[PATCH v3 0/6] powerpc/powernv: PCI Surprise Hotplug Support

[PATCH v3 0/6] powerpc/powernv: PCI Surprise Hotplug Support

[Gavin Shan]

This series of patches supports PCI surprise hotplug on PowerNV platform.
Without the corresponding skiboot patches, this feature won't be enabled
and workable.

   * The skiboot patches can be found in below link (PATCH[01/16):
     https://patchwork.ozlabs.org/project/skiboot/list/?submitter=63923
   * This newly added functionality depends on skiboot's changes. However,
     the functionality is disabled simply when skiboot doesn't support it.
     For one specific slot, property "ibm,slot-surprise-pluggable" of the
     slot's device node is set to 1 when surprise hotplug is claimed by
     skiboot.
   * The interrupts because of presence and link state change are enabled
     in order to support PCI surprise hotplug. The surprise hotplug events
     are queued to the PCI slot and they're picked up for further processing
     in serialized fashion. The surprise and managed hotplug share same code
     flow except: the affected PEs are put into frozen state to avoid unexpected
     EEH error reporting in surprise hot remove path.

PATCH[1/6] to PATCH[3/6] allow to freeze PEs to avoid unexpected EEH error
reporting in PCI surprise hot remove path. PATCH[4/6] clears PE's frozen state
on initializing it because the PE might have been put into frozen state in last
PCI surprise hot remove. PATCH[5/6] removes likely() and unlikely() in pnv_php.c
as they are not too useful. PATCH[6/6] supports PCI surprise hotplug for PowerNV
PCI hotplug driver.

Changelog
=========
v2:
   * Add one patch to remove likely() and unlikely() in pnv_php.c.
   * Remove likely() and unlikely() in PATCH[v1 4/4].
   * The event isn't pre-allocated. It's always allocated from slab
     in the interrupt handler. The removed PE is put into frozen state
     before the event is allocated.
v3:
   * Add one patch to export confirm_error_lock to avoid building error
     when having CONFIG_HOTPLUG_PCI_POWERNV=m

Gavin Shan (6):
  powerpc/eeh: Allow to freeze PE in eeh_pe_set_option()
  powerpc/eeh: Export confirm_error_lock
  powerpc/eeh: Export eeh_pe_state_mark()
  powerpc/powernv: Unfreeze PE on allocation
  drivers/pci/hotplug: Remove likely() and unlikely() in powernv driver
  drivers/pci/hotplug: Support surprise hotplug in powernv driver

 arch/powerpc/include/asm/pnv-pci.h        |   2 +
 arch/powerpc/kernel/eeh.c                 |   2 +
 arch/powerpc/kernel/eeh_pe.c              |   1 +
 arch/powerpc/platforms/powernv/pci-ioda.c |  12 ++
 drivers/pci/hotplug/pnv_php.c             | 268 ++++++++++++++++++++++++++----
 5 files changed, 257 insertions(+), 28 deletions(-)

-- 
2.1.0

[PATCH v3 1/6] powerpc/eeh: Allow to freeze PE in eeh_pe_set_option()

[Gavin Shan]

Function eeh_pe_set_option() is used to apply the requested options
(enable, disable, unfreeze) in EEH virtualization path. The semantics
of this function isn't complete until freezing is supported.

This allows to freeze the indicated PE. The new semantics is going to
be used in PCI surprise hot remove path, to freeze removed PCI devices
(PE) to avoid unexpected EEH error reporting.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 7429556..0699f15 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1502,6 +1502,7 @@ int eeh_pe_set_option(struct eeh_pe *pe, int option)
 		break;
 	case EEH_OPT_THAW_MMIO:
 	case EEH_OPT_THAW_DMA:
+	case EEH_OPT_FREEZE_PE:
 		if (!eeh_ops || !eeh_ops->set_option) {
 			ret = -ENOENT;
 			break;
-- 
2.1.0

[PATCH v3 2/6] powerpc/eeh: Export confirm_error_lock

[Gavin Shan]

