[PATCH v2 0/2] usb: core: acpi: Rely on the sysdev pointer

[PATCH v2 0/2] usb: core: acpi: Rely on the sysdev pointer

[Heikki Krogerus]

Hi,

I've added a comment in the first patch explaining that the sysdev
pointer is the host controller from firmware perspective like
requested by Andy. But please note that I did not make any comments
about the location of the sysdev ACPI companion in ACPI namespace on
purpose. We don't need to, and we actually can't make any assumptions
about that.


original cover letter:

Since we have that sysdev pointer, we need to use it also when
assigning the ACPI companion for the root hub. That should remove the
need to "manually" assign the ACPI companion to the controller device
in the xhci glue drivers like dwc3-host.c.

Assigning the ACPI companion in those glue drivers is very
problematic, because it screws up the fwnode->secondary pointer. But
as said, since we have that sysdev pointer, there is no need to
manually set it. sysdev pointer should always point to the correct
physical device from firmware PoW.

thanks,

Heikki Krogerus (2):
  usb: core: acpi: Use the sysdev pointer instead of controller device
  usb: dwc3: host: Stop setting the ACPI companion

 drivers/usb/core/usb-acpi.c | 7 +++++--
 drivers/usb/dwc3/host.c     | 2 --
 2 files changed, 5 insertions(+), 4 deletions(-)

-- 
2.35.1

[PATCH v2 1/2] usb: core: acpi: Use the sysdev pointer instead of controller device

[Heikki Krogerus]

The controller device (hcd) does not always have the ACPI
companion assigned to it at all. We can not rely on it when
finding the ACPI companion for the root hub. Instead we need
to use the sysdev pointer.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/core/usb-acpi.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
index bb1da35eb891e..d4dcaefd0ea40 100644
--- a/drivers/usb/core/usb-acpi.c
+++ b/drivers/usb/core/usb-acpi.c
@@ -205,8 +205,11 @@ usb_acpi_find_companion_for_device(struct usb_device *udev)
 	struct usb_hub *hub;
 
 	if (!udev->parent) {
-		/* root hub is only child (_ADR=0) under its parent, the HC */
-		adev = ACPI_COMPANION(udev->dev.parent);
+		/*
+		 * root hub is only child (_ADR=0) under its parent, the HC.
+		 * sysdev pointer is the HC as seen from firmware.
+		 */
+		adev = ACPI_COMPANION(udev->bus->sysdev);
 		return acpi_find_child_device(adev, 0, false);
 	}
 
-- 
2.35.1

[PATCH v2 2/2] usb: dwc3: host: Stop setting the ACPI companion

[Heikki Krogerus]

It is no longer needed. The sysdev pointer is now used when
assigning the ACPI companions to the xHCI ports and USB
devices.

Assigning the ACPI companion here resulted in the
fwnode->secondary pointer to be replaced also for the parent
dwc3 device since the primary fwnode (the ACPI companion)
was shared. That was unintentional and it created potential
side effects like resource leaks.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/dwc3/host.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index eda871973d6cc..f56c30cf151e4 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -7,7 +7,6 @@
  * Authors: Felipe Balbi <balbi@ti.com>,
  */
 
-#include <linux/acpi.h>
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -83,7 +82,6 @@ int dwc3_host_init(struct dwc3 *dwc)
 	}
 
 	xhci->dev.parent	= dwc->dev;
-	ACPI_COMPANION_SET(&xhci->dev, ACPI_COMPANION(dwc->dev));
 
 	dwc->xhci = xhci;
 
-- 
2.35.1