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Date: Fri, 3 Jan 2014 15:39:53 -0700
From: Bjorn Helgaas <bhelgaas@...gle.com>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
"H. Peter Anvin" <hpa@...or.com>, Tony Luck <tony.luck@...el.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v5 30/33] PCI, x86, ACPI: Enable ioapic hotplug support
with acpi host bridge.
On Thu, Jan 02, 2014 at 04:06:02PM -0800, Yinghai Lu wrote:
> We need to have ioapic setup before normal pci drivers.
> otherwise other pci driver can not setup irq.
>
> So we should not treat them as normal pci devices.
> Also we will need to support ioapic hotplug without pci device around.
>
> We need to call ioapic add/remove during host-bridge add/remove.
>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
> drivers/acpi/pci_root.c | 4 ++
> drivers/pci/ioapic.c | 147 ++++++++++++++++++++++++++++++-----------------
> include/linux/pci-acpi.h | 8 +++
> 3 files changed, 106 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 20360e4..e666be3 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -599,6 +599,8 @@ static int acpi_pci_root_add(struct acpi_device *device,
> pci_assign_unassigned_root_bus_resources(root->bus);
> }
>
> + acpi_pci_ioapic_add(root);
> +
> pci_bus_add_devices(root->bus);
> return 1;
>
> @@ -613,6 +615,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>
> pci_stop_root_bus(root->bus);
>
> + acpi_pci_ioapic_remove(root);
> +
> device_set_run_wake(root->bus->bridge, false);
> pci_acpi_remove_bus_pm_notifier(device);
>
> diff --git a/drivers/pci/ioapic.c b/drivers/pci/ioapic.c
> index 2c2930e..60351b2 100644
> --- a/drivers/pci/ioapic.c
> +++ b/drivers/pci/ioapic.c
The file comment:
* This driver manages PCI I/O APICs added by hotplug after boot. We try to
* claim all I/O APIC PCI devices, but those present at boot were registered
* when we parsed the ACPI MADT, so we'll fail when we try to re-register
* them.
is now incorrect because this no longer claims all PCI I/O APICs. As far
as I can tell, it now claims every ACPI Device below the host bridge that
has a _GSB method and an associated PCI device. If there is a PCI I/O APIC
that does not appear in the namespace, this driver will not claim it.
I don't have a problem with that, but the comment needs to be updated to
reflect the change.
> @@ -22,101 +22,142 @@
> #include <linux/slab.h>
> #include <acpi/acpi_bus.h>
>
> -struct ioapic {
> - acpi_handle handle;
> +struct acpi_pci_ioapic {
> + acpi_handle root_handle;
> u32 gsi_base;
> + struct pci_dev *pdev;
> + struct list_head list;
> };
>
> -static int ioapic_probe(struct pci_dev *dev, const struct pci_device_id *ent)
> +static LIST_HEAD(ioapic_list);
> +static DEFINE_MUTEX(ioapic_list_lock);
> +
> +static void handle_ioapic_add(acpi_handle handle, struct pci_dev **pdev,
> + u32 *pgsi_base)
> {
> - acpi_handle handle;
> acpi_status status;
> unsigned long long gsb;
> - struct ioapic *ioapic;
> + struct pci_dev *dev;
> + u32 gsi_base;
> int ret;
> char *type;
> - struct resource *res;
> + struct resource r;
> + struct resource *res = &r;
> + char objname[64];
> + struct acpi_buffer buffer = {sizeof(objname), objname};
You can avoid the hard-coded 64-byte buffer with:
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
And of course the corresponding kfree in the exit path. The
acpi_get_name() could be done after all possible error exits, so you'd only
need the kfree in the success path.
> - handle = ACPI_HANDLE(&dev->dev);
> - if (!handle)
> - return -EINVAL;
> + *pdev = NULL;
> + *pgsi_base = 0;
>
> status = acpi_evaluate_integer(handle, "_GSB", NULL, &gsb);
> - if (ACPI_FAILURE(status))
> - return -EINVAL;
> -
> - /*
> - * The previous code in acpiphp evaluated _MAT if _GSB failed, but
> - * ACPI spec 4.0 sec 6.2.2 requires _GSB for hot-pluggable I/O APICs.
> - */
> + if (ACPI_FAILURE(status) || !gsb)
> + return;
>
> - ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL);
> - if (!ioapic)
> - return -ENOMEM;
> + dev = acpi_get_pci_dev(handle);
> + if (!dev)
> + return;
>
> - ioapic->handle = handle;
> - ioapic->gsi_base = (u32) gsb;
> + acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
>
> - if (dev->class == PCI_CLASS_SYSTEM_PIC_IOAPIC)
> - type = "IOAPIC";
> - else
> - type = "IOxAPIC";
> + gsi_base = gsb;
> + type = "IOxAPIC";
>
> ret = pci_enable_device(dev);
> if (ret < 0)
> - goto exit_free;
> + goto exit_put;
>
> pci_set_master(dev);
>
> + if (dev->class == PCI_CLASS_SYSTEM_PIC_IOAPIC)
> + type = "IOAPIC";
Why not keep the 'type = "IOxAPIC"' assignment here as it was before? Then
all the "type" manipulation is in one place.
