diff mbox

[edk2,1/3] ArmPlatformPkg: Fix PL011 FIFO size test

Message ID 20160921203315.11204-2-evan.lloyd@arm.com
State Accepted
Commit 719a347c5df53a1dca6f80e06a285424228436e1
Headers show

Commit Message

Evan Lloyd Sept. 21, 2016, 8:33 p.m. UTC
From: Evan Lloyd <evan.lloyd@arm.com>


This change updates PL011UartInitializePort to compare ReceiveFifoDepth
with the correct hardware FIFO size instead of the constant 32 used
previously.
This corrects a minor bug where a request for a fifo size > 15 and < 32
would not have been honoured on a system with a 16 byte FIFO.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>

Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>

---
 ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

-- 
Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")

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Comments

Leif Lindholm Oct. 10, 2016, 6:58 p.m. UTC | #1
Apologies for delay, now catching up post plugfest and Linaro Connect.

On Wed, Sep 21, 2016 at 09:33:13PM +0100, evan.lloyd@arm.com wrote:
> From: Evan Lloyd <evan.lloyd@arm.com>

> 

> This change updates PL011UartInitializePort to compare ReceiveFifoDepth

> with the correct hardware FIFO size instead of the constant 32 used

> previously.

> This corrects a minor bug where a request for a fifo size > 15 and < 32

> would not have been honoured on a system with a 16 byte FIFO.


Whoops.
Well, even without the bug, the below is an improvement in readability.

> Contributed-under: TianoCore Contribution Agreement 1.0

> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>

> Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>

> ---

>  ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c | 11 ++++++-----

>  1 file changed, 6 insertions(+), 5 deletions(-)

> 

> diff --git a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c

> index 3748972acbfc80f1077b9b928756a72cc77b5c75..b3ea138bf60b93a1000dd29aedaad206f2d15f2b 100644

> --- a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c

> +++ b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c

> @@ -79,17 +79,18 @@ PL011UartInitializePort (

>    UINT32      Divisor;

>    UINT32      Integer;

>    UINT32      Fractional;

> +  UINT32      HardwareFifoDepth;

>  

> +  HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) \

> +                       > PL011_VER_R1P4) \

> +                      ? 32 : 16 ;


I may drop that space before ';' before committing, but apart from
that:
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>


>    // The PL011 supports a buffer of 1, 16 or 32 chars. Therefore we can accept

>    // 1 char buffer as the minimum FIFO size. Because everything can be rounded

>    // down, there is no maximum FIFO size.

> -  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= 32)) {

> +  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= HardwareFifoDepth)) {

>      // Enable FIFO

>      LineControl = PL011_UARTLCR_H_FEN;

> -    if (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) > PL011_VER_R1P4)

> -      *ReceiveFifoDepth = 32;

> -    else

> -      *ReceiveFifoDepth = 16;

> +    *ReceiveFifoDepth = HardwareFifoDepth;

>    } else {

>      // Disable FIFO

>      LineControl = 0;

> -- 

> Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")

> 

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diff mbox

Patch

diff --git a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
index 3748972acbfc80f1077b9b928756a72cc77b5c75..b3ea138bf60b93a1000dd29aedaad206f2d15f2b 100644
--- a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
+++ b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
@@ -79,17 +79,18 @@  PL011UartInitializePort (
   UINT32      Divisor;
   UINT32      Integer;
   UINT32      Fractional;
+  UINT32      HardwareFifoDepth;
 
+  HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) \
+                       > PL011_VER_R1P4) \
+                      ? 32 : 16 ;
   // The PL011 supports a buffer of 1, 16 or 32 chars. Therefore we can accept
   // 1 char buffer as the minimum FIFO size. Because everything can be rounded
   // down, there is no maximum FIFO size.
-  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= 32)) {
+  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= HardwareFifoDepth)) {
     // Enable FIFO
     LineControl = PL011_UARTLCR_H_FEN;
-    if (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) > PL011_VER_R1P4)
-      *ReceiveFifoDepth = 32;
-    else
-      *ReceiveFifoDepth = 16;
+    *ReceiveFifoDepth = HardwareFifoDepth;
   } else {
     // Disable FIFO
     LineControl = 0;