This exports @confirm_error_lock so that eeh_serialize_{lock, unlock}()
can be used to freeze the affected PE in PCI surprise hot remove path.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 0699f15..130bcae 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -116,6 +116,7 @@ struct eeh_ops *eeh_ops = NULL;
 
 /* Lock to avoid races due to multiple reports of an error */
 DEFINE_RAW_SPINLOCK(confirm_error_lock);
+EXPORT_SYMBOL_GPL(confirm_error_lock);
 
 /* Lock to protect passed flags */
 static DEFINE_MUTEX(eeh_dev_mutex);
-- 
2.1.0

[PATCH v3 3/6] powerpc/eeh: Export eeh_pe_state_mark()

[Gavin Shan]

This exports eeh_pe_state_mark(). It will be used to mark the surprise
hot removed PE as isolated to avoid unexpected EEH error reporting in
surprise remove path.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh_pe.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index f0520da..de7d091 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -581,6 +581,7 @@ void eeh_pe_state_mark(struct eeh_pe *pe, int state)
 {
 	eeh_pe_traverse(pe, __eeh_pe_state_mark, &state);
 }
+EXPORT_SYMBOL_GPL(eeh_pe_state_mark);
 
 static void *__eeh_pe_dev_mode_mark(void *data, void *flag)
 {
-- 
2.1.0

[PATCH v3 4/6] powerpc/powernv: Unfreeze PE on allocation

[Gavin Shan]

This unfreezes PE when it's initialized because the PE might be put
into frozen state in the last hot remove path. It's not harmful to
do so if the PE is already in unfrozen state.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 38a5c65..841395e 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -133,9 +133,21 @@ static inline bool pnv_pci_is_m64_flags(unsigned long resource_flags)
 
 static struct pnv_ioda_pe *pnv_ioda_init_pe(struct pnv_phb *phb, int pe_no)
 {
+	s64 rc;
+
 	phb->ioda.pe_array[pe_no].phb = phb;
 	phb->ioda.pe_array[pe_no].pe_number = pe_no;
 
+	/* Clear the PE frozen state as it might be put into frozen state
+	 * in the last PCI remove path. It's not harmful to do so when the
+	 * PE is already in unfrozen state.
+	 */
+	rc = opal_pci_eeh_freeze_clear(phb->opal_id, pe_no,
+				       OPAL_EEH_ACTION_CLEAR_FREEZE_ALL);
+	if (rc != OPAL_SUCCESS)
+		pr_warn("%s: Error %lld unfreezing PHB#%d-PE#%d\n",
+			__func__, rc, phb->hose->global_number, pe_no);
+
 	return &phb->ioda.pe_array[pe_no];
 }
 
-- 
2.1.0

[PATCH v3 5/6] drivers/pci/hotplug: Remove likely() and unlikely() in powernv driver

[Gavin Shan]

This removes likely() and unlikely() in pnv_php.c as the code isn't
running in hot path. Those macros to affect CPU's branch stream don't
help a lot for performance. I used them to identify the cases are
likely or unlikely to happen. No logical changes introduced.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 drivers/pci/hotplug/pnv_php.c | 56 +++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index e6245b0..182f218 100644
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -122,7 +122,7 @@ static void pnv_php_detach_device_nodes(struct device_node *parent)
 
 		of_node_put(dn);
 		refcount = atomic_read(&dn->kobj.kref.refcount);
-		if (unlikely(refcount != 1))
+		if (refcount != 1)
 			pr_warn("Invalid refcount %d on <%s>\n",
 				refcount, of_node_full_name(dn));
 
@@ -184,11 +184,11 @@ static int pnv_php_populate_changeset(struct of_changeset *ocs,
 
 	for_each_child_of_node(dn, child) {
 		ret = of_changeset_attach_node(ocs, child);
-		if (unlikely(ret))
+		if (ret)
 			break;
 
 		ret = pnv_php_populate_changeset(ocs, child);
-		if (unlikely(ret))
+		if (ret)
 			break;
 	}
 
