[ACPI] Fix "ec_burst=1" mode latency issue

http://bugzilla.kernel.org/show_bug.cgi?id=3851

Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 59 insertions, 110 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 1ac5731d45e5..31067a0a3671 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -234,18 +234,29 @@ static int acpi_ec_burst_wait(union acpi_ec *ec, unsigned int event)
         ec->burst.expect_event = event;
         smp_mb();
 
-        result = wait_event_interruptible_timeout(ec->burst.wait,
+        switch (event) {
+        case ACPI_EC_EVENT_OBF:
+                if (acpi_ec_read_status(ec) & event) {
+                        ec->burst.expect_event = 0;
+                        return_VALUE(0);
+                }
+                break;
+
+        case ACPI_EC_EVENT_IBE:
+                if (~acpi_ec_read_status(ec) & event) {
+                        ec->burst.expect_event = 0;
+                        return_VALUE(0);
+                }
+                break;
+        }
+
+        result = wait_event_timeout(ec->burst.wait,
                                         !ec->burst.expect_event,
                                         msecs_to_jiffies(ACPI_EC_DELAY));
         
         ec->burst.expect_event = 0;
         smp_mb();
 
-        if (result < 0){
-                ACPI_DEBUG_PRINT((ACPI_DB_ERROR," result  = %d ", result));
-                return_VALUE(result);
-        }
-
         /*
          * Verify that the event in question has actually happened by
          * querying EC status. Do the check even if operation timed-out
@@ -280,14 +291,14 @@ acpi_ec_enter_burst_mode (
         status = acpi_ec_read_status(ec);
         if (status != -EINVAL &&
                 !(status & ACPI_EC_FLAG_BURST)){
+                status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+                if(status)
+                        goto end;
                 acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->common.command_addr);
                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-                if (status){
-                        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
+                if (status)
                         return_VALUE(-EINVAL);
-                }
                 acpi_hw_low_level_read(8, &tmp, &ec->common.data_addr);
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 if(tmp != 0x90 ) {/* Burst ACK byte*/
                         return_VALUE(-EINVAL);
                 }
@@ -295,31 +306,19 @@ acpi_ec_enter_burst_mode (
 
         atomic_set(&ec->burst.leaving_burst , 0);
         return_VALUE(0);
+end:
+        printk("Error in acpi_ec_wait\n");
+        return_VALUE(-1);
 }
 
 static int
 acpi_ec_leave_burst_mode (
         union acpi_ec           *ec)
 {
-        int                     status =0;
 
         ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");
 
-        atomic_set(&ec->burst.leaving_burst , 1);
-        status = acpi_ec_read_status(ec);
-        if (status != -EINVAL &&
-                (status & ACPI_EC_FLAG_BURST)){
-                acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->common.command_addr);
-                status = acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
-                if (status){
-                        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->wait fail\n"));
-                        return_VALUE(-EINVAL);
-                }
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                status = acpi_ec_read_status(ec);
-        }
-
+        atomic_set(&ec->burst.leaving_burst, 1);
         return_VALUE(0);
 }
 
@@ -461,7 +460,6 @@ acpi_ec_burst_read (
         if (!ec || !data)
                 return_VALUE(-EINVAL);
 
-retry:
         *data = 0;
 
         if (ec->common.global_lock) {
@@ -473,26 +471,25 @@ retry:
         WARN_ON(in_interrupt());
         down(&ec->burst.sem);
 
-        if(acpi_ec_enter_burst_mode(ec))
+        acpi_ec_enter_burst_mode(ec);
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (status) {
+                printk("read EC, IB not empty\n");
                 goto end;
-
+        }
         acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (status) {
-                goto end;
+                printk("read EC, IB not empty\n");
         }
 
         acpi_hw_low_level_write(8, address, &ec->common.data_addr);
         status= acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
         if (status){
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
+                printk("read EC, OB not full\n");
                 goto end;
         }
-
         acpi_hw_low_level_read(8, data, &ec->common.data_addr);
-        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
                 *data, address));
         
@@ -503,15 +500,6 @@ end:
         if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->burst.leaving_burst) == 2){
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                while(atomic_read(&ec->burst.pending_gpe)){
-                        msleep(1);      
-                }
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                goto retry;
-        }
-
         return_VALUE(status);
 }
 
@@ -524,13 +512,12 @@ acpi_ec_burst_write (
 {
         int                     status = 0;
         u32                     glk;
-        u32                     tmp;
 
         ACPI_FUNCTION_TRACE("acpi_ec_write");
 
         if (!ec)
                 return_VALUE(-EINVAL);
-retry:
+
         if (ec->common.global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status))
@@ -540,61 +527,35 @@ retry:
         WARN_ON(in_interrupt());
         down(&ec->burst.sem);
 
