From: Trent Piepho <xyzzy@xxxxxxxxxxxxx> A complete re-implementation of fakephp is necessary if it is to present its former interface (pre-2.6.27, when it broke). The reason is that PCI hotplug drivers call pci_hp_register(), which enforces the rule that only one /sys/bus/pci/slots/ file may be created per physical slot. The change breaks the old fakephp's assumption that it could create a file per function. So we re-implement fakephp to avoid using the standard PCI hotplug API so that we can restore the old fakephp user interface. It puts entries in /sys/bus/pci/slots with the names of all PCI devices/functions, exactly symmetrical to what is shown in /sys/bus/pci/devices. Each slots/ entry has a "power" attribute, which works the same way as the fakephp driver's power attribute has worked. There are a few improvements over old fakephp, which couldn't handle PCI devices being added or removed via a means outside of fakephp's knowledge. If a device was added another way, old fakephp didn't notice and didn't create the fake slot for it. If a device was removed another way, old fakephp didn't delete the fake slot for it (and accessing the stale slot caused an oops). The new implementation overcomes these limitations. As a consequence, removing a bridge with other devices behind it now works as well, which is something else old fakephp couldn't do previously. This duplicates a tiny bit of the code in the PCI core that does this same function. Re-using that code ends up being more complex than duplicating it, and it makes code in the PCI core more ugly just to support this legacy fakephp interface compatibility layer. [achiang@xxxxxx: rewrite changelog] [achiang@xxxxxx: use pci_do_scan_bus()] Reviewed-by: James Cameron <qz@xxxxxx> Signed-off-by: Trent Piepho <xyzzy@xxxxxxxxxxxxx> Signed-off-by: Alex Chiang <achiang@xxxxxx> --- drivers/pci/hotplug/Makefile | 2 drivers/pci/hotplug/fakephp.c | 395 ---------------------------------- drivers/pci/hotplug/legacy_fakephp.c | 162 ++++++++++++++ 3 files changed, 163 insertions(+), 396 deletions(-) delete mode 100644 drivers/pci/hotplug/fakephp.c create mode 100644 drivers/pci/hotplug/legacy_fakephp.c diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile index 2aa117c..3314fe8 100644 --- a/drivers/pci/hotplug/Makefile +++ b/drivers/pci/hotplug/Makefile @@ -20,7 +20,7 @@ obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR) += rpadlpar_io.o obj-$(CONFIG_HOTPLUG_PCI_SGI) += sgi_hotplug.o # Link this last so it doesn't claim devices that have a real hotplug driver -obj-$(CONFIG_HOTPLUG_PCI_FAKE) += fakephp.o +obj-$(CONFIG_HOTPLUG_PCI_FAKE) += legacy_fakephp.o pci_hotplug-objs := pci_hotplug_core.o diff --git a/drivers/pci/hotplug/fakephp.c b/drivers/pci/hotplug/fakephp.c deleted file mode 100644 index d8649e1..0000000 --- a/drivers/pci/hotplug/fakephp.c +++ /dev/null @@ -1,395 +0,0 @@ -/* - * Fake PCI Hot Plug Controller Driver - * - * Copyright (C) 2003 Greg Kroah-Hartman <greg@xxxxxxxxx> - * Copyright (C) 2003 IBM Corp. - * Copyright (C) 2003 Rolf Eike Beer <eike-kernel@xxxxxxxxx> - * - * Based on ideas and code from: - * Vladimir Kondratiev <vladimir.kondratiev@xxxxxxxxx> - * Rolf Eike Beer <eike-kernel@xxxxxxxxx> - * - * All rights reserved. - * - * 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, version 2 of the License. - * - * Send feedback to <greg@xxxxxxxxx> - */ - -/* - * - * This driver will "emulate" removing PCI devices from the system. If - * the "power" file is written to with "0" then the specified PCI device - * will be completely removed from the kernel. - * - * WARNING, this does NOT turn off the power to the PCI device. This is - * a "logical" removal, not a physical or electrical removal. - * - * Use this module at your own risk, you have been warned! - * - * Enabling PCI devices is left as an exercise for the reader... - * - */ -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/pci.h> -#include <linux/pci_hotplug.h> -#include <linux/init.h> -#include <linux/string.h> -#include <linux/slab.h> -#include <linux/workqueue.h> -#include "../pci.h" - -#if !defined(MODULE) - #define MY_NAME "fakephp" -#else - #define MY_NAME THIS_MODULE->name -#endif - -#define dbg(format, arg...) \ - do { \ - if (debug) \ - printk(KERN_DEBUG "%s: " format, \ - MY_NAME , ## arg); \ - } while (0) -#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg) -#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg) - -#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@xxxxxxxxx>" -#define DRIVER_DESC "Fake PCI Hot Plug Controller Driver" - -struct dummy_slot { - struct list_head node; - struct hotplug_slot *slot; - struct pci_dev *dev; - struct work_struct remove_work; - unsigned long removed; -}; - -static int debug; -static int dup_slots; -static LIST_HEAD(slot_list); -static struct workqueue_struct *dummyphp_wq; - -static void pci_rescan_worker(struct work_struct *work); -static DECLARE_WORK(pci_rescan_work, pci_rescan_worker); - -static int enable_slot (struct hotplug_slot *slot); -static int disable_slot (struct hotplug_slot *slot); - -static struct hotplug_slot_ops dummy_hotplug_slot_ops = { - .owner = THIS_MODULE, - .enable_slot = enable_slot, - .disable_slot = disable_slot, -}; - -static void dummy_release(struct hotplug_slot *slot) -{ - struct dummy_slot *dslot = slot->private; - - list_del(&dslot->node); - kfree(dslot->slot->info); - kfree(dslot->slot); - pci_dev_put(dslot->dev); - kfree(dslot); -} - -#define SLOT_NAME_SIZE 8 - -static int add_slot(struct pci_dev *dev) -{ - struct dummy_slot *dslot; - struct hotplug_slot *slot; - char name[SLOT_NAME_SIZE]; - int retval = -ENOMEM; - static int count = 1; - - slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL); - if (!slot) - goto error; - - slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL); - if (!slot->info) - goto error_slot; - - slot->info->power_status = 1; - slot->info->max_bus_speed = PCI_SPEED_UNKNOWN; - slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN; - - dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL); - if (!dslot) - goto error_info; - - if (dup_slots) - snprintf(name, SLOT_NAME_SIZE, "fake"); - else - snprintf(name, SLOT_NAME_SIZE, "fake%d", count++); - dbg("slot->name = %s\n", name); - slot->ops = &dummy_hotplug_slot_ops; - slot->release = &dummy_release; - slot->private = dslot; - - retval = pci_hp_register(slot, dev->bus, PCI_SLOT(dev->devfn), name); - if (retval) { - err("pci_hp_register failed with error %d\n", retval); - goto error_dslot; - } - - dbg("slot->name = %s\n", hotplug_slot_name(slot)); - dslot->slot = slot; - dslot->dev = pci_dev_get(dev); - list_add (&dslot->node, &slot_list); - return retval; - -error_dslot: - kfree(dslot); -error_info: - kfree(slot->info); -error_slot: - kfree(slot); -error: - return retval; -} - -static int __init pci_scan_buses(void) -{ - struct pci_dev *dev = NULL; - int lastslot = 0; - - while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) { - if (PCI_FUNC(dev->devfn) > 0 && - lastslot == PCI_SLOT(dev->devfn)) - continue; - lastslot = PCI_SLOT(dev->devfn); - add_slot(dev); - } - - return 0; -} - -static void remove_slot(struct dummy_slot *dslot) -{ - int retval; - - dbg("removing slot %s\n", hotplug_slot_name(dslot->slot)); - retval = pci_hp_deregister(dslot->slot); - if (retval) - err("Problem unregistering a slot %s\n", - hotplug_slot_name(dslot->slot)); -} - -/* called from the single-threaded workqueue handler to remove a slot */ -static void remove_slot_worker(struct work_struct *work) -{ - struct dummy_slot *dslot = - container_of(work, struct dummy_slot, remove_work); - remove_slot(dslot); -} - -/** - * pci_rescan_slot - Rescan slot - * @temp: Device template. Should be set: bus and devfn. - * - * Tries hard not to re-enable already existing devices; - * also handles scanning of subfunctions. - */ -static int pci_rescan_slot(struct pci_dev *temp) -{ - struct pci_bus *bus = temp->bus; - struct pci_dev *dev; - int func; - u8 hdr_type; - int count = 0; - - if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) { - temp->hdr_type = hdr_type & 0x7f; - if ((dev = pci_get_slot(bus, temp->devfn)) != NULL) - pci_dev_put(dev); - else { - dev = pci_scan_single_device(bus, temp->devfn); - if (dev) { - dbg("New device on %s function %x:%x\n", - bus->name, temp->devfn >> 3, - temp->devfn & 7); - count++; - } - } - /* multifunction device? */ - if (!