diff options
Diffstat (limited to 'include/linux/mlx5/doorbell.h')
| -rw-r--r-- | include/linux/mlx5/doorbell.h | 39 |
1 files changed, 9 insertions, 30 deletions
diff --git a/include/linux/mlx5/doorbell.h b/include/linux/mlx5/doorbell.h index 0787de28f2fc..5c267707e1df 100644 --- a/include/linux/mlx5/doorbell.h +++ b/include/linux/mlx5/doorbell.h @@ -36,46 +36,25 @@ #define MLX5_BF_OFFSET 0x800 #define MLX5_CQ_DOORBELL 0x20 -#if BITS_PER_LONG == 64 /* Assume that we can just write a 64-bit doorbell atomically. s390 * actually doesn't have writeq() but S/390 systems don't even have * PCI so we won't worry about it. + * + * Note that the write is not atomic on 32-bit systems! In contrast to 64-bit + * ones, it requires proper locking. mlx5_write64 doesn't do any locking, so use + * it at your own discretion, protected by some kind of lock on 32 bits. + * + * TODO: use write{q,l}_relaxed() */ -#define MLX5_DECLARE_DOORBELL_LOCK(name) -#define MLX5_INIT_DOORBELL_LOCK(ptr) do { } while (0) -#define MLX5_GET_DOORBELL_LOCK(ptr) (NULL) - -static inline void mlx5_write64(__be32 val[2], void __iomem *dest, - spinlock_t *doorbell_lock) +static inline void mlx5_write64(__be32 val[2], void __iomem *dest) { +#if BITS_PER_LONG == 64 __raw_writeq(*(u64 *)val, dest); -} - #else - -/* Just fall back to a spinlock to protect the doorbell if - * BITS_PER_LONG is 32 -- there's no portable way to do atomic 64-bit - * MMIO writes. - */ - -#define MLX5_DECLARE_DOORBELL_LOCK(name) spinlock_t name; -#define MLX5_INIT_DOORBELL_LOCK(ptr) spin_lock_init(ptr) -#define MLX5_GET_DOORBELL_LOCK(ptr) (ptr) - -static inline void mlx5_write64(__be32 val[2], void __iomem *dest, - spinlock_t *doorbell_lock) -{ - unsigned long flags; - - if (doorbell_lock) - spin_lock_irqsave(doorbell_lock, flags); __raw_writel((__force u32) val[0], dest); __raw_writel((__force u32) val[1], dest + 4); - if (doorbell_lock) - spin_unlock_irqrestore(doorbell_lock, flags); -} - #endif +} #endif /* MLX5_DOORBELL_H */ |