abort(struct ixp4xx_pci *p)
136 {
137 	u32 isr = ixp4xx_readl(p, IXP4XX_PCI_ISR);
138 
139 	if (isr & IXP4XX_PCI_ISR_PFE) {
140 		/* Make sure the master abort bit is reset */
141 		ixp4xx_writel(p, IXP4XX_PCI_ISR, IXP4XX_PCI_ISR_PFE);
142 		dev_dbg(p->dev, "master abort detected\n");
143 		return -EINVAL;
144 	}
145 
146 	return 0;
147 }
148 
149 static int ixp4xx_pci_read_indirect(struct ixp4xx_pci *p, u32 addr, u32 cmd, u32 *data)
150 {
151 	ixp4xx_writel(p, IXP4XX_PCI_NP_AD, addr);
152 
153 	if (p->errata_hammer) {
154 		int i;
155 
156 		/*
157 		 * PCI workaround - only works if NP PCI space reads have
158 		 * no side effects. Hammer the register and read twice 8
159 		 * times. last one will be good.
160 		 */
161 		for (i = 0; i < 8; i++) {
162 			ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
163 			*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
164 			*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
165 		}
166 	} else {
167 		ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
168 		*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
169 	}
170 
171 	return ixp4xx_pci_check_master_abort(p);
172 }
173 
174 static int ixp4xx_pci_write_indirect(struct ixp4xx_pci *p, u32 addr, u32 cmd, u32 data)
175 {
176 	ixp4xx_writel(p, IXP4XX_PCI_NP_AD, addr);
177 
178 	/* Set up the write */
179 	ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
180 
181 	/* Execute the write by writing to NP_WDATA */
182 	ixp4xx_writel(p, IXP4XX_PCI_NP_WDATA, data);
183 
184 	return ixp4xx_pci_check_master_abort(p);
185 }
186 
187 static u32 ixp4xx_config_addr(u8 bus_num, u16 devfn, int where)
188 {
189 	/* Root bus is always 0 in this hardware */
190 	if (bus_num == 0) {
191 		/* type 0 */
192 		return (PCI_CONF1_ADDRESS(0, 0, PCI_FUNC(devfn), where) &
193 			~PCI_CONF1_ENABLE) | BIT(32-PCI_SLOT(devfn));
194 	} else {
195 		/* type 1 */
196 		return (PCI_CONF1_ADDRESS(bus_num, PCI_SLOT(devfn),
197 					  PCI_FUNC(devfn), where) &
198 			~PCI_CONF1_ENABLE) | 1;
199 	}
200 }
201 
202 /*
203  * CRP functions are "Controller Configuration Port" accesses
204  * initiated from within this driver itself to read/write PCI
205  * control information in the config space.
206  */
207 static u32 ixp4xx_crp_byte_lane_enable_bits(u32 n, int size)
208 {
209 	if (size == 1)
210 		return (0xf & ~BIT(n)) << CRP_AD_CBE_BESL;
211 	if (size == 2)
212 		return (0xf & ~(BIT(n) | BIT(n+1))) << CRP_AD_CBE_BESL;
213 	if (size == 4)
214 		return 0;
215 	return 0xffffffff;
216 }
217 
218 static int ixp4xx_crp_read_config(struct ixp4xx_pci *p, int where, int size,
219 				  u32 *value)
220 {
221 	u32 n, cmd, val;
222 
223 	n = where % 4;
224 	cmd = where & ~3;
225 
226 	dev_dbg(p->dev, "%s from %d size %d cmd %08x\n",
227 		__func__, where, size, cmd);
228 
229 	ixp4xx_writel(p, IXP4XX_PCI_CRP_AD_CBE, cmd);
230 	val = ixp4xx_readl(p, IXP4XX_PCI_CRP_RDATA);
231 
232 	val >>= (8*n);
233 	switch (size) {
234 	case 1:
235 		val &= U8_MAX;
236 		dev_dbg(p->dev, "%s read byte %02x\n", __func__, val);
237 		break;
238 	case 2:
239 		val &= U16_MAX;
240 		dev_dbg(p->dev, "%s read word %04x\n", __func__, val);
241 		break;
242 	case 4:
243 		val &= U32_MAX;
244 		dev_dbg(p->dev, "%s read long %08x\n", __func__, val);
245 		break;
246 	default:
247 		/* Should not happen */
248 		dev_err(p->dev, "%s illegal size\n", __func__);
249 		return PCIBIOS_DEVICE_NOT_FOUND;
250 	}
251 	*value = val;
252 
253 	return PCIBIOS_SUCCESSFUL;
254 }
255 
256 static int ixp4xx_crp_write_config(struct ixp4xx_pci *p, int where, int size,
257 				   u32 value)
258 {
259 	u32 n, cmd, val;
260 
261 	n = where % 4;
262 	cmd = ixp4xx_crp_byte_lane_enable_bits(n, size);
263 	if (cmd == 0xffffffff)
264 		return PCIBIOS_BAD_REGISTER_NUMBER;
265 	cmd |= where & ~3;
266 	cmd |= CRP_AD_CBE_WRITE;
267 
268 	val = value << (8*n);
269 
270 	dev_dbg(p->dev, "%s to %d size %d cmd %08x val %08x\n",
271 		__func__, where, size, cmd, val);
272 
273 	ixp4xx_writel(p, IXP4XX_PCI_CRP_AD_CBE, cmd);
274 	ixp4xx_writel(p, IXP4XX_PCI_CRP_WDATA, val);
275 
276 	return PCIBIOS_SUCCESSFUL;
277 }
278 
279 /*
280  * Then follows the functions that read and write from the common PCI
281  * configuration space.
