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    SubjectRe: [PATCH 2/2] PCI, ACPI, x86: update MMCFG information when hot-plugging PCI host bridges
    Hi Yinghai,

    >> +int arch_acpi_pci_root_remove(struct acpi_pci_root *root)
    >> +{
    >> + acpi_status status;
    >> + unsigned long long base_addr;
    >> +
    >> + /* Remove MMCFG information for host bridges with _CBA method */
    >> + status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
    >> + NULL, &base_addr);
    >
    > add one flag in acpi_pci_root about we added mmconf for it before?
    > like mmconf_added?
    >

    I feel adding a flag here doesn't help here. For any hot-pluggable PCI host bridge
    with _CBA method available, arch_acpi_pci_root_remove() should delete the MMCFG
    information, no matter it's added by __pci_mmcfg_init() or arch_acpi_pci_root_add().
    So check existence of _CBA seems simpler here.
    Thanks!

    On 04/09/2012 03:19 AM, Yinghai Lu wrote:
    > On Sun, Apr 8, 2012 at 10:12 AM, Jiang Liu <liuj97@gmail.com> wrote:
    >> This patch enhances pci_root driver to update MMCFG information when
    >> hot-plugging PCI root bridges on x86 platforms.
    >>
    >> Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
    >> ---
    >> arch/x86/pci/acpi.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++
    >> drivers/acpi/pci_root.c | 20 ++++++++++++++++
    >> include/acpi/acnames.h | 1 +
    >> include/linux/pci-acpi.h | 3 ++
    >> 4 files changed, 82 insertions(+), 0 deletions(-)
    >>
    >> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
    >> index da0149d..9184970 100644
    >> --- a/arch/x86/pci/acpi.c
    >> +++ b/arch/x86/pci/acpi.c
    >> @@ -488,6 +488,64 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
    >> return bus;
    >> }
    >>
    >> +int arch_acpi_pci_root_add(struct acpi_pci_root *root)
    >> +{
    >> + int result = 0;
    >> + acpi_status status;
    >> + unsigned long long base_addr;
    >> + struct pci_mmcfg_region *cfg;
    >> +
    >> + /*
    >> + * Try to insert MMCFG information for host bridges with _CBA method
    >> + */
    >> + status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
    >> + NULL, &base_addr);
    >> + if (ACPI_SUCCESS(status)) {
    >> + result = pci_mmconfig_insert(root->segment,
    >> + root->secondary.start,
    >> + root->secondary.end,
    >> + base_addr);
    >> + /*
    >> + * MMCFG information for hot-pluggable host bridges may have
    >> + * already been added by __pci_mmcfg_init();
    >> + */
    >> + if (result == -EEXIST)
    >> + result = 0;
    >> + } else if (status == AE_NOT_FOUND) {
    >> + /*
    >> + * Check whether MMCFG information has been added for
    >> + * host bridges without _CBA method.
    >> + */
    >> + rcu_read_lock();
    >> + cfg = pci_mmconfig_lookup(root->segment, root->secondary.start);
    >> + if (!cfg || cfg->end_bus < root->secondary.end)
    >> + result = -ENODEV;
    >> + rcu_read_unlock();
    >> + } else
    >> + result = -ENODEV;
    >> +
    >> + return result;
    >> +}
    >> +
    >> +int arch_acpi_pci_root_remove(struct acpi_pci_root *root)
    >> +{
    >> + acpi_status status;
    >> + unsigned long long base_addr;
    >> +
    >> + /* Remove MMCFG information for host bridges with _CBA method */
    >> + status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
    >> + NULL, &base_addr);
    >
    > add one flag in acpi_pci_root about we added mmconf for it before?
    > like mmconf_added?
    >
    >> + if (ACPI_SUCCESS(status))
    >> + return pci_mmconfig_delete(root->segment,
    >> + root->secondary.start,
    >> + root->secondary.end,
    >> + base_addr);
    >> + else if (status != AE_NOT_FOUND)
    >> + return -ENODEV;
    >> +
    >> + return 0;
    >> +}
    >> +
    >> int __init pci_acpi_init(void)
    >> {
    >> struct pci_dev *dev = NULL;
    >> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
    >> index 4a7d575..a62bfa8 100644
    >> --- a/drivers/acpi/pci_root.c
    >> +++ b/drivers/acpi/pci_root.c
    >> @@ -448,6 +448,16 @@ out:
    >> }
    >> EXPORT_SYMBOL(acpi_pci_osc_control_set);
    >>
    >> +int __weak arch_acpi_pci_root_add(struct acpi_pci_root *root)
    >> +{
    >> + return 0;
    >> +}
    >> +
    >> +int __weak arch_acpi_pci_root_remove(struct acpi_pci_root *root)
    >> +{
    >> + return 0;
    >> +}
    >> +
    >> static int __devinit acpi_pci_root_add(struct acpi_device *device)
    >> {
    >> unsigned long long segment, bus;
    >> @@ -504,6 +514,14 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
    >> strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
    >> device->driver_data = root;
    >>
    >> + if (arch_acpi_pci_root_add(root)) {
    >> + printk(KERN_ERR PREFIX
    >> + "can't add MMCFG information for Bus %04x:%02x\n",
    >> + root->segment, (unsigned int)root->secondary.start);
    >> + result = -ENODEV;
    >> + goto out_free;
    >> + }
    >> +
    >> /*
    >> * All supported architectures that use ACPI have support for
    >> * PCI domains, so we indicate this in _OSC support capabilities.
    >> @@ -629,6 +647,7 @@ out_del_root:
    >> list_del_rcu(&root->node);
    >> mutex_unlock(&acpi_pci_root_lock);
    >> synchronize_rcu();
    >> + arch_acpi_pci_root_remove(root);
    >> out_free:
    >> kfree(root);
    >> return result;
    >> @@ -679,6 +698,7 @@ out:
    >> list_del_rcu(&root->node);
    >> mutex_unlock(&acpi_pci_root_lock);
    >> synchronize_rcu();
    >> + arch_acpi_pci_root_remove(root);
    >> kfree(root);
    >>
    >> return 0;
    >> diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
    >> index 38f5088..99bda75 100644
    >> --- a/include/acpi/acnames.h
    >> +++ b/include/acpi/acnames.h
    >> @@ -62,6 +62,7 @@
    >> #define METHOD_NAME__AEI "_AEI"
    >> #define METHOD_NAME__PRW "_PRW"
    >> #define METHOD_NAME__SRS "_SRS"
    >> +#define METHOD_NAME__CBA "_CBA"
    >>
    >> /* Method names - these methods must appear at the namespace root */
    >>
    >> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
    >> index ac93634..816b971 100644
    >> --- a/include/linux/pci-acpi.h
    >> +++ b/include/linux/pci-acpi.h
    >> @@ -38,6 +38,9 @@ static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)
    >>
    >> void acpi_pci_root_rescan(void);
    >>
    >> +extern int arch_acpi_pci_root_add(struct acpi_pci_root *root);
    >> +extern int arch_acpi_pci_root_remove(struct acpi_pci_root *root);
    >> +
    >
    > don't need extern here.
    >
    >> #else
    >>
    >> static inline void acpi_pci_root_rescan(void) { }
    >> --
    >> 1.7.5.4
    >>



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