usb: dwc3: ulpi: Use VStsDone to detect PHY regs access completion

commit ce722da66d3e9384aa2de9d33d584ee154e5e157 upstream.

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@linux.intel.com>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201210085008.13264-2-Sergey.Semin@baikalelectronics.ru
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 8747f9f02229e0d21f631dbb5c0e4a2d1030b9dc..8c59a8aeb94092e2406cbd39c08b91729ff9e729 100644 (file)
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -227,6 +227,7 @@
 
 /* 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 e87ce8e9edee90825283b7a06f56fbc00168da3c..d3b68e97096e76f44f93ed051cd1d765003af934 100644 (file)
--- a/drivers/usb/dwc3/ulpi.c
+++ b/drivers/usb/dwc3/ulpi.c
@@ -27,7 +27,7 @@ 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();
        }