@@ -201,7 +201,7 @@ static void *pnv_php_add_one_pdn(struct device_node *dn, void *data)
 	struct pci_dn *pdn;
 
 	pdn = pci_add_device_node_info(hose, dn);
-	if (unlikely(!pdn))
+	if (!pdn)
 		return ERR_PTR(-ENOMEM);
 
 	return NULL;
@@ -224,21 +224,21 @@ static int pnv_php_add_devtree(struct pnv_php_slot *php_slot)
 	 * fits the real size.
 	 */
 	fdt1 = kzalloc(0x10000, GFP_KERNEL);
-	if (unlikely(!fdt1)) {
+	if (!fdt1) {
 		ret = -ENOMEM;
 		dev_warn(&php_slot->pdev->dev, "Cannot alloc FDT blob\n");
 		goto out;
 	}
 
 	ret = pnv_pci_get_device_tree(php_slot->dn->phandle, fdt1, 0x10000);
-	if (unlikely(ret)) {
+	if (ret) {
 		dev_warn(&php_slot->pdev->dev, "Error %d getting FDT blob\n",
 			 ret);
 		goto free_fdt1;
 	}
 
 	fdt = kzalloc(fdt_totalsize(fdt1), GFP_KERNEL);
-	if (unlikely(!fdt)) {
+	if (!fdt) {
 		ret = -ENOMEM;
 		dev_warn(&php_slot->pdev->dev, "Cannot %d bytes memory\n",
 			 fdt_totalsize(fdt1));
@@ -248,7 +248,7 @@ static int pnv_php_add_devtree(struct pnv_php_slot *php_slot)
 	/* Unflatten device tree blob */
 	memcpy(fdt, fdt1, fdt_totalsize(fdt1));
 	dt = of_fdt_unflatten_tree(fdt, php_slot->dn, NULL);
-	if (unlikely(!dt)) {
+	if (!dt) {
 		ret = -EINVAL;
 		dev_warn(&php_slot->pdev->dev, "Cannot unflatten FDT\n");
 		goto free_fdt;
@@ -258,7 +258,7 @@ static int pnv_php_add_devtree(struct pnv_php_slot *php_slot)
 	of_changeset_init(&php_slot->ocs);
 	pnv_php_reverse_nodes(php_slot->dn);
 	ret = pnv_php_populate_changeset(&php_slot->ocs, php_slot->dn);
-	if (unlikely(ret)) {
+	if (ret) {
 		pnv_php_reverse_nodes(php_slot->dn);
 		dev_warn(&php_slot->pdev->dev, "Error %d populating changeset\n",
 			 ret);
@@ -267,7 +267,7 @@ static int pnv_php_add_devtree(struct pnv_php_slot *php_slot)
 
 	php_slot->dn->child = NULL;
 	ret = of_changeset_apply(&php_slot->ocs);
-	if (unlikely(ret)) {
+	if (ret) {
 		dev_warn(&php_slot->pdev->dev, "Error %d applying changeset\n",
 			 ret);
 		goto destroy_changeset;
@@ -301,7 +301,7 @@ int pnv_php_set_slot_power_state(struct hotplug_slot *slot,
 	int ret;
 
