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net: stmmac: dwmac4: fix RX FIFO fill statistics

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In dwmac4_debug(), the wrong shift is used with the RXFSTS mask:

 #define MTL_DEBUG_RXFSTS_MASK          GENMASK(5, 4)
 #define MTL_DEBUG_RXFSTS_SHIFT         4
 #define MTL_DEBUG_RRCSTS_SHIFT         1

                       u32 rxfsts = (value & MTL_DEBUG_RXFSTS_MASK)
                                    >> MTL_DEBUG_RRCSTS_SHIFT;

where rxfsts is tested against small integers 1 .. 3. This results in
the tests always failing, causing the "mtl_rx_fifo__fill_level_empty"
statistic counter to always be incremented no matter what the fill
level actually is.

Fix this by using FIELD_GET() and remove the unnecessary
MTL_DEBUG_RXFSTS_SHIFT definition as FIELD_GET() will shift according
to the least siginificant set bit in the supplied field mask.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vdtvi-00000002GtP-1Os1@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Russell King (Oracle) 2026-01-08 17:36:14 +00:00 committed by Jakub Kicinski
parent 1fd3b57371
commit 65b21a7d4d
2 changed files with 1 additions and 3 deletions
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1
drivers/net/ethernet/stmicro/stmmac/dwmac4.h
View File

@ -460,7 +460,6 @@ static inline u32 mtl_low_credx_base_addr(const struct dwmac4_addrs *addrs,
/* MAC debug: GMII or MII Transmit Protocol Engine Status */
#define MTL_DEBUG_RXFSTS_MASK GENMASK(5, 4)
#define MTL_DEBUG_RXFSTS_SHIFT 4
#define MTL_DEBUG_RXFSTS_EMPTY 0
#define MTL_DEBUG_RXFSTS_BT 1
#define MTL_DEBUG_RXFSTS_AT 2

3
drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
View File

@ -700,8 +700,7 @@ static void dwmac4_debug(struct stmmac_priv *priv, void __iomem *ioaddr,
value = readl(ioaddr + MTL_CHAN_RX_DEBUG(dwmac4_addrs, queue));
if (value & MTL_DEBUG_RXFSTS_MASK) {
u32 rxfsts = (value & MTL_DEBUG_RXFSTS_MASK)
>> MTL_DEBUG_RRCSTS_SHIFT;
u32 rxfsts = FIELD_GET(MTL_DEBUG_RXFSTS_MASK, value);
if (rxfsts == MTL_DEBUG_RXFSTS_FULL)
x->mtl_rx_fifo_fill_level_full++;