This is a note to let you know that I've just added the patch titled
usb: dwc3: ulpi: Use VStsDone to detect PHY regs access completion
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From ce722da66d3e9384aa2de9d33d584ee154e5e157 Mon Sep 17 00:00:00 2001
From: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
Date: Thu, 10 Dec 2020 11:50:06 +0300
Subject: usb: dwc3: ulpi: Use VStsDone to detect PHY regs access completion
In accordance with [1] the DWC_usb3 core sets the GUSB2PHYACCn.VStsDone
bit when the PHY vendor control access is done and clears it when the
application initiates a new transaction. The doc doesn't say anything
about the GUSB2PHYACCn.VStsBsy flag serving for the same purpose. Moreover
we've discovered that the VStsBsy flag can be cleared before the VStsDone
bit. So using the former as a signal of the PHY control registers
completion might be dangerous. Let's have the VStsDone flag utilized
instead then.
[1] Synopsys DesignWare Cores SuperSpeed USB 3.0 xHCI Host Controller
Databook, 2.70a, December 2013, p.388
Fixes: 88bc9d194ff6 ("usb: dwc3: add ULPI interface support")
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20201210085008.13264-2-Sergey.Semin@xxxxxxxxxxxxxxxxxxxx
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/core.h | 1 +
drivers/usb/dwc3/ulpi.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 2f95f08ca511..1b241f937d8f 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -285,6 +285,7 @@
/* Global USB2 PHY Vendor Control Register */
#define DWC3_GUSB2PHYACC_NEWREGREQ BIT(25)
+#define DWC3_GUSB2PHYACC_DONE BIT(24)
#define DWC3_GUSB2PHYACC_BUSY BIT(23)
#define DWC3_GUSB2PHYACC_WRITE BIT(22)
#define DWC3_GUSB2PHYACC_ADDR(n) (n << 16)
diff --git a/drivers/usb/dwc3/ulpi.c b/drivers/usb/dwc3/ulpi.c
index aa213c9815f6..3cc4f4970c05 100644
--- a/drivers/usb/dwc3/ulpi.c
+++ b/drivers/usb/dwc3/ulpi.c
@@ -24,7 +24,7 @@ static int dwc3_ulpi_busyloop(struct dwc3 *dwc)
while (count--) {
reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
- if (!(reg & DWC3_GUSB2PHYACC_BUSY))
+ if (reg & DWC3_GUSB2PHYACC_DONE)
return 0;
cpu_relax();
}
--
2.29.2
