[PATCH 5.15 030/141] net: stmmac: fix FPE events losing

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jianheng Zhang <Jianheng.Zhang@synopsys.com>

[ Upstream commit 37e4b8df27bc68340f3fc80dbb27e3549c7f881c ]

The status bits of register MAC_FPE_CTRL_STS are clear on read. Using
32-bit read for MAC_FPE_CTRL_STS in dwmac5_fpe_configure() and
dwmac5_fpe_send_mpacket() clear the status bits. Then the stmmac interrupt
handler missing FPE event status and leads to FPE handshaking failure and
retries.
To avoid clear status bits of MAC_FPE_CTRL_STS in dwmac5_fpe_configure()
and dwmac5_fpe_send_mpacket(), add fpe_csr to stmmac_fpe_cfg structure to
cache the control bits of MAC_FPE_CTRL_STS and to avoid reading
MAC_FPE_CTRL_STS in those methods.

Fixes: 5a5586112b92 ("net: stmmac: support FPE link partner hand-shaking procedure")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jianheng Zhang <Jianheng.Zhang@synopsys.com>
Link: https://lore.kernel.org/r/CY5PR12MB637225A7CF529D5BE0FBE59CBF81A@CY5PR12MB6372.namprd12.prod.outlook.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac5.c  | 45 ++++++++-----------
 drivers/net/ethernet/stmicro/stmmac/dwmac5.h  |  4 +-
 .../ethernet/stmicro/stmmac/dwxgmac2_core.c   |  3 +-
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  4 +-
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |  8 +++-
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   |  1 +
 include/linux/stmmac.h                        |  1 +
 7 files changed, 36 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac5.c b/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
index e95d35f1e5a0c..8fd167501fa0e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
@@ -710,28 +710,22 @@ void dwmac5_est_irq_status(void __iomem *ioaddr, struct net_device *dev,
 	}
 }
 
-void dwmac5_fpe_configure(void __iomem *ioaddr, u32 num_txq, u32 num_rxq,
+void dwmac5_fpe_configure(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
+			  u32 num_txq, u32 num_rxq,
 			  bool enable)
 {
 	u32 value;
 
-	if (!enable) {
-		value = readl(ioaddr + MAC_FPE_CTRL_STS);
-
-		value &= ~EFPE;
-
-		writel(value, ioaddr + MAC_FPE_CTRL_STS);
-		return;
+	if (enable) {
+		cfg->fpe_csr = EFPE;
+		value = readl(ioaddr + GMAC_RXQ_CTRL1);
+		value &= ~GMAC_RXQCTRL_FPRQ;
+		value |= (num_rxq - 1) << GMAC_RXQCTRL_FPRQ_SHIFT;
+		writel(value, ioaddr + GMAC_RXQ_CTRL1);
+	} else {
+		cfg->fpe_csr = 0;
 	}
-
-	value = readl(ioaddr + GMAC_RXQ_CTRL1);
-	value &= ~GMAC_RXQCTRL_FPRQ;
-	value |= (num_rxq - 1) << GMAC_RXQCTRL_FPRQ_SHIFT;
-	writel(value, ioaddr + GMAC_RXQ_CTRL1);
-
-	value = readl(ioaddr + MAC_FPE_CTRL_STS);
-	value |= EFPE;
-	writel(value, ioaddr + MAC_FPE_CTRL_STS);
+	writel(cfg->fpe_csr, ioaddr + MAC_FPE_CTRL_STS);
 }
 
 int dwmac5_fpe_irq_status(void __iomem *ioaddr, struct net_device *dev)
@@ -741,6 +735,9 @@ int dwmac5_fpe_irq_status(void __iomem *ioaddr, struct net_device *dev)
 
 	status = FPE_EVENT_UNKNOWN;
 
+	/* Reads from the MAC_FPE_CTRL_STS register should only be performed
+	 * here, since the status flags of MAC_FPE_CTRL_STS are "clear on read"
+	 */
 	value = readl(ioaddr + MAC_FPE_CTRL_STS);
 
 	if (value & TRSP) {
@@ -766,19 +763,15 @@ int dwmac5_fpe_irq_status(void __iomem *ioaddr, struct net_device *dev)
 	return status;
 }
 
-void dwmac5_fpe_send_mpacket(void __iomem *ioaddr, enum stmmac_mpacket_type type)
+void dwmac5_fpe_send_mpacket(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
+			     enum stmmac_mpacket_type type)
 {
-	u32 value;
+	u32 value = cfg->fpe_csr;
 
-	value = readl(ioaddr + MAC_FPE_CTRL_STS);
-
-	if (type == MPACKET_VERIFY) {
-		value &= ~SRSP;
+	if (type == MPACKET_VERIFY)
 		value |= SVER;
-	} else {
-		value &= ~SVER;
+	else if (type == MPACKET_RESPONSE)
 		value |= SRSP;
-	}
 
 	writel(value, ioaddr + MAC_FPE_CTRL_STS);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac5.h b/drivers/net/ethernet/stmicro/stmmac/dwmac5.h
index 53c138d0ff480..34e620790eb37 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac5.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac5.h
@@ -153,9 +153,11 @@ int dwmac5_est_configure(void __iomem *ioaddr, struct stmmac_est *cfg,
 			 unsigned int ptp_rate);
 void dwmac5_est_irq_status(void __iomem *ioaddr, struct net_device *dev,
 			   struct stmmac_extra_stats *x, u32 txqcnt);
-void dwmac5_fpe_configure(void __iomem *ioaddr, u32 num_txq, u32 num_rxq,
+void dwmac5_fpe_configure(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
+			  u32 num_txq, u32 num_rxq,
 			  bool enable);
 void dwmac5_fpe_send_mpacket(void __iomem *ioaddr,
+			     struct stmmac_fpe_cfg *cfg,
 			     enum stmmac_mpacket_type type);
 int dwmac5_fpe_irq_status(void __iomem *ioaddr, struct net_device *dev);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index 54aa0fbd1bf63..3568bf3ccfbe7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -1440,7 +1440,8 @@ static int dwxgmac3_est_configure(void __iomem *ioaddr, struct stmmac_est *cfg,
 	return 0;
 }
 
