Re: [PATCH net v2] net: stmmac: dwmac4: mask interrupts when stopping DMA in suspend

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi Luis,

On 7/20/26 13:15, 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>

I wasn't able to reproduce the original issue on dwmac4, however
I could test that suspend/resume as well as WoL still works on a
dwmac4 device with this patch applied.

Thanks for the patch !

Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime

> ---
>  .../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);
>  }
>  
>  /**