--- /dev/null
+From c5324b25fe98c7a4784248b53a75720b226436c2 Mon Sep 17 00:00:00 2001
+From: Li Jun <jun.li@nxp.com>
+Date: Tue, 29 Oct 2019 17:40:25 +0800
+Subject: [PATCH] MLK-22675 usb: dwc3: host: disable park mode
+
+- Advantage of park mode
+ When only a single Async endpoint is active.
+
+- Behavior of park mode
+ 1. The controller prefetches data/TRBs to do 3 * burst_size worth
+ of packets.
+ 2. When park mode is disabled there will be some delay between
+ bursts on the USB. This can be avoided if park mode is enabled
+ in cases of only one endpoint is active.
+ 3. But this delay is significant only with systems of large
+ latencies.
+ 4. We have noticed that in cases where a device NAKs often, it
+ tends to bring down the performance for a single endpoint case.
+
+- Issue on "park mode"
+ 1. LSP (List Processor) goes in and out of park mode irrespective
+ of the fact that there are more endpoints active. #LSP consider
+ that there is only one endpoint active.
+ 2. This causes master scheduler and transaction handlers to think
+ that they are in park mode even though they are not. This is
+ because request to transaction handlers, generated by HSCH is
+ in park mode when the request is made
+ 3. This causes a case where the master scheduler calculates wrongly
+ the number of TRB cache space available.
+ 4. Because of the wrongly calculated number of TRB spaces, the core
+ fetches more TRBS than there is space for.
+ 5. This causes overwriting the TRB cache area into the TRQ cache
+ area which is next to the TRB cache area.
+ 6. This causes invalidating an entry in the TRQ
+ 7. This causes transaction handlers to ignore a request in the TRQ
+ which it should have processed.
+ 8. This causes the main scheduler to hang because it is waiting for
+ status from transaction handler.
+ 9. This causes host controller to hang.
+
+- Work Around
+ Disabling park mode for super speed by setting GUCTL1[17] to be 1.
+
+The STAR number is 9001415732, which is target to be released around
+May,2020.
+
+Reviewed-by: Peter Chen <peter.chen@nxp.com>
+Reviewed-by: Ran Wang <ran.wang_1@nxp.com>
+Signed-off-by: Li Jun <jun.li@nxp.com>
+---
+ drivers/usb/dwc3/core.c | 15 +++++++++++++++
+ drivers/usb/dwc3/core.h | 1 +
+ 2 files changed, 16 insertions(+)
+
+--- a/drivers/usb/dwc3/core.c
++++ b/drivers/usb/dwc3/core.c
+@@ -1030,6 +1030,21 @@ static int dwc3_core_init(struct dwc3 *d
+ reg |= DWC3_GUCTL_HSTINAUTORETRY;
+
+ dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
++
++ /*
++ * Disable Park Mode for super speed:
++ * Park mode is used in host mode when only a single async
++ * endpoint is active, but which has a known issue cause
++ * USB3.0 HC may die when read and write at the same time,
++ * considering the advantages of this mode are minimal,
++ * this issue only impacts super speed and exist on all IP
++ * versions, disable it for SS, Synopsys will release a formal
++ * STAR 9001415732, and disable it by default in next IP
++ * release.
++ */
++ reg = dwc3_readl(dwc->regs, DWC3_GUCTL1);
++ reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
++ dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
+ }
+
+ /*
+--- a/drivers/usb/dwc3/core.h
++++ b/drivers/usb/dwc3/core.h
+@@ -253,6 +253,7 @@
+ /* Global User Control 1 Register */
+ #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS BIT(28)
+ #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW BIT(24)
++#define DWC3_GUCTL1_PARKMODE_DISABLE_SS BIT(17)
+
+ /* Global Status Register */
+ #define DWC3_GSTS_OTG_IP BIT(10)
projects / openwrt / staging / wigyori.git / blobdiff