linux_dsm_epyc7002/drivers/usb/cdns3/host.c
Peter Chen b1234e3b3b usb: cdns3: add runtime PM support
Introduce runtime PM and wakeup interrupt handler for cdns3,
the runtime PM is default off since other cdns3 may not
implement glue layer support for runtime PM.

One typical wakeup event use case is xHCI runtime suspend will clear
USBCMD.RS bit, after that the xHCI will not trigger any interrupts,
so its parent (cdns core device) needs to resume xHCI device when
any (wakeup) events occurs at host port.

When the controller is in low power mode, the lpm flag will be set.
The interrupt triggered later than lpm flag is set considers as
wakeup interrupt and handled at cdns_wakeup_irq. Once the wakeup
occurs, it first disables interrupt to avoid later interrupt
occurrence since the controller is in low power mode at that
time, and access registers may be invalid at that time. At wakeup
handler, it will call pm_request_resume to wakeup xHCI device, and
at runtime resume handler, it will enable interrupt again.

The API platform_suspend is introduced for glue layer to implement
platform specific PM sequence.

Reviewed-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
2020-10-02 09:57:38 +03:00

83 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Cadence USBSS DRD Driver - host side
*
* Copyright (C) 2018-2019 Cadence Design Systems.
* Copyright (C) 2017-2018 NXP
*
* Authors: Peter Chen <peter.chen@nxp.com>
* Pawel Laszczak <pawell@cadence.com>
*/
#include <linux/platform_device.h>
#include "core.h"
#include "drd.h"
#include "host-export.h"
#include <linux/usb/hcd.h>
static int __cdns3_host_init(struct cdns3 *cdns)
{
struct platform_device *xhci;
int ret;
struct usb_hcd *hcd;
cdns3_drd_host_on(cdns);
xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
if (!xhci) {
dev_err(cdns->dev, "couldn't allocate xHCI device\n");
return -ENOMEM;
}
xhci->dev.parent = cdns->dev;
cdns->host_dev = xhci;
ret = platform_device_add_resources(xhci, cdns->xhci_res,
CDNS3_XHCI_RESOURCES_NUM);
if (ret) {
dev_err(cdns->dev, "couldn't add resources to xHCI device\n");
goto err1;
}
ret = platform_device_add(xhci);
if (ret) {
dev_err(cdns->dev, "failed to register xHCI device\n");
goto err1;
}
/* Glue needs to access xHCI region register for Power management */
hcd = platform_get_drvdata(xhci);
if (hcd)
cdns->xhci_regs = hcd->regs;
return 0;
err1:
platform_device_put(xhci);
return ret;
}
static void cdns3_host_exit(struct cdns3 *cdns)
{
platform_device_unregister(cdns->host_dev);
cdns->host_dev = NULL;
cdns3_drd_host_off(cdns);
}
int cdns3_host_init(struct cdns3 *cdns)
{
struct cdns3_role_driver *rdrv;
rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
if (!rdrv)
return -ENOMEM;
rdrv->start = __cdns3_host_init;
rdrv->stop = cdns3_host_exit;
rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
rdrv->name = "host";
cdns->roles[USB_ROLE_HOST] = rdrv;
return 0;
}