Re: [REGRESSION][BISECTED] stmmac: suspend hangs since 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU interrupts")

Thank you for you explanations!

> The interrupt is being enabled in the init_chan call in
> stmmac_dma_ops. Ideally, it should be disabled in a mirror function,
> which currently does not exist. So maybe deinit_chan() needs
> adding. But where to call it from? init_chan() is called from
> stmmac_init_dma_engine(), from stmmac_hw_setup(). stmmac_resume() does
> call this. So we need something in stmmac_suspend(). Maybe in
> stmmac_stop_all_dma()?
> 
> stmmac is messy, there are often not mirror functions. If there is a
> stmmac_init_dma_engine() there should be
> stmmac_deinit_dma_engine(). If there is stmmac_hw_setup() there should
> be stmmac_hw_tairdown(). But none of these seem to exist. 
> 
> Anyway, do you want to try to implement deinit_chan() and call it from
> stmmac_stop_all_dma()?
Yes I'd really like to implement a solution here.
This is my try, but I still have some questions:
- is it ok to disable all interrupts on deinit_chan()?
- maybe the interrupt could also just be disabled in stop_rx?

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 829a23bdad01..65c243fb829f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -125,6 +125,17 @@ 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)
 {
@@ -577,6 +588,7 @@ 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..8504ecc3dbeb 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2560,13 +2560,16 @@ 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 max_chan = max(rx_channels_count, tx_channels_count);
 	u8 chan;
 
-	for (chan = 0; chan < rx_channels_count; chan++)
-		stmmac_stop_rx_dma(priv, chan);
-
-	for (chan = 0; chan < tx_channels_count; chan++)
-		stmmac_stop_tx_dma(priv, chan);
+	for (chan = 0; chan < max_chan; chan++) {
+		if (chan < rx_channels_count)
+			stmmac_stop_rx_dma(priv, chan);
+		if (chan < tx_channels_count)
+			stmmac_stop_tx_dma(priv, chan);
+		stmmac_deinit_chan(priv, priv->ioaddr, chan);
+	}
 }
 
 /**


tresonic