1/*
2 * Simple, generic PCI host controller driver targetting firmware-initialised
3 * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16 *
17 * Copyright (C) 2014 ARM Limited
18 *
19 * Author: Will Deacon <will.deacon@arm.com>
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/of_address.h>
25#include <linux/of_pci.h>
26#include <linux/platform_device.h>
27
28struct gen_pci_cfg_bus_ops {
29	u32 bus_shift;
30	struct pci_ops ops;
31};
32
33struct gen_pci_cfg_windows {
34	struct resource				res;
35	struct resource				*bus_range;
36	void __iomem				**win;
37
38	struct gen_pci_cfg_bus_ops		*ops;
39};
40
41/*
42 * ARM pcibios functions expect the ARM struct pci_sys_data as the PCI
43 * sysdata.  Add pci_sys_data as the first element in struct gen_pci so
44 * that when we use a gen_pci pointer as sysdata, it is also a pointer to
45 * a struct pci_sys_data.
46 */
47struct gen_pci {
48#ifdef CONFIG_ARM
49	struct pci_sys_data			sys;
50#endif
51	struct pci_host_bridge			host;
52	struct gen_pci_cfg_windows		cfg;
53	struct list_head			resources;
54};
55
56static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
57					     unsigned int devfn,
58					     int where)
59{
60	struct gen_pci *pci = bus->sysdata;
61	resource_size_t idx = bus->number - pci->cfg.bus_range->start;
62
63	return pci->cfg.win[idx] + ((devfn << 8) | where);
64}
65
66static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
67	.bus_shift	= 16,
68	.ops		= {
69		.map_bus	= gen_pci_map_cfg_bus_cam,
70		.read		= pci_generic_config_read,
71		.write		= pci_generic_config_write,
72	}
73};
74
75static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
76					      unsigned int devfn,
77					      int where)
78{
79	struct gen_pci *pci = bus->sysdata;
80	resource_size_t idx = bus->number - pci->cfg.bus_range->start;
81
82	return pci->cfg.win[idx] + ((devfn << 12) | where);
83}
84
85static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
86	.bus_shift	= 20,
87	.ops		= {
88		.map_bus	= gen_pci_map_cfg_bus_ecam,
89		.read		= pci_generic_config_read,
90		.write		= pci_generic_config_write,
91	}
92};
93
94static const struct of_device_id gen_pci_of_match[] = {
95	{ .compatible = "pci-host-cam-generic",
96	  .data = &gen_pci_cfg_cam_bus_ops },
97
98	{ .compatible = "pci-host-ecam-generic",
99	  .data = &gen_pci_cfg_ecam_bus_ops },
100
101	{ },
102};
103MODULE_DEVICE_TABLE(of, gen_pci_of_match);
104
105static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
106{
107	pci_free_resource_list(&pci->resources);
108}
109
110static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
111{
112	int err, res_valid = 0;
113	struct device *dev = pci->host.dev.parent;
114	struct device_node *np = dev->of_node;
115	resource_size_t iobase;
116	struct resource_entry *win;
117
118	err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pci->resources,
119					       &iobase);
120	if (err)
121		return err;
122
123	resource_list_for_each_entry(win, &pci->resources) {
124		struct resource *parent, *res = win->res;
125
126		switch (resource_type(res)) {
127		case IORESOURCE_IO:
128			parent = &ioport_resource;
129			err = pci_remap_iospace(res, iobase);
130			if (err) {
131				dev_warn(dev, "error %d: failed to map resource %pR\n",
132					 err, res);
133				continue;
134			}
135			break;
136		case IORESOURCE_MEM:
137			parent = &iomem_resource;
138			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
139			break;
140		case IORESOURCE_BUS:
141			pci->cfg.bus_range = res;
142		default:
143			continue;
144		}
145
146		err = devm_request_resource(dev, parent, res);
147		if (err)
148			goto out_release_res;
149	}
150
151	if (!res_valid) {
152		dev_err(dev, "non-prefetchable memory resource required\n");
153		err = -EINVAL;
