Re: [PATCH 4/4] ACPI PCI slot detection driver

Kenji Kaneshige
2008-03-25T04:52:44Z

Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

Thanks,
Kenji Kaneshige

Alex Chiang wrote:
> Detect all physical PCI slots as described by ACPI, and create
> entries in /sys/bus/pci/slots/.
>
> Not all physical slots are hotpluggable, and the acpiphp module
> does not detect them. Now we know the physical PCI geography of
> our system, without caring about hotplug.
>
> v10 -> v11:
> Thanks to Kenji Kanishige for the following updates:
> - Fix dmi table for Fujitsu PRIMEQUEST
> - Fix _STA evaluation
> - Use list_head for pci slot list
> - Fix slot removal path
>
> v9 -> v10:
> Allow an hp driver to override the pci_slot kobject name.
>
> v8 -> v9:
> Add DMI quirk for Fujitsu machines; eval _STA before _SUN
>
> v6 -> v8:
> No change
>
> v5 -> v6:
> Add debugging information.
>
> v4 -> v5:
> Convert to a tristate module.
>
> Remove #ifdef CONFIG_ACPI_PCI_SLOT, as struct pci_slot
> objects are properly refcounted, and multiple calls to
> pci_create/destroy_slot work just fine.
>
> Remove prior -EBUSY changes, as they have been folded
> into the Introduce pci_slot patch.
>
> v3 -> v4:
> Always attempt to call pci_create_slot from pcihp_core to
> cover cases of
> a) user did not say Y to Kconfig option ACPI_PCI_SLOT
> b) native PCIe hotplug driver registering on a
> non-ACPI system.
>
> Return -EBUSY if an hp driver attempts to register a slot
> that is already registered to another driver. Do not
> consider that to be an error condition in acpiphp and pciehp.
>
> v2 -> v3:
> Add Kconfig option to driver, allowing users to [de]config
> this driver. If configured, take slightly different code
> paths in pci_hp_register and pci_hp_deregister.
>
> v1 -> v2:
> Now recursively discovering p2p bridges and slots
> underneath them. Hopefully, this will prevent us
> from trying to register the same slot multiple times.
>
> Signed-off-by: Alex Chiang <achiang@hp.com>
> ---
> drivers/acpi/Kconfig | 9 +
> drivers/acpi/Makefile | 1 +
> drivers/acpi/pci_slot.c | 370 ++++++++++++++++++++++++++++++++
> drivers/pci/hotplug/pci_hotplug_core.c | 16 ++
> drivers/pci/hotplug/pciehp_core.c | 2 +-
> drivers/pci/hotplug/sgi_hotplug.c | 2 +-
> 6 files changed, 398 insertions(+), 2 deletions(-)
> create mode 100644 drivers/acpi/pci_slot.c
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index b4f5e85..4ccb0e7 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -335,6 +335,15 @@ config ACPI_EC
> the battery and thermal drivers. If you are compiling for a
> mobile system, say Y.
>
> +config ACPI_PCI_SLOT
> + tristate "PCI slot detection driver"
> + default n
> + help
> + This driver will attempt to discover all PCI slots in your system,
> + and creates entries in /sys/bus/pci/slots/. This feature can
> + help you correlate PCI bus addresses with the physical geography
> + of your slots. If you are unsure, say N.
> +
> config ACPI_POWER
> bool
> default y
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 40b0fca..579c29c 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_ACPI_DOCK) += dock.o
> obj-$(CONFIG_ACPI_BAY) += bay.o
> obj-$(CONFIG_ACPI_VIDEO) += video.o
> obj-y += pci_root.o pci_link.o pci_irq.o pci_bind.o
> +obj-$(CONFIG_ACPI_PCI_SLOT) += pci_slot.o
> obj-$(CONFIG_ACPI_POWER) += power.o
> obj-$(CONFIG_ACPI_PROCESSOR) += processor.o
> obj-$(CONFIG_ACPI_CONTAINER) += container.o
> diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
> new file mode 100644
> index 0000000..2b48ea7
> --- /dev/null
> +++ b/drivers/acpi/pci_slot.c
> @@ -0,0 +1,370 @@
> +/*
> + * pci_slot.c - ACPI PCI Slot Driver
> + *
> + * The code here is heavily leveraged from the acpiphp module.
> + * Thanks to Matthew Wilcox <matthew@wil.cx> for much guidance.
> + * Thanks to Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> for code
> + * review and fixes.
