MLK-16101 MU: avoid read mu version register every scu call

Generally read mu registers will take about 225ns.
Overall scu_clk_enable function takes about 8000ns to 150000ns.
Although read version register just take 3% time,
it is not necessary to read version register every time.

Signed-off-by: Frank Li <Frank.Li@nxp.com>

diff --git a/drivers/soc/imx/mu/mx8_mu.c b/drivers/soc/imx/mu/mx8_mu.c
index 7409c2c..894c8fc 100644 (file)
--- a/drivers/soc/imx/mu/mx8_mu.c
+++ b/drivers/soc/imx/mu/mx8_mu.c
@@ -9,6 +9,7 @@
 #include <linux/io.h>
 #include <linux/mx8_mu.h>
 
+static int version;
 
 /*!
  * This function sets the Flag n of the MU.
@@ -21,7 +22,7 @@ int32_t MU_SetFn(void __iomem *base, uint32_t Fn)
        if (reg > 0)
                return -EINVAL;
 
-       offset = unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)
+       offset = unlikely(version == MU_VER_ID_V10)
                          ? MU_V10_ACR_OFFSET1 : MU_ACR_OFFSET1;
 
        reg = readl_relaxed(base + offset);
@@ -40,7 +41,7 @@ uint32_t MU_ReadStatus(void __iomem *base)
 {
        uint32_t reg, offset;
 
-       offset = unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)
+       offset = unlikely(version == MU_VER_ID_V10)
                          ? MU_V10_ASR_OFFSET1 : MU_ASR_OFFSET1;
 
        reg = readl_relaxed(base + offset);
@@ -55,7 +56,7 @@ void MU_EnableRxFullInt(void __iomem *base, uint32_t index)
 {
        uint32_t reg, offset;
 
-       offset = unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)
+       offset = unlikely(version == MU_VER_ID_V10)
                          ? MU_V10_ACR_OFFSET1 : MU_ACR_OFFSET1;
 
        reg = readl_relaxed(base + offset);
@@ -71,7 +72,7 @@ void MU_EnableGeneralInt(void __iomem *base, uint32_t index)
 {
        uint32_t reg, offset;
 
-       offset = unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)
+       offset = unlikely(version == MU_VER_ID_V10)
                          ? MU_V10_ACR_OFFSET1 : MU_ACR_OFFSET1;
 
        reg = readl_relaxed(base + offset);
@@ -87,7 +88,7 @@ void MU_SendMessage(void __iomem *base, uint32_t regIndex, uint32_t msg)
 {
        uint32_t mask = MU_SR_TE0_MASK1 >> regIndex;
 
-       if (unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)) {
+       if (unlikely(version == MU_VER_ID_V10)) {
                /* Wait TX register to be empty. */
                while (!(readl_relaxed(base + MU_V10_ASR_OFFSET1) & mask))
                        ;
@@ -109,7 +110,7 @@ void MU_ReceiveMsg(void __iomem *base, uint32_t regIndex, uint32_t *msg)
 {
        uint32_t mask = MU_SR_RF0_MASK1 >> regIndex;
 
-       if (unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)) {
+       if (unlikely(version == MU_VER_ID_V10)) {
                /* Wait RX register to be full. */
                while (!(readl_relaxed(base + MU_V10_ASR_OFFSET1) & mask))
                        ;
@@ -129,9 +130,10 @@ void MU_Init(void __iomem *base)
 {
        uint32_t reg, offset;
 
-       offset = unlikely((readl_relaxed(base) >> 16) == MU_VER_ID_V10)
-                         ? MU_V10_ACR_OFFSET1 : MU_ACR_OFFSET1;
+       version = readl_relaxed(base) >> 16;
 
+       offset = unlikely(version == MU_VER_ID_V10)
+                         ? MU_V10_ACR_OFFSET1 : MU_ACR_OFFSET1;
 
        reg = readl_relaxed(base + offset);
        /* Clear GIEn, RIEn, TIEn, GIRn and ABFn. */