 	ret = pnv_pci_set_power_state(php_slot->id, state, &msg);
-	if (likely(ret > 0)) {
+	if (ret > 0) {
 		if (be64_to_cpu(msg.params[1]) != php_slot->dn->phandle	||
 		    be64_to_cpu(msg.params[2]) != state			||
 		    be64_to_cpu(msg.params[3]) != OPAL_SUCCESS) {
@@ -311,7 +311,7 @@ int pnv_php_set_slot_power_state(struct hotplug_slot *slot,
 				 be64_to_cpu(msg.params[3]));
 			return -ENOMSG;
 		}
-	} else if (unlikely(ret < 0)) {
+	} else if (ret < 0) {
 		dev_warn(&php_slot->pdev->dev, "Error %d powering %s\n",
 			 ret, (state == OPAL_PCI_SLOT_POWER_ON) ? "on" : "off");
 		return ret;
@@ -338,7 +338,7 @@ static int pnv_php_get_power_state(struct hotplug_slot *slot, u8 *state)
 	 * be on.
 	 */
 	ret = pnv_pci_get_power_state(php_slot->id, &power_state);
-	if (unlikely(ret)) {
+	if (ret) {
 		dev_warn(&php_slot->pdev->dev, "Error %d getting power status\n",
 			 ret);
 	} else {
@@ -360,7 +360,7 @@ static int pnv_php_get_adapter_state(struct hotplug_slot *slot, u8 *state)
 	 * get that, it will fail back to be empty.
 	 */
 	ret = pnv_pci_get_presence_state(php_slot->id, &presence);
-	if (likely(ret >= 0)) {
+	if (ret >= 0) {
 		*state = presence;
 		slot->info->adapter_status = presence;
 		ret = 0;
@@ -393,7 +393,7 @@ static int pnv_php_enable(struct pnv_php_slot *php_slot, bool rescan)
 
 	/* Retrieve slot presence status */
 	ret = pnv_php_get_adapter_state(slot, &presence);
-	if (unlikely(ret))
+	if (ret)
 		return ret;
 
 	/* Proceed if there have nothing behind the slot */
@@ -414,7 +414,7 @@ static int pnv_php_enable(struct pnv_php_slot *php_slot, bool rescan)
 		php_slot->power_state_check = true;
 
 		ret = pnv_php_get_power_state(slot, &power_status);
-		if (unlikely(ret))
+		if (ret)
 			return ret;
 
 		if (power_status != OPAL_PCI_SLOT_POWER_ON)
@@ -423,7 +423,7 @@ static int pnv_php_enable(struct pnv_php_slot *php_slot, bool rescan)
 
 	/* Check the power status. Scan the slot if it is already on */
 	ret = pnv_php_get_power_state(slot, &power_status);
-	if (unlikely(ret))
+	if (ret)
 		return ret;
 
 	if (power_status == OPAL_PCI_SLOT_POWER_ON)
@@ -431,7 +431,7 @@ static int pnv_php_enable(struct pnv_php_slot *php_slot, bool rescan)
 
 	/* Power is off, turn it on and then scan the slot */
 	ret = pnv_php_set_slot_power_state(slot, OPAL_PCI_SLOT_POWER_ON);
-	if (unlikely(ret))
+	if (ret)
 		return ret;
 
 scan:
@@ -515,27 +515,27 @@ static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn)
 	uint64_t id;
 
 	label = of_get_property(dn, "ibm,slot-label", NULL);
-	if (unlikely(!label))
+	if (!label)
 		return NULL;
 
 	if (pnv_pci_get_slot_id(dn, &id))
 		return NULL;
 
 	bus = pci_find_bus_by_node(dn);
-	if (unlikely(!bus))
+	if (!bus)
 		return NULL;
 
 	php_slot = kzalloc(sizeof(*php_slot), GFP_KERNEL);
-	if (unlikely(!php_slot))
+	if (!php_slot)
 		return NULL;
 
 	php_slot->name = kstrdup(label, GFP_KERNEL);
-	if (unlikely(!php_slot->name)) {
+	if (!php_slot->name) {
 		kfree(php_slot);
 		return NULL;
 	}
 
-	if (likely(dn->child && PCI_DN(dn->child)))
+	if (dn->child && PCI_DN(dn->child))
 		php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn);
 	else
 		php_slot->slot_no = -1;   /* Placeholder slot */
@@ -567,7 +567,7 @@ static int pnv_php_register_slot(struct pnv_php_slot *php_slot)
 
