diff options
author | Lukas Wunner <lukas@wunner.de> | 2018-07-19 17:27:36 -0500 |
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committer | Bjorn Helgaas <helgaas@kernel.org> | 2018-07-23 17:04:12 -0500 |
commit | 4aed1cd6fb957fa8de5a9416a9adab98775878e9 (patch) | |
tree | a68474844d38815e77afdc4ad2c35685fdcda607 /drivers/pci/hotplug | |
parent | 1d2e2673dc5b9b374513fd58d5909f0332b47407 (diff) |
PCI: pciehp: Document struct slot and struct controller
Document the driver's data structures to lower the barrier to entry for
contributors.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/hotplug')
-rw-r--r-- | drivers/pci/hotplug/pciehp.h | 48 |
1 files changed, 44 insertions, 4 deletions
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index acdeb08cbcba..c3d63e5b650f 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -57,11 +57,26 @@ do { \ dev_warn(&ctrl->pcie->device, format, ## arg) #define SLOT_NAME_SIZE 10 + +/** + * struct slot - PCIe hotplug slot + * @state: current state machine position + * @ctrl: pointer to the slot's controller structure + * @hotplug_slot: pointer to the structure registered with the PCI hotplug core + * @work: work item to turn the slot on or off after 5 seconds in response to + * an Attention Button press + * @lock: protects reads and writes of @state; + * protects scheduling, execution and cancellation of @work + * @hotplug_lock: serializes calls to pciehp_enable_slot() and + * pciehp_disable_slot() + * @wq: work queue on which @work is scheduled; + * also used to queue interrupt events and slot enablement and disablement + */ struct slot { u8 state; struct controller *ctrl; struct hotplug_slot *hotplug_slot; - struct delayed_work work; /* work for button event */ + struct delayed_work work; struct mutex lock; struct mutex hotplug_lock; struct workqueue_struct *wq; @@ -73,11 +88,36 @@ struct event_info { struct work_struct work; }; +/** + * struct controller - PCIe hotplug controller + * @ctrl_lock: serializes writes to the Slot Control register + * @pcie: pointer to the controller's PCIe port service device + * @slot: pointer to the controller's slot structure + * @queue: wait queue to wake up on reception of a Command Completed event, + * used for synchronous writes to the Slot Control register + * @slot_cap: cached copy of the Slot Capabilities register + * @slot_ctrl: cached copy of the Slot Control register + * @poll_timer: timer to poll for slot events if no IRQ is available, + * enabled with pciehp_poll_mode module parameter + * @cmd_started: jiffies when the Slot Control register was last written; + * the next write is allowed 1 second later, absent a Command Completed + * interrupt (PCIe r4.0, sec 6.7.3.2) + * @cmd_busy: flag set on Slot Control register write, cleared by IRQ handler + * on reception of a Command Completed event + * @link_active_reporting: cached copy of Data Link Layer Link Active Reporting + * Capable bit in Link Capabilities register; if this bit is zero, the + * Data Link Layer Link Active bit in the Link Status register will never + * be set and the driver is thus confined to wait 1 second before assuming + * the link to a hotplugged device is up and accessing it + * @notification_enabled: whether the IRQ was requested successfully + * @power_fault_detected: whether a power fault was detected by the hardware + * that has not yet been cleared by the user + */ struct controller { - struct mutex ctrl_lock; /* controller lock */ - struct pcie_device *pcie; /* PCI Express port service */ + struct mutex ctrl_lock; + struct pcie_device *pcie; struct slot *slot; - wait_queue_head_t queue; /* sleep & wake process */ + wait_queue_head_t queue; u32 slot_cap; u16 slot_ctrl; struct timer_list poll_timer; |