/* pci-frv.c: low-level PCI access routines * * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from the i386 equivalent stuff * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include "pci-frv.h" /* * We need to avoid collisions with `mirrored' VGA ports * and other strange ISA hardware, so we always want the * addresses to be allocated in the 0x000-0x0ff region * modulo 0x400. * * Why? Because some silly external IO cards only decode * the low 10 bits of the IO address. The 0x00-0xff region * is reserved for motherboard devices that decode all 16 * bits, so it's ok to allocate at, say, 0x2800-0x28ff, * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { resource_size_t start = res->start; if ((res->flags & IORESOURCE_IO) && (start & 0x300)) start = (start + 0x3ff) & ~0x3ff; return start; } /* * Handle resources of PCI devices. If the world were perfect, we could * just allocate all the resource regions and do nothing more. It isn't. * On the other hand, we cannot just re-allocate all devices, as it would * require us to know lots of host bridge internals. So we attempt to * keep as much of the original configuration as possible, but tweak it * when it's found to be wrong. * * Known BIOS problems we have to work around: * - I/O or memory regions not configured * - regions configured, but not enabled in the command register * - bogus I/O addresses above 64K used * - expansion ROMs left enabled (this may sound harmless, but given * the fact the PCI specs explicitly allow address decoders to be * shared between expansion ROMs and other resource regions, it's * at least dangerous) * * Our solution: * (1) Allocate resources for all buses behind PCI-to-PCI bridges. * This gives us fixed barriers on where we can allocate. * (2) Allocate resources for all enabled devices. If there is * a collision, just mark the resource as unallocated. Also * disable expansion ROMs during this step. * (3) Try to allocate resources for disabled devices. If the * resources were assigned correctly, everything goes well, * if they weren't, they won't disturb allocation of other * resources. * (4) Assign new addresses to resources which were either * not configured at all or misconfigured. If explicitly * requested by the user, configure expansion ROM address * as well. */ static void __init pcibios_allocate_bus_resources(struct list_head *bus_list) { struct list_head *ln; struct pci_bus *bus; struct pci_dev *dev; int idx; struct resource *r; /* Depth-First Search on bus tree */ for (ln=bus_list->next; ln != bus_list; ln=ln->next) { bus = pci_bus_b(ln); if ((dev = bus->self)) { for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) { r = &dev->resource[idx]; if (!r->start) continue; pci_claim_resource(dev, idx); } } pcibios_allocate_bus_resources(&bus->children); } } static void __init pcibios_allocate_resources(int pass) { struct pci_dev *dev = NULL; int idx, disabled; u16 command; struct resource *r; for_each_pci_dev(dev) { pci_read_config_word(dev, PCI_COMMAND, &command); for(idx = 0; idx < 6; idx++) { r = &dev->resource[idx]; if (r->parent) /* Already allocated */ continue; if (!r->start) /* Address not assigned at all */ continue; if (r->flags & IORESOURCE_IO) disabled = !(command & PCI_COMMAND_IO); else disabled = !(command & PCI_COMMAND_MEMORY); if (pass == disabled) { DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)\n", r->start, r->end, r->flags, disabled, pass); if (pci_claim_resource(dev, idx) < 0) { /* We'll assign a new address later */ r->end -= r->start; r->start = 0; } } } if (!pass) { r = &dev->resource[PCI_ROM_RESOURCE]; if (r->flags & IORESOURCE_ROM_ENABLE) { /* Turn the ROM off, leave the resource region, but keep it unregistered. */ u32 reg; DBG("PCI: Switching off ROM of %s\n", pci_name(dev)); r->flags &= ~IORESOURCE_ROM_ENABLE; pci_read_config_dword(dev, dev->rom_base_reg, ®); pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE); } } } } static void __init pcibios_assign_resources(void) { struct pci_dev *dev = NULL; int idx; struct resource *r; for_each_pci_dev(dev) { int class = dev->class >> 8; /* Don't touch classless devices and host bridges */ if (!class || class == PCI_CLASS_BRIDGE_HOST) continue; for(idx=0; idx<6; idx++) { r = &dev->resource[idx]; /* * Don't touch IDE controllers and I/O ports of video cards! */ if ((class == PCI_CLASS_STORAGE_IDE && idx < 4) || (class == PCI_CLASS_DISPLAY_VGA && (r->flags & IORESOURCE_IO))) continue; /* * We shall assign a new address to this resource, either because * the BIOS forgot to do so or because we have decided the old * address was unusable for some reason. */ if (!r->start && r->end) pci_assign_resource(dev, idx); } if (pci_probe & PCI_ASSIGN_ROMS) { r = &dev->resource[PCI_ROM_RESOURCE]; r->end -= r->start; r->start = 0; if (r->end) pci_assign_resource(dev, PCI_ROM_RESOURCE); } } } void __init pcibios_resource_survey(void) { DBG("PCI: Allocating resources\n"); pcibios_allocate_bus_resources(&pci_root_buses); pcibios_allocate_resources(0); pcibios_allocate_resources(1); pcibios_assign_resources(); } /* * If we set up a device for bus mastering, we need to check the latency * timer as certain crappy BIOSes forget to set it properly. */ unsigned int pcibios_max_latency = 255; void pcibios_set_master(struct pci_dev *dev) { u8 lat; pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat); if (lat < 16) lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency; else if (lat > pcibios_max_latency) lat = pcibios_max_latency; else return; printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n", pci_name(dev), lat); pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat); }