282  */
283 static u32 ixp4xx_byte_lane_enable_bits(u32 n, int size)
284 {
285 	if (size == 1)
286 		return (0xf & ~BIT(n)) << 4;
287 	if (size == 2)
288 		return (0xf & ~(BIT(n) | BIT(n+1))) << 4;
289 	if (size == 4)
290 		return 0;
291 	return 0xffffffff;
292 }
293 
294 static int ixp4xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
295 				  int where, int size, u32 *value)
296 {
297 	struct ixp4xx_pci *p = bus->sysdata;
298 	u32 n, addr, val, cmd;
299 	u8 bus_num = bus->number;
300 	int ret;
301 
302 	*value = 0xffffffff;
303 	n = where % 4;
304 	cmd = ixp4xx_byte_lane_enable_bits(n, size);
305 	if (cmd == 0xffffffff)
306 		return PCIBIOS_BAD_REGISTER_NUMBER;
307 
308 	addr = ixp4xx_config_addr(bus_num, devfn, where);
309 	cmd |= NP_CMD_CONFIGREAD;
310 	dev_dbg(p->dev, "read_config from %d size %d dev %d:%d:%d address: %08x cmd: %08x\n",
311 		where, size, bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn), addr, cmd);
312 
313 	ret = ixp4xx_pci_read_indirect(p, addr, cmd, &val);
314 	if (ret)
315 		return PCIBIOS_DEVICE_NOT_FOUND;
316 
317 	val >>= (8*n);
318 	switch (size) {
319 	case 1:
320 		val &= U8_MAX;
321 		dev_dbg(p->dev, "%s read byte %02x\n", __func__, val);
322 		break;
323 	case 2:
324 		val &= U16_MAX;
325 		dev_dbg(p->dev, "%s read word %04x\n", __func__, val);
326 		break;
327 	case 4:
328 		val &= U32_MAX;
329 		dev_dbg(p->dev, "%s read long %08x\n", __func__, val);
330 		break;
331 	default:
332 		/* Should not happen */
333 		dev_err(p->dev, "%s illegal size\n", __func__);
334 		return PCIBIOS_DEVICE_NOT_FOUND;
335 	}
336 	*value = val;
337 
338 	return PCIBIOS_SUCCESSFUL;
339 }
340 
341 static int ixp4xx_pci_write_config(struct pci_bus *bus,  unsigned int devfn,
342 				   int where, int size, u32 value)
343 {
344 	struct ixp4xx_pci *p = bus->sysdata;
345 	u32 n, addr, val, cmd;
346 	u8 bus_num = bus->number;
347 	int ret;
348 
349 	n = where % 4;
350 	cmd = ixp4xx_byte_lane_enable_bits(n, size);
351 	if (cmd == 0xffffffff)
352 		return PCIBIOS_BAD_REGISTER_NUMBER;
353 
354 	addr = ixp4xx_config_addr(bus_num, devfn, where);
355 	cmd |= NP_CMD_CONFIGWRITE;
356 	val = value << (8*n);
357 
358 	dev_dbg(p->dev, "write_config_byte %#x to %d size %d dev %d:%d:%d addr: %08x cmd %08x\n",
359 		value, where, size, bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn), addr, cmd);
360 
361 	ret = ixp4xx_pci_write_indirect(p, addr, cmd, val);
362 	if (ret)
363 		return PCIBIOS_DEVICE_NOT_FOUND;
364 
365 	return PCIBIOS_SUCCESSFUL;
366 }
367 
368 static struct pci_ops ixp4xx_pci_ops = {
369 	.read = ixp4xx_pci_read_config,
370 	.write = ixp4xx_pci_write_config,
371 };
372 