 	/* Check if the slot is registered or not */
 	parent = pnv_php_find_slot(php_slot->dn);
-	if (unlikely(parent)) {
+	if (parent) {
 		pnv_php_put_slot(parent);
 		return -EEXIST;
 	}
@@ -575,7 +575,7 @@ static int pnv_php_register_slot(struct pnv_php_slot *php_slot)
 	/* Register PCI slot */
 	ret = pci_hp_register(&php_slot->slot, php_slot->bus,
 			      php_slot->slot_no, php_slot->name);
-	if (unlikely(ret)) {
+	if (ret) {
 		dev_warn(&php_slot->pdev->dev, "Error %d registering slot\n",
 			 ret);
 		return ret;
@@ -625,15 +625,15 @@ static int pnv_php_register_one(struct device_node *dn)
 		return -ENXIO;
 
 	php_slot = pnv_php_alloc_slot(dn);
-	if (unlikely(!php_slot))
+	if (!php_slot)
 		return -ENODEV;
 
 	ret = pnv_php_register_slot(php_slot);
-	if (unlikely(ret))
+	if (ret)
 		goto free_slot;
 
 	ret = pnv_php_enable(php_slot, false);
-	if (unlikely(ret))
+	if (ret)
 		goto unregister_slot;
 
 	return 0;
-- 
2.1.0

[PATCH v3 6/6] drivers/pci/hotplug: Support surprise hotplug in powernv driver

[Gavin Shan]

This supports PCI surprise hotplug. The design is highlighted as
below:

   * The PCI slot's surprise hotplug capability is exposed through
     device node property "ibm,slot-surprise-pluggable", meaning
     PCI surprise hotplug will be disabled if skiboot doesn't support
     it yet.
   * The interrupt because of presence or link state change is raised
     on surprise hotplug event. One event is allocated and queued to
     the PCI slot for workqueue to pick it up and process in serialized
     fashion. The code flow for surprise hotplug is same to that for
     managed hotplug except: the affected PEs are put into frozen state
     to avoid unexpected EEH error reporting in surprise hot remove path.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pnv-pci.h |   2 +
 drivers/pci/hotplug/pnv_php.c      | 212 +++++++++++++++++++++++++++++++++++++
 2 files changed, 214 insertions(+)

diff --git a/arch/powerpc/include/asm/pnv-pci.h b/arch/powerpc/include/asm/pnv-pci.h
index 0cbd813..17e89dd 100644
--- a/arch/powerpc/include/asm/pnv-pci.h
+++ b/arch/powerpc/include/asm/pnv-pci.h
@@ -60,6 +60,8 @@ struct pnv_php_slot {
 #define PNV_PHP_STATE_POPULATED		2
 #define PNV_PHP_STATE_OFFLINE		3
 	int				state;
+	int				irq;
+	struct workqueue_struct		*wq;
 	struct device_node		*dn;
 	struct pci_dev			*pdev;
 	struct pci_bus			*bus;
diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index 182f218..ea4ec72d 100644
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -22,6 +22,12 @@
 #define DRIVER_AUTHOR	"Gavin Shan, IBM Corporation"
 #define DRIVER_DESC	"PowerPC PowerNV PCI Hotplug Driver"
 
+struct pnv_php_event {
+	bool			added;
+	struct pnv_php_slot	*php_slot;
+	struct work_struct	work;
+};
+
 static LIST_HEAD(pnv_php_slot_list);
 static DEFINE_SPINLOCK(pnv_php_lock);
 
@@ -29,12 +35,40 @@ static void pnv_php_register(struct device_node *dn);
 static void pnv_php_unregister_one(struct device_node *dn);
 static void pnv_php_unregister(struct device_node *dn);
 
+static void pnv_php_disable_irq(struct pnv_php_slot *php_slot)
+{
+	struct pci_dev *pdev = php_slot->pdev;
+	u16 ctrl;
+
+	if (php_slot->irq > 0) {
+		pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &ctrl);
+		ctrl &= ~(PCI_EXP_SLTCTL_HPIE |
+			  PCI_EXP_SLTCTL_PDCE |
+			  PCI_EXP_SLTCTL_DLLSCE);
+		pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, ctrl);
+
+		free_irq(php_slot->irq, php_slot);
+		php_slot->irq = 0;
+	}
+
+	if (php_slot->wq) {
+		destroy_workqueue(php_slot->wq);
+		php_slot->wq = NULL;
+	}
+
+	if (pdev->msix_enabled)
+		pci_disable_msix(pdev);
+	else if (pdev->msi_enabled)
+		pci_disable_msi(pdev);
+}
+
 static void pnv_php_free_slot(struct kref *kref)
 {
 	struct pnv_php_slot *php_slot = container_of(kref,
 					struct pnv_php_slot, kref);
 
