On Wednesday, September 08, 2010 12:59:58 am Ram Pai wrote: > PCI: override BIOS/firmware resource allocation through command line parameters > > git commit 977d17bb1749517b353874ccdc9b85abc7a58c2a > released and reallocated all resources when allocation of any > resource of any type, ioport and memory, failed. This caused > failure to reallocate fragile io port resources, as reported in > https://bugzilla.kernel.org/show_bug.cgi?id=15960 > > The problem was solved by reverting the commit, through > git commit 769d9968e42c995eaaf61ac5583d998f32e0769a. > > However reverting the original patch fails MMIO resource allocation > for SRIOV PCI-Bars on some platforms. Especially on platforms > where the BIOS is unaware of SRIOV resource BARs. > > The following code, an idea proposed by Linus, allows the user > to tailor the resource allocation for devices through kernel > command line parameter. Details of the idea can be found at > http://marc.info/?l=linux-kernel&m=127846075028242&w=2 This changelog doesn't really tell me why we want this patch. I see it has something to do with BARs of SR-IOV devices, but otherwise, it's just low-level details about past history. What specific problem are you solving? Does this patch enable us to assign resources to a device that previously had none? A concrete example might help. > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx> > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index f084af0..eec068f 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -1961,6 +1961,21 @@ and is between 256 and 4096 characters. It is defined in the file > PAGE_SIZE is used as alignment. > PCI-PCI bridge can be specified, if resource > windows need to be expanded. > + override=[off, conflict, always, <device>] > + off : Do not override BIOS/firmware allocations. This is the > + default > + conflict : override BIOS/firmware allocations if conflicting > + or not allocated. > + always : override all BIOS/firmware allocations > + <device>: Format [<domain>:]<bus>:<slot>.<func>[; ...] > + override BIOS/firmware allocations of specified > + devices > + > + clear=<device> > + <device>: Format [<domain>:]<bus>:<slot>.<func>[; ...] > + release BIOS/firmware allocations of specified > + devices. By default no allocations are cleared. I object in principle to new kernel parameters that users might need to use just to get their box to work. How would a user know that he might need this option? Isn't it possible for the kernel to figure that out automatically? Bjorn > ecrc= Enable/disable PCIe ECRC (transaction layer > end-to-end CRC checking). > bios: Use BIOS/firmware settings. This is the > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 7fa3cbd..5676416 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2984,6 +2984,85 @@ void __weak pci_fixup_cardbus(struct pci_bus *bus) > } > EXPORT_SYMBOL(pci_fixup_cardbus); > > +#define RESOURCE_RELEASE_PARAM_SIZE COMMAND_LINE_SIZE > +static char __initdata resource_release_param[RESOURCE_RELEASE_PARAM_SIZE]; > +int pci_override=PCI_OVERRIDE_OFF; > + > +/* > + * Return success if 'dev' is listed as one of the devices > + * through the kernel command line > + * pci=[override|clear]=device[;device]* > + */ > +int __init is_pci_reset_device(struct pci_dev *dev) > +{ > + int seg, bus, slot, func, count; > + char *p; > + > + p = resource_release_param; > + while (*p) { > + count = 0; > + if (sscanf(p, "%x:%x:%x.%x%n", > + &seg, &bus, &slot, &func, &count) != 4) { > + seg = 0; > + if (sscanf(p, "%x:%x.