Hi Sandeep,
On Thu, Jul 23, 2020 at 11:57:36PM +0530, Sandeep Maheswaram wrote:
> Add interconnect support in dwc3-qcom driver to vote for bus
> bandwidth.
>
> This requires for two different paths - from USB to
> DDR. The other is from APPS to USB.
>
> Signed-off-by: Sandeep Maheswaram <sanm@xxxxxxxxxxxxxx>
> Signed-off-by: Chandana Kishori Chiluveru <cchiluve@xxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/dwc3-qcom.c | 127 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 125 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index e1e78e9..712efb7 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;
> @@ -76,6 +85,8 @@ struct dwc3_qcom {
> enum usb_dr_mode mode;
> bool is_suspended;
> bool pm_suspended;
> + struct icc_path *icc_path_ddr;
> + struct icc_path *icc_path_apps;
> };
>
> static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
> @@ -190,6 +201,103 @@ static int dwc3_qcom_register_extcon(struct dwc3_qcom *qcom)
> return 0;
> }
>
> +static int dwc3_qcom_interconnect_enable(struct dwc3_qcom *qcom)
> +{
> + int ret;
> +
> + ret = icc_enable(qcom->icc_path_ddr);
> + if (ret)
> + return ret;
> +
> + ret = icc_enable(qcom->icc_path_apps);
> + if (ret)
> + return icc_disable(qcom->icc_path_ddr);
You are returning the result of icc_disable(), but it should be the
previous error. Just do
icc_disable(qcom->icc_path_ddr);
and use the below statement for returning (if not it should be 'return 0').
> +
> + return ret;
> +}
> +
> +static int dwc3_qcom_interconnect_disable(struct dwc3_qcom *qcom)
> +{
> + int ret;
> +
> + ret = icc_disable(qcom->icc_path_ddr);
> + if (ret)
> + return ret;
> +
> + ret = icc_disable(qcom->icc_path_apps);
> + if (ret)
> + goto err_reenable_memory_path;
Please make the error handling in _enable() and _disable() symmetrical, either
call icc_enable/disable() directly or use a goto in both functions (IMO the goto
is not needed in this case, it makes the code more complex rather than
simplifying it).
> +
> + return 0;
> +
> + /* Re-enable things in the event of an error */
> +err_reenable_memory_path:
> + dwc3_qcom_interconnect_enable(qcom);
Why this function which disables both paths and not just
icc_enable(qcom->icc_path_ddr), analogous to dwc3_qcom_interconnect_enable()?
> +
> + return ret;
> +}
> +
> +/**
> + * dwc3_qcom_interconnect_init() - Get interconnect path handles
> + * and set bandwidhth.
> + * @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->icc_path_ddr = of_icc_get(dev, "usb-ddr");
> + if (IS_ERR(qcom->icc_path_ddr)) {
> + dev_err(dev, "failed to get usb-ddr path: %ld\n",
> + PTR_ERR(qcom->icc_path_ddr));
> + return PTR_ERR(qcom->icc_path_ddr);
> + }
> +
> + qcom->icc_path_apps = of_icc_get(dev, "apps-usb");
> + if (IS_ERR(qcom->icc_path_apps)) {
> + dev_err(dev, "failed to get apps-usb path: %ld\n",
> + PTR_ERR(qcom->icc_path_apps));
> + return PTR_ERR(qcom->icc_path_apps);
> + }
> +
> + if (usb_get_maximum_speed(&qcom->dwc3->dev) >= USB_SPEED_SUPER ||
> + usb_get_maximum_speed(&qcom->dwc3->dev) == USB_SPEED_UNKNOWN)
> + ret = icc_set_bw(qcom->icc_path_ddr,
> + USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW);
> + else
> + ret = icc_set_bw(qcom->icc_path_ddr,
> + USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
> +
> + if (ret) {
> + dev_err(dev, "failed to set bandwidth for usb-ddr path: %d\n", ret);
> + return ret;
> + }
> +
> + ret = icc_set_bw(qcom->icc_path_apps,
> + APPS_USB_AVG_BW, APPS_USB_PEAK_BW);
> +
nit: remove empty line, the call and the if block belong together.
> + if (ret) {
> + dev_err(dev, "failed to set bandwidth for apps-usb path: %d\n", ret);
> + return ret;
> + }
