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Message-ID: <20231020221811.pvm7m4ilntp4owvv@synopsys.com>
Date: Fri, 20 Oct 2023 22:18:37 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Bjorn Andersson <quic_bjorande@...cinc.com>
CC: Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Wesley Cheng <quic_wcheng@...cinc.com>,
Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
Felipe Balbi <balbi@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Johan Hovold <johan@...nel.org>,
Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
Subject: Re: [PATCH 04/12] usb: dwc3: Expose core driver as library
On Mon, Oct 16, 2023, 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 platfrom_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 <quic_bjorande@...cinc.com>
> ---
> drivers/usb/dwc3/core.c | 134 ++++++++++++++++++++++++++++++++----------------
> drivers/usb/dwc3/core.h | 10 ++++
> 2 files changed, 100 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index d25490965b27..71e376bebb16 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1876,7 +1876,7 @@ static int dwc3_get_clocks(struct dwc3 *dwc)
> return 0;
> }
>
> -static int dwc3_probe(struct platform_device *pdev)
> +struct dwc3 *dwc3_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct resource *res, dwc_res;
> @@ -1886,14 +1886,14 @@ static int dwc3_probe(struct platform_device *pdev)
>
> dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
> if (!dwc)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> dwc->dev = dev;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (!res) {
> dev_err(dev, "missing memory resource\n");
> - return -ENODEV;
> + return ERR_PTR(-ENODEV);
> }
>
> dwc->xhci_resources[0].start = res->start;
> @@ -1922,7 +1922,7 @@ static int dwc3_probe(struct platform_device *pdev)
>
> regs = devm_ioremap_resource(dev, &dwc_res);
> if (IS_ERR(regs))
> - return PTR_ERR(regs);
> + return ERR_CAST(regs);
>
> dwc->regs = regs;
> dwc->regs_size = resource_size(&dwc_res);
> @@ -1953,7 +1953,6 @@ static int dwc3_probe(struct platform_device *pdev)
> goto err_disable_clks;
> }
>
> - platform_set_drvdata(pdev, dwc);
> dwc3_cache_hwparams(dwc);
>
> if (!dwc->sysdev_is_parent &&
> @@ -2006,7 +2005,7 @@ static int dwc3_probe(struct platform_device *pdev)
>
> pm_runtime_put(dev);
>
> - return 0;
> + return dwc;
>
> err_exit_debugfs:
> dwc3_debugfs_exit(dwc);
> @@ -2030,14 +2029,26 @@ static int dwc3_probe(struct platform_device *pdev)
> if (dwc->usb_psy)
> power_supply_put(dwc->usb_psy);
>
> - return ret;
> + return ERR_PTR(ret);
> }
> +EXPORT_SYMBOL_GPL(dwc3_probe);
>
> -static void dwc3_remove(struct platform_device *pdev)
> +static int dwc3_plat_probe(struct platform_device *pdev)
> {
> - struct dwc3 *dwc = platform_get_drvdata(pdev);
> + struct dwc3 *dwc;
> +
> + dwc = dwc3_probe(pdev);
> + if (IS_ERR(dwc))
> + return PTR_ERR(dwc);
> +
> + platform_set_drvdata(pdev, dwc);
> +
> + return 0;
> +}
>
> - pm_runtime_get_sync(&pdev->dev);
> +void dwc3_remove(struct dwc3 *dwc)
> +{
> + pm_runtime_get_sync(dwc->dev);
>
> dwc3_core_exit_mode(dwc);
> dwc3_debugfs_exit(dwc);
> @@ -2045,22 +2056,28 @@ 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_remove);
> +
> +static void dwc3_plat_remove(struct platform_device *pdev)
> +{
> + dwc3_remove(platform_get_drvdata(pdev));
> +}
>
> #ifdef CONFIG_PM
> static int dwc3_core_init_for_resume(struct dwc3 *dwc)
> @@ -2227,9 +2244,8 @@ 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))
> @@ -2241,10 +2257,10 @@ 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);
> int ret;
>
> ret = dwc3_resume_common(dwc, PMSG_AUTO_RESUME);
> @@ -2261,15 +2277,14 @@ static int dwc3_runtime_resume(struct device *dev)
