rocksdb: Implement timer for armv6+

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-dbs/rocksdb/files/arm.patch

@@ -0,0 +1,26 @@
+implement timer for arm >= v6
+
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+--- a/utilities/transactions/lock/range/range_tree/lib/portability/toku_time.h
++++ b/utilities/transactions/lock/range/range_tree/lib/portability/toku_time.h
+@@ -161,6 +161,20 @@ static inline tokutime_t toku_time_now(v
+   struct timeval tv;
+   gettimeofday(&tv, nullptr);
+   return (uint64_t)tv.tv_sec * 1000000 + tv.tv_usec;
++#elif (__ARM_ARCH >= 6)
++  uint32_t pmccntr;
++  uint32_t pmuseren;
++  uint32_t pmcntenset;
++  // Read the user mode perf monitor counter access permissions.
++  asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r"(pmuseren));
++  if (pmuseren & 1) {  // Allows reading perfmon counters for user mode code.
++    asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(pmcntenset));
++    if (pmcntenset & 0x80000000ul) {  // Is it counting?
++      asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"(pmccntr));
++      // The counter is set up to count every 64th cycle
++      return (uint64_t)pmccntr * 64;  // Should optimize to << 6
++    }
++  }
+ #else
+ #error No timer implementation for this platform
+ #endif

meta-oe/recipes-dbs/rocksdb/rocksdb_6.20.3.bb

@@ -17,6 +17,7 @@ SRC_URI = "git://github.com/facebook/${BPN}.git;branch=${SRCBRANCH} \
            file://0001-range_tree-Implement-toku_time_now-for-rv32-rv64-in-.patch \
            file://ppc64.patch \
            file://mips.patch \
+           file://arm.patch \
           "
 
 S = "${WORKDIR}/git"