[PATCH 4/6] usb: xhci-pci: Move reset logic out of XHCI core

[Samuel Holland <samuel@sholland.org>]

Resetting an XHCI controller inside xhci_register undoes any register
setup performed by the platform driver. And at least on the Allwinner
H6, resetting the XHCI controller also resets the PHY, which prevents
the controller from working. That means the controller must be taken out
of reset before initializing the PHY, which must be done before calling
xhci_register.

The logic in the XHCI core was added to support the Raspberry Pi 4
(although this was not mentioned in the commit log!), which uses the
xhci-pci platform driver. Move the reset logic to the platform driver,
where it belongs, and where it cannot interfere with other platform
drivers.

Fixes: 0b80371b350e ("usb: xhci: Add reset controller support")
Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 drivers/usb/host/xhci-mem.c |  2 --
 drivers/usb/host/xhci-pci.c | 38 +++++++++++++++++++++++++++++++++++--
 drivers/usb/host/xhci.c     | 35 ----------------------------------
 include/usb/xhci.h          |  2 --
 4 files changed, 36 insertions(+), 41 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index b002d6f1664..ccec64ff564 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -180,8 +180,6 @@ void xhci_cleanup(struct xhci_ctrl *ctrl)
 	xhci_free_virt_devices(ctrl);
 	free(ctrl->erst.entries);
 	free(ctrl->dcbaa);
-	if (reset_valid(&ctrl->reset))
-		reset_free(&ctrl->reset);
 	memset(ctrl, '\0', sizeof(struct xhci_ctrl));
 }
 
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 2b445f21b55..2459b4b62f0 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -10,9 +10,14 @@
 #include <init.h>
 #include <log.h>
 #include <pci.h>
+#include <reset.h>
 #include <usb.h>
 #include <usb/xhci.h>
 
+struct xhci_pci_plat {
+	struct reset_ctl reset;
+};
+
 static void xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
 			  struct xhci_hcor **ret_hcor)
 {
@@ -39,14 +44,43 @@ static void xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
 
 static int xhci_pci_probe(struct udevice *dev)
 {
+	struct xhci_pci_plat = dev_get_plat(dev);
 	struct xhci_hccr *hccr;
 	struct xhci_hcor *hcor;
+	int ret;
+
+	ret = reset_get_by_index(dev, 0, &plat->reset);
+	if (ret && ret != -ENOENT && ret != -ENOTSUPP) {
+		dev_err(dev, "failed to get reset\n");
+		return ret;
+	}
+
+	if (reset_valid(&plat->reset)) {
+		ret = reset_assert(&plat->reset);
+		if (ret)
+			return ret;
+
+		ret = reset_deassert(&plat->reset);
+		if (ret)
+			return ret;
+	}
 
 	xhci_pci_init(dev, &hccr, &hcor);
 
 	return xhci_register(dev, hccr, hcor);
 }
 
+static int xhci_pci_remove(struct udevice *dev)
+{
+	struct xhci_pci_plat = dev_get_plat(dev);
+
+	xhci_deregister(dev);
+	if (reset_valid(&plat->reset))
+		reset_free(&plat->reset);
+
+	return 0;
+}
+
 static const struct udevice_id xhci_pci_ids[] = {
 	{ .compatible = "xhci-pci" },
 	{ }
@@ -56,10 +90,10 @@ U_BOOT_DRIVER(xhci_pci) = {
 	.name	= "xhci_pci",
 	.id	= UCLASS_USB,
 	.probe = xhci_pci_probe,
-	.remove = xhci_deregister,
+	.remove	= xhci_pci_remove,
 	.of_match = xhci_pci_ids,
 	.ops	= &xhci_usb_ops,
-	.plat_auto	= sizeof(struct usb_plat),
+	.plat_auto	= sizeof(struct xhci_pci_plat),
 	.priv_auto	= sizeof(struct xhci_ctrl),
 	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
 };
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 7080f8fabe7..171f39f90b5 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -188,37 +188,6 @@ static int xhci_start(struct xhci_hcor *hcor)
 	return ret;
 }
 
-#if CONFIG_IS_ENABLED(DM_USB)
-/**
- * Resets XHCI Hardware
- *
- * @param ctrl	pointer to host controller
- * @return 0 if OK, or a negative error code.
- */
-static int xhci_reset_hw(struct xhci_ctrl *ctrl)
-{
-	int ret;
-
-	ret = reset_get_by_index(ctrl->dev, 0, &ctrl->reset);
-	if (ret && ret != -ENOENT && ret != -ENOTSUPP) {
-		dev_err(ctrl->dev, "failed to get reset\n");
-		return ret;
-	}
-
-	if (reset_valid(&ctrl->reset)) {
-		ret = reset_assert(&ctrl->reset);
-		if (ret)
-			return ret;
-
-		ret = reset_deassert(&ctrl->reset);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-#endif
-
 /**
  * Resets the XHCI Controller
  *
@@ -1534,10 +1503,6 @@ int xhci_register(struct udevice *dev, struct xhci_hccr *hccr,
 
 	ctrl->dev = dev;
 
-	ret = xhci_reset_hw(ctrl);
-	if (ret)
-		goto err;
-
 	/*
 	 * XHCI needs to issue a Address device command to setup
 	 * proper device context structures, before it can interact
diff --git a/include/usb/xhci.h b/include/usb/xhci.h
index e1d382369a3..c12706c6a58 100644
--- a/include/usb/xhci.h
+++ b/include/usb/xhci.h
@@ -16,7 +16,6 @@
 #ifndef HOST_XHCI_H_
 #define HOST_XHCI_H_
 
-#include <reset.h>
 #include <asm/types.h>
 #include <asm/cache.h>
 #include <asm/io.h>
@@ -1199,7 +1198,6 @@ struct xhci_ctrl {
 #if CONFIG_IS_ENABLED(DM_USB)
 	struct udevice *dev;
 #endif
-	struct reset_ctl reset;
 	struct xhci_hccr *hccr;	/* R/O registers, not need for volatile */
 	struct xhci_hcor *hcor;
 	struct xhci_doorbell_array *dba;
-- 
2.26.2