From f9004dbfff8a3fbbd7e2a88c8a4327c7f2f8e5b2 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 31 Jan 2024 01:04:47 +0000
Subject: [PATCH] add driver 5G
---
kernel/include/linux/mlx5/doorbell.h | 39 +++++++++------------------------------
1 files changed, 9 insertions(+), 30 deletions(-)
diff --git a/kernel/include/linux/mlx5/doorbell.h b/kernel/include/linux/mlx5/doorbell.h
index 0787de2..5c26770 100644
--- a/kernel/include/linux/mlx5/doorbell.h
+++ b/kernel/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 */
--
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