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alistair23-linux/drivers/acpi/acpica/evgpeutil.c
Lv Zheng 0d0988af81 ACPICA: Events: Introduce ACPI_GPE_DISPATCH_RAW_HANDLER to fix 2 issues for the current GPE APIs 
ACPICA commit 199cad16530a45aea2bec98e528866e20c5927e1

Since whether the GPE should be disabled/enabled/cleared should only be
determined by the GPE driver's state machine:
1. GPE should be disabled if the driver wants to switch to the GPE polling
   mode when a GPE storm condition is indicated and should be enabled if
   the driver wants to switch back to the GPE interrupt mode when all of
   the storm conditions are cleared. The conditions should be protected by
   the driver's specific lock.
2. GPE should be enabled if the driver has accepted more than one request
   and should be disabled if the driver has completed all of the requests.
   The request count should be protected by the driver's specific lock.
3. GPE should be cleared either when the driver is about to handle an edge
   triggered GPE or when the driver has completed to handle a level
   triggered GPE. The handling code should be protected by the driver's
   specific lock.
Thus the GPE enabling/disabling/clearing operations are likely to be
performed with the driver's specific lock held while we currently cannot do
this. This is because:
1. We have the acpi_gbl_gpe_lock held before invoking the GPE driver's
   handler. Driver's specific lock is likely to be held inside of the
   handler, thus we can see some dead lock issues due to the reversed
   locking order or recursive locking. In order to solve such dead lock
   issues, we need to unlock the acpi_gbl_gpe_lock before invoking the
   handler. BZ 1100.
2. Since GPE disabling/enabling/clearing should be determined by the GPE
   driver's state machine, we shouldn't perform such operations inside of
   ACPICA for a GPE handler to mess up the driver's state machine. BZ 1101.

Originally this patch includes a logic to flush GPE handlers, it is dropped
due to the following reasons:
1. This is a different issue;
2. Linux OSL has fixed this by flushing SCI in acpi_os_wait_events_complete().
We will pick up this topic when the Linux OSL fix turns out to be not
sufficient.

Note that currently the internal operations and the acpi_gbl_gpe_lock are
also used by ACPI_GPE_DISPATCH_METHOD and ACPI_GPE_DISPATCH_NOTIFY. In
order not to introduce regressions, we add one
ACPI_GPE_DISPATCH_RAW_HANDLER type to be distiguished from
ACPI_GPE_DISPATCH_HANDLER. For which the acpi_gbl_gpe_lock is unlocked before
invoking the GPE handler and the internal enabling/disabling operations are
bypassed to allow drivers to perform them at a proper position using the
GPE APIs and ACPI_GPE_DISPATCH_RAW_HANDLER users should invoke acpi_set_gpe()
instead of acpi_enable_gpe()/acpi_disable_gpe() to bypass the internal GPE
clearing code in acpi_enable_gpe(). Lv Zheng.

Known issues:
1. Edge-triggered GPE lost for frequent enablings
   On some buggy silicon platforms, GPE enable line may not be directly
   wired to the GPE trigger line. In that case, when GPE enabling is
   frequently performed for edge-triggered GPEs, GPE status may stay set
   without being triggered.
   This patch may maginify this problem as it allows GPE enabling to be
   parallel performed during the process the GPEs are handled.
   This is an existing issue, because:
   1. For task context:
      Current ACPI_GPE_DISPATCH_METHOD practices have proven that this
      isn't a real issue - we can re-enable edge-triggered GPE in a work
      queue where the GPE status bit might already be set.
   2. For IRQ context:
      This can even happen when the GPE enabling occurs before returning
      from the GPE handler and after unlocking the GPE lock.
   Thus currently no code is included to protect this.

