1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2006 PA Semi, Inc
4  *
5  * Authors: Kip Walker, PA Semi
6  *	    Olof Johansson, PA Semi
7  *
8  * Maintained by: Olof Johansson <olof@lixom.net>
9  *
10  * Based on arch/powerpc/platforms/maple/pci.c
11  */
12 
13 
14 #include <linux/kernel.h>
15 #include <linux/pci.h>
16 
17 #include <asm/pci-bridge.h>
18 #include <asm/isa-bridge.h>
19 #include <asm/machdep.h>
20 
21 #include <asm/ppc-pci.h>
22 
23 #include "pasemi.h"
24 
25 #define PA_PXP_CFA(bus, devfn, off) (((bus) << 20) | ((devfn) << 12) | (off))
26 
27 static inline int pa_pxp_offset_valid(u8 bus, u8 devfn, int offset)
28 {
29 	/* Device 0 Function 0 is special: It's config space spans function 1 as
30 	 * well, so allow larger offset. It's really a two-function device but the
31 	 * second function does not probe.
32 	 */
33 	if (bus == 0 && devfn == 0)
34 		return offset < 8192;
35 	else
36 		return offset < 4096;
37 }
38 
39 static void volatile __iomem *pa_pxp_cfg_addr(struct pci_controller *hose,
40 				       u8 bus, u8 devfn, int offset)
41 {
42 	return hose->cfg_data + PA_PXP_CFA(bus, devfn, offset);
43 }
44 
45 static inline int is_root_port(int busno, int devfn)
46 {
47 	return ((busno == 0) && (PCI_FUNC(devfn) < 4) &&
48 		 ((PCI_SLOT(devfn) == 16) || (PCI_SLOT(devfn) == 17)));
49 }
50 
51 static inline int is_5945_reg(int reg)
52 {
53 	return (((reg >= 0x18) && (reg < 0x34)) ||
54 		((reg >= 0x158) && (reg < 0x178)));
55 }
56 
57 static int workaround_5945(struct pci_bus *bus, unsigned int devfn,
58 			   int offset, int len, u32 *val)
59 {
60 	struct pci_controller *hose;
61 	void volatile __iomem *addr, *dummy;
62 	int byte;
63 	u32 tmp;
64 
65 	if (!is_root_port(bus->number, devfn) || !is_5945_reg(offset))
66 		return 0;
67 
68 	hose = pci_bus_to_host(bus);
69 
70 	addr = pa_pxp_cfg_addr(hose, bus->number, devfn, offset & ~0x3);
71 	byte = offset & 0x3;
72 
73 	/* Workaround bug 5945: write 0 to a dummy register before reading,
74 	 * and write back what we read. We must read/write the full 32-bit
75 	 * contents so we need to shift and mask by hand.
76 	 */
77 	dummy = pa_pxp_cfg_addr(hose, bus->number, devfn, 0x10);
78 	out_le32(dummy, 0);
79 	tmp = in_le32(addr);
80 	out_le32(addr, tmp);
81 
82 	switch (len) {
83 	case 1:
84 		*val = (tmp >> (8*byte)) & 0xff;
85 		break;
86 	case 2:
87 		if (byte == 0)
88 			*val = tmp & 0xffff;
89 		else
90 			*val = (tmp >> 16) & 0xffff;
91 		break;
92 	default:
93 		*val = tmp;
94 		break;
95 	}
96 
97 	return 1;
98 }
99 
100 #ifdef CONFIG_PPC_PASEMI_NEMO
101 #define PXP_ERR_CFG_REG	0x4
102 #define PXP_IGNORE_PCIE_ERRORS	0x800
103 #define SB600_BUS 5
104 
105 static void sb600_set_flag(int bus)
106 {
107 	static void __iomem *iob_mapbase = NULL;
108 	struct resource res;
109 	struct device_node *dn;
110 	int err;
111 
112 	if (iob_mapbase == NULL) {
113 		dn = of_find_compatible_node(NULL, "isa", "pasemi,1682m-iob");
114 		if (!dn) {
115 			pr_crit("NEMO SB600 missing iob node\n");
116 			return;
117 		}
118 
119 		err = of_address_to_resource(dn, 0, &res);
120 		of_node_put(dn);
121 
122 		if (err) {
123 			pr_crit("NEMO SB600 missing resource\n");
124 			return;
125 		}
126 
127 		pr_info("NEMO SB600 IOB base %08llx\n",res.start);
128 
129 		iob_mapbase = ioremap(res.start + 0x100, 0x94);
130 	}
131 
132 	if (iob_mapbase != NULL) {
133 		if (bus == SB600_BUS) {
134 			/*
135 			 * This is the SB600's bus, tell the PCI-e root port
136 			 * to allow non-zero devices to enumerate.
