On Tue, Mar 18, 2025, Bjorn Andersson wrote:
> The DWC3 IP block is handled by three distinct device drivers: XHCI,
> DWC3 core and a platform specific (optional) DWC3 glue driver.
>
> This has resulted in, at least in the case of the Qualcomm glue, the
> presence of a number of layering violations, where the glue code either
> can't handle, or has to work around, the fact that core might not probe
> deterministically.
>
> An example of this is that the suspend path should operate slightly
> different depending on the device operating in host or peripheral mode,
> and the only way to determine the operating state is to peek into the
> core's drvdata.
>
> The Qualcomm glue driver is expected to make updates in the qscratch
> register region (the "glue" region) during role switch events, but with
> the glue and core split using the driver model, there is no reasonable
> way to introduce listeners for mode changes.
>
> Split the dwc3 core platform_driver callbacks and their implementation
> and export the implementation, to make it possible to deterministically
> instantiate the dwc3 core as part of the dwc3 glue drivers and to
> allow flattening of the DeviceTree representation.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/core.c | 142 +++++++++++++++++++++++++++++++++---------------
> drivers/usb/dwc3/glue.h | 32 +++++++++++
> 2 files changed, 129 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 66a08b5271653abd458f9ec85ca730afd7779d71..b428b6fc3d0a55811e2f75d33d79df4b0c67dcac 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -36,6 +36,7 @@
>
> #include "core.h"
> #include "gadget.h"
> +#include "glue.h"
> #include "io.h"
>
> #include "debug.h"
> @@ -2148,27 +2149,16 @@ static struct power_supply *dwc3_get_usb_power_supply(struct dwc3 *dwc)
> return usb_psy;
> }
>
> -static int dwc3_probe(struct platform_device *pdev)
> +int dwc3_core_probe(const struct dwc3_probe_data *data)
> {
> - struct device *dev = &pdev->dev;
> - struct resource *res, dwc_res;
> + struct dwc3 *dwc = data->dwc;
> + struct device *dev = dwc->dev;
> + struct resource dwc_res;
> unsigned int hw_mode;
> void __iomem *regs;
> - struct dwc3 *dwc;
> + struct resource *res = data->res;
> int ret;
>
> - dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
> - if (!dwc)
> - return -ENOMEM;
> -
> - dwc->dev = dev;
> -
> - res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - if (!res) {
> - dev_err(dev, "missing memory resource\n");
> - return -ENODEV;
> - }
> -
> dwc->xhci_resources[0].start = res->start;
> dwc->xhci_resources[0].end = dwc->xhci_resources[0].start +
> DWC3_XHCI_REGS_END;
> @@ -2232,7 +2222,7 @@ static int dwc3_probe(struct platform_device *pdev)
> goto err_disable_clks;
> }
>
> - platform_set_drvdata(pdev, dwc);
> + dev_set_drvdata(dev, dwc);
> dwc3_cache_hwparams(dwc);
>
> if (!dwc->sysdev_is_parent &&
> @@ -2327,12 +2317,35 @@ static int dwc3_probe(struct platform_device *pdev)
>
> return ret;
> }
> +EXPORT_SYMBOL_GPL(dwc3_core_probe);
>
> -static void dwc3_remove(struct platform_device *pdev)
> +static int dwc3_probe(struct platform_device *pdev)
> {
> - struct dwc3 *dwc = platform_get_drvdata(pdev);
> + struct dwc3_probe_data probe_data;
> + struct resource *res;
> + struct dwc3 *dwc;
>
> - pm_runtime_get_sync(&pdev->dev);
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(&pdev->dev, "missing memory resource\n");
> + return -ENODEV;
> + }
> +
> + dwc = devm_kzalloc(&pdev->dev, sizeof(*dwc), GFP_KERNEL);
> + if (!dwc)
> + return -ENOMEM;
> +
> + dwc->dev = &pdev->dev;
> +
> + probe_data.dwc = dwc;
> + probe_data.res = res;
> +
> + return dwc3_core_probe(&probe_data);
> +}
> +
> +void dwc3_core_remove(struct dwc3 *dwc)
> +{
> + pm_runtime_get_sync(dwc->dev);
>
> dwc3_core_exit_mode(dwc);
> dwc3_debugfs_exit(dwc);
> @@ -2340,22 +2353,28 @@ static void dwc3_remove(struct platform_device *pdev)
> dwc3_core_exit(dwc);
> dwc3_ulpi_exit(dwc);
>
> - pm_runtime_allow(&pdev->dev);
> - pm_runtime_disable(&pdev->dev);
> - pm_runtime_dont_use_autosuspend(&pdev->dev);
> - pm_runtime_put_noidle(&pdev->dev);
> + pm_runtime_allow(dwc->dev);
> + pm_runtime_disable(dwc->dev);
> + pm_runtime_dont_use_autosuspend(dwc->dev);
> + pm_runtime_put_noidle(dwc->dev);
> /*
> * HACK: Clear the driver data, which is currently accessed by parent
> * glue drivers, before allowing the parent to suspend.