373 static u32 ixp4xx_pci_addr_to_64mconf(phys_addr_t addr)
374 {
375 	u8 base;
376 
377 	base = ((addr & 0xff000000) >> 24);
378 	return (base << 24) | ((base + 1) << 16)
379 		| ((base + 2) << 8) | (base + 3);
380 }
381 
382 static int ixp4xx_pci_parse_map_ranges(struct ixp4xx_pci *p)
383 {
384 	struct device *dev = p->dev;
385 	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(p);
386 	struct resource_entry *win;
387 	struct resource *res;
388 	phys_addr_t addr;
389 
390 	win = resource_list_first_type(&bridge->windows, IORESOURCE_MEM);
391 	if (win) {
392 		u32 pcimembase;
393 
394 		res = win->res;
395 		addr = res->start - win->offset;
396 
397 		if (res->flags & IORESOURCE_PREFETCH)
398 			res->name = "IXP4xx PCI PRE-MEM";
399 		else
400 			res->name = "IXP4xx PCI NON-PRE-MEM";
401 
402 		dev_dbg(dev, "%s window %pR, bus addr %pa\n",
403 			res->name, res, &addr);
404 		if (resource_size(res) != SZ_64M) {
405 			dev_err(dev, "memory range is not 64MB\n");
406 			return -EINVAL;
407 		}
408 
409 		pcimembase = ixp4xx_pci_addr_to_64mconf(addr);
410 		/* Commit configuration */
411 		ixp4xx_writel(p, IXP4XX_PCI_PCIMEMBASE, pcimembase);
412 	} else {
413 		dev_err(dev, "no AHB memory mapping defined\n");
414 	}
415 
416 	win = resource_list_first_type(&bridge->windows, IORESOURCE_IO);
417 	if (win) {
418 		res = win->res;
419 
420 		addr = pci_pio_to_address(res->start);
421 		if (addr & 0xff) {
422 			dev_err(dev, "IO mem at uneven address: %pa\n", &addr);
423 			return -EINVAL;
424 		}
425 
426 		res->name = "IXP4xx PCI IO MEM";
427 		/*
428 		 * Setup I/O space location for PCI->AHB access, the
429 		 * upper 24 bits of the address goes into the lower
430 		 * 24 bits of this register.
431 		 */
432 		ixp4xx_writel(p, IXP4XX_PCI_AHBIOBASE, (addr >> 8));
433 	} else {
434 		dev_info(dev, "no IO space AHB memory mapping defined\n");
435 	}
436 
437 	return 0;
438 }
439 
440 static int ixp4xx_pci_parse_map_dma_ranges(struct ixp4xx_pci *p)
441 {
442 	struct device *dev = p->dev;
443 	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(p);
444 	struct resource_entry *win;
445 	struct resource *res;
446 	phys_addr_t addr;
447 	u32 ahbmembase;
448 
449 	win = resource_list_first_type(&bridge->dma_ranges, IORESOURCE_MEM);
450 	if (win) {
451 		res = win->res;
452 		addr = res->start - win->offset;
453 
454 		if (resource_size(res) != SZ_64M) {
455 			dev_err(dev, "DMA memory range is not 64MB\n");
456 			return -EINVAL;
457 		}
458 
459 		dev_dbg(dev, "DMA MEM BASE: %pa\n", &addr);
460 		/*
461 		 * 4 PCI-to-AHB windows of 16 MB each, write the 8 high bits
462 		 * into each byte of the PCI_AHBMEMBASE register.
