commit 466675c23daf37f6f9971b7321910e47c0c0b794
author Soren Brinkmann <soren.brinkmann@xilinx.com> Fri Sep 16 10:34:47 2016 -0700
committer Soren Brinkmann <soren.brinkmann@xilinx.com> Wed Nov 16 15:48:48 2016 -0800
tree 161ecd76092d0c90c4c80e9c508e2de3444ba504
parent 90d2956aeaa9f0838400eb40d6c48935ec4c988b

zynqmp: Read silicon ID register only once

The silicon ID does not change at runtime. Skip the IO access if the
ID has been read before.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>

plat/xilinx/zynqmp/aarch64/zynqmp_common.c

diff --git a/plat/xilinx/zynqmp/aarch64/zynqmp_common.c b/plat/xilinx/zynqmp/aarch64/zynqmp_common.c
index 60a1605..562cac8 100644
--- a/plat/xilinx/zynqmp/aarch64/zynqmp_common.c
+++ b/plat/xilinx/zynqmp/aarch64/zynqmp_common.c
@@ -49,11 +49,14 @@
 
 static unsigned int zynqmp_get_silicon_ver(void)
 {
-	unsigned int ver;
+	static unsigned int ver;
 
-	ver = mmio_read_32(ZYNQMP_CSU_BASEADDR + ZYNQMP_CSU_VERSION_OFFSET);
-	ver &= ZYNQMP_SILICON_VER_MASK;
-	ver >>= ZYNQMP_SILICON_VER_SHIFT;
+	if (!ver) {
+		ver = mmio_read_32(ZYNQMP_CSU_BASEADDR +
+				   ZYNQMP_CSU_VERSION_OFFSET);
+		ver &= ZYNQMP_SILICON_VER_MASK;
+		ver >>= ZYNQMP_SILICON_VER_SHIFT;
+	}
 
 	return ver;
 }