From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from szxga03-in.huawei.com ([58.251.152.66]:52403 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750956Ab2DRIDZ (ORCPT ); Wed, 18 Apr 2012 04:03:25 -0400 Received: from huawei.com (szxga03-in [172.24.2.9]) by szxga03-in.huawei.com (iPlanet Messaging Server 5.2 HotFix 2.14 (built Aug 8 2006)) with ESMTP id <0M2O00DJT0GQA6@szxga03-in.huawei.com> for linux-pci@vger.kernel.org; Wed, 18 Apr 2012 15:50:50 +0800 (CST) Received: from szxrg02-dlp.huawei.com ([172.24.2.119]) by szxga03-in.huawei.com (iPlanet Messaging Server 5.2 HotFix 2.14 (built Aug 8 2006)) with ESMTP id <0M2O00FR50GO3Y@szxga03-in.huawei.com> for linux-pci@vger.kernel.org; Wed, 18 Apr 2012 15:50:50 +0800 (CST) Date: Wed, 18 Apr 2012 15:49:59 +0800 From: Jiang Liu Subject: Re: [PATCH V4 6/6] PCI, ACPI, x86: update MMCFG information when hot-plugging PCI host bridges In-reply-to: <20120418154725.92833e4d.izumi.taku@jp.fujitsu.com> To: Taku Izumi Cc: Jiang Liu , Yinghai Lu , Kenji Kaneshige , Bjorn Helgaas , Keping Chen , linux-pci@vger.kernel.org Message-id: <4F8E7227.1050707@huawei.com> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed References: <1334103063-2283-1-git-send-email-jiang.liu@huawei.com> <1334103063-2283-7-git-send-email-jiang.liu@huawei.com> <20120418154725.92833e4d.izumi.taku@jp.fujitsu.com> Sender: linux-pci-owner@vger.kernel.org List-ID: Hi Taku, Thanks for your comments and please refer to inline comments below. gerry On 2012-4-18 14:47, Taku Izumi wrote: > > Hi Jiang, > > On Wed, 11 Apr 2012 08:11:03 +0800 > Jiang Liu 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 >> --- >> arch/x86/include/asm/pci_x86.h | 1 + >> arch/x86/pci/acpi.c | 58 ++++++++++++++++++++++++++++++++++++++++ >> arch/x86/pci/mmconfig_32.c | 2 +- >> arch/x86/pci/mmconfig_64.c | 2 +- >> drivers/acpi/pci_root.c | 16 +++++++++++ >> include/acpi/acnames.h | 1 + >> include/acpi/acpi_bus.h | 1 + >> include/linux/pci-acpi.h | 3 ++ >> 8 files changed, 82 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h >> index 3252c97..5e1d9a6 100644 >> --- a/arch/x86/include/asm/pci_x86.h >> +++ b/arch/x86/include/asm/pci_x86.h >> @@ -100,6 +100,7 @@ struct pci_raw_ops { >> extern const struct pci_raw_ops *raw_pci_ops; >> extern const struct pci_raw_ops *raw_pci_ext_ops; >> >> +extern const struct pci_raw_ops pci_mmcfg; >> extern const struct pci_raw_ops pci_direct_conf1; >> extern bool port_cf9_safe; >> >> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c >> index da0149d..729d694 100644 >> --- a/arch/x86/pci/acpi.c >> +++ b/arch/x86/pci/acpi.c >> @@ -4,6 +4,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> >> @@ -488,6 +489,63 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root) >> return bus; >> } >> >> +int __devinit arch_acpi_pci_root_add(struct acpi_pci_root *root) >> +{ >> + int result = 0; >> + acpi_status status; >> + unsigned long long base_addr; >> + >> + /* MMCFG not in use */ >> + if (raw_pci_ext_ops&& raw_pci_ext_ops !=&pci_mmcfg) >> + return result; >> + >> + status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA, >> + NULL,&base_addr); >> + if (ACPI_FAILURE(status)) >> + base_addr = 0; >> + /* >> + * Try to insert MMCFG information for host bridge >> + */ >> + result = pci_mmconfig_insert(root->segment, root->secondary.start, >> + root->secondary.end, base_addr); > > This logic looks strange. > If the evaluation of "_CBA" failed (for example, "_CBA" didn't exist), > pci_mmconfig_insert() should not be invoked. > Yes, the code looks a little strange here, maybe need more clear comments here. For hotplug capable (physical hotplug) host bridges, BIOS should provide _CBA method for them and we should insert the new MMCFG info here. For non-hotplug-capable host bridges, we check that MMCFG information for the host bridge already exists. So the magic part is in function