Link: https://github.com/acpica/acpica/commit/199cad16
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-02-05 15:34:51 +01:00

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/******************************************************************************
*
* Module Name: evgpeutil - GPE utilities
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2015, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include <acpi/acpi.h>
#include "accommon.h"
#include "acevents.h"
#define _COMPONENT ACPI_EVENTS
ACPI_MODULE_NAME("evgpeutil")
#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
/*******************************************************************************
*
* FUNCTION: acpi_ev_walk_gpe_list
*
* PARAMETERS: gpe_walk_callback - Routine called for each GPE block
* context - Value passed to callback
*
* RETURN: Status
*
* DESCRIPTION: Walk the GPE lists.
*
******************************************************************************/
acpi_status
acpi_ev_walk_gpe_list(acpi_gpe_callback gpe_walk_callback, void *context)
{
struct acpi_gpe_block_info *gpe_block;
struct acpi_gpe_xrupt_info *gpe_xrupt_info;
acpi_status status = AE_OK;
acpi_cpu_flags flags;
ACPI_FUNCTION_TRACE(ev_walk_gpe_list);
flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
/* Walk the interrupt level descriptor list */
gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
while (gpe_xrupt_info) {
/* Walk all Gpe Blocks attached to this interrupt level */
gpe_block = gpe_xrupt_info->gpe_block_list_head;
while (gpe_block) {
/* One callback per GPE block */
status =
gpe_walk_callback(gpe_xrupt_info, gpe_block,
context);
if (ACPI_FAILURE(status)) {
if (status == AE_CTRL_END) { /* Callback abort */
status = AE_OK;
}
goto unlock_and_exit;
}
gpe_block = gpe_block->next;
}
gpe_xrupt_info = gpe_xrupt_info->next;
}
unlock_and_exit:
acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
return_ACPI_STATUS(status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_get_gpe_device
*
* PARAMETERS: GPE_WALK_CALLBACK
*
* RETURN: Status
*
* DESCRIPTION: Matches the input GPE index (0-current_gpe_count) with a GPE
* block device. NULL if the GPE is one of the FADT-defined GPEs.
*
******************************************************************************/
acpi_status
acpi_ev_get_gpe_device(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
struct acpi_gpe_block_info *gpe_block, void *context)
{
struct acpi_gpe_device_info *info = context;
/* Increment Index by the number of GPEs in this block */
info->next_block_base_index += gpe_block->gpe_count;
if (info->index < info->next_block_base_index) {
/*
* The GPE index is within this block, get the node. Leave the node
* NULL for the FADT-defined GPEs
*/
if ((gpe_block->node)->type == ACPI_TYPE_DEVICE) {
info->gpe_device = gpe_block->node;
}
info->status = AE_OK;
return (AE_CTRL_END);
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_get_gpe_xrupt_block
*
* PARAMETERS: interrupt_number - Interrupt for a GPE block
* gpe_xrupt_block - Where the block is returned
*
* RETURN: Status
*
* DESCRIPTION: Get or Create a GPE interrupt block. There is one interrupt
* block per unique interrupt level used for GPEs. Should be
* called only when the GPE lists are semaphore locked and not
* subject to change.
*
******************************************************************************/
acpi_status
acpi_ev_get_gpe_xrupt_block(u32 interrupt_number,
struct acpi_gpe_xrupt_info ** gpe_xrupt_block)
{
struct acpi_gpe_xrupt_info *next_gpe_xrupt;
struct acpi_gpe_xrupt_info *gpe_xrupt;
acpi_status status;
acpi_cpu_flags flags;
ACPI_FUNCTION_TRACE(ev_get_gpe_xrupt_block);
/* No need for lock since we are not changing any list elements here */
next_gpe_xrupt = acpi_gbl_gpe_xrupt_list_head;
while (next_gpe_xrupt) {
if (next_gpe_xrupt->interrupt_number == interrupt_number) {
*gpe_xrupt_block = next_gpe_xrupt;
return_ACPI_STATUS(AE_OK);
}
next_gpe_xrupt = next_gpe_xrupt->next;
}
/* Not found, must allocate a new xrupt descriptor */
gpe_xrupt = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_xrupt_info));
if (!gpe_xrupt) {