(hdr_type & 0x80)) - return count; - - /* continue scanning for other functions */ - for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) { - if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) - continue; - temp->hdr_type = hdr_type & 0x7f; - - if ((dev = pci_get_slot(bus, temp->devfn)) != NULL) - pci_dev_put(dev); - else { - dev = pci_scan_single_device(bus, temp->devfn); - if (dev) { - dbg("New device on %s function %x:%x\n", - bus->name, temp->devfn >> 3, - temp->devfn & 7); - count++; - } - } - } - } - - return count; -} - - -/** - * pci_rescan_bus - Rescan PCI bus - * @bus: the PCI bus to rescan - * - * Call pci_rescan_slot for each possible function of the bus. - */ -static void pci_rescan_bus(const struct pci_bus *bus) -{ - unsigned int devfn; - struct pci_dev *dev; - int retval; - int found = 0; - dev = alloc_pci_dev(); - if (!dev) - return; - - dev->bus = (struct pci_bus*)bus; - dev->sysdata = bus->sysdata; - for (devfn = 0; devfn < 0x100; devfn += 8) { - dev->devfn = devfn; - found += pci_rescan_slot(dev); - } - - if (found) { - pci_bus_assign_resources(bus); - list_for_each_entry(dev, &bus->devices, bus_list) { - /* Skip already-added devices */ - if (dev->is_added) - continue; - retval = pci_bus_add_device(dev); - if (retval) - dev_err(&dev->dev, - "Error adding device, continuing\n"); - else - add_slot(dev); - } - pci_bus_add_devices(bus); - } - kfree(dev); -} - -/* recursively scan all buses */ -static void pci_rescan_buses(const struct list_head *list) -{ - const struct list_head *l; - list_for_each(l,list) { - const struct pci_bus *b = pci_bus_b(l); - pci_rescan_bus(b); - pci_rescan_buses(&b->children); - } -} - -/* initiate rescan of all pci buses */ -static inline void pci_rescan(void) { - pci_rescan_buses(&pci_root_buses); -} - -/* called from the single-threaded workqueue handler to rescan all pci buses */ -static void pci_rescan_worker(struct work_struct *work) -{ - pci_rescan(); -} - -static int enable_slot(struct hotplug_slot *hotplug_slot) -{ - /* mis-use enable_slot for rescanning of the pci bus */ - cancel_work_sync(&pci_rescan_work); - queue_work(dummyphp_wq, &pci_rescan_work); - return 0; -} - -static int disable_slot(struct hotplug_slot *slot) -{ - struct dummy_slot *dslot; - struct pci_dev *dev; - int func; - - if (!slot) - return -ENODEV; - dslot = slot->private; - - dbg("%s - physical_slot = %s\n", __func__, hotplug_slot_name(slot)); - - for (func = 7; func >= 0; func--) { - dev = pci_get_slot(dslot->dev->bus, dslot->dev->devfn + func); - if (!dev) - continue; - - if (test_and_set_bit(0, &dslot->removed)) { - dbg("Slot already scheduled for removal\n"); - pci_dev_put(dev); - return -ENODEV; - } - - /* remove the device from the pci core */ - pci_remove_bus_device(dev); - - /* queue work item to blow away this sysfs entry and other - * parts. - */ - INIT_WORK(&dslot->remove_work, remove_slot_worker); - queue_work(dummyphp_wq, &dslot->remove_work); - - pci_dev_put(dev); - } - return 0; -} - -static void cleanup_slots (void) -{ - struct list_head *tmp; - struct list_head *next; - struct dummy_slot *dslot; - - destroy_workqueue(dummyphp_wq); - list_for_each_safe (tmp, next, &slot_list) { - dslot = list_entry (tmp, struct dummy_slot, node); - remove_slot(dslot); - } - -} - -static int __init dummyphp_init(void) -{ - info(DRIVER_DESC "\n"); - - dummyphp_wq = create_singlethread_workqueue(MY_NAME); - if (!dummyphp_wq) - return -ENOMEM; - - return pci_scan_buses(); -} - - -static void __exit dummyphp_exit(void) -{ - cleanup_slots(); -} - -module_init(dummyphp_init); -module_exit(dummyphp_exit); - -MODULE_AUTHOR(DRIVER_AUTHOR); -MODULE_DESCRIPTION(DRIVER_DESC); -MODULE_LICENSE("GPL"); -module_param(debug, bool, S_IRUGO | S_IWUSR); -MODULE_PARM_DESC(debug, "Debugging