1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * leon_pci.c: LEON Host PCI support
4 *
5 * Copyright (C) 2011 Aeroflex Gaisler AB, Daniel Hellstrom
6 *
7 * Code is partially derived from pcic.c
8 */
9
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/kernel.h>
13 #include <linux/pci.h>
14 #include <linux/export.h>
15 #include <asm/leon.h>
16 #include <asm/leon_pci.h>
17
18 /* The LEON architecture does not rely on a BIOS or bootloader to setup
19 * PCI for us. The Linux generic routines are used to setup resources,
20 * reset values of configuration-space register settings are preserved.
21 *
22 * PCI Memory and Prefetchable Memory is direct-mapped. However I/O Space is
23 * accessed through a Window which is translated to low 64KB in PCI space, the
24 * first 4KB is not used so 60KB is available.
25 */
26 void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
27 {
28 LIST_HEAD(resources);
29 struct pci_bus *root_bus;
30 struct pci_host_bridge *bridge;
31 int ret;
32
33 bridge = pci_alloc_host_bridge(0);
34 if (!bridge)
35 return;
36
37 pci_add_resource_offset(&resources, &info->io_space,
38 info->io_space.start - 0x1000);
39 pci_add_resource(&resources, &info->mem_space);
40 info->busn.flags = IORESOURCE_BUS;
41 pci_add_resource(&resources, &info->busn);
42
43 list_splice_init(&resources, &bridge->windows);
44 bridge->dev.parent = &ofdev->dev;
45 bridge->sysdata = info;
46 bridge->busnr = 0;
47 bridge->ops = info->ops;
48 bridge->swizzle_irq = pci_common_swizzle;
49 bridge->map_irq = info->map_irq;
50
51 ret = pci_scan_root_bus_bridge(bridge);
52 if (ret) {
53 pci_free_host_bridge(bridge);
54 return;
55 }
56
57 root_bus = bridge->bus;
58
59 /* Assign devices with resources */
60 pci_assign_unassigned_resources();
61 pci_bus_add_devices(root_bus);
62 }
63
64 int pcibios_enable_device(struct pci_dev *dev, int mask)
65 {
66 struct resource *res;
67 u16 cmd, oldcmd;
68 int i;
69
70 pci_read_config_word(dev, PCI_COMMAND, &cmd);
71 oldcmd = cmd;
72
73 pci_dev_for_each_resource(dev, res, i) {
74 /* Only set up the requested stuff */
75 if (!(mask & (1<<i)))
76 continue;
77
78 if (res->flags & IORESOURCE_IO)
79 cmd |= PCI_COMMAND_IO;
80 if (res->flags & IORESOURCE_MEM)
81 cmd |= PCI_COMMAND_MEMORY;
82 }
83
84 if (cmd != oldcmd) {
85 pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
86 pci_write_config_word(dev, PCI_COMMAND, cmd);
87 }
88 return 0;
89 }
90
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