[PATCH] net: stmmac: mmc_core: Assign, don't add interrupt registers

From: Jesper Nilsson <jesper.nilsson@axis.com>
To: Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: <netdev@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <kernel@axis.com>,
	Jesper Nilsson <jesper.nilsson@axis.com>
Subject: [PATCH] net: stmmac: mmc_core: Assign, don't add interrupt registers
Date: Fri, 16 Feb 2024 16:24:21 +0100	[thread overview]
Message-ID: <20240216-stmmac_stats-v1-1-7065fa4613f8@axis.com> (raw)

The MMC IPC interrupt status and interrupt mask registers are of
little use as Ethernet statistics, but incrementing counters
based on the current interrupt and interrupt mask registers
makes them worse than useless.

For example, if the interrupt mask is set to 0x08420842,
the current code will increment by that amount each iteration,
leading to the following sequence of nonsense:

mmc_rx_ipc_intr_mask: 969816526
mmc_rx_ipc_intr_mask: 1108361744

Change the increment to a straight assignment to make the
statistics at least nominally useful.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
---
 drivers/net/ethernet/stmicro/stmmac/mmc_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
index 6a7c1d325c46..6051a22b3cec 100644
--- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
@@ -280,8 +280,8 @@ static void dwmac_mmc_read(void __iomem *mmcaddr, struct stmmac_counters *mmc)
 	mmc->mmc_rx_vlan_frames_gb += readl(mmcaddr + MMC_RX_VLAN_FRAMES_GB);
 	mmc->mmc_rx_watchdog_error += readl(mmcaddr + MMC_RX_WATCHDOG_ERROR);
 	/* IPC */
-	mmc->mmc_rx_ipc_intr_mask += readl(mmcaddr + MMC_RX_IPC_INTR_MASK);
-	mmc->mmc_rx_ipc_intr += readl(mmcaddr + MMC_RX_IPC_INTR);
+	mmc->mmc_rx_ipc_intr_mask = readl(mmcaddr + MMC_RX_IPC_INTR_MASK);
+	mmc->mmc_rx_ipc_intr = readl(mmcaddr + MMC_RX_IPC_INTR);
 	/* IPv4 */
 	mmc->mmc_rx_ipv4_gd += readl(mmcaddr + MMC_RX_IPV4_GD);
 	mmc->mmc_rx_ipv4_hderr += readl(mmcaddr + MMC_RX_IPV4_HDERR);

---
base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a
change-id: 20240216-stmmac_stats-e3561d460d0e

Best regards,
-- 

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com

