[PATCH net v5 5/5] net: macb: avoid dealing with endianness in macb_set_hwaddr()

Théo Lebrun
2025-09-10T16:16:55Z

bp->dev->dev_addr is of type `unsigned char *`. Casting it to a u32
pointer and dereferencing implies dealing manually with endianness,
which is error-prone.

Replace by calls to get_unaligned_le32|le16() helpers.

This was found using sparse:
⟩ make C=2 drivers/net/ethernet/cadence/macb_main.o
warning: incorrect type in assignment (different base types)
expected unsigned int [usertype] bottom
got restricted __le32 [usertype]
warning: incorrect type in assignment (different base types)
expected unsigned short [usertype] top
got restricted __le16 [usertype]
...

Reviewed-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
drivers/net/ethernet/cadence/macb_main.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index fc082a7a5a313be3d58a008533c3815cb1b1639a..c16d60048185b4cb473ddfcf4633fa2f6dea20cc 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -271,12 +271,10 @@ static bool hw_is_gem(void __iomem *addr, bool native_io)

static void macb_set_hwaddr(struct macb *bp)
{
- u32 bottom;
- u16 top;
+ u32 bottom = get_unaligned_le32(bp->dev->dev_addr);
+ u16 top = get_unaligned_le16(bp->dev->dev_addr + 4);

- bottom = cpu_to_le32(*((u32 *)bp->dev->dev_addr));
macb_or_gem_writel(bp, SA1B, bottom);
- top = cpu_to_le16(*((u16 *)(bp->dev->dev_addr + 4)));
macb_or_gem_writel(bp, SA1T, top);

if (gem_has_ptp(bp)) {

--
2.51.0