ACPI: EC: wait for last write gpe

There is a possibility that EC might break if next command is
issued within 1 us after write or burst-disable command.

Suggestd-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index b340e08cf1d9..cebd65d2e2a9 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -102,6 +102,7 @@ struct transaction {
         u8 command;
         u8 wlen;
         u8 rlen;
+        bool done;
 };
 
 static struct acpi_ec {
@@ -178,7 +179,7 @@ static int ec_transaction_done(struct acpi_ec *ec)
         unsigned long flags;
         int ret = 0;
         spin_lock_irqsave(&ec->curr_lock, flags);
-        if (!ec->curr || (!ec->curr->wlen && !ec->curr->rlen))
+        if (!ec->curr || ec->curr->done)
                 ret = 1;
         spin_unlock_irqrestore(&ec->curr_lock, flags);
         return ret;
@@ -195,17 +196,20 @@ static void gpe_transaction(struct acpi_ec *ec, u8 status)
                         acpi_ec_write_data(ec, *(ec->curr->wdata++));
                         --ec->curr->wlen;
                 } else
-                        /* false interrupt, state didn't change */
-                        ++ec->curr->irq_count;
-
+                        goto err;
         } else if (ec->curr->rlen > 0) {
                 if ((status & ACPI_EC_FLAG_OBF) == 1) {
                         *(ec->curr->rdata++) = acpi_ec_read_data(ec);
-                        --ec->curr->rlen;
+                        if (--ec->curr->rlen == 0)
+                                ec->curr->done = true;
                 } else
-                        /* false interrupt, state didn't change */
-                        ++ec->curr->irq_count;
-        }
+                        goto err;
+        } else if (ec->curr->wlen == 0 && (status & ACPI_EC_FLAG_IBF) == 0)
+                ec->curr->done = true;
+        goto unlock;
+err:
+        /* false interrupt, state didn't change */
+        ++ec->curr->irq_count;
 unlock:
         spin_unlock_irqrestore(&ec->curr_lock, flags);
 }
@@ -265,6 +269,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
         spin_lock_irqsave(&ec->curr_lock, tmp);
         /* following two actions should be kept atomic */
         t->irq_count = 0;
+        t->done = false;
         ec->curr = t;
         acpi_ec_write_cmd(ec, ec->curr->command);
         if (ec->curr->command == ACPI_EC_COMMAND_QUERY)