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(priv: 0); |
34 | if (!bridge) |
35 | return; |
36 | |
37 | pci_add_resource_offset(resources: &resources, res: &info->io_space, |
38 | offset: info->io_space.start - 0x1000); |
39 | pci_add_resource(resources: &resources, res: &info->mem_space); |
40 | info->busn.flags = IORESOURCE_BUS; |
41 | pci_add_resource(resources: &resources, res: &info->busn); |
42 | |
43 | list_splice_init(list: &resources, head: &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(bus: 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, val: &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, val: cmd); |
87 | } |
88 | return 0; |
89 | } |
90 | |