| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | #include <linux/kernel.h> |
| 3 | #include <linux/init.h> |
| 4 | #include <linux/pci.h> |
| 5 | #include <linux/types.h> |
| 6 | #include <cpu/irq.h> |
| 7 | #include "pci-sh5.h" |
| 8 | |
| 9 | int pcibios_map_platform_irq(const struct pci_dev *dev, u8 slot, u8 pin) |
| 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); |
| 41 | pin = path[i].pin = pci_swizzle_interrupt_pin(dev, pin); |
| 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. */ |
| 55 | result = IRQ_INTA + pci_swizzle_interrupt_pin(dev, pin) - 1; |
| 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 | } |