| /* |
| * SDK7786 FPGA PCIe mux handling |
| * |
| * Copyright (C) 2010 Paul Mundt |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| */ |
| #define pr_fmt(fmt) "PCI: " fmt |
| |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/pci.h> |
| #include <mach/fpga.h> |
| |
| /* |
| * The SDK7786 FPGA supports mangling of most of the slots in some way or |
| * another. Slots 3/4 are special in that only one can be supported at a |
| * time, and both appear on port 3 to the PCI bus scan. Enabling slot 4 |
| * (the horizontal edge connector) will disable slot 3 entirely. |
| * |
| * Misconfigurations can be detected through the FPGA via the slot |
| * resistors to determine card presence. Hotplug remains unsupported. |
| */ |
| static unsigned int slot4en __devinitdata; |
| |
| char *__devinit pcibios_setup(char *str) |
| { |
| if (strcmp(str, "slot4en") == 0) { |
| slot4en = 1; |
| return NULL; |
| } |
| |
| return str; |
| } |
| |
| static int __init sdk7786_pci_init(void) |
| { |
| u16 data = fpga_read_reg(PCIECR); |
| |
| /* |
| * Enable slot #4 if it's been specified on the command line. |
| * |
| * Optionally reroute if slot #4 has a card present while slot #3 |
| * does not, regardless of command line value. |
| * |
| * Card presence is logically inverted. |
| */ |
| slot4en ?: (!(data & PCIECR_PRST4) && (data & PCIECR_PRST3)); |
| if (slot4en) { |
| pr_info("Activating PCIe slot#4 (disabling slot#3)\n"); |
| |
| data &= ~PCIECR_PCIEMUX1; |
| fpga_write_reg(data, PCIECR); |
| |
| /* Warn about forced rerouting if slot#3 is occupied */ |
| if ((data & PCIECR_PRST3) == 0) { |
| pr_warning("Unreachable card detected in slot#3\n"); |
| return -EBUSY; |
| } |
| } else |
| pr_info("PCIe slot#4 disabled\n"); |
| |
| return 0; |
| } |
| postcore_initcall(sdk7786_pci_init); |