PCI: ACPI PCI slot detection driver

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.

[kaneshige.kenji@jp.fujitsu.com: export-kobject_rename-for-pci_hotplug_core]
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: Greg KH <greg@kroah.com>
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix build with CONFIG_DMI=n]
Signed-off-by: Alex Chiang <achiang@hp.com>
Cc: Greg KH <greg@kroah.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Len Brown <len.brown@intel.com>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 368 insertions, 0 deletions

diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
new file mode 100644
index 000000000000..b9ab030a52d5
--- /dev/null
+++ b/drivers/acpi/pci_slot.c
@@ -0,0 +1,368 @@
+/*
+ *  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)
+
+#define SLOT_NAME_SIZE 20               /* Inspired by #define in acpiphp.h */
+
+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[SLOT_NAME_SIZE];
+        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: %p, pci_bus: %x, device: %d, name: %s\n",
+                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;
+}
+
+/*
+ * 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_DEVICE_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);
+}
+
+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"),
+                },
+        },
+        {}
+};
+
+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);