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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
b6d7b666 PM |
2 | #include <linux/kernel.h> |
3 | #include <linux/init.h> | |
4 | #include <linux/pci.h> | |
5 | #include <linux/types.h> | |
f15cbe6f | 6 | #include <cpu/irq.h> |
b6d7b666 PM |
7 | #include "pci-sh5.h" |
8 | ||
2b8ff9f2 | 9 | int pcibios_map_platform_irq(const struct pci_dev *dev, u8 slot, u8 pin) |
b6d7b666 PM |
10 | { |
11 | int result = -1; | |
12 | ||
13 | /* The complication here is that the PCI IRQ lines from the Cayman's 2 | |
14 | 5V slots get into the CPU via a different path from the IRQ lines | |
15 | from the 3 3.3V slots. Thus, we have to detect whether the card's | |
16 | interrupts go via the 5V or 3.3V path, i.e. the 'bridge swizzling' | |
17 | at the point where we cross from 5V to 3.3V is not the normal case. | |
18 | ||
19 | The added complication is that we don't know that the 5V slots are | |
20 | always bus 2, because a card containing a PCI-PCI bridge may be | |
21 | plugged into a 3.3V slot, and this changes the bus numbering. | |
22 | ||
23 | Also, the Cayman has an intermediate PCI bus that goes a custom | |
24 | expansion board header (and to the secondary bridge). This bus has | |
25 | never been used in practice. | |
26 | ||
27 | The 1ary onboard PCI-PCI bridge is device 3 on bus 0 | |
28 | The 2ary onboard PCI-PCI bridge is device 0 on the 2ary bus of | |
29 | the 1ary bridge. | |
30 | */ | |
31 | ||
32 | struct slot_pin { | |
33 | int slot; | |
34 | int pin; | |
35 | } path[4]; | |
36 | int i=0; | |
37 | ||
38 | while (dev->bus->number > 0) { | |
39 | ||
40 | slot = path[i].slot = PCI_SLOT(dev->devfn); | |
6aa6e498 | 41 | pin = path[i].pin = pci_swizzle_interrupt_pin(dev, pin); |
b6d7b666 PM |
42 | dev = dev->bus->self; |
43 | i++; | |
44 | if (i > 3) panic("PCI path to root bus too long!\n"); | |
45 | } | |
46 | ||
47 | slot = PCI_SLOT(dev->devfn); | |
48 | /* This is the slot on bus 0 through which the device is eventually | |
49 | reachable. */ | |
50 | ||
51 | /* Now work back up. */ | |
52 | if ((slot < 3) || (i == 0)) { | |
53 | /* Bus 0 (incl. PCI-PCI bridge itself) : perform the final | |
54 | swizzle now. */ | |
6aa6e498 | 55 | result = IRQ_INTA + pci_swizzle_interrupt_pin(dev, pin) - 1; |
b6d7b666 PM |
56 | } else { |
57 | i--; | |
58 | slot = path[i].slot; | |
59 | pin = path[i].pin; | |
60 | if (slot > 0) { | |
61 | panic("PCI expansion bus device found - not handled!\n"); | |
62 | } else { | |
63 | if (i > 0) { | |
64 | /* 5V slots */ | |
65 | i--; | |
66 | slot = path[i].slot; | |
67 | pin = path[i].pin; | |
68 | /* 'pin' was swizzled earlier wrt slot, don't do it again. */ | |
69 | result = IRQ_P2INTA + (pin - 1); | |
70 | } else { | |
71 | /* IRQ for 2ary PCI-PCI bridge : unused */ | |
72 | result = -1; | |
73 | } | |
74 | } | |
75 | } | |
76 | ||
77 | return result; | |
78 | } |