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linux-next/drivers/pci/hotplug/pciehp.h
Lukas Wunner 125450f814 PCI: hotplug: Embed hotplug_slot 
When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of().  But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths.  Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference.  And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct.  The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00

219 lines
8.7 KiB
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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* PCI Express Hot Plug Controller Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2003-2004 Intel Corporation
*
* All rights reserved.
*
* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
*
*/
#ifndef _PCIEHP_H
#define _PCIEHP_H
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/workqueue.h>
#include "../pcie/portdrv.h"
#define MY_NAME "pciehp"
extern bool pciehp_poll_mode;
extern int pciehp_poll_time;
extern bool pciehp_debug;
#define dbg(format, arg...) \
do { \
if (pciehp_debug) \
printk(KERN_DEBUG "%s: " format, MY_NAME, ## arg); \
} while (0)
#define err(format, arg...) \
printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
#define info(format, arg...) \
printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
#define warn(format, arg...) \
printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)
#define ctrl_dbg(ctrl, format, arg...) \
do { \
if (pciehp_debug) \
dev_printk(KERN_DEBUG, &ctrl->pcie->device, \
format, ## arg); \
} while (0)
#define ctrl_err(ctrl, format, arg...) \
dev_err(&ctrl->pcie->device, format, ## arg)
#define ctrl_info(ctrl, format, arg...) \
dev_info(&ctrl->pcie->device, format, ## arg)
#define ctrl_warn(ctrl, format, arg...) \
dev_warn(&ctrl->pcie->device, format, ## arg)
#define SLOT_NAME_SIZE 10
/**
* struct controller - PCIe hotplug controller
* @pcie: pointer to the controller's PCIe port service device
* @slot_cap: cached copy of the Slot Capabilities register
* @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
* @slot_ctrl: cached copy of the Slot Control register
* @ctrl_lock: serializes writes to the Slot Control register
* @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
* @queue: wait queue to wake up on reception of a Command Completed event,
* used for synchronous writes to the Slot Control register
* @pending_events: used by the IRQ handler to save events retrieved from the
* Slot Status register for later consumption by the IRQ thread
* @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
* @poll_thread: thread to poll for slot events if no IRQ is available,
* enabled with pciehp_poll_mode module parameter
* @state: current state machine position
* @state_lock: protects reads and writes of @state;
* protects scheduling, execution and cancellation of @button_work
* @button_work: work item to turn the slot on or off after 5 seconds
* in response to an Attention Button press
* @hotplug_slot: structure registered with the PCI hotplug core
* @reset_lock: prevents access to the Data Link Layer Link Active bit in the
* Link Status register and to the Presence Detect State bit in the Slot
* Status register during a slot reset which may cause them to flap
* @request_result: result of last user request submitted to the IRQ thread
* @requester: wait queue to wake up on completion of user request,
* used for synchronous slot enable/disable request via sysfs
*
* PCIe hotplug has a 1:1 relationship between controller and slot, hence
* unlike other drivers, the two aren't represented by separate structures.
*/
struct controller {
struct pcie_device *pcie;
u32 slot_cap; /* capabilities and quirks */
unsigned int link_active_reporting:1;
u16 slot_ctrl; /* control register access */
struct mutex ctrl_lock;
unsigned long cmd_started;
unsigned int cmd_busy:1;
wait_queue_head_t queue;
atomic_t pending_events; /* event handling */
unsigned int notification_enabled:1;
unsigned int power_fault_detected;
struct task_struct *poll_thread;
u8 state; /* state machine */
struct mutex state_lock;
struct delayed_work button_work;
struct hotplug_slot hotplug_slot; /* hotplug core interface */
struct rw_semaphore reset_lock;
int request_result;
wait_queue_head_t requester;
};
/**
* DOC: Slot state
*
* @OFF_STATE: slot is powered off, no subordinate devices are enumerated
* @BLINKINGON_STATE: slot will be powered on after the 5 second delay,
* green led is blinking
* @BLINKINGOFF_STATE: slot will be powered off after the 5 second delay,
* green led is blinking
* @POWERON_STATE: slot is currently powering on
* @POWEROFF_STATE: slot is currently powering off
* @ON_STATE: slot is powered on, subordinate devices have been enumerated
*/
#define OFF_STATE 0
#define BLINKINGON_STATE 1
#define BLINKINGOFF_STATE 2
#define POWERON_STATE 3
#define POWEROFF_STATE 4
#define ON_STATE 5
/**
* DOC: Flags to request an action from the IRQ thread
*
* These are stored together with events read from the Slot Status register,
* hence must be greater than its 16-bit width.