 	WARN_ON(!list_empty(&php_slot->children));
+	pnv_php_disable_irq(php_slot);
 	kfree(php_slot->name);
 	kfree(php_slot);
 }
@@ -609,6 +643,179 @@ static int pnv_php_register_slot(struct pnv_php_slot *php_slot)
 	return 0;
 }
 
+static int pnv_php_enable_msix(struct pnv_php_slot *php_slot)
+{
+	struct pci_dev *pdev = php_slot->pdev;
+	struct msix_entry entry;
+	int nr_entries, ret;
+	u16 pcie_flag;
+
+	/* Get total number of MSIx entries */
+	nr_entries = pci_msix_vec_count(pdev);
+	if (nr_entries < 0)
+		return nr_entries;
+
+	/* Check hotplug MSIx entry is in range */
+	pcie_capability_read_word(pdev, PCI_EXP_FLAGS, &pcie_flag);
+	entry.entry = (pcie_flag & PCI_EXP_FLAGS_IRQ) >> 9;
+	if (entry.entry >= nr_entries)
+		return -ERANGE;
+
+	/* Enable MSIx */
+	ret = pci_enable_msix_exact(pdev, &entry, 1);
+	if (ret) {
+		dev_warn(&pdev->dev, "Error %d enabling MSIx\n", ret);
+		return ret;
+	}
+
+	return entry.vector;
+}
+
+static void pnv_php_event_handler(struct work_struct *work)
+{
+	struct pnv_php_event *event =
+		container_of(work, struct pnv_php_event, work);
+	struct pnv_php_slot *php_slot = event->php_slot;
+
+	if (event->added)
+		pnv_php_enable_slot(&php_slot->slot);
+	else
+		pnv_php_disable_slot(&php_slot->slot);
+
+	kfree(event);
+}
+
+static irqreturn_t pnv_php_interrupt(int irq, void *data)
+{
+	struct pnv_php_slot *php_slot = data;
+	struct pci_dev *pchild, *pdev = php_slot->pdev;
+	struct eeh_dev *edev;
+	struct eeh_pe *pe;
+	struct pnv_php_event *event;
+	u16 sts, lsts;
+	u8 presence;
+	bool added;
+	unsigned long flags;
+	int ret;
+
+	pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &sts);
+	sts &= (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
+	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, sts);
+	if (sts & PCI_EXP_SLTSTA_DLLSC) {
+		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lsts);
+		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
+	} else if (sts & PCI_EXP_SLTSTA_PDC) {
+		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
+		if (!ret)
+			return IRQ_HANDLED;
+		added = !!(presence == OPAL_PCI_SLOT_PRESENT);
+	} else {
+		return IRQ_NONE;
+	}
+
+	/* Freeze the removed PE to avoid unexpected error reporting */
+	if (!added) {
+		pchild = list_first_entry_or_null(&php_slot->bus->devices,
+						  struct pci_dev, bus_list);
+		edev = pchild ? pci_dev_to_eeh_dev(pchild) : NULL;
+		pe = edev ? edev->pe : NULL;
+		if (pe) {
+			eeh_serialize_lock(&flags);
+			eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
+			eeh_serialize_unlock(flags);
+			eeh_pe_set_option(pe, EEH_OPT_FREEZE_PE);
+		}
+	}
+
+	/* The PE is left in frozen state if the event is missed. It's
+	 * fine as the PCI devices (PE) aren't functional any more.
+	 */
+	event = kzalloc(sizeof(*event), GFP_ATOMIC);
+	if (!event) {
+		dev_warn(&pdev->dev, "PCI slot [%s] missed hotplug event 0x%04x\n",
+			 php_slot->name, sts);
+		return IRQ_HANDLED;
+	}
+
+	dev_info(&pdev->dev, "PCI slot [%s] %s (IRQ: %d)\n",
+		 php_slot->name, added ? "added" : "removed", irq);
