[platforms: PATCH v3 03/10] Marvell/Drivers: MvI2cDxe: Reduce bus occupation time

[Marcin Wojtas <mw@semihalf.com>]

From: David Greeson <dgreeson@cisco.com>

During each transaction start, clearing the I2C_CONTROL_FLAG
was surrounded by 3 uncoditional stalls. This was not necessary,
so replace them with one busy-wait loop, whose polling
count could be also safely reduced.

Above improvements result in faster transfer initialization
and allow to reduce the I2C bus occupation.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: David Greeson <dgreeson@cisco.com>
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c | 6 +-----
 Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.h | 2 +-
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
index a62383f..d6f590d 100755
--- a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
+++ b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
@@ -243,9 +243,8 @@ MvI2cClearIflg (
  IN I2C_MASTER_CONTEXT *I2cMasterContext
  )
 {
-  gBS->Stall(I2C_OPERATION_TIMEOUT);
+  MvI2cPollCtrl (I2cMasterContext, I2C_OPERATION_TIMEOUT, I2C_CONTROL_IFLG);
   MvI2cControlClear(I2cMasterContext, I2C_CONTROL_IFLG);
-  gBS->Stall(I2C_OPERATION_TIMEOUT);
 }
 
 /* Timeout is given in us */
@@ -295,9 +294,6 @@ MvI2cLockedStart (
     MvI2cClearIflg(I2cMasterContext);
   }
 
-  /* Without this delay we Timeout checking IFLG if the Timeout is 0 */
-  gBS->Stall(I2C_OPERATION_TIMEOUT);
-
   if (MvI2cPollCtrl(I2cMasterContext, Timeout, I2C_CONTROL_IFLG)) {
     DEBUG((DEBUG_ERROR, "MvI2cDxe: Timeout sending %sSTART condition\n",
         Mask == I2C_STATUS_START ? "" : "repeated "));
diff --git a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.h b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.h
index 028fd54..3c9beaf 100644
--- a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.h
+++ b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.h
@@ -68,7 +68,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #define I2C_SOFT_RESET    0x1c
 #define I2C_TRANSFER_TIMEOUT 10000
-#define I2C_OPERATION_TIMEOUT 1000
+#define I2C_OPERATION_TIMEOUT 100
 
 #define I2C_UNKNOWN        0x0
 #define I2C_SLOW           0x1
-- 
2.7.4