137 			 */
138 			out_le32(iob_mapbase + PXP_ERR_CFG_REG, in_le32(iob_mapbase + PXP_ERR_CFG_REG) | PXP_IGNORE_PCIE_ERRORS);
139 		} else {
140 			/*
141 			 * Only scan device 0 on other busses
142 			 */
143 			out_le32(iob_mapbase + PXP_ERR_CFG_REG, in_le32(iob_mapbase + PXP_ERR_CFG_REG) & ~PXP_IGNORE_PCIE_ERRORS);
144 		}
145 	}
146 }
147 
148 #else
149 
150 static void sb600_set_flag(int bus)
151 {
152 }
153 #endif
154 
155 static int pa_pxp_read_config(struct pci_bus *bus, unsigned int devfn,
156 			      int offset, int len, u32 *val)
157 {
158 	struct pci_controller *hose;
159 	void volatile __iomem *addr;
160 
161 	hose = pci_bus_to_host(bus);
162 	if (!hose)
163 		return PCIBIOS_DEVICE_NOT_FOUND;
164 
165 	if (!pa_pxp_offset_valid(bus->number, devfn, offset))
166 		return PCIBIOS_BAD_REGISTER_NUMBER;
167 
168 	if (workaround_5945(bus, devfn, offset, len, val))
169 		return PCIBIOS_SUCCESSFUL;
170 
171 	addr = pa_pxp_cfg_addr(hose, bus->number, devfn, offset);
172 
173 	sb600_set_flag(bus->number);
174 
175 	/*
176 	 * Note: the caller has already checked that offset is
177 	 * suitably aligned and that len is 1, 2 or 4.
178 	 */
179 	switch (len) {
180 	case 1:
181 		*val = in_8(addr);
182 		break;
183 	case 2:
184 		*val = in_le16(addr);
185 		break;
186 	default:
187 		*val = in_le32(addr);
188 		break;
189 	}
190 
191 	return PCIBIOS_SUCCESSFUL;
192 }
193 
194 static int pa_pxp_write_config(struct pci_bus *bus, unsigned int devfn,
195 			       int offset, int len, u32 val)
196 {
197 	struct pci_controller *hose;
198 	void volatile __iomem *addr;
199 
200 	hose = pci_bus_to_host(bus);
201 	if (!hose)
202 		return PCIBIOS_DEVICE_NOT_FOUND;
203 
204 	if (!pa_pxp_offset_valid(bus->number, devfn, offset))
205 		return PCIBIOS_BAD_REGISTER_NUMBER;
206 
207 	addr = pa_pxp_cfg_addr(hose, bus->number, devfn, offset);
208 
209 	sb600_set_flag(bus->number);
210 
211 	/*
212 	 * Note: the caller has already checked that offset is
213 	 * suitably aligned and that len is 1, 2 or 4.
214 	 */
215 	switch (len) {
216 	case 1:
217 		out_8(addr, val);
218 		break;
219 	case 2:
220 		out_le16(addr, val);
221 		break;
222 	default:
223 		out_le32(addr, val);
224 		break;
225 	}
226 	return PCIBIOS_SUCCESSFUL;
227 }
228 
229 static struct pci_ops pa_pxp_ops = {
230 	.read = pa_pxp_read_config,
231 	.write = pa_pxp_write_config,
232 };
233 
234 static void __init setup_pa_pxp(struct pci_controller *hose)
235 {
236 	hose->ops = &pa_pxp_ops;
237 	hose->cfg_data = ioremap(0xe0000000, 0x10000000);
238 }
239 
240 static int __init pas_add_bridge(struct device_node *dev)
241 {
242 	struct pci_controller *hose;
243 
244 	pr_debug("Adding PCI host bridge %pOF\n", dev);
245 
246 	hose = pcibios_alloc_controller(dev);
247 	if (!hose)
248 		return -ENOMEM;
249 
250 	hose->first_busno = 0;
251 	hose->last_busno = 0xff;
252 	hose->controller_ops = pasemi_pci_controller_ops;
253 
254 	setup_pa_pxp(hose);
255 
256 	pr_info("Found PA-PXP PCI host bridge.\n");
257 
258 	/* Interpret the "ranges" property */
259 	pci_process_bridge_OF_ranges(hose, dev, 1);
260 
261 	/*
262 	 * Scan for an isa bridge. This is needed to find the SB600 on the nemo
263 	 * and does nothing on machines without one.
264 	 */
265 	isa_bridge_find_early(hose);
266 
267 	return 0;
268 }
269 
270 void __init pas_pci_init(void)
271 {
272 	struct device_node *np, *root;
273 	int res;
274 
275 	root = of_find_node_by_path("/");
276 	if (!root) {
277 		pr_crit("pas_pci_init: can't find root of device tree\n");
278 		return;
279 	}
280 
281 	pci_set_flags(PCI_SCAN_ALL_PCIE_DEVS);
282 
283 	np = of_find_compatible_node(root, NULL, "pasemi,rootbus");
284 	if (np) {
285 		res = pas_add_bridge(np);
286 		of_node_put(np);
287 	}
288 }
289 
290 void __iomem *pasemi_pci_getcfgaddr(struct pci_dev *dev, int offset)
291 {
292 	struct pci_controller *hose;
293 
294 	hose = pci_bus_to_host(dev->bus);
295 
296 	return (void __iomem *)pa_pxp_cfg_addr(hose, dev->bus->number, dev->devfn, offset);
297 }
298 
299 struct pci_controller_ops pasemi_pci_controller_ops;
300