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	void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
31};
32
33struct gen_pci_cfg_windows {
34	struct resource				res;
35	struct resource				*bus_range;
36	void __iomem				**win;
37
38	const struct gen_pci_cfg_bus_ops	*ops;
39};
40
41struct gen_pci {
42	struct pci_host_bridge			host;
43	struct gen_pci_cfg_windows		cfg;
44	struct list_head			resources;
45};
46
47static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
48					     unsigned int devfn,
49					     int where)
50{
51	struct pci_sys_data *sys = bus->sysdata;
52	struct gen_pci *pci = sys->private_data;
53	resource_size_t idx = bus->number - pci->cfg.bus_range->start;
54
55	return pci->cfg.win[idx] + ((devfn << 8) | where);
56}
57
58static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
59	.bus_shift	= 16,
60	.map_bus	= gen_pci_map_cfg_bus_cam,
61};
62
63static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
64					      unsigned int devfn,
65					      int where)
66{
67	struct pci_sys_data *sys = bus->sysdata;
68	struct gen_pci *pci = sys->private_data;
69	resource_size_t idx = bus->number - pci->cfg.bus_range->start;
70
71	return pci->cfg.win[idx] + ((devfn << 12) | where);
72}
73
74static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
75	.bus_shift	= 20,
76	.map_bus	= gen_pci_map_cfg_bus_ecam,
77};
78
79static struct pci_ops gen_pci_ops = {
80	.read	= pci_generic_config_read,
81	.write	= pci_generic_config_write,
82};
83
84static const struct of_device_id gen_pci_of_match[] = {
85	{ .compatible = "pci-host-cam-generic",
86	  .data = &gen_pci_cfg_cam_bus_ops },
87
88	{ .compatible = "pci-host-ecam-generic",
89	  .data = &gen_pci_cfg_ecam_bus_ops },
90
91	{ },
92};
93MODULE_DEVICE_TABLE(of, gen_pci_of_match);
94
95static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
96{
97	pci_free_resource_list(&pci->resources);
98}
99
100static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
101{
102	int err, res_valid = 0;
103	struct device *dev = pci->host.dev.parent;
104	struct device_node *np = dev->of_node;
105	resource_size_t iobase;
106	struct resource_entry *win;
107
108	err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pci->resources,
109					       &iobase);
110	if (err)
111		return err;
112
113	resource_list_for_each_entry(win, &pci->resources) {
114		struct resource *parent, *res = win->res;
115
116		switch (resource_type(res)) {
117		case IORESOURCE_IO:
118			parent = &ioport_resource;
119			err = pci_remap_iospace(res, iobase);
120			if (err) {
121				dev_warn(dev, "error %d: failed to map resource %pR\n",
122					 err, res);
123				continue;
124			}
125			break;
126		case IORESOURCE_MEM:
127			parent = &iomem_resource;
128			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
129			break;
130		case IORESOURCE_BUS:
131			pci->cfg.bus_range = res;
132		default:
133			continue;
134		}
135
136		err = devm_request_resource(dev, parent, res);
137		if (err)
138			goto out_release_res;
139	}
140
141	if (!res_valid) {
142		dev_err(dev, "non-prefetchable memory resource required\n");
143		err = -EINVAL;
144		goto out_release_res;
145	}
146
147	return 0;
148
149out_release_res:
150	gen_pci_release_of_pci_ranges(pci);
151	return err;
152}
153
154static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
155{
156	int err;
157	u8 bus_max;
158	resource_size_t busn;
159	struct resource *bus_range;
160	struct device *dev = pci->host.dev.parent;
161	struct device_node *np = dev->of_node;
162
163	err = of_address_to_resource(np, 0, &pci->cfg.res);
164	if (err) {
165		dev_err(dev, "missing \"reg\" property\n");
166		return err;
167	}
168
169	/* Limit the bus-range to fit within reg */
170	bus_max = pci->cfg.bus_range->start +
171		  (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
172	pci->cfg.bus_range->end = min_t(resource_size_t,
173					pci->cfg.bus_range->end, bus_max);
174
175	pci->cfg.win = devm_kcalloc(dev, resource_size(pci->cfg.bus_range),
176				    sizeof(*pci->cfg.win), GFP_KERNEL);
177	if (!pci->cfg.win)
178		return -ENOMEM;
179
180	/* Map our Configuration Space windows */
181	if (!devm_request_mem_region(dev, pci->cfg.res.start,
182				     resource_size(&pci->cfg.res),
183				     "Configuration Space"))
184		return -ENOMEM;
185
186	bus_range = pci->cfg.bus_range;
187	for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
188		u32 idx = busn - bus_range->start;
189		u32 sz = 1 << pci->cfg.ops->bus_shift;
190
191		pci->cfg.win[idx] = devm_ioremap(dev,
192						 pci->cfg.res.start + busn * sz,
193						 sz);
194		if (!pci->cfg.win[idx])
195			return -ENOMEM;
196	}
197
198	return 0;
199}
200
201static int gen_pci_setup(int nr, struct pci_sys_data *sys)
202{
203	struct gen_pci *pci = sys->private_data;
204	list_splice_init(&pci->resources, &sys->resources);
205	return 1;
206}
207
208static int gen_pci_probe(struct platform_device *pdev)
209{
210	int err;
211	const char *type;
212	const struct of_device_id *of_id;
213	const int *prop;
214	struct device *dev = &pdev->dev;
215	struct device_node *np = dev->of_node;
216	struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
217	struct hw_pci hw = {
218		.nr_controllers	= 1,
219		.private_data	= (void **)&pci,
220		.setup		= gen_pci_setup,
221		.map_irq	= of_irq_parse_and_map_pci,
222		.ops		= &gen_pci_ops,
223	};
224
225	if (!pci)
226		return -ENOMEM;
227
228	type = of_get_property(np, "device_type", NULL);
229	if (!type || strcmp(type, "pci")) {
230		dev_err(dev, "invalid \"device_type\" %s\n", type);
231		return -EINVAL;
232	}
233
234	prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
235	if (prop) {
236		if (*prop)
237			pci_add_flags(PCI_PROBE_ONLY);
238		else
239			pci_clear_flags(PCI_PROBE_ONLY);
240	}
241
242	of_id = of_match_node(gen_pci_of_match, np);
243	pci->cfg.ops = of_id->data;
244	gen_pci_ops.map_bus = pci->cfg.ops->map_bus;
245	pci->host.dev.parent = dev;
246	INIT_LIST_HEAD(&pci->host.windows);
247	INIT_LIST_HEAD(&pci->resources);
248
249	/* Parse our PCI ranges and request their resources */
250	err = gen_pci_parse_request_of_pci_ranges(pci);
251	if (err)
252		return err;
253
254	/* Parse and map our Configuration Space windows */
255	err = gen_pci_parse_map_cfg_windows(pci);
256	if (err) {
257		gen_pci_release_of_pci_ranges(pci);
258		return err;
259	}
260
261	pci_common_init_dev(dev, &hw);
262	return 0;
263}
264
265static struct platform_driver gen_pci_driver = {
266	.driver = {
267		.name = "pci-host-generic",
268		.of_match_table = gen_pci_of_match,
269	},
270	.probe = gen_pci_probe,
271};
272module_platform_driver(gen_pci_driver);
273
274MODULE_DESCRIPTION("Generic PCI host driver");
275MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
276MODULE_LICENSE("GPL v2");
277