Revert "thunderbolt: Add quirk to reset host interface on DMA path teardown for AMD USB4 routers"

This commit has caused a deadlock at shutdown. A proper fix with
another approach will be coming later.  Revert commit
f1de1fc5f632cdeae1f5c2984572ab710d4dfcaa for now.

Reported-by: juan.martinez@amd.com
Closes: https://lore.kernel.org/linux-usb/20260825214237.4179813-1-juan.martinez@amd.com/
Cc: Sanath S <Sanath.S@amd.com>
Cc: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

5 files changed, 3 insertions, 97 deletions

diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
index 12c88509a..24611f05b 100644
--- a/drivers/thunderbolt/domain.c
+++ b/drivers/thunderbolt/domain.c
@@ -788,21 +788,6 @@ int tb_domain_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
 			transmit_ring, receive_path, receive_ring);
 }
 
-static void tb_domain_reset_interface(struct tb *tb)
-{
-	struct tb_nhi *nhi = tb->nhi;
-
-	if (!nhi->ops->reset_interface)
-		return;
-
-	guard(mutex)(&tb->lock);
-
-	/* The reset clears the ring state so stop the control channel */
-	tb_ctl_stop(tb->ctl);
-	nhi->ops->reset_interface(nhi);
-	tb_ctl_start(tb->ctl);
-}
-
 /**
  * tb_domain_disconnect_xdomain_paths() - Disable DMA paths for XDomain
  * @tb: Domain disabling the DMA paths
@@ -825,20 +810,11 @@ int tb_domain_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
 				       int transmit_path, int transmit_ring,
 				       int receive_path, int receive_ring)
 {
-	int ret;
-
 	if (!tb->cm_ops->disconnect_xdomain_paths)
 		return -ENOTSUPP;
 
-	ret = tb->cm_ops->disconnect_xdomain_paths(tb, xd, transmit_path,
+	return tb->cm_ops->disconnect_xdomain_paths(tb, xd, transmit_path,
 			transmit_ring, receive_path, receive_ring);
-	if (ret)
-		return ret;
-
-	if (tb->nhi->quirks & QUIRK_RESET_DMA_ON_TEARDOWN)
-		tb_domain_reset_interface(tb);
-
-	return 0;
 }
 
 static int disconnect_xdomain(struct device *dev, void *data)
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index d4d1efa2a..be18f7b65 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -1180,32 +1180,6 @@ static void nhi_reset(struct tb_nhi *nhi)
 	dev_warn(nhi->dev, "timeout resetting host router\n");
 }
 
-/**
- * nhi_reset_interface() - Reset the host interface
- * @nhi: Host interface to reset
- *
- * Brings the registers in the memory BAR back to their default state and
- * clears the End-to-End Flow Control state. The caller is responsible for
- * stopping the control channel over the reset because it clears the ring
- * state as well.
- */
-void nhi_reset_interface(struct tb_nhi *nhi)
-{
-	u32 val;
-
-	val = ioread32(nhi->iobase + REG_CAPS);
-	/* Only v1 host interfaces implement the reset */
-	if (FIELD_GET(REG_CAPS_VERSION_MASK, val) >= REG_CAPS_VERSION_2)
-		return;
-
-	dev_dbg(nhi->dev, "issuing host interface reset\n");
-
-	iowrite32(REG_HOST_INTERFACE_RESET_RST,
-		  nhi->iobase + REG_HOST_INTERFACE_RESET);
-	/* Wait for tHIReset (10 ms) to complete */
-	usleep_range(10000, 20000);
-}
-
 static struct tb *nhi_select_cm(struct tb_nhi *nhi)
 {
 	struct tb *tb;
diff --git a/drivers/thunderbolt/nhi.h b/drivers/thunderbolt/nhi.h
index f72d6b274..d488eadad 100644
--- a/drivers/thunderbolt/nhi.h
+++ b/drivers/thunderbolt/nhi.h
@@ -36,8 +36,6 @@ irqreturn_t nhi_msi(int irq, void *data);
 irqreturn_t ring_msix(int irq, void *data);
 int nhi_probe(struct tb_nhi *nhi);
 void nhi_shutdown(struct tb_nhi *nhi);
-void nhi_reset_interface(struct tb_nhi *nhi);
-
 extern const struct dev_pm_ops nhi_pm_ops;
 
 /**
@@ -54,7 +52,6 @@ extern const struct dev_pm_ops nhi_pm_ops;
  * @release_ring_irq: NHI specific interrupt release hook
  * @is_present: Whether the device is currently present on the parent bus
  * @init_interrupts: NHI specific interrupt initialization hook
- * @reset_interface: Resets the host interface
  */
 struct tb_nhi_ops {
 	int (*init)(struct tb_nhi *nhi);
@@ -69,7 +66,6 @@ struct tb_nhi_ops {
 	void (*release_ring_irq)(struct tb_ring *ring);
 	bool (*is_present)(struct tb_nhi *nhi);
 	int (*init_interrupts)(struct tb_nhi *nhi);
-	void (*reset_interface)(struct tb_nhi *nhi);
 };
 
