ACPI: EC: Remove unnecessary delay added by previous transation patch.

Remove unnecessary delay (50 ms) while reading data from EC in interrupt mode.

Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 50 insertions, 53 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index a0dcbad97c45..b6f935d0c3ad 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -100,7 +100,7 @@ union acpi_ec {
                 struct acpi_generic_address command_addr;
                 struct acpi_generic_address data_addr;
                 unsigned long global_lock;
-                unsigned int expect_event;
+                u8 expect_event;
                 atomic_t leaving_burst; /* 0 : No, 1 : Yes, 2: abort */
                 atomic_t pending_gpe;
                 struct semaphore sem;
@@ -121,7 +121,7 @@ union acpi_ec {
 };
 
 static int acpi_ec_poll_wait(union acpi_ec *ec, u8 event);
-static int acpi_ec_intr_wait(union acpi_ec *ec, unsigned int event);
+static int acpi_ec_intr_wait(union acpi_ec *ec, u8 event);
 static int acpi_ec_poll_transaction(union acpi_ec *ec, u8 command,
                                     const u8 *wdata, unsigned wdata_len,
                                     u8 *rdata, unsigned rdata_len);
@@ -161,6 +161,22 @@ static u32 acpi_ec_read_status(union acpi_ec *ec)
         return status;
 }
 
+static int acpi_ec_check_status(u32 status, u8 event) {
+
+        switch (event) {
+        case ACPI_EC_EVENT_OBF:
+                if (status & ACPI_EC_FLAG_OBF)
+                        return 1;
+        case ACPI_EC_EVENT_IBE:
+                if (!(status & ACPI_EC_FLAG_IBF))
+                        return 1;
+        default:
+                break;
+        }
+
+        return 0;
+}
+
 static int acpi_ec_wait(union acpi_ec *ec, u8 event)
 {
         if (acpi_ec_poll_mode)
@@ -203,47 +219,28 @@ static int acpi_ec_poll_wait(union acpi_ec *ec, u8 event)
 
         return -ETIME;
 }
-static int acpi_ec_intr_wait(union acpi_ec *ec, unsigned int event)
-{
-        int result = 0;
 
+static int acpi_ec_intr_wait(union acpi_ec *ec, u8 event)
+{
+        long            time_left;
 
         ec->intr.expect_event = event;
-        smp_mb();
 
-        switch (event) {
-        case ACPI_EC_EVENT_IBE:
-                if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) {
+        if (acpi_ec_check_status(acpi_ec_read_status(ec), event)) {
                         ec->intr.expect_event = 0;
                         return 0;
-                }
-                break;
-        default:
-                break;
         }
 
-        result = wait_event_timeout(ec->intr.wait,
-                                    !ec->intr.expect_event,
-                                    msecs_to_jiffies(ACPI_EC_DELAY));
+        time_left = wait_event_timeout(ec->intr.wait, !ec->intr.expect_event,
+                                        msecs_to_jiffies(ACPI_EC_DELAY));
 
         ec->intr.expect_event = 0;
-        smp_mb();
-
-        /*
-         * Verify that the event in question has actually happened by
-         * querying EC status. Do the check even if operation timed-out
-         * to make sure that we did not miss interrupt.
-         */
-        switch (event) {
-        case ACPI_EC_EVENT_OBF:
-                if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
-                        return 0;
-                break;
-
-        case ACPI_EC_EVENT_IBE:
-                if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
-                        return 0;
-                break;
+        if (time_left <= 0) {
+                if (acpi_ec_check_status(acpi_ec_read_status(ec), event)) {
+                                return 0;
+                }
+        } else {
+                return 0;
         }
 
         return -ETIME;
@@ -293,7 +290,7 @@ int acpi_ec_leave_burst_mode(union acpi_ec *ec)
                         goto end;
                 acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->common.command_addr);
                 acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
-        } 
+        }
         atomic_set(&ec->intr.leaving_burst, 1);
         return 0;
 end:
@@ -333,32 +330,32 @@ static int acpi_ec_transaction_unlocked(union acpi_ec *ec, u8 command,
 
         acpi_hw_low_level_write(8, command, &ec->common.command_addr);
 
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        if (result)
-                return result;
-
-        for (; wdata_len > 0; wdata_len --) {
-
-                acpi_hw_low_level_write(8, *(wdata++), &ec->common.data_addr);
+        for (; wdata_len > 0; wdata_len --) {
+                result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+                if (result)
+                        return result;
 
-                result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-                if (result)
-                        return result;
+                acpi_hw_low_level_write(8, *(wdata++), &ec->common.data_addr);
         }
 
+        if (command == ACPI_EC_COMMAND_WRITE) {
+                result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+                if (result)
+                        return result;
+        }
 
-        for (; rdata_len > 0; rdata_len --) {
-                u32 d;
+        for (; rdata_len > 0; rdata_len --) {
+                u32 d;
 
-                result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-                if (result)
-                        return result;
+                result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+                if (result)
+                        return result;
 
-                acpi_hw_low_level_read(8, &d, &ec->common.data_addr);
-                *(rdata++) = (u8) d;
-        }
+                acpi_hw_low_level_read(8, &d, &ec->common.data_addr);
+                *(rdata++) = (u8) d;
+        }
 
-        return 0;
+        return 0;
 }
 
 static int acpi_ec_poll_transaction(union acpi_ec *ec, u8 command,