[PATCH v1 1/1] net: stmmac: dwmac-tegra: Read iommu stream id from device tree

[Parker Newman <parker@finest.io>]

From: Parker Newman <pnewman@connecttech.com>

Read the iommu stream id from device tree rather than hard coding to mgbe0.
Fixes kernel panics when using mgbe controllers other than mgbe0.

Tested with Orin AGX 64GB module on Connect Tech Forge carrier board.

Signed-off-by: Parker Newman <pnewman@connecttech.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
index 3827997d2132..dc903b846b1b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
+#include <linux/iommu.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/module.h>
@@ -19,6 +20,8 @@ struct tegra_mgbe {
 	struct reset_control *rst_mac;
 	struct reset_control *rst_pcs;

+	u32 iommu_sid;
+
 	void __iomem *hv;
 	void __iomem *regs;
 	void __iomem *xpcs;
@@ -50,7 +53,6 @@ struct tegra_mgbe {
 #define MGBE_WRAP_COMMON_INTR_ENABLE	0x8704
 #define MAC_SBD_INTR			BIT(2)
 #define MGBE_WRAP_AXI_ASID0_CTRL	0x8400
-#define MGBE_SID			0x6

 static int __maybe_unused tegra_mgbe_suspend(struct device *dev)
 {
@@ -84,7 +86,7 @@ static int __maybe_unused tegra_mgbe_resume(struct device *dev)
 	writel(MAC_SBD_INTR, mgbe->regs + MGBE_WRAP_COMMON_INTR_ENABLE);

 	/* Program SID */
-	writel(MGBE_SID, mgbe->hv + MGBE_WRAP_AXI_ASID0_CTRL);
+	writel(mgbe->iommu_sid, mgbe->hv + MGBE_WRAP_AXI_ASID0_CTRL);

 	value = readl(mgbe->xpcs + XPCS_WRAP_UPHY_STATUS);
 	if ((value & XPCS_WRAP_UPHY_STATUS_TX_P_UP) == 0) {
@@ -241,6 +243,12 @@ static int tegra_mgbe_probe(struct platform_device *pdev)
 	if (IS_ERR(mgbe->xpcs))
 		return PTR_ERR(mgbe->xpcs);

+	/* get controller's stream id from iommu property in device tree */
+	if (!tegra_dev_iommu_get_stream_id(mgbe->dev, &mgbe->iommu_sid)) {
+		dev_err(mgbe->dev, "failed to get iommu stream id\n");
+		return -EINVAL;
+	}
+
 	res.addr = mgbe->regs;
 	res.irq = irq;

@@ -346,7 +354,7 @@ static int tegra_mgbe_probe(struct platform_device *pdev)
 	writel(MAC_SBD_INTR, mgbe->regs + MGBE_WRAP_COMMON_INTR_ENABLE);

 	/* Program SID */
-	writel(MGBE_SID, mgbe->hv + MGBE_WRAP_AXI_ASID0_CTRL);
+	writel(mgbe->iommu_sid, mgbe->hv + MGBE_WRAP_AXI_ASID0_CTRL);

 	plat->flags |= STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP;

--
2.47.0