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 */
26void 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
64int 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