xref: /OK3568_Linux_fs/yocto/meta-openembedded/meta-oe/recipes-dbs/rocksdb/files/arm.patch (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1implement timer for arm >= v6
2
3Signed-off-by: Khem Raj <raj.khem@gmail.com>
4--- a/utilities/transactions/lock/range/range_tree/lib/portability/toku_time.h
5+++ b/utilities/transactions/lock/range/range_tree/lib/portability/toku_time.h
6@@ -161,6 +161,20 @@ static inline tokutime_t toku_time_now(v
7   struct timeval tv;
8   gettimeofday(&tv, nullptr);
9   return (uint64_t)tv.tv_sec * 1000000 + tv.tv_usec;
10+#elif (__ARM_ARCH >= 6)
11+  uint32_t pmccntr;
12+  uint32_t pmuseren;
13+  uint32_t pmcntenset;
14+  // Read the user mode perf monitor counter access permissions.
15+  asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r"(pmuseren));
16+  if (pmuseren & 1) {  // Allows reading perfmon counters for user mode code.
17+    asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(pmcntenset));
18+    if (pmcntenset & 0x80000000ul) {  // Is it counting?
19+      asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"(pmccntr));
20+      // The counter is set up to count every 64th cycle
21+      return (uint64_t)pmccntr * 64;  // Should optimize to << 6
22+    }
23+  }
24 #else
25 #error No timer implementation for this platform
26 #endif
27