[coreboot-gerrit] Change in coreboot[master]: drivers/intel/gma/edid: Use byte swap function

[Paul Menzel (Code Review)]

Paul Menzel has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/38647 )

Change subject: drivers/intel/gma/edid: Use byte swap function
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drivers/intel/gma/edid: Use byte swap function

Instead of open coding the byte swapping (endianess), use the built-in.

The compiler can use the instruction `bswap` now. As EDID data is not
big, the difference in execution time won’t be measurable.

With gcc (Debian 9.2.1-25) 9.2.1 20200123:

.LBE128:
     .LBE127:
    -       .loc 1 94 3 is_stmt 1 discriminator 3 view .LVU157
    -       addl    $4, %ebp
    -       .loc 1 94 15 is_stmt 0 discriminator 3 view .LVU158
    -       movb    %al, -4(%ebp)
    -       .loc 1 95 3 is_stmt 1 discriminator 3 view .LVU159
    -       .loc 1 96 28 is_stmt 0 discriminator 3 view .LVU160
    -       movl    %eax, %edx
    -       .loc 1 95 19 discriminator 3 view .LVU161
    -       movb    %ah, -3(%ebp)
    -       .loc 1 96 3 is_stmt 1 discriminator 3 view .LVU162
    -       .loc 1 96 28 is_stmt 0 discriminator 3 view .LVU163
    -       shrl    $16, %edx
    -       .loc 1 96 19 discriminator 3 view .LVU164
    -       movb    %dl, -2(%ebp)
    -       .loc 1 97 3 is_stmt 1 discriminator 3 view .LVU165
    -       .loc 1 97 35 is_stmt 0 discriminator 3 view .LVU166
    -       shrl    $24, %eax
    +       .loc 1 96 3 is_stmt 1 discriminator 3 view .LVU159
    +       .loc 1 96 15 is_stmt 0 discriminator 3 view .LVU160
    +       movl    76(%esp), %edx
    +       .loc 1 96 17 discriminator 3 view .LVU161
    +       bswap   %eax

Change-Id: I818318361a83b2b3f0c6d8637dd3b6917590c836
Signed-off-by: Paul Menzel 
---
M src/drivers/intel/gma/edid.c
1 file changed, 3 insertions(+), 4 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/47/38647/1

diff --git a/src/drivers/intel/gma/edid.c b/src/drivers/intel/gma/edid.c
index 6885f98..5f1cfe8 100644
--- a/src/drivers/intel/gma/edid.c
+++ b/src/drivers/intel/gma/edid.c
@@ -15,6 +15,7 @@
 #include <device/mmio.h>
 #include <console/console.h>
 #include <delay.h>
+#include <swab.h>
 #include <timer.h>

#include "i915_reg.h"
@@ -91,10 +92,8 @@
    	u32 reg32;
    	wait_rdy(mmio);
    	reg32 = read32(GMBUS3_ADDR);
-		edid[4 * i] = reg32 & 0xff;
-		edid[4 * i + 1] = (reg32 >> 8) & 0xff;
-		edid[4 * i + 2] = (reg32 >> 16) & 0xff;
-		edid[4 * i + 3] = (reg32 >> 24) & 0xff;
+		/* Writes 4 * i to (4 * i) + 3 */
+		edid[4 * i] = swab32(reg32);
    }
    wait_rdy(mmio);
    write32(GMBUS1_ADDR, GMBUS_SW_RDY