> break;
> }
>
> - pm_runtime_mark_last_busy(dev);
> + pm_runtime_mark_last_busy(dwc->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);
> -
> switch (dwc->current_dr_role) {
> case DWC3_GCTL_PRTCAP_DEVICE:
> if (dwc3_runtime_checks(dwc))
> @@ -2281,49 +2296,64 @@ static int dwc3_runtime_idle(struct device *dev)
> break;
> }
>
> - pm_runtime_mark_last_busy(dev);
> - pm_runtime_autosuspend(dev);
> + pm_runtime_mark_last_busy(dwc->dev);
> + pm_runtime_autosuspend(dwc->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_suspend(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> int ret;
>
> ret = dwc3_suspend_common(dwc, PMSG_SUSPEND);
> if (ret)
> return ret;
>
> - pinctrl_pm_select_sleep_state(dev);
> + pinctrl_pm_select_sleep_state(dwc->dev);
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_suspend);
>
> -static int dwc3_resume(struct device *dev)
> +int dwc3_resume(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> int ret;
>
> - pinctrl_pm_select_default_state(dev);
> + pinctrl_pm_select_default_state(dwc->dev);
>
> ret = dwc3_resume_common(dwc, PMSG_RESUME);
> if (ret)
> return ret;
>
> - pm_runtime_disable(dev);
> - pm_runtime_set_active(dev);
> - pm_runtime_enable(dev);
> + pm_runtime_disable(dwc->dev);
> + pm_runtime_set_active(dwc->dev);
> + pm_runtime_enable(dwc->dev);
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(dwc3_resume);
>
> -static void dwc3_complete(struct device *dev)
> +void dwc3_complete(struct dwc3 *dwc)
> {
> - struct dwc3 *dwc = dev_get_drvdata(dev);
> u32 reg;
>
> if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_HOST &&
> @@ -2333,15 +2363,31 @@ static void dwc3_complete(struct device *dev)
> dwc3_writel(dwc->regs, DWC3_GUCTL3, reg);
> }
> }
> +EXPORT_SYMBOL_GPL(dwc3_complete);
> +
> +static int dwc3_plat_suspend(struct device *dev)
> +{
> + return dwc3_suspend(dev_get_drvdata(dev));
> +}
> +
> +static int dwc3_plat_resume(struct device *dev)
> +{
> + return dwc3_resume(dev_get_drvdata(dev));
> +}
> +
> +static void dwc3_plat_complete(struct device *dev)
> +{
> + dwc3_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_RUNTIME_PM_OPS(dwc3_runtime_suspend, dwc3_runtime_resume,
> - dwc3_runtime_idle)
> + SET_SYSTEM_SLEEP_PM_OPS(dwc3_plat_suspend, dwc3_plat_resume)
> + .complete = dwc3_plat_complete,
> + SET_RUNTIME_PM_OPS(dwc3_plat_runtime_suspend, dwc3_plat_runtime_resume,
> + dwc3_plat_runtime_idle)
> };
>
> #ifdef CONFIG_OF
> @@ -2369,8 +2415,8 @@ MODULE_DEVICE_TABLE(acpi, dwc3_acpi_match);
> #endif
>
> static struct platform_driver dwc3_driver = {
> - .probe = dwc3_probe,
> - .remove_new = dwc3_remove,
> + .probe = dwc3_plat_probe,
> + .remove_new = dwc3_plat_remove,
> .driver = {
> .name = "dwc3",
> .of_match_table = of_match_ptr(of_dwc3_match),
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index c6c87acbd376..f5e22559bb73 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1568,6 +1568,16 @@ void dwc3_event_buffers_cleanup(struct dwc3 *dwc);
>
> int dwc3_core_soft_reset(struct dwc3 *dwc);
>
> +struct dwc3 *dwc3_probe(struct platform_device *pdev);
> +void dwc3_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_suspend(struct dwc3 *dwc);
> +int dwc3_resume(struct dwc3 *dwc);
> +void dwc3_complete(struct dwc3 *dwc);
> +
Can we make this new interface clear? It's being buried under core.h
this way. Perhaps add some comments and divider, or move to another
header file?
Thanks,
Thinh
> #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
> int dwc3_host_init(struct dwc3 *dwc);
> void dwc3_host_exit(struct dwc3 *dwc);
>
> --
> 2.25.1
>
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