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PCI: pciehp: Document struct slot and struct controller

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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>
This commit is contained in:
Lukas Wunner 2018-07-19 17:27:36 -05:00 committed by Bjorn Helgaas
parent 1d2e2673dc
commit 4aed1cd6fb
1 changed files with 44 additions and 4 deletions
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48
drivers/pci/hotplug/pciehp.h
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@ -57,11 +57,26 @@ do { \
dev_warn(&ctrl->pcie->device, format, ## arg) dev_warn(&ctrl->pcie->device, format, ## arg)
#define SLOT_NAME_SIZE 10 #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 { struct slot {
u8 state; u8 state;
struct controller *ctrl; struct controller *ctrl;
struct hotplug_slot *hotplug_slot; struct hotplug_slot *hotplug_slot;
struct delayed_work work; /* work for button event */ struct delayed_work work;
struct mutex lock; struct mutex lock;
struct mutex hotplug_lock; struct mutex hotplug_lock;
struct workqueue_struct *wq; struct workqueue_struct *wq;
@ -73,11 +88,36 @@ struct event_info {
struct work_struct work; 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 controller {
struct mutex ctrl_lock; /* controller lock */ struct mutex ctrl_lock;
struct pcie_device *pcie; /* PCI Express port service */ struct pcie_device *pcie;
struct slot *slot; struct slot *slot;
wait_queue_head_t queue; /* sleep & wake process */ wait_queue_head_t queue;
u32 slot_cap; u32 slot_cap;
u16 slot_ctrl; u16 slot_ctrl;
struct timer_list poll_timer; struct timer_list poll_timer;