1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * arch/sh/drivers/pci/fixups-dreamcast.c
4  *
5  * PCI fixups for the Sega Dreamcast
6  *
7  * Copyright (C) 2001, 2002  M. R. Brown
8  * Copyright (C) 2002, 2003, 2006  Paul Mundt
9  *
10  * This file originally bore the message (with enclosed-$):
11  *	Id: pci.c,v 1.3 2003/05/04 19:29:46 lethal Exp
12  *	Dreamcast PCI: Supports SEGA Broadband Adaptor only.
13  */
14 
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/param.h>
18 #include <linux/interrupt.h>
19 #include <linux/init.h>
20 #include <linux/irq.h>
21 #include <linux/pci.h>
22 #include <linux/dma-mapping.h>
23 
24 #include <asm/io.h>
25 #include <asm/irq.h>
26 #include <mach/pci.h>
27 
28 static void gapspci_fixup_resources(struct pci_dev *dev)
29 {
30 	struct pci_channel *p = dev->sysdata;
31 	struct resource res;
32 	struct pci_bus_region region;
33 
34 	printk(KERN_NOTICE "PCI: Fixing up device %s\n", pci_name(dev));
35 
36 	switch (dev->device) {
37 	case PCI_DEVICE_ID_SEGA_BBA:
38 		/*
39 		 * We also assume that dev->devfn == 0
40 		 */
41 		dev->resource[1].start	= p->resources[0].start  + 0x100;
42 		dev->resource[1].end	= dev->resource[1].start + 0x200 - 1;
43 
44 		/*
45 		 * This is not a normal BAR, prevent any attempts to move
46 		 * the BAR, as this will result in a bus lock.
47 		 */
48 		dev->resource[1].flags |= IORESOURCE_PCI_FIXED;
49 
50 		/*
51 		 * Redirect dma memory allocations to special memory window.
52 		 *
53 		 * If this GAPSPCI region were mapped by a BAR, the CPU
54 		 * phys_addr_t would be pci_resource_start(), and the bus
55 		 * address would be pci_bus_address(pci_resource_start()).
56 		 * But apparently there's no BAR mapping it, so we just
57 		 * "know" its CPU address is GAPSPCI_DMA_BASE.
58 		 */
59 		res.start = GAPSPCI_DMA_BASE;
60 		res.end = GAPSPCI_DMA_BASE + GAPSPCI_DMA_SIZE - 1;
61 		res.flags = IORESOURCE_MEM;
62 		pcibios_resource_to_bus(dev->bus, &region, &res);
63 		BUG_ON(dma_declare_coherent_memory(&dev->dev,
64 						res.start,
65 						region.start,
66 						resource_size(&res),
67 						DMA_MEMORY_EXCLUSIVE));
68 		break;
69 	default:
70 		printk("PCI: Failed resource fixup\n");
71 	}
72 }
73 DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, gapspci_fixup_resources);
74 
75 int pcibios_map_platform_irq(const struct pci_dev *dev, u8 slot, u8 pin)
76 {
77 	/*
78 	 * The interrupt routing semantics here are quite trivial.
79 	 *
80 	 * We basically only support one interrupt, so we only bother
81 	 * updating a device's interrupt line with this single shared
82 	 * interrupt. Keeps routing quite simple, doesn't it?
83 	 */
84 	return GAPSPCI_IRQ;
85 }
86