154		goto out_release_res;
155	}
156
157	return 0;
158
159out_release_res:
160	gen_pci_release_of_pci_ranges(pci);
161	return err;
162}
163
164static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
165{
166	int err;
167	u8 bus_max;
168	resource_size_t busn;
169	struct resource *bus_range;
170	struct device *dev = pci->host.dev.parent;
171	struct device_node *np = dev->of_node;
172	u32 sz = 1 << pci->cfg.ops->bus_shift;
173
174	err = of_address_to_resource(np, 0, &pci->cfg.res);
175	if (err) {
176		dev_err(dev, "missing \"reg\" property\n");
177		return err;
178	}
179
180	/* Limit the bus-range to fit within reg */
181	bus_max = pci->cfg.bus_range->start +
182		  (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
183	pci->cfg.bus_range->end = min_t(resource_size_t,
184					pci->cfg.bus_range->end, bus_max);
185
186	pci->cfg.win = devm_kcalloc(dev, resource_size(pci->cfg.bus_range),
187				    sizeof(*pci->cfg.win), GFP_KERNEL);
188	if (!pci->cfg.win)
189		return -ENOMEM;
190
191	/* Map our Configuration Space windows */
192	if (!devm_request_mem_region(dev, pci->cfg.res.start,
193				     resource_size(&pci->cfg.res),
194				     "Configuration Space"))
195		return -ENOMEM;
196
197	bus_range = pci->cfg.bus_range;
198	for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
199		u32 idx = busn - bus_range->start;
200
201		pci->cfg.win[idx] = devm_ioremap(dev,
202						 pci->cfg.res.start + idx * sz,
203						 sz);
204		if (!pci->cfg.win[idx])
205			return -ENOMEM;
206	}
207
208	return 0;
209}
210
211static int gen_pci_probe(struct platform_device *pdev)
212{
213	int err;
214	const char *type;
215	const struct of_device_id *of_id;
216	struct device *dev = &pdev->dev;
217	struct device_node *np = dev->of_node;
218	struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
219	struct pci_bus *bus, *child;
220
221	if (!pci)
222		return -ENOMEM;
223
224	type = of_get_property(np, "device_type", NULL);
225	if (!type || strcmp(type, "pci")) {
226		dev_err(dev, "invalid \"device_type\" %s\n", type);
227		return -EINVAL;
228	}
229
230	of_pci_check_probe_only();
231
232	of_id = of_match_node(gen_pci_of_match, np);
233	pci->cfg.ops = (struct gen_pci_cfg_bus_ops *)of_id->data;
234	pci->host.dev.parent = dev;
235	INIT_LIST_HEAD(&pci->host.windows);
236	INIT_LIST_HEAD(&pci->resources);
237
238	/* Parse our PCI ranges and request their resources */
239	err = gen_pci_parse_request_of_pci_ranges(pci);
240	if (err)
241		return err;
242
243	/* Parse and map our Configuration Space windows */
244	err = gen_pci_parse_map_cfg_windows(pci);
245	if (err) {
246		gen_pci_release_of_pci_ranges(pci);
247		return err;
248	}
249
250	/* Do not reassign resources if probe only */
251	if (!pci_has_flag(PCI_PROBE_ONLY))
252		pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);
253
254
255	bus = pci_scan_root_bus(dev, pci->cfg.bus_range->start,
256				&pci->cfg.ops->ops, pci, &pci->resources);
257	if (!bus) {
258		dev_err(dev, "Scanning rootbus failed");
259		return -ENODEV;
260	}
261
262	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
263
264	if (!pci_has_flag(PCI_PROBE_ONLY)) {
265		pci_bus_size_bridges(bus);
266		pci_bus_assign_resources(bus);
267
268		list_for_each_entry(child, &bus->children, node)
269			pcie_bus_configure_settings(child);
270	}
271
272	pci_bus_add_devices(bus);
273	return 0;
274}
275
276static struct platform_driver gen_pci_driver = {
277	.driver = {
278		.name = "pci-host-generic",
279		.of_match_table = gen_pci_of_match,
280	},
281	.probe = gen_pci_probe,
282};
283module_platform_driver(gen_pci_driver);
284
285MODULE_DESCRIPTION("Generic PCI host driver");
286MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
287MODULE_LICENSE("GPL v2");
288