 /*
@@ -120,24 +116,11 @@ struct tb_nhi_ops {
 #define PCI_DEVICE_ID_INTEL_PTL_P_NHI0			0xe433
 #define PCI_DEVICE_ID_INTEL_PTL_P_NHI1			0xe434
 
-#define PCI_DEVICE_ID_AMD_1AH_M60H_NHI0			0x1120
-#define PCI_DEVICE_ID_AMD_1AH_M60H_NHI1			0x1121
-#define PCI_DEVICE_ID_AMD_1AH_M68H_NHI0			0x113b
-#define PCI_DEVICE_ID_AMD_1AH_M68H_NHI1			0x113c
-#define PCI_DEVICE_ID_AMD_1AH_M80H_NHI0			0x1155
-#define PCI_DEVICE_ID_AMD_1AH_M80H_NHI1			0x1158
-#define PCI_DEVICE_ID_AMD_1AH_M80H_NHI2			0x1159
-#define PCI_DEVICE_ID_AMD_1AH_M24H_NHI0			0x151c
-#define PCI_DEVICE_ID_AMD_1AH_M24H_NHI1			0x151d
-#define PCI_DEVICE_ID_AMD_1AH_M70H_NHI0			0x158d
-#define PCI_DEVICE_ID_AMD_1AH_M70H_NHI1			0x158e
-
 #define PCI_CLASS_SERIAL_USB_USB4			0x0c0340
 
 /* Host interface quirks */
-#define QUIRK_AUTO_CLEAR_INT				BIT(0)
-#define QUIRK_E2E					BIT(1)
-#define QUIRK_RESET_DMA_ON_TEARDOWN			BIT(2)
+#define QUIRK_AUTO_CLEAR_INT	BIT(0)
+#define QUIRK_E2E		BIT(1)
 
 /*
  * Minimal number of vectors when we use MSI-X. Two for control channel
diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
index 99df60b6d..d6a197fab 100644
--- a/drivers/thunderbolt/nhi_regs.h
+++ b/drivers/thunderbolt/nhi_regs.h
@@ -115,10 +115,6 @@ struct ring_desc {
 #define REG_CAPS_VERSION_MASK		GENMASK(23, 16)
 #define REG_CAPS_VERSION_2		0x40
 
-/* Host Interface Reset - resets TX/RX rings and E2E flow control counters */
-#define REG_HOST_INTERFACE_RESET	0x39858
-#define REG_HOST_INTERFACE_RESET_RST	BIT(0)
-
 #define REG_DMA_MISC			0x39864
 #define REG_DMA_MISC_INT_AUTO_CLEAR     BIT(2)
 #define REG_DMA_MISC_DISABLE_AUTO_CLEAR	BIT(17)
diff --git a/drivers/thunderbolt/pci.c b/drivers/thunderbolt/pci.c
index 99333729f..8462ccb59 100644
--- a/drivers/thunderbolt/pci.c
+++ b/drivers/thunderbolt/pci.c
@@ -62,27 +62,6 @@ static void nhi_pci_check_quirks(struct tb_nhi_pci *nhi_pci)
 			nhi->quirks |= QUIRK_E2E;
 			break;
 		}
-	} else if (pdev->vendor == PCI_VENDOR_ID_AMD) {
-		switch (pdev->device) {
-		case PCI_DEVICE_ID_AMD_1AH_M60H_NHI0:
-		case PCI_DEVICE_ID_AMD_1AH_M60H_NHI1:
-		case PCI_DEVICE_ID_AMD_1AH_M68H_NHI0:
-		case PCI_DEVICE_ID_AMD_1AH_M68H_NHI1:
-		case PCI_DEVICE_ID_AMD_1AH_M80H_NHI0:
-		case PCI_DEVICE_ID_AMD_1AH_M80H_NHI1:
-		case PCI_DEVICE_ID_AMD_1AH_M80H_NHI2:
-		case PCI_DEVICE_ID_AMD_1AH_M24H_NHI0:
-		case PCI_DEVICE_ID_AMD_1AH_M24H_NHI1:
-		case PCI_DEVICE_ID_AMD_1AH_M70H_NHI0:
-		case PCI_DEVICE_ID_AMD_1AH_M70H_NHI1:
-			/*
-			 * These AMD hosts may hang the Tx ring when the
-			 * DMA paths are torn down so they need the host
-			 * interface reset after each teardown.
-			 */
-			nhi->quirks |= QUIRK_RESET_DMA_ON_TEARDOWN;
-			break;
-		}
 	}
 }
 
@@ -279,7 +258,6 @@ static const struct tb_nhi_ops pci_nhi_default_ops = {
 	.shutdown = nhi_pci_release_irq,
 	.is_present = nhi_pci_is_present,
 	.init_interrupts = nhi_pci_init_msi,
-	.reset_interface = nhi_reset_interface,
 };
 
 /* Ice Lake specific NHI operations */
@@ -463,7 +441,6 @@ static const struct tb_nhi_ops icl_nhi_ops = {
 	.release_ring_irq = nhi_pci_ring_release_msix,
 	.is_present = nhi_pci_is_present,
 	.init_interrupts = nhi_pci_init_msi,
-	.reset_interface = nhi_reset_interface,
 };
 
 static int nhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)