> */
> - platform_set_drvdata(pdev, NULL);
> - pm_runtime_set_suspended(&pdev->dev);
> + dev_set_drvdata(dwc->dev, NULL);
> + pm_runtime_set_suspended(dwc->dev);
>
> dwc3_free_event_buffers(dwc);
>
> if (dwc->usb_psy)
> power_supply_put(dwc->usb_psy);
> }
> +EXPORT_SYMBOL_GPL(dwc3_core_remove);
> +
> +static void dwc3_remove(struct platform_device *pdev)
> +{
> + dwc3_core_remove(platform_get_drvdata(pdev));
> +}
>
> #ifdef CONFIG_PM
> static int dwc3_core_init_for_resume(struct dwc3 *dwc)
> @@ -2544,9 +2563,8 @@ static int dwc3_runtime_checks(struct dwc3 *dwc)
> return 0;
> }
>
> -static int dwc3_runtime_suspend(struct device *dev)
> +int dwc3_runtime_suspend(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> int ret;
>
> if (dwc3_runtime_checks(dwc))
> @@ -2558,10 +2576,11 @@ static int dwc3_runtime_suspend(struct device *dev)
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_runtime_suspend);
>
> -static int dwc3_runtime_resume(struct device *dev)
> +int dwc3_runtime_resume(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> + struct device *dev = dwc->dev;
> int ret;
>
> ret = dwc3_resume_common(dwc, PMSG_AUTO_RESUME);
> @@ -2571,7 +2590,7 @@ static int dwc3_runtime_resume(struct device *dev)
> switch (dwc->current_dr_role) {
> case DWC3_GCTL_PRTCAP_DEVICE:
> if (dwc->pending_events) {
> - pm_runtime_put(dwc->dev);
> + pm_runtime_put(dev);
> dwc->pending_events = false;
> enable_irq(dwc->irq_gadget);
> }
> @@ -2586,10 +2605,11 @@ static int dwc3_runtime_resume(struct device *dev)
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_runtime_resume);
>
> -static int dwc3_runtime_idle(struct device *dev)
> +int dwc3_runtime_idle(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> + struct device *dev = dwc->dev;
>
> switch (dwc->current_dr_role) {
> case DWC3_GCTL_PRTCAP_DEVICE:
> @@ -2607,12 +2627,28 @@ static int dwc3_runtime_idle(struct device *dev)
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_runtime_idle);
> +
> +static int dwc3_plat_runtime_suspend(struct device *dev)
> +{
> + return dwc3_runtime_suspend(dev_get_drvdata(dev));
> +}
> +
> +static int dwc3_plat_runtime_resume(struct device *dev)
> +{
> + return dwc3_runtime_resume(dev_get_drvdata(dev));
> +}
> +
> +static int dwc3_plat_runtime_idle(struct device *dev)
> +{
> + return dwc3_runtime_idle(dev_get_drvdata(dev));
> +}
> #endif /* CONFIG_PM */
>
> #ifdef CONFIG_PM_SLEEP
> -static int dwc3_suspend(struct device *dev)
> +int dwc3_pm_suspend(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> + struct device *dev = dwc->dev;
> int ret;
>
> ret = dwc3_suspend_common(dwc, PMSG_SUSPEND);
> @@ -2623,10 +2659,11 @@ static int dwc3_suspend(struct device *dev)
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_pm_suspend);
>
> -static int dwc3_resume(struct device *dev)
> +int dwc3_pm_resume(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> + struct device *dev = dwc->dev;
