Hi,
John Youn <johnyoun@xxxxxxxxxxxx> writes:
> Implement interrupt moderation which allows the interrupt rate to be
> throttled. To enable this feature the dwc->imod_interval must be set to
> 1 or greater. This value specifies the minimum inter-interrupt interval,
> in 250 ns increments. A value of 0 disables interrupt moderation.
>
> This applies for DWC_usb3 version 3.00a and higher and for DWC_usb31
> version 1.20a and higher.
>
> Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/core.c | 16 ++++++++++++++++
> drivers/usb/dwc3/core.h | 15 +++++++++++++++
> drivers/usb/dwc3/gadget.c | 16 ++++++++++++++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 87d0cfb..889dbab 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -982,12 +982,28 @@ static void dwc3_get_properties(struct dwc3 *dwc)
> dwc->hird_threshold = hird_threshold
> | (dwc->is_utmi_l1_suspend << 4);
>
> + dwc->imod_interval = 0;
> +}
> +
> +/* check whether the core supports IMOD */
> +bool dwc3_has_imod(struct dwc3 *dwc)
> +{
> + return ((dwc3_is_usb3(dwc) &&
> + dwc->revision >= DWC3_REVISION_300A) ||
> + (dwc3_is_usb31(dwc) &&
> + dwc->revision >= DWC3_USB31_REVISION_120A));
> }
>
> static void dwc3_check_params(struct dwc3 *dwc)
> {
> struct device *dev = dwc->dev;
>
> + /* Check for proper value of imod_interval */
> + if (dwc->imod_interval && !dwc3_has_imod(dwc)) {
> + dev_warn(dwc->dev, "Interrupt moderation not supported\n");
> + dwc->imod_interval = 0;
> + }
> +
> /* Check the maximum_speed parameter */
> switch (dwc->maximum_speed) {
> case USB_SPEED_LOW:
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index bf63756..ef81fa5 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -67,6 +67,7 @@
> #define DWC3_DEVICE_EVENT_OVERFLOW 11
>
> #define DWC3_GEVNTCOUNT_MASK 0xfffc
> +#define DWC3_GEVNTCOUNT_EHB (1 << 31)
> #define DWC3_GSNPSID_MASK 0xffff0000
> #define DWC3_GSNPSREV_MASK 0xffff
>
> @@ -149,6 +150,8 @@
> #define DWC3_DEPCMDPAR0 0x08
> #define DWC3_DEPCMD 0x0c
>
> +#define DWC3_DEV_IMOD(n) (0xca00 + (n * 0x4))
> +
> /* OTG Registers */
> #define DWC3_OCFG 0xcc00
> #define DWC3_OCTL 0xcc04
> @@ -465,6 +468,11 @@
> #define DWC3_DEPCMD_TYPE_BULK 2
> #define DWC3_DEPCMD_TYPE_INTR 3
>
> +#define DWC3_DEV_IMOD_COUNT_SHIFT 16
> +#define DWC3_DEV_IMOD_COUNT_MASK (0xffff << 16)
> +#define DWC3_DEV_IMOD_INTERVAL_SHIFT 0
> +#define DWC3_DEV_IMOD_INTERVAL_MASK (0xffff << 0)
> +
> /* Structures */
>
> struct dwc3_trb;
> @@ -846,6 +854,8 @@ struct dwc3_scratchpad_array {
> * 1 - -3.5dB de-emphasis
> * 2 - No de-emphasis
> * 3 - Reserved
> + * @imod_interval: set the interrupt moderation interval in 250ns
> + * increments or 0 to disable.
> */
> struct dwc3 {
> struct usb_ctrlrequest *ctrl_req;
> @@ -933,6 +943,7 @@ struct dwc3 {
> */
> #define DWC3_REVISION_IS_DWC31 0x80000000
> #define DWC3_USB31_REVISION_110A (0x3131302a | DWC3_REVISION_IS_DWC31)
> +#define DWC3_USB31_REVISION_120A (0x3132302a | DWC3_REVISION_IS_DWC31)
>
> enum dwc3_ep0_next ep0_next_event;
> enum dwc3_ep0_state ep0state;
> @@ -991,6 +1002,8 @@ struct dwc3 {
>
> unsigned tx_de_emphasis_quirk:1;
> unsigned tx_de_emphasis:2;
> +
> + u16 imod_interval;
> };
>
> /* -------------------------------------------------------------------------- */
> @@ -1162,6 +1175,8 @@ static inline bool dwc3_is_usb31(struct dwc3 *dwc)
> return !!(dwc->revision & DWC3_REVISION_IS_DWC31);
> }
>
> +bool dwc3_has_imod(struct dwc3 *dwc);
> +
> #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);
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index baa2c64..0973167 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1685,6 +1685,17 @@ static int __dwc3_gadget_start(struct dwc3 *dwc)
> int ret = 0;
> u32 reg;
>
> + /*
> + * Use IMOD if enabled via dwc->imod_interval. Otherwise, if
> + * the core supports IMOD, disable it.
> + */
> + if (dwc->imod_interval) {
> + dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), dwc->imod_interval);
> + dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), DWC3_GEVNTCOUNT_EHB);
is this safe? You're doing this after request_threaded_irq(). Sure, IRQs
are still masked, but couldn't clear events that would get fired as soon
as we unmask events?
> + } else if (dwc3_has_imod(dwc)) {
> + dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), 0);
> + }
> +
> reg = dwc3_readl(dwc->regs, DWC3_DCFG);
> reg &= ~(DWC3_DCFG_SPEED_MASK);
>
> @@ -2847,6 +2858,11 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt)
> reg &= ~DWC3_GEVNTSIZ_INTMASK;
> dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
>
> + if (dwc->imod_interval) {
> + dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), DWC3_GEVNTCOUNT_EHB);
is this really safe? Aren't you forcefully clearing GEVNTCOUNT back to
zero here? Why couldn't you do a single write to GEVNTCOUNT?
Waiting for you reply before applying. BTW, I've applied patch 1, but
broke it down into smaller patches. I'll send them to linux-usb shortly.
--
balbi
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