[PATCH 3/(3+1)] ACPI PCI slot detection driver

Kenji Kaneshige
2008-03-11T13:25:07Z

v9 -> v10:
Remove DMI quirk for Fujitsu machines; eval _STA before _SUN.
Skip device object whose _STA indicates not present.

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>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
---
drivers/acpi/Kconfig | 9
drivers/acpi/Makefile | 1
drivers/acpi/pci_slot.c | 328 +++++++++++++++++++++++++++++++++
drivers/pci/hotplug/pci_hotplug_core.c | 11 +
drivers/pci/hotplug/pciehp_core.c | 2
drivers/pci/hotplug/sgi_hotplug.c | 2
6 files changed, 350 insertions(+), 3 deletions(-)

Index: linux-2.6.25-rc4/drivers/acpi/Kconfig
===================================================================
--- linux-2.6.25-rc4.orig/drivers/acpi/Kconfig
+++ linux-2.6.25-rc4/drivers/acpi/Kconfig
@@ -347,6 +347,15 @@ 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
Index: linux-2.6.25-rc4/drivers/acpi/Makefile
===================================================================
--- linux-2.6.25-rc4.orig/drivers/acpi/Makefile
+++ linux-2.6.25-rc4/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
Index: linux-2.6.25-rc4/drivers/acpi/pci_slot.c
===================================================================
--- /dev/null
+++ linux-2.6.25-rc4/drivers/acpi/pci_slot.c
@@ -0,0 +1,328 @@
+/*
+ * 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.
+ *
+ * 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;
+
+#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)
+
+static int acpi_pci_slot_add(acpi_handle handle);
+static void acpi_pci_slot_remove(acpi_handle handle);
+
+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);
+
+ 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;
+}
+
+/*
+ * unregister_slot
+ *
+ * Called once for each SxFy object in the namespace. Each call to
+ * pci_destroy_slot decrements the refcount on the pci_slot, and
+ * eventually calls kobject_unregister at the appropriate time.
+ */
+static acpi_status
+unregister_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+ int device;
+ unsigned long sun;
+ struct pci_slot *slot;
+ struct pci_bus *pci_bus = context;
+
+ if (check_slot(handle, &device, &sun))
+ return AE_OK;
+
+ for (slot = pci_bus->slot; slot; slot = slot->next) {
+ if (slot->number == device)
+ pci_destroy_slot(slot);
+ }
+
+ return AE_OK;
+}
+
+/*
+ * 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 pci_slot *pci_slot;
+ struct pci_bus *pci_bus = context;
+
+ if (check_slot(handle, &device, &sun))
+ 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));
+
+ dbg("pci_slot: %#lx, pci_bus: %x, device: %d, name: %s\n",
+ (uint64_t)pci_slot, pci_bus->number, device, name);
+
+ return AE_OK;
+}
+
+struct p2p_bridge_context
+{
+ acpi_walk_callback user_function;
+ struct pci_bus *pci_bus;
+};
+
+/*
+ * 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 p2p_bridge_context child_context;
+ struct p2p_bridge_context *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;
+
+ dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
+ user_function, dev->subordinate, NULL);
+ if (ACPI_FAILURE(status))
+ goto out;
+
+ child_context.pci_bus = dev->subordinate;
+ child_context.user_function = user_function;
+ 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 p2p_bridge_context 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", __FUNCTION__);
+ 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;
+
+ dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
+ user_function, pci_bus, NULL);
+ if (ACPI_FAILURE(status))
+ return status;
+
+ context.pci_bus = pci_bus;
+ context.user_function = user_function;
+ 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", __FUNCTION__, 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", __FUNCTION__, status);
+
+ return status;
+}
+
+/*
+ * acpi_pci_slot_remove
+ * @handle: points to an acpi_pci_root
+ */
+static void
+acpi_pci_slot_remove(acpi_handle handle)
+{
+ acpi_status status;
+
+ status = walk_root_bridge(handle, unregister_slot);
+ if (ACPI_FAILURE(status))
+ err("%s: unregister_slot failure - %d\n", __FUNCTION__, status);
+}
+
+static int __init
+acpi_pci_slot_init(void)
+{
+ 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);
Index: linux-2.6.25-rc4/drivers/pci/hotplug/pci_hotplug_core.c
===================================================================
--- linux-2.6.25-rc4.orig/drivers/pci/hotplug/pci_hotplug_core.c
+++ linux-2.6.25-rc4/drivers/pci/hotplug/pci_hotplug_core.c
@@ -567,6 +567,11 @@ int pci_hp_register(struct hotplug_slot
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);
@@ -613,8 +618,12 @@ int pci_hp_deregister(struct hotplug_slo

slot = hotplug->pci_slot;
fs_remove_slot(slot);
- pci_destroy_slot(slot);
dbg("Removed slot %s from the list\n", hotplug->name);
+
+ hotplug_release(slot);
+ slot->release = NULL;
+ pci_destroy_slot(slot);
+
return 0;
}

Index: linux-2.6.25-rc4/drivers/pci/hotplug/pciehp_core.c
===================================================================
--- linux-2.6.25-rc4.orig/drivers/pci/hotplug/pciehp_core.c
+++ linux-2.6.25-rc4/drivers/pci/hotplug/pciehp_core.c
@@ -249,7 +249,7 @@ static int init_slots(struct controller
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 */
Index: linux-2.6.25-rc4/drivers/pci/hotplug/sgi_hotplug.c
===================================================================
--- linux-2.6.25-rc4.orig/drivers/pci/hotplug/sgi_hotplug.c
+++ linux-2.6.25-rc4/drivers/pci/hotplug/sgi_hotplug.c
@@ -668,7 +668,7 @@ static int sn_hotplug_slot_register(stru

register_err:
dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
- rc);
+ rc);

alloc_err:
if (rc == -ENOMEM)