> int ret = 0;
>
> pinctrl_pm_select_default_state(dev);
> @@ -2645,10 +2682,10 @@ static int dwc3_resume(struct device *dev)
>
> return ret;
> }
> +EXPORT_SYMBOL_GPL(dwc3_pm_resume);
>
> -static void dwc3_complete(struct device *dev)
> +void dwc3_pm_complete(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> u32 reg;
>
> if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_HOST &&
> @@ -2658,21 +2695,36 @@ static void dwc3_complete(struct device *dev)
> dwc3_writel(dwc->regs, DWC3_GUCTL3, reg);
> }
> }
> +EXPORT_SYMBOL_GPL(dwc3_pm_complete);
> +
> +static int dwc3_plat_suspend(struct device *dev)
> +{
> + return dwc3_pm_suspend(dev_get_drvdata(dev));
> +}
> +
> +static int dwc3_plat_resume(struct device *dev)
> +{
> + return dwc3_pm_resume(dev_get_drvdata(dev));
> +}
> +
> +static void dwc3_plat_complete(struct device *dev)
> +{
> + dwc3_pm_complete(dev_get_drvdata(dev));
> +}
> #else
> -#define dwc3_complete NULL
> +#define dwc3_plat_complete NULL
> #endif /* CONFIG_PM_SLEEP */
>
> static const struct dev_pm_ops dwc3_dev_pm_ops = {
> - SET_SYSTEM_SLEEP_PM_OPS(dwc3_suspend, dwc3_resume)
> - .complete = dwc3_complete,
> -
> + SET_SYSTEM_SLEEP_PM_OPS(dwc3_plat_suspend, dwc3_plat_resume)
> + .complete = dwc3_plat_complete,
> /*
> * Runtime suspend halts the controller on disconnection. It relies on
> * platforms with custom connection notification to start the controller
> * again.
> */
> - SET_RUNTIME_PM_OPS(dwc3_runtime_suspend, dwc3_runtime_resume,
> - dwc3_runtime_idle)
> + SET_RUNTIME_PM_OPS(dwc3_plat_runtime_suspend, dwc3_plat_runtime_resume,
> + dwc3_plat_runtime_idle)
> };
>
> #ifdef CONFIG_OF
> diff --git a/drivers/usb/dwc3/glue.h b/drivers/usb/dwc3/glue.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..e73cfc466012f07214291abe56454934ab014013
> --- /dev/null
> +++ b/drivers/usb/dwc3/glue.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * glue.h - DesignWare USB3 DRD glue header
> + */
> +
> +#ifndef __DRIVERS_USB_DWC3_GLUE_H
> +#define __DRIVERS_USB_DWC3_GLUE_H
> +
> +#include <linux/types.h>
> +#include "core.h"
> +
> +/**
> + * dwc3_probe_data: Initialization parameters passed to dwc3_core_probe()
> + * @dwc: Reference to dwc3 context structure
> + * @res: resource for the DWC3 core mmio region
> + */
> +struct dwc3_probe_data {
> + struct dwc3 *dwc;
> + struct resource *res;
> +};
> +
> +int dwc3_core_probe(const struct dwc3_probe_data *data);
> +void dwc3_core_remove(struct dwc3 *dwc);
> +
> +int dwc3_runtime_suspend(struct dwc3 *dwc);
> +int dwc3_runtime_resume(struct dwc3 *dwc);
> +int dwc3_runtime_idle(struct dwc3 *dwc);
> +int dwc3_pm_suspend(struct dwc3 *dwc);
> +int dwc3_pm_resume(struct dwc3 *dwc);
> +void dwc3_pm_complete(struct dwc3 *dwc);
> +
> +#endif
>
> --
> 2.48.1
>
Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
Thanks,
Thinh
