Re: [PATCH v5 2/3] usb: dwc3: qcom: Add interconnect support in dwc3 driver

From: Matthias Kaehlcke
Date: Tue Mar 24 2020 - 13:07:29 EST

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On Mon, Mar 16, 2020 at 03:11:32PM +0530, Sandeep Maheswaram (Temp) wrote:
> Hi Matthias
>
> On 2/15/2020 1:41 AM, Matthias Kaehlcke wrote:
> > Hi Sandeep,
> >
> > On Fri, Feb 14, 2020 at 01:54:43PM +0530, Sandeep Maheswaram 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: Sandeep Maheswaram <sanm@xxxxxxxxxxxxxx>
> > > Signed-off-by: Chandana Kishori Chiluveru <cchiluve@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/usb/dwc3/dwc3-qcom.c | 135 ++++++++++++++++++++++++++++++++++++++++++-
> > > 1 file changed, 133 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> > > index 261af9e..2ed6c20 100644
> > > --- a/drivers/usb/dwc3/dwc3-qcom.c
> > > +++ b/drivers/usb/dwc3/dwc3-qcom.c
> > > @@ -13,6 +13,7 @@
> > > #include <linux/module.h>
> > > #include <linux/kernel.h>
> > > #include <linux/extcon.h>
> > > +#include <linux/interconnect.h>
> > > #include <linux/of_platform.h>
> > > #include <linux/platform_device.h>
> > > #include <linux/phy/phy.h>
> > > @@ -43,6 +44,14 @@
> > > #define SDM845_QSCRATCH_SIZE 0x400
> > > #define SDM845_DWC3_CORE_SIZE 0xcd00
> > > +/* Interconnect path bandwidths in MBps */
> > > +#define USB_MEMORY_AVG_HS_BW MBps_to_icc(240)
> > > +#define USB_MEMORY_PEAK_HS_BW MBps_to_icc(700)
> > > +#define USB_MEMORY_AVG_SS_BW MBps_to_icc(1000)
> > > +#define USB_MEMORY_PEAK_SS_BW MBps_to_icc(2500)
> > > +#define APPS_USB_AVG_BW 0
> > > +#define APPS_USB_PEAK_BW MBps_to_icc(40)
> > > +
> > > struct dwc3_acpi_pdata {
> > > u32 qscratch_base_offset;
> > > u32 qscratch_base_size;
> > > @@ -76,8 +85,13 @@ struct dwc3_qcom {
> > > enum usb_dr_mode mode;
> > > bool is_suspended;
> > > bool pm_suspended;
> > > + struct icc_path *usb_ddr_icc_path;
> > > + struct icc_path *apps_usb_icc_path;
> > > };
> > > +static int dwc3_qcom_interconnect_enable(struct dwc3_qcom *qcom);
> > > +static int dwc3_qcom_interconnect_disable(struct dwc3_qcom *qcom);
> > > +
> > > static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
> > > {
> > > u32 reg;
> > > @@ -239,7 +253,7 @@ static void dwc3_qcom_enable_interrupts(struct dwc3_qcom *qcom)
> > > static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
> > > {
> > > u32 val;
> > > - int i;
> > > + int i, ret;
> > > if (qcom->is_suspended)
> > > return 0;
> > > @@ -251,6 +265,10 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
> > > for (i = qcom->num_clocks - 1; i >= 0; i--)
> > > clk_disable_unprepare(qcom->clks[i]);
> > > + ret = dwc3_qcom_interconnect_disable(qcom);
> > > + if (ret)
> > > + dev_warn(qcom->dev, "failed to disable interconnect %d\n", ret);
> > > +
> > This assumes that all QCA systems with a DWC3 have an interconnect
> > configuration, however after applying this series SDM845 is the only
> > platform. You need to track somewhere if the controller in question has
> > an ICC config for not.
>
> This is handled in drivers <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/>/interconnect <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/>/core.c <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/core.c>Â
> icc_set_bw function.

Thanks for the clarification!

> >
> > > qcom->is_suspended = true;
> > > dwc3_qcom_enable_interrupts(qcom);
> > > @@ -276,6 +294,10 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom)
> > > }
> > > }
> > > + ret = dwc3_qcom_interconnect_enable(qcom);
> > > + if (ret)
> > > + dev_warn(qcom->dev, "failed to enable interconnect %d\n", ret);
> > > +
> > same as above
> This is handled in drivers <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/>/interconnect <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/>/core.c <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/core.c>Â
> icc_set_bw function

ok

> > > /* Clear existing events from PHY related to L2 in/out */
> > > dwc3_qcom_setbits(qcom->qscratch_base, PWR_EVNT_IRQ_STAT_REG,
> > > PWR_EVNT_LPM_IN_L2_MASK | PWR_EVNT_LPM_OUT_L2_MASK);
> > > @@ -285,6 +307,108 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom)
> > > return 0;
> > > }
> > > +
> > > +/**
> > > + * dwc3_qcom_interconnect_init() - Get interconnect path handles
> > > + * @qcom: Pointer to the concerned usb core.
> > > + *
> > > + */
> > > +static int dwc3_qcom_interconnect_init(struct dwc3_qcom *qcom)
> > > +{
> > > + struct device *dev = qcom->dev;
> > > + int ret;
> > > +
> > > + if (!device_is_bound(&qcom->dwc3->dev))
> > > + return -EPROBE_DEFER;
> > > +
> > > + 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);
> > > + }
> > This will break all QCA platforms with DWC3, except SDM845. Instead of
> > failing you could interpret the basence of the 'usb-ddr' patch in the DT
> > as signal that the controller has no ICC configuration, and continue without
> > it (i.e. return 0 from here, don't print an error, at most a dev_info() log),
> > and track somewhere that the controller has no ICC config.
> >
> > Alternatively you could check above with of_find_property() whether the
> > controller has an 'interconnects' property at all. If it doesn't exist
> > return zero, otherwise return an error if any of the paths doesn't exist,
> > as you do now.
> This is handled in drivers <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/>/interconnect <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/>/core.c <https://opengrok.qualcomm.com/source/xref/LC.UM.3.0/src/third_party/kernel/v5.4/drivers/interconnect/core.c>Â
> of_icc_get function.

You are right, of_icc_get() returns NULL if the property doesn't exist, and this
is handled gracefully by the other ICC functions.

> > > +
> > > + 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);
> > > + }
> > Failing here is ok, if 'usb-ddr' exists, we expect the rest of the config
> > to be in place.
> This may be required for error handling

Agreed, my comment meant to say the above handling seems correct.

> > > +
> > > + ret = dwc3_qcom_interconnect_enable(qcom);
> > > + if (ret) {
> > > + dev_err(dev, "failed to enable interconnect %d\n", ret);
> > > + 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 = platform_get_drvdata(qcom->dwc3);
> > > + int ret;
> > > +
> > > + 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);
> > > + } else {
> > > + ret = icc_set_bw(qcom->usb_ddr_icc_path,
> > > + USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
> > > + }
> > nit: curly braces are not needed here
> Will remove in next version.
> >
> > > +
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = icc_set_bw(qcom->apps_usb_icc_path,
> > > + APPS_USB_AVG_BW, APPS_USB_PEAK_BW);
> > > + if (ret)
> > > + 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);
> > instead of the above:
> >
> > dwc3_qcom_interconnect_enable(qcom);
> Will change in next version.

With that changed:

Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>

Next message: Arnaud Pouliquen: "[PATCH v7 1/2] rpmsg: core: add API to get MTU"
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