-        if(acpi_ec_enter_burst_mode(ec))
-                goto end;
+        acpi_ec_enter_burst_mode(ec);
 
-        status = acpi_ec_read_status(ec);
-        if (status != -EINVAL &&
-                !(status & ACPI_EC_FLAG_BURST)){
-                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->common.command_addr);
-                status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-                if (status)
-                        goto end;
-                acpi_hw_low_level_read(8, &tmp, &ec->common.data_addr);
-                if(tmp != 0x90 ) /* Burst ACK byte*/
-                        goto end;
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if ( status) {
+                printk("write EC, IB not empty\n");
         }
-        /*Now we are in burst mode*/
-
         acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-        if (status){
-                goto end;
+        if (status) {
+                printk ("write EC, IB not empty\n");
         }
 
         acpi_hw_low_level_write(8, address, &ec->common.data_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
         if (status){
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                goto end;
+                printk("write EC, IB not empty\n");
         }
 
         acpi_hw_low_level_write(8, data, &ec->common.data_addr);
-        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-        if (status)
-                goto end;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Wrote [%02x] to address [%02x]\n",
                 data, address));
 
-end:
         acpi_ec_leave_burst_mode(ec);
         up(&ec->burst.sem);
 
         if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->burst.leaving_burst) == 2){
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                while(atomic_read(&ec->burst.pending_gpe)){
-                        msleep(1);      
-                }
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                goto retry;
-        }
-
         return_VALUE(status);
 }
 
@@ -719,8 +680,12 @@ acpi_ec_burst_query (
         }
 
         down(&ec->burst.sem);
-        if(acpi_ec_enter_burst_mode(ec))
+
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (status) {
+                printk("query EC, IB not empty\n");
                 goto end;
+        }
         /*
          * Query the EC to find out which _Qxx method we need to evaluate.
          * Note that successful completion of the query causes the ACPI_EC_SCI
@@ -729,27 +694,20 @@ acpi_ec_burst_query (
         acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
         if (status){
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
+                printk("query EC, OB not full\n");
                 goto end;
         }
 
         acpi_hw_low_level_read(8, data, &ec->common.data_addr);
-        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (!*data)
                 status = -ENODATA;
 
 end:
-        acpi_ec_leave_burst_mode(ec);
         up(&ec->burst.sem);
 
         if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->burst.leaving_burst) == 2){
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
-                status = -ENODATA;
-        }
         return_VALUE(status);
 }
 
@@ -885,31 +843,21 @@ acpi_ec_gpe_burst_handler (
         if (!ec)
                 return ACPI_INTERRUPT_NOT_HANDLED;
 
-        acpi_disable_gpe(NULL, ec->common.gpe_bit, ACPI_ISR);
-
+        acpi_clear_gpe(NULL, ec->common.gpe_bit, ACPI_ISR);
         value = acpi_ec_read_status(ec);
 
-        if((value & ACPI_EC_FLAG_IBF) &&
-                !(value & ACPI_EC_FLAG_BURST) &&
-                        (atomic_read(&ec->burst.leaving_burst) == 0)) { 
-        /*
-         * the embedded controller disables 
-         * burst mode for any reason other 
-         * than the burst disable command
-         * to process critical event.
-         */
-                atomic_set(&ec->burst.leaving_burst , 2); /* block current pending transaction
-                                        and retry */
+        switch ( ec->burst.expect_event) {
+        case ACPI_EC_EVENT_OBF:
+                if (!(value & ACPI_EC_FLAG_OBF))
+                        break;
+        case ACPI_EC_EVENT_IBE:
+                if ((value & ACPI_EC_FLAG_IBF))
+                        break;
+                ec->burst.expect_event = 0;
                 wake_up(&ec->burst.wait);
-        }else {
-                if ((ec->burst.expect_event == ACPI_EC_EVENT_OBF &&
-                                (value & ACPI_EC_FLAG_OBF)) ||
-                                (ec->burst.expect_event == ACPI_EC_EVENT_IBE &&
-                                !(value & ACPI_EC_FLAG_IBF))) {
-                        ec->burst.expect_event = 0;
-                        wake_up(&ec->burst.wait);
-                        return ACPI_INTERRUPT_HANDLED;
-                }
+                return ACPI_INTERRUPT_HANDLED;
+        default:
+                break;
         }
 
         if (value & ACPI_EC_FLAG_SCI){
@@ -1242,6 +1190,7 @@ acpi_ec_burst_add (
         if (result)
                 goto end;
 
+        printk("burst-mode-ec-10-Aug\n");
         printk(KERN_INFO PREFIX "%s [%s] (gpe %d)\n",
                 acpi_device_name(device), acpi_device_bid(device),
                 (u32) ec->common.gpe_bit);