463 		 */
464 		ahbmembase = ixp4xx_pci_addr_to_64mconf(addr);
465 		/* Commit AHB membase */
466 		ixp4xx_writel(p, IXP4XX_PCI_AHBMEMBASE, ahbmembase);
467 	} else {
468 		dev_err(dev, "no DMA memory range defined\n");
469 	}
470 
471 	return 0;
472 }
473 
474 /* Only used to get context for abort handling */
475 static struct ixp4xx_pci *ixp4xx_pci_abort_singleton;
476 
477 static int ixp4xx_pci_abort_handler(unsigned long addr, unsigned int fsr,
478 				    struct pt_regs *regs)
479 {
480 	struct ixp4xx_pci *p = ixp4xx_pci_abort_singleton;
481 	u32 isr, status;
482 	int ret;
483 
484 	isr = ixp4xx_readl(p, IXP4XX_PCI_ISR);
485 	ret = ixp4xx_crp_read_config(p, PCI_STATUS, 2, &status);
486 	if (ret) {
487 		dev_err(p->dev, "unable to read abort status\n");
488 		return -EINVAL;
489 	}
490 
491 	dev_err(p->dev,
492 		"PCI: abort_handler addr = %#lx, isr = %#x, status = %#x\n",
493 		addr, isr, status);
494 
495 	/* Make sure the Master Abort bit is reset */
496 	ixp4xx_writel(p, IXP4XX_PCI_ISR, IXP4XX_PCI_ISR_PFE);
497 	status |= PCI_STATUS_REC_MASTER_ABORT;
498 	ret = ixp4xx_crp_write_config(p, PCI_STATUS, 2, status);
499 	if (ret)
500 		dev_err(p->dev, "unable to clear abort status bit\n");
501 
502 	/*
503 	 * If it was an imprecise abort, then we need to correct the
504 	 * return address to be _after_ the instruction.
505 	 */
506 	if (fsr & (1 << 10)) {
507 		dev_err(p->dev, "imprecise abort\n");
508 		regs->ARM_pc += 4;
509 	}
510 
511 	return 0;
512 }
513 
514 static int __init ixp4xx_pci_probe(struct platform_device *pdev)
515 {
516 	struct device *dev = &pdev->dev;
517 	struct device_node *np = dev->of_node;
518 	struct ixp4xx_pci *p;
519 	struct pci_host_bridge *host;
520 	int ret;
521 	u32 val;
522 	phys_addr_t addr;
523 	u32 basereg[4] = {
524 		PCI_BASE_ADDRESS_0,
525 		PCI_BASE_ADDRESS_1,
526 		PCI_BASE_ADDRESS_2,
527 		PCI_BASE_ADDRESS_3,
528 	};
529 	int i;
530 
531 	host = devm_pci_alloc_host_bridge(dev, sizeof(*p));
532 	if (!host)
533 		return -ENOMEM;
534 
535 	host->ops = &ixp4xx_pci_ops;
536 	p = pci_host_bridge_priv(host);
537 	host->sysdata = p;
538 	p->dev = dev;
539 	dev_set_drvdata(dev, p);
540 
541 	/*
542 	 * Set up quirk for erratic behaviour in the 42x variant
543 	 * when accessing config space.
544 	 */
545 	if (of_device_is_compatible(np, "intel,ixp42x-pci")) {
546 		p->errata_hammer = true;
547 		dev_info(dev, "activate hammering errata\n");
548 	}
549 
550 	p->base = devm_platform_ioremap_resource(pdev, 0);
551 	if (IS_ERR(p->base))
552 		return PTR_ERR(p->base);
553 
554 	val = ixp4xx_readl(p, IXP4XX_PCI_CSR);
555 	p->host_mode = !!(val & IXP4XX_PCI_CSR_HOST);
556 	dev_info(dev, "controller is in %s mode\n",
557 		 p->host_mode ? "host" : "option");
558 
559 	/* Hook in our fault handler for PCI errors */
560 	ixp4xx_pci_abort_singleton = p;
561 	hook_fault_code(16+6, ixp4xx_pci_abort_handler, SIGBUS, 0,
562 			"imprecise external abort");
563 
564 	ret = ixp4xx_pci_parse_map_ranges(p);
565 	if (ret)
566 		return ret;
567 
568 	ret = ixp4xx_pci_parse_map_dma_ranges(p);
569 	if (ret)
570 		return ret;
571 
572 	/* This is only configured in host mode */
573 	if (p->host_mode) {
574 		addr = __pa(PAGE_OFFSET);
575 		/* This is a noop (0x00) but explains what is going on */
576 		addr |= PCI_BASE_ADDRESS_SPACE_MEMORY;
577 
578 		for (i = 0; i < 4; i++) {
579 			/* Write this directly into the config space */
580 			ret = ixp4xx_crp_write_config(p, basereg[i], 4, addr);
581 			if (ret)
582 				dev_err(dev, "failed to set up PCI_BASE_ADDRESS_%d\n", i);
583 			else
584 				dev_info(dev, "set PCI_BASE_ADDR_%d to %pa\n", i, &addr);
585 			addr += SZ_16M;
586 		}
587 
588 		/*
589 		 * Enable CSR window at 64 MiB to allow PCI masters to continue
590 		 * prefetching past the 64 MiB boundary, if all AHB to PCI
591 		 * windows are consecutive.
