arm: socfpga: mailbox: Refactor mailbox timeout event handling

Add miliseconds delay when waiting for mailbox event to happen
before timeout. This will ensure the timeout duration is predictive.

Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>

diff --git a/arch/arm/mach-socfpga/mailbox_s10.c b/arch/arm/mach-socfpga/mailbox_s10.c
index f30e7f8..729d9b0 100644 (file)
--- a/arch/arm/mach-socfpga/mailbox_s10.c
+++ b/arch/arm/mach-socfpga/mailbox_s10.c
@@ -29,13 +29,14 @@ DECLARE_GLOBAL_DATA_PTR;
 static __always_inline int mbox_polling_resp(u32 rout)
 {
        u32 rin;
-       unsigned long i = ~0;
+       unsigned long i = 2000;
 
        while (i) {
                rin = MBOX_READL(MBOX_RIN);
                if (rout != rin)
                        return 0;
 
+               udelay(1000);
                i--;
        }
 
@@ -176,11 +177,15 @@ static __always_inline int mbox_send_cmd_common(u8 id, u32 cmd, u8 is_indirect,
        MBOX_WRITEL(1, MBOX_DOORBELL_TO_SDM);
 
        while (1) {
-               ret = ~0;
+               ret = 1000;
 
                /* Wait for doorbell from SDM */
-               while (!MBOX_READL(MBOX_DOORBELL_FROM_SDM) && ret--)
-                       ;
+               do {
+                       if (MBOX_READL(MBOX_DOORBELL_FROM_SDM))
+                               break;
+                       udelay(1000);
+               } while (--ret);
+
                if (!ret)
                        return -ETIMEDOUT;