mode enabled or not"); -module_param(dup_slots, bool, S_IRUGO | S_IWUSR); -MODULE_PARM_DESC(dup_slots, "Force duplicate slot names for debugging"); diff --git a/drivers/pci/hotplug/legacy_fakephp.c b/drivers/pci/hotplug/legacy_fakephp.c new file mode 100644 index 0000000..e75af9e --- /dev/null +++ b/drivers/pci/hotplug/legacy_fakephp.c @@ -0,0 +1,162 @@ +/* Works like the fakephp driver used to, except a little better. + * + * - It's possible to remove devices with subordinate busses. + * - New PCI devices that appear via any method, not just a fakephp triggered + * rescan, will be noticed. + * - Devices that are removed via any method, not just a fakephp triggered + * removal, will also be noticed. + * + * Uses nothing from the pci-hotplug subsystem. + * + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/list.h> +#include <linux/kobject.h> +#include <linux/sysfs.h> +#include <linux/init.h> +#include <linux/pci.h> +#include "../pci.h" + +struct legacy_slot { + struct kobject kobj; + struct pci_dev *dev; + struct list_head list; +}; + +static LIST_HEAD(legacy_list); + +static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj); + strcpy(buf, "1\n"); + return 2; +} + +static void remove_callback(void *data) +{ + pci_remove_bus_device((struct pci_dev *)data); +} + +static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t len) +{ + struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj); + unsigned long val; + + if (strict_strtoul(buf, 0, &val) < 0) + return -EINVAL; + + if (val) + pci_do_scan_bus(slot->dev->bus); + else + sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback, + slot->dev, THIS_MODULE); + return len; +} + +static struct attribute *legacy_attrs[] = { + &(struct attribute){ .name = "power", .mode = 0644 }, + NULL, +}; + +static void legacy_release(struct kobject *kobj) +{ + struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj); + + pci_dev_put(slot->dev); + kfree(slot); +} + +static struct kobj_type legacy_ktype = { + .sysfs_ops = &(struct sysfs_ops){ + .store = legacy_store, .show = legacy_show + }, + .release = &legacy_release, + .default_attrs = legacy_attrs, +}; + +static int legacy_add_slot(struct pci_dev *pdev) +{ + struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL); + + if (!slot) + return -ENOMEM; + + if (kobject_init_and_add(&slot->kobj, &legacy_ktype, + &pci_slots_kset->kobj, "%s", + pdev->dev.bus_id)) { + dev_warn(&pdev->dev, "Failed to created legacy fake slot\n"); + return -EINVAL; + } + slot->dev = pci_dev_get(pdev); + + list_add(&slot->list, &legacy_list); + + return 0; +} + +static int legacy_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct pci_dev *pdev = to_pci_dev(data); + + if (action == BUS_NOTIFY_ADD_DEVICE) { + legacy_add_slot(pdev); + } else if (action == BUS_NOTIFY_DEL_DEVICE) { + struct legacy_slot *slot; + + list_for_each_entry(slot, &legacy_list, list) + if (slot->dev == pdev) + goto found; + + dev_warn(&pdev->dev, "Missing legacy fake slot?"); + return -ENODEV; +found: + kobject_del(&slot->kobj); + list_del(&slot->list); + kobject_put(&slot->kobj); + } + + return 0; +} + +static struct notifier_block legacy_notifier = { + .notifier_call = legacy_notify +}; + +static int __init init_legacy(void) +{ + struct pci_dev *pdev = NULL; + + /* Add existing devices */ + while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev))) + legacy_add_slot(pdev); + + /* Be alerted of any new ones */ + bus_register_notifier(&pci_bus_type, &legacy_notifier); + return 0; +} +module_init(init_legacy); + +static void __exit remove_legacy(void) +{ + struct legacy_slot *slot, *tmp; + + bus_unregister_notifier(&pci_bus_type, &legacy_notifier); + + list_for_each_entry_safe(slot, tmp, &legacy_list, list) { + list_del(&slot->list); + kobject_del(&slot->kobj); + kobject_put(&slot->kobj); + } +} +module_exit(remove_legacy); + + +MODULE_AUTHOR("Trent Piepho <xyzzy@xxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Legacy version of the fakephp interface"); 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