%x%n", > + &bus, &slot, &func, &count) != 3) { > + /* Invalid format */ > + printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n", > + p); > + return 0; > + } > + } > + p += count; > + if (seg == pci_domain_nr(dev->bus) && > + bus == dev->bus->number && > + slot == PCI_SLOT(dev->devfn) && > + func == PCI_FUNC(dev->devfn)) { > + return 1; > + } > + if (*p != ';') { > + /* End of param or invalid format */ > + return 0; > + } > + p++; > + } > + return 0; > +} > + > + > +static void __init pci_override_setup(const char *str, int override) > +{ > + if (override && !strncmp(str, "off", 3)) { > + > + pci_override = PCI_OVERRIDE_OFF; > + printk(KERN_INFO "pci: do not override " > + "BIOS/uEFI allocations\n"); > + > + } else if (override && !strncmp(str, "conflict", 8)) { > + > + pci_override = PCI_OVERRIDE_CONFLICT; > + printk(KERN_INFO "pci: reallocate BIOS/uEFI " > + "allocated resources on conflicts\n"); > + > + } else if (override && !strncmp(str, "always", 6)) { > + > + pci_override = PCI_OVERRIDE_ALWAYS; > + printk(KERN_INFO "pci: override all BIOS/uEFI allocations\n"); > + > + } else { > + int count=strlen(str); > + > + pci_override = override ? PCI_OVERRIDE_DEVICE : > + PCI_CLEAR_DEVICE; > + if (count > RESOURCE_RELEASE_PARAM_SIZE - 1) > + count = RESOURCE_RELEASE_PARAM_SIZE - 1; > + strncpy(resource_release_param, str, count); > + resource_release_param[count] = '\0'; > + printk(KERN_INFO "pci: %s BIOS/uEFI allocations for %s\n", > + override ? "override" : "clear", resource_release_param); > + } > + return; > +} > + > static int __init pci_setup(char *str) > { > while (str) { > @@ -3010,6 +3089,10 @@ static int __init pci_setup(char *str) > pci_hotplug_io_size = memparse(str + 9, &str); > } else if (!strncmp(str, "hpmemsize=", 10)) { > pci_hotplug_mem_size = memparse(str + 10, &str); > + } else if (!strncmp(str, "override=", 9)) { > + pci_override_setup(str + 9, 1); > + } else if (!strncmp(str, "clear=", 6)) { > + pci_override_setup(str + 6, 0); > } else { > printk(KERN_ERR "PCI: Unknown option `%s'\n", > str); > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index 66cb8f4..e215ee9 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -838,21 +838,195 @@ static void pci_bus_dump_resources(struct pci_bus *bus) > } > } > > +static void __init > +__pci_dev_reset_resource(struct pci_dev *dev, > + struct resource_list_x *fail_head) > +{ > + int idx, start, end; > + struct resource *r; > + u16 class = dev->class >> 8; > + > + if (class == PCI_CLASS_BRIDGE_PCI) { > + start=PCI_BRIDGE_RESOURCES; > + end=PCI_BRIDGE_RESOURCE_END+1; > + } else { > + start=0; > + end=PCI_NUM_RESOURCES; > + } > + > + for (idx = start; idx < end; idx++) { > + r = &dev->resource[idx]; > + > + if (r->flags & IORESOURCE_PCI_FIXED) > + continue; > + > + if ( idx == PCI_ROM_RESOURCE || > + r->flags & IORESOURCE_ROM_ENABLE) > + continue; > + > + if (fail_head) > + add_to_failed_list(fail_head, dev, r); > + > + /* keep the old size */ > + r->end = 0; > + r->start = 0; > + r->flags = 0; > + } > +} > + > +/* > + * reset the resource requirement of the device tree under 'dev'. > + * Capture and add each resource's original requirement to the list 'head' > + */ > +static void __init > +pci_dev_reset_resource(struct pci_dev *dev, > + struct resource_list_x *head) > +{ > + u16 class = dev->class >> 8; > + > + /* Don't touch classless devices or host bridges or ioapics. */ > + if (class == PCI_CLASS_NOT_DEFINED || class == PCI_CLASS_BRIDGE_HOST) > + return; > + > + /* Don't touch ioapic devices already enabled by firmware */ > + if (class == PCI_CLASS_SYSTEM_PIC) { > + u16 command; > + pci_read_config_word(dev, PCI_COMMAND, &command); > + if (command & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) > + return; > + } > + > + if (class == PCI_CLASS_BRIDGE_PCI) { > + struct pci_bus *bus = dev->subordinate; > + if (bus) { > + struct pci_dev *dev1; > + list_for_each_entry(dev1, &bus->devices, bus_list) > + pci_dev_reset_resource(dev1, head); > + } > + } > + __pci_dev_reset_resource(dev, head); > + return; > +} > + > + > +/* > + * Reset the resource requirement of all devices under 'bus' that > + * specified by the kernel parameter 'pci=[override|clear]=<device>[;<device>]*' > + * Capture and add each resource's original requirement to the > + * list 'head' > + */ > +static void __init > +pci_bus_reset_resource(struct pci_bus *bus, > + struct resource_list_x *head) > +{ > + struct pci_bus *b; > + struct pci_dev *dev; > + > + if (bus->self && (pci_override == PCI_OVERRIDE_ALWAYS || > + is_pci_reset_device(bus->self))) { > + pci_dev_reset_resource(bus->self, head); > + return; > + } > + > + list_for_each_entry(dev, &bus->devices, bus_list) { > + if (is_pci_reset_device(dev)) { > + pci_dev_reset_resource(dev, head); > + continue; > + } > + if ((b = dev->subordinate)) > + pci_bus_reset_resource(b, head); > + } > + return; > +} > + > +/* > + * Release all the resources in the list 'head'. > + */ > +static void __init > +pci_release_resources(struct resource_list_x *head) > +{ > + struct resource_list_x *list; > + unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM | > + IORESOURCE_PREFETCH; > + enum release_type rel_type = whole_subtree; > + /* > + * Try to release leaf bridge's resources that doesn't fit resource of > + * child device under that bridge > + */ > + for (list = head->next; list;) { > + struct pci_bus *bus = list->dev->bus; > + pci_bus_release_bridge_resources(bus, list->flags & type_mask, > + rel_type); > + list = list->next; > + } > + /* restore size and flags */ > + for (list = head->next; list;) { > + struct resource *res = list->res; > + > + res->start = list->start; > + res->end = list->end; > + res->flags = list->flags; > + if (list->dev->subordinate) > + res->flags = 0; > + > + list = list->next; > + } > + free_failed_list(head); > +} > + > + > void __init > pci_assign_unassigned_resources(void) > { > struct pci_bus *bus; > + int tried_times = 0; > + struct resource_list_x head; > + > + head.next = NULL; > > - /* Depth first, calculate sizes and alignments of all > - subordinate buses. */ > list_for_each_entry(bus, &pci_root_buses, node) { > - pci_bus_size_bridges(bus); > + if (pci_override == PCI_OVERRIDE_DEVICE || > + pci_override == PCI_OVERRIDE_ALWAYS) { > + pci_bus_reset_resource(bus, &head); > + pci_release_resources(&head); > + } else if (pci_override == PCI_CLEAR_DEVICE) { > + pci_bus_reset_resource(bus, NULL); > + } > } > - /* Depth last, allocate resources and update the hardware. */ > - list_for_each_entry(bus, &pci_root_buses, node) { > - pci_bus_assign_resources(bus); > + > + do { /* loop at most 2 times */ > + /* Depth first, calculate sizes and alignments of all > + subordinate buses. */ > + list_for_each_entry(bus, &pci_root_buses, node) { > + pci_bus_size_bridges(bus); > + } > + > + /* Depth last, allocate resources and update the hardware. */ > + list_for_each_entry(bus, &pci_root_buses, node) { > + __pci_bus_assign_resources(bus, &head); > + } > + > + /* happily exit the loop if all devices are happy */ > + if (!head.next) > + goto enable_and_dump; > + > + /* dont' care if any device complained, unless asked to care */ > + if (pci_override != PCI_OVERRIDE_CONFLICT) { > + free_failed_list(&head); > + goto enable_and_dump; > + } > + > + printk(KERN_INFO "PCI: No. %d try to assign unassigned res\n", > + tried_times); > + > + pci_release_resources(&head); > + > + } while (!tried_times++); > + > +enable_and_dump: > + /* Depth last, update the hardware. */ > + list_for_each_entry(bus, &pci_root_buses, node) > pci_enable_bridges(bus); > - } > > /* dump the resource on buses */ > list_for_each_entry(bus, &pci_root_buses, node) { > diff --git a/include/linux/pci.h b/include/linux/pci.h > index b1d1795..c001005 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1357,10 +1357,18 @@ extern u8 pci_cache_line_size; > extern unsigned long pci_hotplug_io_size; > extern unsigned long pci_hotplug_mem_size; > > +extern int pci_override; > +#define PCI_OVERRIDE_OFF 1 > +#define PCI_OVERRIDE_CONFLICT 2 > +#define PCI_OVERRIDE_ALWAYS 3 > +#define PCI_OVERRIDE_DEVICE 4 > +#define PCI_CLEAR_DEVICE 5 > + > int pcibios_add_platform_entries(struct pci_dev *dev); > void pcibios_disable_device(struct pci_dev *dev); > int pcibios_set_pcie_reset_state(struct pci_dev *dev, > enum pcie_reset_state state); > +int is_pci_reset_device(struct pci_dev *dev); > > #ifdef CONFIG_PCI_MMCONFIG > extern void __init pci_mmcfg_early_init(void); > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