> + *
> + * Copyright (C) 2007 Alex Chiang <achiang@hp.com>
> + * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/types.h>
> +#include <linux/pci.h>
> +#include <linux/acpi.h>
> +#include <acpi/acpi_bus.h>
> +#include <acpi/acpi_drivers.h>
> +
> +static int debug;
> +static int check_sta_before_sun;
> +
> +#define DRIVER_VERSION "0.1"
> +#define DRIVER_AUTHOR "Alex Chiang <achiang@hp.com>"
> +#define DRIVER_DESC "ACPI PCI Slot Detection Driver"
> +MODULE_AUTHOR(DRIVER_AUTHOR);
> +MODULE_DESCRIPTION(DRIVER_DESC);
> +MODULE_LICENSE("GPL");
> +MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
> +module_param(debug, bool, 0644);
> +
> +#define _COMPONENT ACPI_PCI_COMPONENT
> +ACPI_MODULE_NAME("pci_slot");
> +
> +#define MY_NAME "pci_slot"
> +#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 dbg(format, arg...) \
> + do { \
> + if (debug) \
> + printk(KERN_DEBUG "%s: " format, \
> + MY_NAME , ## arg); \
> + } while (0)
> +
> +struct acpi_pci_slot {
> + acpi_handle root_handle; /* handle of the root bridge */
> + struct pci_slot *pci_slot; /* corresponding pci_slot */
> + struct list_head list; /* node in the list of slots */
> +};
> +
> +static int acpi_pci_slot_add(acpi_handle handle);
> +static void acpi_pci_slot_remove(acpi_handle handle);
> +
> +static LIST_HEAD(slot_list);
> +static DEFINE_MUTEX(slot_list_lock);
> +static struct acpi_pci_driver acpi_pci_slot_driver = {
> + .add = acpi_pci_slot_add,
> + .remove = acpi_pci_slot_remove,
> +};
> +
> +static int
> +check_slot(acpi_handle handle, int *device, unsigned long *sun)
> +{
> + int retval = 0;
> + unsigned long adr, sta;
> + acpi_status status;
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +
> + acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
> + dbg("Checking slot on path: %s\n", (char *)buffer.pointer);
> +
> + if (check_sta_before_sun) {
> + /* If SxFy doesn't have _STA, we just assume it's there */
> + status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
> + if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT)) {
> + retval = -1;
> + goto out;
> + }
> + }
> +
> + status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
> + if (ACPI_FAILURE(status)) {
> + dbg("_ADR returned %d on %s\n", status, (char *)buffer.pointer);
> + retval = -1;
> + goto out;
> + }
> +
> + *device = (adr >> 16) & 0xffff;
> +
> + /* No _SUN == not a slot == bail */
> + status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
> + if (ACPI_FAILURE(status)) {
> + dbg("_SUN returned %d on %s\n", status, (char *)buffer.pointer);
> + retval = -1;
> + goto out;
> + }
> +
> +out:
> + kfree(buffer.pointer);
> + return retval;
> +}
> +
> +struct callback_args {
> + acpi_walk_callback user_function; /* only for walk_p2p_bridge */
> + struct pci_bus *pci_bus;
> + acpi_handle root_handle;
> +};
> +
> +/*
> + * register_slot
> + *
> + * Called once for each SxFy object in the namespace. Don't worry about
> + * calling pci_create_slot multiple times for the same pci_bus:device,
> + * since each subsequent call simply bumps the refcount on the pci_slot.
> + *
> + * The number of calls to pci_destroy_slot from unregister_slot is
> + * symmetrical.
> + */
> +static acpi_status
> +register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> +{
> + int device;
> + unsigned long sun;
> + char name[KOBJ_NAME_LEN];
> + struct acpi_pci_slot *slot;
> + struct pci_slot *pci_slot;
> + struct callback_args *parent_context = context;
> + struct pci_bus *pci_bus = parent_context->pci_bus;
> +
> + if (check_slot(handle, &device, &sun))
> + return AE_OK;
> +
> + slot = kmalloc(sizeof(*slot), GFP_KERNEL);
> + if (!slot) {
> + err("%s: cannot allocate memory\n", __func__);
> + return AE_OK;
> + }
> +
> + snprintf(name, sizeof(name), "%u", (u32)sun);
> + pci_slot = pci_create_slot(pci_bus, device, name);
> + if (IS_ERR(pci_slot)) {
> + err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
> + kfree(slot);
> + }
> +
> + slot->root_handle = parent_context->root_handle;
> + slot->pci_slot = pci_slot;
> + INIT_LIST_HEAD(&slot->list);
> + mutex_lock(&slot_list_lock);
> + list_add(&slot->list, &slot_list);
> + mutex_unlock(&slot_list_lock);
> +
> + dbg("pci_slot: %#lx, pci_bus: %x, device: %d, name: %s\n",
> + (uint64_t)pci_slot, pci_bus->number, device, name);
> +
> + return AE_OK;
> +}
> +
> +/*
> + * walk_p2p_bridge - discover and walk p2p bridges
> + * @handle: points to an acpi_pci_root
> + * @context: p2p_bridge_context pointer
> + *
> + * Note that when we call ourselves recursively, we pass a different
> + * value of pci_bus in the child_context.