592 		 */
593 		ret = ixp4xx_crp_write_config(p, PCI_BASE_ADDRESS_4, 4, addr);
594 		if (ret)
595 			dev_err(dev, "failed to set up PCI_BASE_ADDRESS_4\n");
596 		else
597 			dev_info(dev, "set PCI_BASE_ADDR_4 to %pa\n", &addr);
598 
599 		/*
600 		 * Put the IO memory window at the very end of physical memory
601 		 * at 0xfffffc00. This is when the system is trying to access IO
602 		 * memory over AHB.
603 		 */
604 		addr = 0xfffffc00;
605 		addr |= PCI_BASE_ADDRESS_SPACE_IO;
606 		ret = ixp4xx_crp_write_config(p, PCI_BASE_ADDRESS_5, 4, addr);
607 		if (ret)
608 			dev_err(dev, "failed to set up PCI_BASE_ADDRESS_5\n");
609 		else
610 			dev_info(dev, "set PCI_BASE_ADDR_5 to %pa\n", &addr);
611 
612 		/*
613 		 * Retry timeout to 0x80
614 		 * Transfer ready timeout to 0xff
615 		 */
616 		ret = ixp4xx_crp_write_config(p, IXP4XX_PCI_RTOTTO, 4,
617 					      0x000080ff);
618 		if (ret)
619 			dev_err(dev, "failed to set up TRDY limit\n");
620 		else
621 			dev_info(dev, "set TRDY limit to 0x80ff\n");
622 	}
623 
624 	/* Clear interrupts */
625 	val = IXP4XX_PCI_ISR_PSE | IXP4XX_PCI_ISR_PFE | IXP4XX_PCI_ISR_PPE | IXP4XX_PCI_ISR_AHBE;
626 	ixp4xx_writel(p, IXP4XX_PCI_ISR, val);
627 
628 	/*
629 	 * Set Initialize Complete in PCI Control Register: allow IXP4XX to
630 	 * generate PCI configuration cycles. Specify that the AHB bus is
631 	 * operating in big-endian mode. Set up byte lane swapping between
632 	 * little-endian PCI and the big-endian AHB bus.
633 	 */
634 	val = IXP4XX_PCI_CSR_IC | IXP4XX_PCI_CSR_ABE;
635 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
636 		val |= (IXP4XX_PCI_CSR_PDS | IXP4XX_PCI_CSR_ADS);
637 	ixp4xx_writel(p, IXP4XX_PCI_CSR, val);
638 
639 	ret = ixp4xx_crp_write_config(p, PCI_COMMAND, 2, PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
640 	if (ret)
641 		dev_err(dev, "unable to initialize master and command memory\n");
642 	else
643 		dev_info(dev, "initialized as master\n");
644 
645 	pci_host_probe(host);
646 
647 	return 0;
648 }
649 
650 static const struct of_device_id ixp4xx_pci_of_match[] = {
651 	{
652 		.compatible = "intel,ixp42x-pci",
653 	},
654 	{
655 		.compatible = "intel,ixp43x-pci",
656 	},
657 	{},
658 };
659 
660 /*
661  * This driver needs to be a builtin module with suppressed bind
662  * attributes since the probe() is initializing a hard exception
663  * handler and this can only be done from __init-tagged code
664  * sections. This module cannot be removed and inserted at all.
665  */
666 static struct platform_driver ixp4xx_pci_driver = {
667 	.driver = {
668 		.name = "ixp4xx-pci",
669 		.suppress_bind_attrs = true,
670 		.of_match_table = ixp4xx_pci_of_match,
671 	},
672 };
673 builtin_platform_driver_probe(ixp4xx_pci_driver, ixp4xx_pci_probe);
674