By default when core sees any transaction error(CRC or overflow)
it replies with terminating retry ACK (Retry=1 and Nump == 0).
Enabling this Auto Retry feature in controller, on seeing any
transaction errors makes the core to send an non-terminating ACK
transaction packet (that is, ACK TP with Retry=1 and Nump != 0).
Doing so will give controller a chance to recover from the error
condition.
Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx>
---
Documentation/devicetree/bindings/usb/dwc3.txt | 5 +++++
drivers/usb/dwc3/core.c | 16 ++++++++++++++++
drivers/usb/dwc3/core.h | 6 ++++++
3 files changed, 27 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 7f13ebe..2ba2bc2 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -94,6 +94,11 @@ Optional properties:
this and tx-thr-num-pkt-prd to a valid, non-zero value
1-16 (DWC_usb31 programming guide section 1.2.3) to
enable periodic ESS TX threshold.
+ - snps,enable_auto_retry: Set to enable Auto retry Feature to make the
+ controller operating in Host mode on seeing transaction
+ errors(CRC errors or internal overrun scenerios) on IN
+ transfers to reply to the device with a non-terminating
+ retry ACK (i.e, an ACK TP with Retry=1 & Nump != 0)
- <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 1038075..1c1ab93 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -883,6 +883,20 @@ static int dwc3_core_init(struct dwc3 *dwc)
dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
}
+ if (dwc->autoretry_enable) {
+ reg = dwc3_readl(dwc->regs, DWC3_GUCTL);
+
+ /* Enable Auto retry Feature to make the controller operating in
+ * Host mode on seeing transaction errors(CRC errors or internal
+ * overrun scenerios) on IN transfers to reply to the device
+ * with a non-terminating retry ACK (i.e, an ACK transcation
+ * packet with Retry=1 & Nump != 0)
+ */
+ reg |= DWC3_GUCTL_HSTINAUTORETRY;
+
+ dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
+ }
+
/*
* Must config both number of packets and max burst settings to enable
* RX and/or TX threshold.
@@ -1179,6 +1193,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
dwc->dis_metastability_quirk = device_property_read_bool(dev,
"snps,dis_metastability_quirk");
+ dwc->autoretry_enable = device_property_read_bool(dev,
+ "snps,enable_auto_retry");
dwc->lpm_nyet_threshold = lpm_nyet_threshold;
dwc->tx_de_emphasis = tx_de_emphasis;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 285ce0e..558dfda 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -227,6 +227,9 @@
#define DWC3_GCTL_GBLHIBERNATIONEN BIT(1)
#define DWC3_GCTL_DSBLCLKGTNG BIT(0)
+/* Global User Control Register */
+#define DWC3_GUCTL_HSTINAUTORETRY BIT(14)
+
/* Global User Control 1 Register */
#define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS BIT(28)
#define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW BIT(24)
@@ -984,6 +987,8 @@ struct dwc3_scratchpad_array {
* 2 - No de-emphasis
* 3 - Reserved
* @dis_metastability_quirk: set to disable metastability quirk.
+ * @autoretry_enable: set to enable AutoRetry feature in controller to
+ * give an non terminating retry ACK (Retry=1 & Nump != 0)
* @imod_interval: set the interrupt moderation interval in 250ns
* increments or 0 to disable.
*/
@@ -1153,6 +1158,7 @@ struct dwc3 {
unsigned tx_de_emphasis:2;
unsigned dis_metastability_quirk:1;
+ unsigned autoretry_enable:1;
u16 imod_interval;
};
--
2.1.1
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