*
* %DISABLE_SLOT: Disable the slot in response to a user request via sysfs or
* an Attention Button press after the 5 second delay
* %RERUN_ISR: Used by the IRQ handler to inform the IRQ thread that the
* hotplug port was inaccessible when the interrupt occurred, requiring
* that the IRQ handler is rerun by the IRQ thread after it has made the
* hotplug port accessible by runtime resuming its parents to D0
*/
#define DISABLE_SLOT (1 << 16)
#define RERUN_ISR (1 << 17)
#define ATTN_BUTTN(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_ABP)
#define POWER_CTRL(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_PCP)
#define MRL_SENS(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_MRLSP)
#define ATTN_LED(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_AIP)
#define PWR_LED(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_PIP)
#define HP_SUPR_RM(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_HPS)
#define EMI(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_EIP)
#define NO_CMD_CMPL(ctrl) ((ctrl)->slot_cap & PCI_EXP_SLTCAP_NCCS)
#define PSN(ctrl) (((ctrl)->slot_cap & PCI_EXP_SLTCAP_PSN) >> 19)
void pciehp_request(struct controller *ctrl, int action);
void pciehp_handle_button_press(struct controller *ctrl);
void pciehp_handle_disable_request(struct controller *ctrl);
void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events);
int pciehp_configure_device(struct controller *ctrl);
void pciehp_unconfigure_device(struct controller *ctrl, bool presence);
void pciehp_queue_pushbutton_work(struct work_struct *work);
struct controller *pcie_init(struct pcie_device *dev);
int pcie_init_notification(struct controller *ctrl);
void pcie_shutdown_notification(struct controller *ctrl);
void pcie_clear_hotplug_events(struct controller *ctrl);
int pciehp_power_on_slot(struct controller *ctrl);
void pciehp_power_off_slot(struct controller *ctrl);
void pciehp_get_power_status(struct controller *ctrl, u8 *status);
void pciehp_set_attention_status(struct controller *ctrl, u8 status);
void pciehp_get_latch_status(struct controller *ctrl, u8 *status);
int pciehp_query_power_fault(struct controller *ctrl);
void pciehp_green_led_on(struct controller *ctrl);
void pciehp_green_led_off(struct controller *ctrl);
void pciehp_green_led_blink(struct controller *ctrl);
bool pciehp_card_present(struct controller *ctrl);
bool pciehp_card_present_or_link_active(struct controller *ctrl);
int pciehp_check_link_status(struct controller *ctrl);
bool pciehp_check_link_active(struct controller *ctrl);
void pciehp_release_ctrl(struct controller *ctrl);
int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot);
int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot);
int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, int probe);
int pciehp_get_attention_status(struct hotplug_slot *hotplug_slot, u8 *status);
int pciehp_set_raw_indicator_status(struct hotplug_slot *h_slot, u8 status);
int pciehp_get_raw_indicator_status(struct hotplug_slot *h_slot, u8 *status);
static inline const char *slot_name(struct controller *ctrl)
{
return hotplug_slot_name(&ctrl->hotplug_slot);
}
static inline struct controller *to_ctrl(struct hotplug_slot *hotplug_slot)
{
return container_of(hotplug_slot, struct controller, hotplug_slot);
}
#endif /* _PCIEHP_H */
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