+	INIT_WORK(&event->work, pnv_php_event_handler);
+	event->added = added;
+	event->php_slot = php_slot;
+	queue_work(php_slot->wq, &event->work);
+
+	return IRQ_HANDLED;
+}
+
+static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq)
+{
+	struct pci_dev *pdev = php_slot->pdev;
+	u16 sts, ctrl;
+	int ret;
+
+	/* Allocate workqueue */
+	php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name);
+	if (!php_slot->wq) {
+		dev_warn(&pdev->dev, "Cannot alloc workqueue\n");
+		pnv_php_disable_irq(php_slot);
+		return;
+	}
+
+	/* Clear pending interrupts */
+	pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &sts);
+	sts |= (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
+	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, sts);
+
+	/* Request the interrupt */
+	ret = request_irq(irq, pnv_php_interrupt, IRQF_SHARED,
+			  php_slot->name, php_slot);
+	if (ret) {
+		pnv_php_disable_irq(php_slot);
+		dev_warn(&pdev->dev, "Error %d enabling IRQ %d\n", ret, irq);
+		return;
+	}
+
+	/* Enable the interrupts */
+	pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &ctrl);
+	ctrl |= (PCI_EXP_SLTCTL_HPIE |
+		 PCI_EXP_SLTCTL_PDCE |
+		 PCI_EXP_SLTCTL_DLLSCE);
+	pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, ctrl);
+
+	/* The interrupt is initialized successfully when @irq is valid */
+	php_slot->irq = irq;
+}
+
+static void pnv_php_enable_irq(struct pnv_php_slot *php_slot)
+{
+	struct pci_dev *pdev = php_slot->pdev;
+	int irq, ret;
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		dev_warn(&pdev->dev, "Error %d enabling device\n", ret);
+		return;
+	}
+
+	pci_set_master(pdev);
+
+	/* Enable MSIx interrupt */
+	irq = pnv_php_enable_msix(php_slot);
+	if (irq > 0) {
+		pnv_php_init_irq(php_slot, irq);
+		return;
+	}
+
+	/* Use MSI if MSIx doesn't work. Fail back to legacy INTx
+	 * if MSI doesn't work either
+	 */
+	ret = pci_enable_msi(pdev);
+	if (!ret || pdev->irq) {
+		irq = pdev->irq;
+		pnv_php_init_irq(php_slot, irq);
+	}
+}
+
 static int pnv_php_register_one(struct device_node *dn)
 {
 	struct pnv_php_slot *php_slot;
@@ -636,6 +843,11 @@ static int pnv_php_register_one(struct device_node *dn)
 	if (ret)
 		goto unregister_slot;
 
+	/* Enable interrupt if the slot supports surprise hotplug */
+	prop32 = of_get_property(dn, "ibm,slot-surprise-pluggable", NULL);
+	if (prop32 && of_read_number(prop32, 1))
+		pnv_php_enable_irq(php_slot);
+
 	return 0;
 
 unregister_slot:
-- 
2.1.0

Re: [v3,1/6] powerpc/eeh: Allow to freeze PE in eeh_pe_set_option()

[Michael Ellerman]

On Wed, 2016-28-09 at 04:34:53 UTC, Gavin Shan wrote:
> Function eeh_pe_set_option() is used to apply the requested options
> (enable, disable, unfreeze) in EEH virtualization path. The semantics
> of this function isn't complete until freezing is supported.
> 
> This allows to freeze the indicated PE. The new semantics is going to
> be used in PCI surprise hot remove path, to freeze removed PCI devices
> (PE) to avoid unexpected EEH error reporting.
> 
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/de5a6622495117ef2e0335d509e917

cheers