> if (pci_request_region(dev, 0, type))
> goto exit_disable;
>
> res = &dev->resource[0];
> - if (acpi_register_ioapic(ioapic->handle, res->start, ioapic->gsi_base))
> +
> + if (acpi_register_ioapic(handle, res->start, gsi_base))
> goto exit_release;
>
> - pci_set_drvdata(dev, ioapic);
> - dev_info(&dev->dev, "%s at %pR, GSI %u\n", type, res, ioapic->gsi_base);
> - return 0;
> + pr_info("%s %s %s at %pR, GSI %u\n",
> + dev_name(&dev->dev), objname, type,
> + res, gsi_base);
Why did you change the dev_info() to pr_info()? They look equivalent for
what you're doing here.
> + *pdev = dev;
> + *pgsi_base = gsi_base;
> + return;
>
> exit_release:
> pci_release_region(dev, 0);
> exit_disable:
> pci_disable_device(dev);
> -exit_free:
> - kfree(ioapic);
> - return -ENODEV;
> +exit_put:
> + pci_dev_put(dev);
> }
>
> -static void ioapic_remove(struct pci_dev *dev)
> +static void handle_ioapic_remove(acpi_handle handle, struct pci_dev *dev,
> + u32 gsi_base)
> {
> - struct ioapic *ioapic = pci_get_drvdata(dev);
> + acpi_unregister_ioapic(handle, gsi_base);
>
> - acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base);
> pci_release_region(dev, 0);
> pci_disable_device(dev);
> - kfree(ioapic);
> + pci_dev_put(dev);
> }
>
> +static acpi_status register_ioapic(acpi_handle handle, u32 lvl,
> + void *context, void **rv)
> +{
> + acpi_handle root_handle = context;
> + struct pci_dev *pdev;
> + u32 gsi_base;
> + struct acpi_pci_ioapic *ioapic;
>
> -static DEFINE_PCI_DEVICE_TABLE(ioapic_devices) = {
> - { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOAPIC, ~0) },
> - { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOXAPIC, ~0) },
> - { }
> -};
> -MODULE_DEVICE_TABLE(pci, ioapic_devices);
> + handle_ioapic_add(handle, &pdev, &gsi_base);
> + if (!gsi_base)
> + return AE_OK;
>
> -static struct pci_driver ioapic_driver = {
> - .name = "ioapic",
> - .id_table = ioapic_devices,
> - .probe = ioapic_probe,
> - .remove = ioapic_remove,
> -};
> + ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL);
> + if (!ioapic) {
> + pr_err("%s: cannot allocate memory\n", __func__);
I don't know if this message is necessary, but if it is, please include
device identification, e.g., with dev_info() on the struct pci_dev.
> + handle_ioapic_remove(root_handle, pdev, gsi_base);
> + return AE_OK;
> + }
> + ioapic->root_handle = root_handle;
> + ioapic->pdev = pdev;
> + ioapic->gsi_base = gsi_base;
> +
> + mutex_lock(&ioapic_list_lock);
> + list_add(&ioapic->list, &ioapic_list);
> + mutex_unlock(&ioapic_list_lock);
> +
> + return AE_OK;
> +}
>
> -static int __init ioapic_init(void)
> +void acpi_pci_ioapic_add(struct acpi_pci_root *root)
> {
> - return pci_register_driver(&ioapic_driver);
> + acpi_status status;
> +
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
> + (u32)1, register_ioapic, NULL,
> + root->device->handle,
> + NULL);
> + if (ACPI_FAILURE(status))
> + pr_err("%s: register_ioapic failure - %d", __func__, status);
This message should include the part of the namespace where we had the
problem, e.g., the pathname of the host bridge device.
> }
> -module_init(ioapic_init);
>
> -MODULE_LICENSE("GPL");
> +void acpi_pci_ioapic_remove(struct acpi_pci_root *root)
> +{
> + struct acpi_pci_ioapic *ioapic, *tmp;
> +
> + mutex_lock(&ioapic_list_lock);
> + list_for_each_entry_safe(ioapic, tmp, &ioapic_list, list) {
> + if (root->device->handle != ioapic->root_handle)
> + continue;
> + list_del(&ioapic->list);
> + handle_ioapic_remove(ioapic->root_handle, ioapic->pdev,
> + ioapic->gsi_base);
> + kfree(ioapic);
> + }
> + mutex_unlock(&ioapic_list_lock);
> +}
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index 5a462c4..d2a976a 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -67,6 +67,14 @@ static inline void acpiphp_remove_slots(struct pci_bus *bus) { }
> static inline void acpiphp_check_host_bridge(acpi_handle handle) { }
> #endif
>
> +#ifdef CONFIG_PCI_IOAPIC
> +void acpi_pci_ioapic_add(struct acpi_pci_root *root);
> +void acpi_pci_ioapic_remove(struct acpi_pci_root *root);
> +#else
> +static inline void acpi_pci_ioapic_add(struct acpi_pci_root *root) { }
> +static inline void acpi_pci_ioapic_remove(struct acpi_pci_root *root) { }
> +#endif
> +
> #else /* CONFIG_ACPI */
> static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
> static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
> --
> 1.8.4
>
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