On Mon, Mar 02, 2020 at 04:47:32PM -0600, Bjorn Helgaas wrote: > [+cc Nicholas, Ben, beginning of thread: > https://lore.kernel.org/r/CAEdQ38GUhL0R4c7ZjEZv89TmqQ0cwhnvBawxuXonSb9On=+B6A@xxxxxxxxxxxxxx] > > On Fri, Feb 28, 2020 at 03:51:01PM -0800, Matt Turner wrote: > > On Sat, Feb 22, 2020 at 8:55 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > > > On Mon, Apr 16, 2018 at 07:33:57AM -0700, Matt Turner wrote: > > > > Commit f75b99d5a77d63f20e07bd276d5a427808ac8ef6 (PCI: Enforce bus > > > > address limits in resource allocation) broke Alpha systems using > > > > CONFIG_ALPHA_NAUTILUS. Alpha is 64-bit, but Nautilus systems use a > > > > 32-bit AMD 751/761 chipset. arch/alpha/kernel/sys_nautilus.c maps PCI > > > > into the upper addresses just below 4GB. > > > > > > > > I can get a working kernel by ifdef'ing out the code in > > > > drivers/pci/bus.c:pci_bus_alloc_resource. We can't tie > > > > PCI_BUS_ADDR_T_64BIT to ALPHA_NAUTILUS without breaking generic > > > > kernels. > > > > > > > > How can we get Nautilus working again? > > > > > > I don't see a resolution in this thread, so I assume this is still > > > broken? Anybody have any more ideas? > > > > Indeed, still broken. > > > > I can add Kconfig logic to unselect ARCH_DMA_ADDR_T_64BIT if > > ALPHA_NAUTILUS, but then generic kernels won't work on Nautilus. It > > doesn't look like we have any way of opting out of > > ARCH_DMA_ADDR_T_64BIT at runtime, and doing enough plumbing to make > > that work is not worth it for such niche hardware. Maybe removing > > Nautilus from the generic kernel build is what I should do until such > > a time that we really fix this? > > > > Or maybe I could put a hack in pci.c that more or less undoes > > d56dbf5bab8c on Nautilus. #if defined CONFIG_ARCH_DMA_ADDR_T_64BIT && > > !defined SYS_NAUTILUS. > > > > Or maybe I just need to take a weekend and try to understand the PCI > > code, instead of applying patches I don't understand and praying :) > > I don't have any *useful* ideas, but I think we did screw up the PCI > resource discovery when we started assuming that we know the host > bridge apertures up front. > > That's generally true for many ACPI and DT systems, but in principle, > we *should* be able to enumerate the devices and learn their resource > requirements before computing the required host bridge apertures and > assigning the BARs. Wholeheartedly agree. In fact, changes to generic PCI code required for proper root bus sizing are quite minimal now since we have struct pci_host_bridge. It's mostly additional checks for bus->self being NULL (as it normally is on the root bus) in the __pci_bus_size_bridges() path, plus new bridge->size_windows flag. See patch below (tested on UP1500). Note that on irongate we're only interested in calculation of non-prefetchable PCI memory aperture, but one can do the same for io and prefetchable memory as well. Ivan. diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c index cd9a112d67ff..84eaf7f54982 100644 --- a/arch/alpha/kernel/sys_nautilus.c +++ b/arch/alpha/kernel/sys_nautilus.c @@ -187,10 +187,6 @@ nautilus_machine_check(unsigned long vector, unsigned long la_ptr) extern void pcibios_claim_one_bus(struct pci_bus *); -static struct resource irongate_io = { - .name = "Irongate PCI IO", - .flags = IORESOURCE_IO, -}; static struct resource irongate_mem = { .name = "Irongate PCI MEM", .flags = IORESOURCE_MEM, @@ -211,14 +207,13 @@ nautilus_init_pci(void) struct pci_dev *irongate; unsigned long bus_align, bus_size, pci_mem; unsigned long memtop = max_low_pfn << PAGE_SHIFT; - int ret; bridge = pci_alloc_host_bridge(0); if (!bridge) return; pci_add_resource(&bridge->windows, &ioport_resource); - pci_add_resource(&bridge->windows, &iomem_resource); + pci_add_resource(&bridge->windows, &irongate_mem); pci_add_resource(&bridge->windows, &busn_resource); bridge->dev.parent = NULL; bridge->sysdata = hose; @@ -226,59 +221,47 @@ nautilus_init_pci(void) bridge->ops = alpha_mv.pci_ops; bridge->swizzle_irq = alpha_mv.pci_swizzle; bridge->map_irq = alpha_mv.pci_map_irq; + bridge->size_windows = 1; /* Scan our single hose. */ - ret = pci_scan_root_bus_bridge(bridge); - if (ret) { + if (pci_scan_root_bus_bridge(bridge)) { pci_free_host_bridge(bridge); return; } - bus = hose->bus = bridge->bus; pcibios_claim_one_bus(bus); - irongate = pci_get_domain_bus_and_slot(pci_domain_nr(bus), 0, 0); - bus->self = irongate; - bus->resource[0] = &irongate_io; - bus->resource[1] = &irongate_mem; - pci_bus_size_bridges(bus); - /* IO port range. */ - bus->resource[0]->start = 0; - bus->resource[0]->end = 0xffff; - - /* Set up PCI memory range - limit is hardwired to 0xffffffff, - base must be at aligned to 16Mb. */ - bus_align = bus->resource[1]->start; - bus_size = bus->resource[1]->end + 1 - bus_align; + /* Now we have PCI memory resources size and alignment stored + in irongate_mem. Set up PCI memory range - limit is hardwired + to 0xffffffff, base must be aligned to 16Mb. */ + bus_align = irongate_mem.start; + bus_size = irongate_mem.end + 1 - bus_align; if (bus_align < 0x1000000UL) bus_align = 