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 | 18 ++++++++++++++++++
drivers/usb/dwc3/core.h | 15 +++++++++++++++
drivers/usb/dwc3/gadget.c | 16 ++++++++++++++++
3 files changed, 49 insertions(+)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 1a034f1..6733838 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1026,12 +1026,30 @@ static void dwc3_get_properties(struct dwc3 *dwc)
dwc->hird_threshold = hird_threshold
| (dwc->is_utmi_l1_suspend << 4);
+ dwc->imod_interval = 0;
+ device_property_read_u16(dev, "snps,imod_interval",
+ &dwc->imod_interval);
+}
+
+/* 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 4f15c23..e09888f 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;
@@ -843,6 +851,8 @@ 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;
@@ -930,6 +940,7 @@ 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;
@@ -988,6 +999,8 @@ struct dwc3 {
unsigned tx_de_emphasis_quirk:1;
unsigned tx_de_emphasis:2;
+
+ u16 imod_interval;
};
/* -------------------------------------------------------------------------- */
@@ -1159,6 +1172,8 @@ 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 54ebbd9..083b2dea 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1680,6 +1680,17 @@ 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);
+ } 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);
@@ -2876,6 +2887,11 @@ 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);
+ dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), dwc->imod_interval);
+ }
+
return ret;
}
--
2.10.0
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