-static void dwxgmac3_fpe_configure(void __iomem *ioaddr, u32 num_txq,
+static void dwxgmac3_fpe_configure(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
+				   u32 num_txq,
 				   u32 num_rxq, bool enable)
 {
 	u32 value;
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index fe2660d5694d7..cc229ccd5d81d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -395,9 +395,11 @@ struct stmmac_ops {
 			     unsigned int ptp_rate);
 	void (*est_irq_status)(void __iomem *ioaddr, struct net_device *dev,
 			       struct stmmac_extra_stats *x, u32 txqcnt);
-	void (*fpe_configure)(void __iomem *ioaddr, u32 num_txq, u32 num_rxq,
+	void (*fpe_configure)(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
+			      u32 num_txq, u32 num_rxq,
 			      bool enable);
 	void (*fpe_send_mpacket)(void __iomem *ioaddr,
+				 struct stmmac_fpe_cfg *cfg,
 				 enum stmmac_mpacket_type type);
 	int (*fpe_irq_status)(void __iomem *ioaddr, struct net_device *dev);
 };
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2b4c30a5ffcd9..7042abc6979a9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1054,7 +1054,8 @@ static void stmmac_fpe_link_state_handle(struct stmmac_priv *priv, bool is_up)
 	bool *hs_enable = &fpe_cfg->hs_enable;
 
 	if (is_up && *hs_enable) {
-		stmmac_fpe_send_mpacket(priv, priv->ioaddr, MPACKET_VERIFY);
+		stmmac_fpe_send_mpacket(priv, priv->ioaddr, fpe_cfg,
+					MPACKET_VERIFY);
 	} else {
 		*lo_state = FPE_STATE_OFF;
 		*lp_state = FPE_STATE_OFF;
@@ -5621,6 +5622,7 @@ static void stmmac_fpe_event_status(struct stmmac_priv *priv, int status)
 		/* If user has requested FPE enable, quickly response */
 		if (*hs_enable)
 			stmmac_fpe_send_mpacket(priv, priv->ioaddr,
+						fpe_cfg,
 						MPACKET_RESPONSE);
 	}
 
@@ -6958,6 +6960,7 @@ static void stmmac_fpe_lp_task(struct work_struct *work)
 		if (*lo_state == FPE_STATE_ENTERING_ON &&
 		    *lp_state == FPE_STATE_ENTERING_ON) {
 			stmmac_fpe_configure(priv, priv->ioaddr,
+					     fpe_cfg,
 					     priv->plat->tx_queues_to_use,
 					     priv->plat->rx_queues_to_use,
 					     *enable);
@@ -6976,6 +6979,7 @@ static void stmmac_fpe_lp_task(struct work_struct *work)
 			netdev_info(priv->dev, SEND_VERIFY_MPAKCET_FMT,
 				    *lo_state, *lp_state);
 			stmmac_fpe_send_mpacket(priv, priv->ioaddr,
+						fpe_cfg,
 						MPACKET_VERIFY);
 		}
 		/* Sleep then retry */
@@ -6990,6 +6994,7 @@ void stmmac_fpe_handshake(struct stmmac_priv *priv, bool enable)
 	if (priv->plat->fpe_cfg->hs_enable != enable) {
 		if (enable) {
 			stmmac_fpe_send_mpacket(priv, priv->ioaddr,
+						priv->plat->fpe_cfg,
 						MPACKET_VERIFY);
 		} else {
 			priv->plat->fpe_cfg->lo_fpe_state = FPE_STATE_OFF;
@@ -7399,6 +7404,7 @@ int stmmac_suspend(struct device *dev)
 	if (priv->dma_cap.fpesel) {
 		/* Disable FPE */
 		stmmac_fpe_configure(priv, priv->ioaddr,
+				     priv->plat->fpe_cfg,
 				     priv->plat->tx_queues_to_use,
 				     priv->plat->rx_queues_to_use, false);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index d0a2b289f4603..08cffc0558743 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -952,6 +952,7 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 
 	priv->plat->fpe_cfg->enable = false;
 	stmmac_fpe_configure(priv, priv->ioaddr,
+			     priv->plat->fpe_cfg,
 			     priv->plat->tx_queues_to_use,
 			     priv->plat->rx_queues_to_use,
 			     false);
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 24bc3f7967c3b..a266e11525220 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -172,6 +172,7 @@ struct stmmac_fpe_cfg {
 	bool hs_enable;				/* FPE handshake enable */
 	enum stmmac_fpe_state lp_fpe_state;	/* Link Partner FPE state */
 	enum stmmac_fpe_state lo_fpe_state;	/* Local station FPE state */
+	u32 fpe_csr;				/* MAC_FPE_CTRL_STS reg cache */
 };
 
 struct stmmac_safety_feature_cfg {
-- 
2.42.0