0x1000000UL; pci_mem = (0x100000000UL - bus_size) & -bus_align; - bus->resource[1]->start = pci_mem; - bus->resource[1]->end = 0xffffffffUL; - if (request_resource(&iomem_resource, bus->resource[1]) < 0) + irongate_mem.start = pci_mem; + irongate_mem.end = 0xffffffffUL; + if (request_resource(&iomem_resource, &irongate_mem) < 0) printk(KERN_ERR "Failed to request MEM on hose 0\n"); + printk(KERN_INFO "Irongate pci_mem %pR\n", &irongate_mem); + if (pci_mem < memtop) memtop = pci_mem; if (memtop > alpha_mv.min_mem_address) { free_reserved_area(__va(alpha_mv.min_mem_address), __va(memtop), -1, NULL); - printk("nautilus_init_pci: %ldk freed\n", + printk(KERN_INFO "nautilus_init_pci: %ldk freed\n", (memtop - alpha_mv.min_mem_address) >> 10); } - if ((IRONGATE0->dev_vendor >> 16) > 0x7006) /* Albacore? */ IRONGATE0->pci_mem = pci_mem; pci_bus_assign_resources(bus); - - /* pci_common_swizzle() relies on bus->self being NULL - for the root bus, so just clear it. */ - bus->self = NULL; pci_bus_add_devices(bus); } diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index f2461bf9243d..aecc81338a1f 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -846,7 +846,7 @@ static resource_size_t window_alignment(struct pci_bus *bus, unsigned long type) * Per spec, I/O windows are 4K-aligned, but some bridges have * an extension to support 1K alignment. */ - if (bus->self->io_window_1k) + if (bus->self && bus->self->io_window_1k) align = PCI_P2P_DEFAULT_IO_ALIGN_1K; else align = PCI_P2P_DEFAULT_IO_ALIGN; @@ -920,7 +920,7 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, calculate_iosize(size, min_size, size1, add_size, children_add_size, resource_size(b_res), min_align); if (!size0 && !size1) { - if (b_res->start || b_res->end) + if (bus->self && (b_res->start || b_res->end)) pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n", b_res, &bus->busn_res); b_res->flags = 0; @@ -930,7 +930,7 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, b_res->start = min_align; b_res->end = b_res->start + size0 - 1; b_res->flags |= IORESOURCE_STARTALIGN; - if (size1 > size0 && realloc_head) { + if (bus->self && size1 > size0 && realloc_head) { add_to_list(realloc_head, bus->self, b_res, size1-size0, min_align); pci_info(bus->self, "bridge window %pR to %pR add_size %llx\n", @@ -1073,7 +1073,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, calculate_memsize(size, min_size, add_size, children_add_size, resource_size(b_res), add_align); if (!size0 && !size1) { - if (b_res->start || b_res->end) + if (bus->self && (b_res->start || b_res->end)) pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n", b_res, &bus->busn_res); b_res->flags = 0; @@ -1082,7 +1082,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, b_res->start = min_align; b_res->end = size0 + min_align - 1; b_res->flags |= IORESOURCE_STARTALIGN; - if (size1 > size0 && realloc_head) { + if (bus->self && size1 > size0 && realloc_head) { add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align); pci_info(bus->self, "bridge window %pR to %pR add_size %llx add_align %llx\n", b_res, &bus->busn_res, @@ -1196,8 +1196,9 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head) unsigned long mask, prefmask, type2 = 0, type3 = 0; resource_size_t additional_io_size = 0, additional_mmio_size = 0, additional_mmio_pref_size = 0; - struct resource *b_res; - int ret; + struct resource *pref; + struct pci_host_bridge *host; + int hdr_type, i, ret; list_for_each_entry(dev, &bus->devices, bus_list) { struct pci_bus *b = dev->subordinate; @@ -1217,10 +1218,20 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head) } /* The root bus? */ - if (pci_is_root_bus(bus)) - return; + if (pci_is_root_bus(bus)) { + host = to_pci_host_bridge(bus->bridge); + if (!host->size_windows) + return; + pci_bus_for_each_resource(bus, pref, i) + if (pref && (pref->flags & IORESOURCE_PREFETCH)) + break; + hdr_type = -1; + } else { + pref = &bus->self->resource[PCI_BRIDGE_RESOURCES + 2]; + hdr_type = bus->self->hdr_type; + } - switch (bus->self->hdr_type) { + switch (hdr_type) { case PCI_HEADER_TYPE_CARDBUS: /* Don't size CardBuses yet */ break; @@ -1242,10 +1253,9 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head) * the size required to put all 64-bit prefetchable * resources in it. */ - b_res = &bus->self->resource[PCI_BRIDGE_RESOURCES]; mask = IORESOURCE_MEM; prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH; - if (b_res[2].flags & IORESOURCE_MEM_64) { + if (pref && (pref->flags & IORESOURCE_MEM_64)) { prefmask |= IORESOURCE_MEM_64; ret = pbus_size_mem(bus, prefmask, prefmask, prefmask, prefmask, diff --git a/include/linux/pci.h b/include/linux/pci.h index 3840a541a9de..681c79b4dc85 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -511,6 +511,7 @@ struct pci_host_bridge { unsigned int native_pme:1; /* OS may use PCIe PME */ unsigned int native_ltr:1; /* OS may use PCIe LTR */ unsigned int preserve_config:1; /* Preserve FW resource setup */ + unsigned int size_windows:1; /* Enable root bus sizing */ /* Resource alignment requirements */ resource_size_t (*align_resource)(struct pci_dev *dev,