pci_mmconfig_insert(). The algorithm for function pci_mmconfig_insert() is { if (base_addr is not zero) return try_to_insert_MMCFG_info(); else if (MMCFG info for (seg, start, bus) already exists) return -EEXIST; else return -EINVAL; } We will check for -EEXIST on return from pci_mmconfig_insert() for the special case. > >> + if (result == -EEXIST) >> + result = 0; >> + else if (!result) { >> + root->mmconf_added = true; >> + >> + /* Try to enable MMCFG if it hasn't been enabled yet */ >> + if (raw_pci_ext_ops == NULL) { >> + if (pci_probe& PCI_PROBE_MMCONF) >> + raw_pci_ext_ops =&pci_mmcfg; >> + else { >> + arch_acpi_pci_root_remove(root); >> + result = -ENODEV; >> + } >> + } >> + } >> + if (result) >> + printk(KERN_ERR >> + "can't add MMCFG information for Bus %04x:%02x\n", >> + root->segment, (unsigned int)root->secondary.start); >> + >> + /* still could use conf1 with it */ >> + if (!root->segment) >> + result = 0; >> + >> + return result; >> +} >> + >> +void arch_acpi_pci_root_remove(struct acpi_pci_root *root) >> +{ >> + if (root->mmconf_added) { >> + pci_mmconfig_delete(root->segment, >> + root->secondary.start, >> + root->secondary.end); >> + root->mmconf_added = false; >> + } >> +} >> + >> int __init pci_acpi_init(void) >> { >> struct pci_dev *dev = NULL; >> diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c >> index a22785d..db63ac2 100644 >> --- a/arch/x86/pci/mmconfig_32.c >> +++ b/arch/x86/pci/mmconfig_32.c >> @@ -126,7 +126,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus, >> return 0; >> } >> >> -static const struct pci_raw_ops pci_mmcfg = { >> +const struct pci_raw_ops pci_mmcfg = { >> .read = pci_mmcfg_read, >> .write = pci_mmcfg_write, >> }; >> diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c >> index 4e05779..34c08dd 100644 >> --- a/arch/x86/pci/mmconfig_64.c >> +++ b/arch/x86/pci/mmconfig_64.c >> @@ -90,7 +90,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus, >> return 0; >> } >> >> -static const struct pci_raw_ops pci_mmcfg = { >> +const struct pci_raw_ops pci_mmcfg = { >> .read = pci_mmcfg_read, >> .write = pci_mmcfg_write, >> }; >> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c >> index 4a7d575..b7c0b53 100644 >> --- a/drivers/acpi/pci_root.c >> +++ b/drivers/acpi/pci_root.c >> @@ -448,6 +448,15 @@ out: >> } >> EXPORT_SYMBOL(acpi_pci_osc_control_set); >> >> +int __weak arch_acpi_pci_root_add(struct acpi_pci_root *root) >> +{ >> + return 0; >> +} >> + >> +void __weak arch_acpi_pci_root_remove(struct acpi_pci_root *root) >> +{ >> +} >> + >> static int __devinit acpi_pci_root_add(struct acpi_device *device) >> { >> unsigned long long segment, bus; >> @@ -504,6 +513,11 @@ 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)) { >> + 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 +643,7 @@ 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 +694,7 @@ 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/acpi/acpi_bus.h b/include/acpi/acpi_bus.h >> index f1c8ca6..cb4f402 100644 >> --- a/include/acpi/acpi_bus.h >> +++ b/include/acpi/acpi_bus.h >> @@ -370,6 +370,7 @@ struct acpi_pci_root { >> >> u32 osc_support_set; /* _OSC state of support bits */ >> u32 osc_control_set; /* _OSC state of control bits */ >> + bool mmconf_added; >> }; >> >> /* helper */ >> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h >> index ac93634..7745b8a 100644 >> --- a/include/linux/pci-acpi.h >> +++ b/include/linux/pci-acpi.h >> @@ -18,6 +18,9 @@ extern acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev, >> struct pci_dev *pci_dev); >> extern acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev); >> >> +int arch_acpi_pci_root_add(struct acpi_pci_root *root); >> +void arch_acpi_pci_root_remove(struct acpi_pci_root *root); >> + >> static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev) >> { >> struct pci_bus *pbus = pdev->bus; >> -- >> 1.7.5.4 >> >> > >