return_ACPI_STATUS(AE_NO_MEMORY);
}
gpe_xrupt->interrupt_number = interrupt_number;
/* Install new interrupt descriptor with spin lock */
flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
if (acpi_gbl_gpe_xrupt_list_head) {
next_gpe_xrupt = acpi_gbl_gpe_xrupt_list_head;
while (next_gpe_xrupt->next) {
next_gpe_xrupt = next_gpe_xrupt->next;
}
next_gpe_xrupt->next = gpe_xrupt;
gpe_xrupt->previous = next_gpe_xrupt;
} else {
acpi_gbl_gpe_xrupt_list_head = gpe_xrupt;
}
acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
/* Install new interrupt handler if not SCI_INT */
if (interrupt_number != acpi_gbl_FADT.sci_interrupt) {
status = acpi_os_install_interrupt_handler(interrupt_number,
acpi_ev_gpe_xrupt_handler,
gpe_xrupt);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Could not install GPE interrupt handler at level 0x%X",
interrupt_number));
return_ACPI_STATUS(status);
}
}
*gpe_xrupt_block = gpe_xrupt;
return_ACPI_STATUS(AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_delete_gpe_xrupt
*
* PARAMETERS: gpe_xrupt - A GPE interrupt info block
*
* RETURN: Status
*
* DESCRIPTION: Remove and free a gpe_xrupt block. Remove an associated
* interrupt handler if not the SCI interrupt.
*
******************************************************************************/
acpi_status acpi_ev_delete_gpe_xrupt(struct acpi_gpe_xrupt_info *gpe_xrupt)
{
acpi_status status;
acpi_cpu_flags flags;
ACPI_FUNCTION_TRACE(ev_delete_gpe_xrupt);
/* We never want to remove the SCI interrupt handler */
if (gpe_xrupt->interrupt_number == acpi_gbl_FADT.sci_interrupt) {
gpe_xrupt->gpe_block_list_head = NULL;
return_ACPI_STATUS(AE_OK);
}
/* Disable this interrupt */
status =
acpi_os_remove_interrupt_handler(gpe_xrupt->interrupt_number,
acpi_ev_gpe_xrupt_handler);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/* Unlink the interrupt block with lock */
flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
if (gpe_xrupt->previous) {
gpe_xrupt->previous->next = gpe_xrupt->next;
} else {
/* No previous, update list head */
acpi_gbl_gpe_xrupt_list_head = gpe_xrupt->next;
}
if (gpe_xrupt->next) {
gpe_xrupt->next->previous = gpe_xrupt->previous;
}
acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
/* Free the block */
ACPI_FREE(gpe_xrupt);
return_ACPI_STATUS(AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_delete_gpe_handlers
*
* PARAMETERS: gpe_xrupt_info - GPE Interrupt info
* gpe_block - Gpe Block info
*
* RETURN: Status
*
* DESCRIPTION: Delete all Handler objects found in the GPE data structs.
* Used only prior to termination.
*
******************************************************************************/
acpi_status
acpi_ev_delete_gpe_handlers(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
struct acpi_gpe_block_info *gpe_block,
void *context)
{
struct acpi_gpe_event_info *gpe_event_info;
struct acpi_gpe_notify_info *notify;
struct acpi_gpe_notify_info *next;
u32 i;
u32 j;
ACPI_FUNCTION_TRACE(ev_delete_gpe_handlers);
/* Examine each GPE Register within the block */
for (i = 0; i < gpe_block->register_count; i++) {
/* Now look at the individual GPEs in this byte register */
for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
gpe_event_info = &gpe_block->event_info[((acpi_size) i *
ACPI_GPE_REGISTER_WIDTH)
+ j];
if ((ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags) ==
ACPI_GPE_DISPATCH_HANDLER) ||
(ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags) ==
ACPI_GPE_DISPATCH_RAW_HANDLER)) {
/* Delete an installed handler block */
ACPI_FREE(gpe_event_info->dispatch.handler);
gpe_event_info->dispatch.handler = NULL;
gpe_event_info->flags &=
~ACPI_GPE_DISPATCH_MASK;
} else if (ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags)
== ACPI_GPE_DISPATCH_NOTIFY) {
/* Delete the implicit notification device list */
notify = gpe_event_info->dispatch.notify_list;
while (notify) {
next = notify->next;
ACPI_FREE(notify);
notify = next;
}
gpe_event_info->dispatch.notify_list = NULL;
gpe_event_info->flags &=
~ACPI_GPE_DISPATCH_MASK;
}
}
}
return_ACPI_STATUS(AE_OK);
}
#endif /* !ACPI_REDUCED_HARDWARE */
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