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Date: Wed, 3 Aug 2016 16:01:24 +0800
From: Lv Zheng <lv.zheng@...el.com>
To: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <len.brown@...el.com>
Cc: Lv Zheng <lv.zheng@...el.com>, Lv Zheng <zetalog@...il.com>,
<linux-kernel@...r.kernel.org>, linux-acpi@...r.kernel.org
Subject: [PATCH v3 1/5] ACPI / EC: Add EC_FLAGS_QUERY_ENABLED to reveal a hidden logic
There is a hidden logic in the EC driver:
1. During boot, EC_FLAGS_QUERY_PENDING is responsible for blocking event
handling;
2. During suspend, EC_FLAGS_STARTED is responsible for blocking event
handling.
This patch uses a new EC_FLAGS_QUERY_ENABLED flag to make this hidden
logic explicit and have code cleaned up. No functional change.
Signed-off-by: Lv Zheng <lv.zheng@...el.com>
Tested-by: Todd E Brandt <todd.e.brandt@...ux.intel.com>
---
drivers/acpi/ec.c | 103 ++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 71 insertions(+), 32 deletions(-)
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 6f6c7d1..4ab34d7 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -104,6 +104,7 @@ enum ec_command {
#define ACPI_EC_MAX_QUERIES 16 /* Maximum number of parallel queries */
enum {
+ EC_FLAGS_QUERY_ENABLED, /* Query is enabled */
EC_FLAGS_QUERY_PENDING, /* Query is pending */
EC_FLAGS_QUERY_GUARDING, /* Guard for SCI_EVT check */
EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
@@ -239,6 +240,22 @@ static bool acpi_ec_started(struct acpi_ec *ec)
!test_bit(EC_FLAGS_STOPPED, &ec->flags);
}
+static bool acpi_ec_event_enabled(struct acpi_ec *ec)
+{
+ /*
+ * There is an OSPM early stage logic. During the early stages
+ * (boot/resume), OSPMs shouldn't enable the event handling, only
+ * the EC transactions are allowed to be performed.
+ */
+ if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
+ return false;
+ /*
+ * The EC event handling is automatically disabled as soon as the
+ * EC driver is stopped.
+ */
+ return test_bit(EC_FLAGS_STARTED, &ec->flags);
+}
+
static bool acpi_ec_flushed(struct acpi_ec *ec)
{
return ec->reference_count == 1;
@@ -429,7 +446,8 @@ static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
static void acpi_ec_submit_query(struct acpi_ec *ec)
{
- if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
+ if (acpi_ec_event_enabled(ec) &&
+ !test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
ec_dbg_evt("Command(%s) submitted/blocked",
acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
ec->nr_pending_queries++;
@@ -446,6 +464,52 @@ static void acpi_ec_complete_query(struct acpi_ec *ec)
}
}
+static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
+{
+ if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
+ ec_log_drv("event unblocked");
+}
+
+static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
+{
+ if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
+ ec_log_drv("event blocked");
+}
+
+/*
+ * Process _Q events that might have accumulated in the EC.
+ * Run with locked ec mutex.
+ */
+static void acpi_ec_clear(struct acpi_ec *ec)
+{
+ int i, status;
+ u8 value = 0;
+
+ for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
+ status = acpi_ec_query(ec, &value);
+ if (status || !value)
+ break;
+ }
+ if (unlikely(i == ACPI_EC_CLEAR_MAX))
+ pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
+ else
+ pr_info("%d stale EC events cleared\n", i);
+}
+
+static void acpi_ec_enable_event(struct acpi_ec *ec)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ec->lock, flags);
+ if (acpi_ec_started(ec))
+ __acpi_ec_enable_event(ec);
+ spin_unlock_irqrestore(&ec->lock, flags);
+
+ /* Drain additional events if hardware requires that */
+ if (EC_FLAGS_CLEAR_ON_RESUME)
+ acpi_ec_clear(ec);
+}
+
static bool acpi_ec_guard_event(struct acpi_ec *ec)
{
bool guarded = true;
@@ -832,27 +896,6 @@ acpi_handle ec_get_handle(void)
}
EXPORT_SYMBOL(ec_get_handle);
-/*
- * Process _Q events that might have accumulated in the EC.
- * Run with locked ec mutex.
- */
-static void acpi_ec_clear(struct acpi_ec *ec)
-{
- int i, status;
- u8 value = 0;
-
- for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
- status = acpi_ec_query(ec, &value);
- if (status || !value)
- break;
- }
-
- if (unlikely(i == ACPI_EC_CLEAR_MAX))
- pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
- else
- pr_info("%d stale EC events cleared\n", i);
-}
-
static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
{
unsigned long flags;
@@ -864,7 +907,8 @@ static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
if (!resuming) {
acpi_ec_submit_request(ec);
ec_dbg_ref(ec, "Increase driver");
- }
+ } else
+ __acpi_ec_enable_event(ec);
ec_log_drv("EC started");
}
spin_unlock_irqrestore(&ec->lock, flags);
@@ -896,7 +940,8 @@ static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
if (!suspending) {
acpi_ec_complete_request(ec);
ec_dbg_ref(ec, "Decrease driver");
- }
+ } else
+ __acpi_ec_disable_event(ec);
clear_bit(EC_FLAGS_STARTED, &ec->flags);
clear_bit(EC_FLAGS_STOPPED, &ec->flags);
ec_log_drv("EC stopped");
@@ -927,8 +972,7 @@ void acpi_ec_unblock_transactions(void)
/* Allow transactions to be carried out again */
acpi_ec_start(ec, true);
- if (EC_FLAGS_CLEAR_ON_RESUME)
- acpi_ec_clear(ec);
+ acpi_ec_enable_event(ec);
}
void acpi_ec_unblock_transactions_early(void)
@@ -1234,7 +1278,6 @@ static struct acpi_ec *make_acpi_ec(void)
if (!ec)
return NULL;
- ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
mutex_init(&ec->mutex);
init_waitqueue_head(&ec->wait);
INIT_LIST_HEAD(&ec->list);
@@ -1421,11 +1464,7 @@ static int acpi_ec_add(struct acpi_device *device)
acpi_walk_dep_device_list(ec->handle);
/* EC is fully operational, allow queries */
- clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
-
- /* Clear stale _Q events if hardware might require that */
- if (EC_FLAGS_CLEAR_ON_RESUME)
- acpi_ec_clear(ec);
+ acpi_ec_enable_event(ec);
return ret;
}
--
1.7.10
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