On Tue, Sep 17, 2019 at 04:40:48PM +0530, Chandana Kishori Chiluveru wrote: > Add interconnect support in dwc3-qcom driver to vote for bus > bandwidth. > > This requires for two different paths - from USB master to > DDR slave. The other is from APPS master to USB slave. > > Signed-off-by: Chandana Kishori Chiluveru <cchiluve@xxxxxxxxxxxxxx> > --- > drivers/usb/dwc3/dwc3-qcom.c | 145 ++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 143 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c > index 184df4d..2a2f5af 100644 > --- a/drivers/usb/dwc3/dwc3-qcom.c > +++ b/drivers/usb/dwc3/dwc3-qcom.c > > ... > > +/** > + * dwc3_qcom_interconnect_init() - Get interconnect path handles nit: "Initialize the interconnect" or similar? > + * @qcom: Pointer to the concerned usb core. > + * > + */ > +static int dwc3_qcom_interconnect_init(struct dwc3_qcom *qcom) > +{ > + struct device *dev = qcom->dev; > + int ret; > + > + qcom->usb_ddr_icc_path = of_icc_get(dev, "usb-ddr"); > + if (IS_ERR(qcom->usb_ddr_icc_path)) { > + dev_err(dev, "Error: (%ld) failed getting usb-ddr path\n", > + PTR_ERR(qcom->usb_ddr_icc_path)); > + return PTR_ERR(qcom->usb_ddr_icc_path); > + } > + > + qcom->apps_usb_icc_path = of_icc_get(dev, "apps-usb"); > + if (IS_ERR(qcom->apps_usb_icc_path)) { > + dev_err(dev, "Error: (%ld) failed getting apps-usb path\n", > + PTR_ERR(qcom->apps_usb_icc_path)); > + return PTR_ERR(qcom->apps_usb_icc_path); > + } > + > + ret = dwc3_qcom_interconnect_enable(qcom); > + if (ret) { > + dev_err(dev, "failed to enable interconnect %d\n", ret); nit: 'interconnect: %d', otherwise the message could be read as 'failed to enable interconnect number N'. > + return ret; > + } > + > + return 0; > +} > + > +/** > + * dwc3_qcom_interconnect_exit() - Release interconnect path handles > + * @qcom: Pointer to the concerned usb core. > + * > + * This function is used to release interconnect path handle. > + */ > +static void dwc3_qcom_interconnect_exit(struct dwc3_qcom *qcom) > +{ > + icc_put(qcom->usb_ddr_icc_path); > + icc_put(qcom->apps_usb_icc_path); > +} > + > +/* Currently we only use bandwidth level, so just "enable" interconnects */ > +static int dwc3_qcom_interconnect_enable(struct dwc3_qcom *qcom) > +{ > + struct dwc3 *dwc; > + int ret; > + > + dwc = platform_get_drvdata(qcom->dwc3); > + if (!dwc) { > + dev_err(qcom->dev, "Failed to get dwc3 device\n"); > + return -EPROBE_DEFER; > + } I understand the need for the/some check (see https://patchwork.kernel.org/patch/11146903/#22885491 and my reply), but I'm not convinced it should be done here. The function can be called from other contexts than _probe(), so returning -EPROBE_DEFER seems wrong, although I understand that you want _probe() to return this value. I would suggest to do this (or another) check early in _probe(). Returning -EPROBE_DEFER from that context makes sense, and it should be the only time the check is actually needed. As commented on v2 I don't particularly like the idea of using a half initialized struct (dwc3), even more when what is initialized or not varies at runtime (since dwc3_probe() and qwc3_qcom_probe() appear to run in parallel). IIUC device_is_bound() returns true when a device is fully initialized (i.e. it's _probe() completed), I'd suggest to evaluate to use it instead of checking the drvdata. In this case the drvdata check should be ok, but in general these kind of races don't seem a good idea, maybe tomorrow someone wants to access another struct member, which isn't always initialized. Others: please correct me if using half-initialized structs is routine in kernel drivers or device_is_bound() is the wrong tool. > + > + if (dwc->maximum_speed == USB_SPEED_SUPER) { > + ret = icc_set_bw(qcom->usb_ddr_icc_path, > + USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW); > + if (ret) > + return ret; > + } else { > + ret = icc_set_bw(qcom->usb_ddr_icc_path, > + USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW); > + if (ret) > + return ret; > + } > + > + ret = icc_set_bw(qcom->apps_usb_icc_path, > + APPS_USB_AVG_BW, APPS_USB_PEAK_BW); > + if (ret) > + goto err_disable_mem_path; > + > + return 0; > + > +err_disable_mem_path: > + icc_set_bw(qcom->usb_ddr_icc_path, 0, 0); > + > + return ret; > +} > + > +/* To disable an interconnect, we just set its bandwidth to 0 */ > +static int dwc3_qcom_interconnect_disable(struct dwc3_qcom *qcom) > +{ > + struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3); > + int ret; > + > + ret = icc_set_bw(qcom->usb_ddr_icc_path, 0, 0); > + if (ret) > + return ret; > + > + ret = icc_set_bw(qcom->apps_usb_icc_path, 0, 0); > + if (ret) > + goto err_reenable_memory_path; > + > + return 0; > + > + /* Re-enable things in the event of an error */ > +err_reenable_memory_path: > + if (dwc->maximum_speed == USB_SPEED_SUPER) > + icc_set_bw(qcom->usb_ddr_icc_path, > + USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW); > + else > + icc_set_bw(qcom->usb_ddr_icc_path, > + USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW); This is essentially the same as in _interconnect_enable(). You could consider a helper function (inline?) for 'enabling' the memory path, which would make things more compact and also allow to get rid of the goto: if (ret) qcom_dwc3_interconnect_enable_mempath(qcom); return ret; > + > + return ret; > +} > + > static irqreturn_t qcom_dwc3_resume_irq(int irq, void *data) > { > struct dwc3_qcom *qcom = data; > @@ -494,6 +626,12 @@ static int dwc3_qcom_probe(struct platform_device *pdev) > goto depopulate; > } > > + ret = dwc3_qcom_interconnect_init(qcom); > + if (ret) { > + dev_err(dev, "failed to init interconnect handles %d\n", ret); nit: remove 'handles' (and add ':' before the error code), it's an implementation detail, and now _icc_init() also calls _icc_enable(), hence it's not only the handles.