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

Georgi Djakov
2019-09-12T12:54:28Z

Hi Chandana,

Thank you for the patch!

On 9/11/19 07:54, 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@codeaurora.org>
> ---
> drivers/usb/dwc3/dwc3-qcom.c | 147 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 145 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index 184df4d..4b8c2ae 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -14,6 +14,7 @@
> #include <linux/extcon.h>
> #include <linux/of_platform.h>
> #include <linux/platform_device.h>
> +#include <linux/interconnect.h>
> #include <linux/phy/phy.h>
> #include <linux/usb/of.h>
> #include <linux/reset.h>
> @@ -38,6 +39,9 @@
> #define PWR_EVNT_LPM_IN_L2_MASK BIT(4)
> #define PWR_EVNT_LPM_OUT_L2_MASK BIT(5)
>
> +#define USB_DDR "usb-ddr"
> +#define APPS_USB "apps-usb"

What is the benefit of adding these defines? Please remove them.

> struct dwc3_qcom {
> struct device *dev;
> void __iomem *qscratch_base;
> @@ -59,8 +63,13 @@ 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;

Nit: Maybe try to make the indentation style consistent with the existing code?

> };
>
> +static int usb_interconnect_enable(struct dwc3_qcom *qcom);
> +static int usb_interconnect_disable(struct dwc3_qcom *qcom);
> +
> static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
> {
> u32 reg;
> @@ -222,7 +231,7 @@ 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;
> @@ -234,6 +243,11 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
> for (i = qcom->num_clocks - 1; i >= 0; i--)
> clk_disable_unprepare(qcom->clks[i]);
>
> + /* Remove bus voting */
> + ret = usb_interconnect_disable(qcom);
> + if (ret)
> + dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> +
> qcom->is_suspended = true;
> dwc3_qcom_enable_interrupts(qcom);
>
> @@ -259,6 +273,11 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom)
> }
> }
>
> + /* Add bus voting */
> + ret = usb_interconnect_enable(qcom);
> + if (ret)
> + dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> +
> /* 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);
> @@ -409,6 +428,116 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
> return 0;
> }
>
> +/* Interconnect path bandwidths in KBps */
> +#define USB_MEMORY_AVG_HS_BW 240000
> +#define USB_MEMORY_PEAK_HS_BW 700000
> +#define USB_MEMORY_AVG_SS_BW 1000000
> +#define USB_MEMORY_PEAK_SS_BW 2500000
> +#define APPS_USB_AVG_BW 0
> +#define APPS_USB_PEAK_BW 40000

I would suggest to wrap the values with kBps_to_icc() or MBps_to_icc() macro.

> +
> +/**
> + * usb_interconnect_init() - Request to get interconnect path handle
> + * @qcom: Pointer to the concerned usb core.
> + *
> + */
> +static int usb_interconnect_init(struct dwc3_qcom *qcom)
> +{
> + struct device *dev = qcom->dev;
> +
> + 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 %s path\n",
> + PTR_ERR(qcom->usb_ddr_icc_path), USB_DDR);
> + 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 %s path\n",
> + PTR_ERR(qcom->apps_usb_icc_path), APPS_USB);
> + return PTR_ERR(qcom->usb_ddr_icc_path);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * geni_interconnect_exit() - Request to release interconnect path handle
> + * @qcom: Pointer to the concerned usb core.
> + *
> + * This function is used to release interconnect path handle.
> + */
> +static void usb_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 usb_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;
> + }
> +
> + 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 its bandwidth to 0 */

Missing the word "set"?

> +static int usb_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; /* Success */

Nit: This comment seems useless.

> +
> + /* 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);
> +
> + return ret;
> +}
> static int dwc3_qcom_probe(struct platform_device *pdev)
> {
> struct device_node *np = pdev->dev.of_node, *dwc3_np;
> @@ -494,6 +623,17 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
> goto depopulate;
> }
>
> + ret = usb_interconnect_init(qcom);
> + if (ret) {
> + dev_err(dev, "failed to get interconnect handle ret:%d\n", ret);
> + goto depopulate;
> + }
> + ret = usb_interconnect_enable(qcom);
> + if (ret) {
> + dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> + goto interconnect_exit;
> + }
> +
> qcom->mode = usb_get_dr_mode(&qcom->dwc3->dev);
>
> /* enable vbus override for device mode */
> @@ -503,7 +643,7 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
> /* register extcon to override sw_vbus on Vbus change later */
> ret = dwc3_qcom_register_extcon(qcom);
> if (ret)
> - goto depopulate;
> + goto interconnect_exit;
>
> device_init_wakeup(&pdev->dev, 1);
> qcom->is_suspended = false;
> @@ -513,6 +653,8 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
>
> return 0;
>
> +interconnect_exit:
> + usb_interconnect_exit(qcom);
> depopulate:
> of_platform_depopulate(&pdev->dev);
> clk_disable:
> @@ -540,6 +682,7 @@ static int dwc3_qcom_remove(struct platform_device *pdev)
> }
> qcom->num_clocks = 0;
>
> + usb_interconnect_exit(qcom);
> reset_control_assert(qcom->resets);
>
> pm_runtime_allow(dev);
>
The patch looks ok, but does not apply to neither mainline or linux-next.

Thanks,
Georgi