[RFC PATCH v5 7/8] PCI/PCIe: add "pci=nopciehp" to disable PCIe native hotplug

[Jiang Liu <liuj97@gmail.com>]

If user specifies "pci=nopciehp" on kernel boot command line, OSPM
won't claim PCIe native hotplug service from firmware and no PCIe
port devices will be created for PCIe native hotplug service.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 Documentation/kernel-parameters.txt |    2 ++
 drivers/acpi/pci_root.c             |    3 ++-
 drivers/pci/pci.c                   |    2 ++
 drivers/pci/pcie/portdrv_core.c     |    5 +++--
 drivers/pci/pcie/portdrv_pci.c      |    3 +++
 include/linux/pci.h                 |    9 +++++++++
 6 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9776f06..28dd0ad 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2106,6 +2106,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 		noaer		[PCIE] If the PCIEAER kernel config parameter is
 				enabled, this kernel boot option can be used to
 				disable the use of PCIE advanced error reporting.
+		nopciehp	[PCIE] this kernel boot option can be used to
+				disable PCIe native hotplug.
 		nodomains	[PCI] Disable support for multiple PCI
 				root domains (aka PCI segments, in ACPI-speak).
 		nommconf	[X86] Disable use of MMCONFIG for PCI
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index c6200ff..c37eedb 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -551,8 +551,9 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	if (!pcie_ports_disabled
 	    && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
 		flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
-			| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
 			| OSC_PCI_EXPRESS_PME_CONTROL;
+		if (!pcie_native_hotplug_disabled)
+			flags |= OSC_PCI_EXPRESS_NATIVE_HP_CONTROL;
 
 		if (pci_aer_available()) {
 			if (aer_acpi_firmware_first())
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 2f8f4c6..34b2c83 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3869,6 +3869,8 @@ static int __init pci_setup(char *str)
 				pci_no_msi();
 			} else if (!strcmp(str, "noaer")) {
 				pci_no_aer();
+			} else if (!strcmp(str, "nopciehp")) {
+				pcie_no_native_hotplug();
 			} else if (!strncmp(str, "realloc=", 8)) {
 				pci_realloc_get_opt(str + 8);
 			} else if (!strncmp(str, "realloc", 7)) {
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index ed129b4..e7e1679 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -263,8 +263,9 @@ static int get_port_device_capability(struct pci_dev *dev)
 
 	err = pcie_port_platform_notify(dev, &cap_mask);
 	if (!pcie_ports_auto) {
-		cap_mask = PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP
-				| PCIE_PORT_SERVICE_VC;
+		cap_mask = PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_VC;
+		if (!pcie_native_hotplug_disabled)
+			cap_mask |= PCIE_PORT_SERVICE_HP;
 		if (pci_aer_available())
 			cap_mask |= PCIE_PORT_SERVICE_AER;
 	} else if (err) {
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index 0761d90..018cee0 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -40,6 +40,9 @@ bool pcie_ports_disabled;
  */
 bool pcie_ports_auto = true;
 
+/* If set, the PCIe native hotplug will not be used. */
+bool pcie_native_hotplug_disabled;
+
 static int __init pcie_port_setup(char *str)
 {
 	if (!strncmp(str, "compat", 6)) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 12e5447..715e17b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1138,9 +1138,18 @@ extern int pci_msi_enabled(void);
 #ifdef CONFIG_PCIEPORTBUS
 extern bool pcie_ports_disabled;
 extern bool pcie_ports_auto;
+extern bool pcie_native_hotplug_disabled;
+
+static inline void pcie_no_native_hotplug(void)
+{
+	pcie_native_hotplug_disabled = true;
+}
 #else
 #define pcie_ports_disabled	true
 #define pcie_ports_auto		false
+#define pcie_native_hotplug_disabled	true
+
+static inline void pcie_no_native_hotplug(void) { }
 #endif
 
 #ifndef CONFIG_PCIEASPM
-- 
1.7.9.5