> + */
> +static acpi_status
> +walk_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
> +{
> + int device, function;
> + unsigned long adr;
> + acpi_status status;
> + acpi_handle dummy_handle;
> + acpi_walk_callback user_function;
> +
> + struct pci_dev *dev;
> + struct pci_bus *pci_bus;
> + struct callback_args child_context;
> + struct callback_args *parent_context = context;
> +
> + pci_bus = parent_context->pci_bus;
> + user_function = parent_context->user_function;
> +
> + status = acpi_get_handle(handle, "_ADR", &dummy_handle);
> + if (ACPI_FAILURE(status))
> + return AE_OK;
> +
> + status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
> + if (ACPI_FAILURE(status))
> + return AE_OK;
> +
> + device = (adr >> 16) & 0xffff;
> + function = adr & 0xffff;
> +
> + dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
> + if (!dev || !dev->subordinate)
> + goto out;
> +
> + child_context.pci_bus = dev->subordinate;
> + child_context.user_function = user_function;
> + child_context.root_handle = parent_context->root_handle;
> +
> + dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> + user_function, &child_context, NULL);
> + if (ACPI_FAILURE(status))
> + goto out;
> +
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> + walk_p2p_bridge, &child_context, NULL);
> +out:
> + pci_dev_put(dev);
> + return AE_OK;
> +}
> +
> +#define ACPI_STA_FUNCTIONING (0x00000008)
> +
> +/*
> + * walk_root_bridge - generic root bridge walker
> + * @handle: points to an acpi_pci_root
> + * @user_function: user callback for slot objects
> + *
> + * Call user_function for all objects underneath this root bridge.
> + * Walk p2p bridges underneath us and call user_function on those too.
> + */
> +static int
> +walk_root_bridge(acpi_handle handle, acpi_walk_callback user_function)
> +{
> + int seg, bus;
> + unsigned long tmp;
> + acpi_status status;
> + acpi_handle dummy_handle;
> + struct pci_bus *pci_bus;
> + struct callback_args context;
> +
> + /* If the bridge doesn't have _STA, we assume it is always there */
> + status = acpi_get_handle(handle, "_STA", &dummy_handle);
> + if (ACPI_SUCCESS(status)) {
> + status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
> + if (ACPI_FAILURE(status)) {
> + info("%s: _STA evaluation failure\n", __func__);
> + return 0;
> + }
> + if ((tmp & ACPI_STA_FUNCTIONING) == 0)
> + /* don't register this object */
> + return 0;
> + }
> +
> + status = acpi_evaluate_integer(handle, "_SEG", NULL, &tmp);
> + seg = ACPI_SUCCESS(status) ? tmp : 0;
> +
> + status = acpi_evaluate_integer(handle, "_BBN", NULL, &tmp);
> + bus = ACPI_SUCCESS(status) ? tmp : 0;
> +
> + pci_bus = pci_find_bus(seg, bus);
> + if (!pci_bus)
> + return 0;
> +
> + context.pci_bus = pci_bus;
> + context.user_function = user_function;
> + context.root_handle = handle;
> +
> + dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> + user_function, &context, NULL);
> + if (ACPI_FAILURE(status))
> + return status;
> +
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> + walk_p2p_bridge, &context, NULL);
> + if (ACPI_FAILURE(status))
> + err("%s: walk_p2p_bridge failure - %d\n", __func__, status);
> +
> + return status;
> +}
> +
> +/*
> + * acpi_pci_slot_add
> + * @handle: points to an acpi_pci_root
> + */
> +static int
> +acpi_pci_slot_add(acpi_handle handle)
> +{
> + acpi_status status;
> +
> + status = walk_root_bridge(handle, register_slot);
> + if (ACPI_FAILURE(status))
> + err("%s: register_slot failure - %d\n", __func__, status);
> +
> + return status;
> +}
> +
> +/*
> + * acpi_pci_slot_remove
> + * @handle: points to an acpi_pci_root
