[PATCH 13/14] pciehp: add support for bridge resource reallocation

[Yinghai Lu]

From: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>

With this patch, pciehp driver try to clear PCI bridge resources to
parent bridge (root port or switch downstream port) of the slot

so we can shrink pci bridge resource for those port

This feature is enabled when 'pciehp_realloc' option is specified.

-v2: make it could be appiled after Yinghai patchset that touch pci bridge
     resource also remove poweron check, because pci_bridge_release_res will
     check child at first

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
 drivers/pci/hotplug/pciehp.h      |    1 +
 drivers/pci/hotplug/pciehp_core.c |    7 +++++++
 drivers/pci/hotplug/pciehp_pci.c  |    4 ++++
 3 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 4ed76b4..78cf0f4 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -43,6 +43,7 @@ extern int pciehp_poll_mode;
 extern int pciehp_poll_time;
 extern int pciehp_debug;
 extern int pciehp_force;
+extern int pciehp_realloc;
 extern struct workqueue_struct *pciehp_wq;
 
 #define dbg(format, arg...)						\
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 5674b20..cc3fc5d 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -41,6 +41,7 @@ int pciehp_debug;
 int pciehp_poll_mode;
 int pciehp_poll_time;
 int pciehp_force;
+int pciehp_realloc;
 struct workqueue_struct *pciehp_wq;
 
 #define DRIVER_VERSION	"0.4"
@@ -55,10 +56,12 @@ module_param(pciehp_debug, bool, 0644);
 module_param(pciehp_poll_mode, bool, 0644);
 module_param(pciehp_poll_time, int, 0644);
 module_param(pciehp_force, bool, 0644);
+module_param(pciehp_realloc, bool, 0644);
 MODULE_PARM_DESC(pciehp_debug, "Debugging mode enabled or not");
 MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
 MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");
 MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if _OSC and OSHP are missing");
+MODULE_PARM_DESC(pciehp_realloc, "Realloc resources for slot's parent bridge");
 
 #define PCIE_MODULE_NAME "pciehp"
 
@@ -297,6 +300,10 @@ static int pciehp_probe(struct pcie_device *dev)
 	if (!occupied && poweron && POWER_CTRL(ctrl))
 		pciehp_power_off_slot(slot);
 
+	/* Release I/O window of the slots's parent bridge */
+	if (pciehp_realloc)
+		pci_bridge_release_res(dev->port->subordinate);
+
 	return 0;
 
 err_out_free_ctrl_slot:
diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 0a16444..f6119e4 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -166,5 +166,9 @@ int pciehp_unconfigure_device(struct slot *p_slot)
 		pci_dev_put(temp);
 	}
 
+	/* Release I/O window of the slots's parent bridge */
+	if (pciehp_realloc)
+		pci_bridge_release_res(parent);
+
 	return rc;
 }
-- 
1.6.0.2

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