Since commit 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU
interrupts"), suspending causes an interrupt storm from the RPS
interrupt.
Fix this by adding a deinit_chan() op to stmmac_dma_ops, which
masks all default dma channel interrupts. This is called from
stmmac_stop_all_dma(), so interrupts don't trigger while suspending.

Fixes: 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU interrupts")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Suggested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Luis Lang <luis.la@mail.de>
---
 .../net/ethernet/stmicro/stmmac/dwmac4_dma.c  | 24 +++++++++++++++++++
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  4 ++++
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |  4 ++++
 3 files changed, 32 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 829a23bdad01..23ffe1adcd0d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -106,6 +106,17 @@ static void dwmac4_dma_init_channel(struct stmmac_priv *priv,
 	       ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
 }
 
+static void dwmac4_dma_deinit_channel(struct stmmac_priv *priv,
+				      void __iomem *ioaddr, u32 chan)
+{
+	const struct dwmac4_addrs *dwmac4_addrs = priv->plat->dwmac4_addrs;
+	u32 value;
+
+	value = readl(ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
+	value &= ~DMA_CHAN_INTR_DEFAULT_MASK;
+	writel(value, ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
+}
+
 static void dwmac410_dma_init_channel(struct stmmac_priv *priv,
 				      void __iomem *ioaddr,
 				      struct stmmac_dma_cfg *dma_cfg, u32 chan)
@@ -125,6 +136,17 @@ static void dwmac410_dma_init_channel(struct stmmac_priv *priv,
 	       ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
 }
 
+static void dwmac410_dma_deinit_channel(struct stmmac_priv *priv,
+					void __iomem *ioaddr, u32 chan)
+{
+	const struct dwmac4_addrs *dwmac4_addrs = priv->plat->dwmac4_addrs;
+	u32 value;
+
+	value = readl(ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
+	value &= ~DMA_CHAN_INTR_DEFAULT_MASK_4_10;
+	writel(value, ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
+}
+
 static void dwmac4_dma_init(void __iomem *ioaddr,
 			    struct stmmac_dma_cfg *dma_cfg)
 {
@@ -548,6 +570,7 @@ const struct stmmac_dma_ops dwmac4_dma_ops = {
 	.reset = dwmac4_dma_reset,
 	.init = dwmac4_dma_init,
 	.init_chan = dwmac4_dma_init_channel,
+	.deinit_chan = dwmac4_dma_deinit_channel,
 	.init_rx_chan = dwmac4_dma_init_rx_chan,
 	.init_tx_chan = dwmac4_dma_init_tx_chan,
 	.axi = dwmac4_dma_axi,
@@ -577,6 +600,7 @@ const struct stmmac_dma_ops dwmac410_dma_ops = {
 	.reset = dwmac4_dma_reset,
 	.init = dwmac4_dma_init,
 	.init_chan = dwmac410_dma_init_channel,
+	.deinit_chan = dwmac410_dma_deinit_channel,
 	.init_rx_chan = dwmac4_dma_init_rx_chan,
 	.init_tx_chan = dwmac4_dma_init_tx_chan,
 	.axi = dwmac4_dma_axi,
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index e6317b94fff7..04dafec021b4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -170,6 +170,8 @@ struct stmmac_dma_ops {
 	void (*init)(void __iomem *ioaddr, struct stmmac_dma_cfg *dma_cfg);
 	void (*init_chan)(struct stmmac_priv *priv, void __iomem *ioaddr,
 			  struct stmmac_dma_cfg *dma_cfg, u32 chan);
+	void (*deinit_chan)(struct stmmac_priv *priv, void __iomem *ioaddr,
+			    u32 chan);
 	void (*init_rx_chan)(struct stmmac_priv *priv, void __iomem *ioaddr,
 			     struct stmmac_dma_cfg *dma_cfg,
 			     dma_addr_t phy, u32 chan);
@@ -235,6 +237,8 @@ struct stmmac_dma_ops {
 	stmmac_do_void_callback(__priv, dma, init, __args)
 #define stmmac_init_chan(__priv, __args...) \
 	stmmac_do_void_callback(__priv, dma, init_chan, __priv, __args)
+#define stmmac_deinit_chan(__priv, __args...) \
+	stmmac_do_void_callback(__priv, dma, deinit_chan, __priv, __args)
 #define stmmac_init_rx_chan(__priv, __args...) \
 	stmmac_do_void_callback(__priv, dma, init_rx_chan, __priv, __args)
 #define stmmac_init_tx_chan(__priv, __args...) \
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2a0d7eff88d3..af29a50ddb89 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2560,6 +2560,7 @@ static void stmmac_stop_all_dma(struct stmmac_priv *priv)
 {
 	u8 rx_channels_count = priv->plat->rx_queues_to_use;
 	u8 tx_channels_count = priv->plat->tx_queues_to_use;
+	u8 dma_csr_ch = max(rx_channels_count, tx_channels_count);
 	u8 chan;
 
