From: Christoffer Dall <[email protected]> Add simple busy-wait spinlock implementation for ARM.
Signed-off-by: Christoffer Dall <[email protected]> Signed-off-by: Andrew Jones <[email protected]> --- config/config-arm.mak | 3 ++- lib/arm/asm/spinlock.h | 9 ++------- lib/arm/spinlock.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 32 insertions(+), 8 deletions(-) create mode 100644 lib/arm/spinlock.c diff --git a/config/config-arm.mak b/config/config-arm.mak index 3225018faf933..fb160b6c65e2a 100644 --- a/config/config-arm.mak +++ b/config/config-arm.mak @@ -36,7 +36,8 @@ cflatobjs += \ lib/virtio.o \ lib/chr-testdev.o \ lib/arm/io.o \ - lib/arm/setup.o + lib/arm/setup.o \ + lib/arm/spinlock.o libeabi = lib/arm/libeabi.a eabiobjs = lib/arm/eabi_compat.o diff --git a/lib/arm/asm/spinlock.h b/lib/arm/asm/spinlock.h index 04f5a1a5538e2..2118a4b3751e0 100644 --- a/lib/arm/asm/spinlock.h +++ b/lib/arm/asm/spinlock.h @@ -5,12 +5,7 @@ struct spinlock { int v; }; -//TODO -static inline void spin_lock(struct spinlock *lock __unused) -{ -} -static inline void spin_unlock(struct spinlock *lock __unused) -{ -} +extern void spin_lock(struct spinlock *lock); +extern void spin_unlock(struct spinlock *lock); #endif /* _ASMARM_SPINLOCK_H_ */ diff --git a/lib/arm/spinlock.c b/lib/arm/spinlock.c new file mode 100644 index 0000000000000..d8a6d4c3383d6 --- /dev/null +++ b/lib/arm/spinlock.c @@ -0,0 +1,28 @@ +#include "libcflat.h" +#include "asm/spinlock.h" +#include "asm/barrier.h" + +void spin_lock(struct spinlock *lock) +{ + u32 val, fail; + + dmb(); + do { + asm volatile( + "1: ldrex %0, [%2]\n" + " teq %0, #0\n" + " bne 1b\n" + " mov %0, #1\n" + " strex %1, %0, [%2]\n" + : "=&r" (val), "=&r" (fail) + : "r" (&lock->v) + : "cc" ); + } while (fail); + dmb(); +} + +void spin_unlock(struct spinlock *lock) +{ + lock->v = 0; + dmb(); +} -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