> + */
> +static void
> +acpi_pci_slot_remove(acpi_handle handle)
> +{
> + struct acpi_pci_slot *slot, *tmp;
> +
> + mutex_lock(&slot_list_lock);
> + list_for_each_entry_safe(slot, tmp, &slot_list, list) {
> + if (slot->root_handle == handle) {
> + list_del(&slot->list);
> + pci_destroy_slot(slot->pci_slot);
> + kfree(slot);
> + }
> + }
> + mutex_unlock(&slot_list_lock);
> +}
> +
> +#ifdef CONFIG_DMI
> +static int do_sta_before_sun(const struct dmi_system_id *d)
> +{
> + info("%s detected: will evaluate _STA before calling _SUN\n", d->ident);
> + check_sta_before_sun = 1;
> + return 0;
> +}
> +
> +static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
> + /*
> + * Fujitsu Primequest machines will return 1023 to indicate an
> + * error if the _SUN method is evaluated on SxFy objects that
> + * are not present (as indicated by _STA), so for those machines,
> + * we want to check _STA before evaluating _SUN.
> + */
> + {
> + .callback = do_sta_before_sun,
> + .ident = "Fujitsu PRIMEQUEST",
> + .matches = {
> + DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
> + DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
> + },
> + },
> + {}
> +};
> +#endif /* CONFIG_DMI */
> +
> +static int __init
> +acpi_pci_slot_init(void)
> +{
> + dmi_check_system(acpi_pci_slot_dmi_table);
> + acpi_pci_register_driver(&acpi_pci_slot_driver);
> + return 0;
> +}
> +
> +static void __exit
> +acpi_pci_slot_exit(void)
> +{
> + acpi_pci_unregister_driver(&acpi_pci_slot_driver);
> +}
> +
> +module_init(acpi_pci_slot_init);
> +module_exit(acpi_pci_slot_exit);
> diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
> index 5208786..8181bf6 100644
> --- a/drivers/pci/hotplug/pci_hotplug_core.c
> +++ b/drivers/pci/hotplug/pci_hotplug_core.c
> @@ -566,6 +566,11 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr)
> return -EINVAL;
> }
>
> + /*
> + * No problems if we call this interface from both ACPI_PCI_SLOT
> + * driver and call it here again. If we've already created the
> + * pci_slot, the interface will simply bump the refcount.
> + */
> pci_slot = pci_create_slot(bus, slot_nr, slot->name);
> if (IS_ERR(pci_slot))
> return PTR_ERR(pci_slot);
> @@ -579,6 +584,17 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr)
> slot->pci_slot = pci_slot;
> pci_slot->hotplug = slot;
>
> + /*
> + * Allow pcihp drivers to override the ACPI_PCI_SLOT name.
> + */
> + if (strcmp(kobject_name(&pci_slot->kobj), slot->name)) {
> + result = kobject_rename(&pci_slot->kobj, slot->name);
> + if (result) {
> + pci_destroy_slot(pci_slot);
> + return result;
> + }
> + }
> +
> spin_lock(&pci_hotplug_slot_list_lock);
> list_add(&slot->slot_list, &pci_hotplug_slot_list);
> spin_unlock(&pci_hotplug_slot_list_lock);
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index e6d3d4d..7561d17 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -249,7 +249,7 @@ static int init_slots(struct controller *ctrl)
> if (retval == -EBUSY)
> goto error_info;
> if (retval) {
> - err ("pci_hp_register failed with error %d\n", retval);
> + err("pci_hp_register failed with error %d\n", retval);
> goto error_info;
> }
> /* create additional sysfs entries */
> diff --git a/drivers/pci/hotplug/sgi_hotplug.c b/drivers/pci/hotplug/sgi_hotplug.c
> index 8908834..5fd6887 100644
> --- a/drivers/pci/hotplug/sgi_hotplug.c
> +++ b/drivers/pci/hotplug/sgi_hotplug.c
> @@ -668,7 +668,7 @@ static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
>
> register_err:
> dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
> - rc);
> + rc);
>
> alloc_err:
> if (rc == -ENOMEM)