[PATCH v3 3/9] pci: Implement reset_slot for pciehp

Alex Williamson
2013-08-01T16:55:35Z

PCIe hotplug has a bus per slot, so we can just use a normal
secondary bus reset. However, if a slot supports surprise removal
then a bus reset can be seen as a presence detection change triggering
a hot-remove followed by a hot-add. Disable presence detection from
triggering an interrupt or being polled around the bus reset.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/pci/hotplug/pciehp.h | 1 +
drivers/pci/hotplug/pciehp_core.c | 12 ++++++++++++
drivers/pci/hotplug/pciehp_hpc.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+)

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 7fb3269..541bbe6 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -155,6 +155,7 @@ void pciehp_green_led_off(struct slot *slot);
void pciehp_green_led_blink(struct slot *slot);
int pciehp_check_link_status(struct controller *ctrl);
void pciehp_release_ctrl(struct controller *ctrl);
+int pciehp_reset_slot(struct slot *slot, int probe);

static inline const char *slot_name(struct slot *slot)
{
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 7d72c5e..f4a18f5 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -69,6 +69,7 @@ static int get_power_status (struct hotplug_slot *slot, u8 *value);
static int get_attention_status (struct hotplug_slot *slot, u8 *value);
static int get_latch_status (struct hotplug_slot *slot, u8 *value);
static int get_adapter_status (struct hotplug_slot *slot, u8 *value);
+static int reset_slot (struct hotplug_slot *slot, int probe);

/**
* release_slot - free up the memory used by a slot
@@ -111,6 +112,7 @@ static int init_slot(struct controller *ctrl)
ops->disable_slot = disable_slot;
ops->get_power_status = get_power_status;
ops->get_adapter_status = get_adapter_status;
+ ops->reset_slot = reset_slot;
if (MRL_SENS(ctrl))
ops->get_latch_status = get_latch_status;
if (ATTN_LED(ctrl)) {
@@ -223,6 +225,16 @@ static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
return pciehp_get_adapter_status(slot, value);
}

+static int reset_slot(struct hotplug_slot *hotplug_slot, int probe)
+{
+ struct slot *slot = hotplug_slot->private;
+
+ ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
+ __func__, slot_name(slot));
+
+ return pciehp_reset_slot(slot, probe);
+}
+
static int pciehp_probe(struct pcie_device *dev)
{
int rc;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index b225573..51f56ef 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -749,6 +749,37 @@ static void pcie_disable_notification(struct controller *ctrl)
ctrl_warn(ctrl, "Cannot disable software notification\n");
}

+/*
+ * pciehp has a 1:1 bus:slot relationship so we ultimately want a secondary
+ * bus reset of the bridge, but if the slot supports surprise removal we need
+ * to disable presence detection around the bus reset and clear any spurious
+ * events after.
+ */
+int pciehp_reset_slot(struct slot *slot, int probe)
+{
+ struct controller *ctrl = slot->ctrl;
+
+ if (probe)
+ return 0;
+
+ if (HP_SUPR_RM(ctrl)) {
+ pcie_write_cmd(ctrl, 0, PCI_EXP_SLTCTL_PDCE);
+ if (pciehp_poll_mode)
+ del_timer_sync(&ctrl->poll_timer);
+ }
+
+ pci_reset_bridge_secondary_bus(ctrl->pcie->port);
+
+ if (HP_SUPR_RM(ctrl)) {
+ pciehp_writew(ctrl, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_PDC);
+ pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PDCE, PCI_EXP_SLTCTL_PDCE);
+ if (pciehp_poll_mode)
+ int_poll_timeout(ctrl->poll_timer.data);
+ }
+
+ return 0;
+}
+
int pcie_init_notification(struct controller *ctrl)
{
if (pciehp_request_irq(ctrl))