 	for (chan = 0; chan < rx_channels_count; chan++)
@@ -2567,6 +2568,9 @@ static void stmmac_stop_all_dma(struct stmmac_priv *priv)
 
 	for (chan = 0; chan < tx_channels_count; chan++)
 		stmmac_stop_tx_dma(priv, chan);
+
+	for (chan = 0; chan < dma_csr_ch; chan++)
+		stmmac_deinit_chan(priv, priv->ioaddr, chan);
 }
 
 /**
-- 
2.55.0

Hi Luis,

On 7/18/26 17:27, Luis Lang wrote:
> Since commit 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU
> interrupts"), suspending causes an interrupt storm from the RPS
> interrupt.
> Fix this by adding a deinit_chan() op to stmmac_dma_ops, which
> masks all default dma channel interrupts. This is called from
> stmmac_stop_all_dma(), so interrupts don't trigger while suspending.
> 
> Fixes: 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU interrupts")
> Suggested-by: Andrew Lunn <andrew@lunn.ch>
> Suggested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> Signed-off-by: Luis Lang <luis.la@mail.de>

This is almost perfect for a new submission, only 2 things to improve :

 - you're missing the tree name in the patch subject. As this is a fix, it should be :

   [PATCH net] net: stmmac: dwmac4: mask interrupts before stopping DMA in suspend

   you can find instructions for this in the doc Andrew linked :

   https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

 - When submitting a patch, do so in a dedicated thread, and not in reply to
   other threads.

You should send a V2 addressing the tree name in the patch subject.

Sashiko noted something on the patch :

  https://sashiko.dev/#/patchset/20260718152802.83553-1-luis.la%40mail.de

It looks to me that sashiko is just wrong there though, I can't make sense
of what it is saying.

Maxime

Hi Maxime,
> This is almost perfect for a new submission, only 2 things to improve :
> 
>  - you're missing the tree name in the patch subject. As this is a fix, it should be :
> 
>    [PATCH net] net: stmmac: dwmac4: mask interrupts before stopping DMA in suspend
> 
>    you can find instructions for this in the doc Andrew linked :
> 
>    https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html
> 
>  - When submitting a patch, do so in a dedicated thread, and not in reply to
>    other threads.
> 
> You should send a V2 addressing the tree name in the patch subject.

Thanks for the feedback, I addressed these changes and sent a v2 patch.

> Sashiko noted something on the patch :
> 
>   https://sashiko.dev/#/patchset/20260718152802.83553-1-luis.la%40mail.de
> 
> It looks to me that sashiko is just wrong there though, I can't make sense
> of what it is saying.

This seems to be because strictly speaking the title of the commit was wrong,
the interrupts don't get deactivated before stopping dma.
I changed it, but only read after that it is discouraged to change the Subject, sorry...
I hope the patch now meets the requirements,
Luis