This is a note to let you know that I've just added the patch titled
usb: dwc2: Don't reset the core after setting turnaround time
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-dwc2-don-t-reset-the-core-after-setting-turnarou.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 95ad814a73a442ffa5de141af700ae6c3bf0f3e8
Author: Clément Lassieur <clement@xxxxxxxxxxxx>
Date: Thu Jun 3 17:59:21 2021 +0200
usb: dwc2: Don't reset the core after setting turnaround time
[ Upstream commit aafe93516b8567ab5864e1f4cd3eeabc54fb0e5a ]
Every time the hub signals a reset while we (device) are hsotg->connected,
dwc2_hsotg_core_init_disconnected() is called, which in turn calls
dwc2_hs_phy_init().
GUSBCFG.USBTrdTim is cleared upon Core Soft Reset, so if
hsotg->params.phy_utmi_width is 8-bit, the value of GUSBCFG.USBTrdTim (the
default one: 0x5, corresponding to 16-bit) is always different from
hsotg->params.phy_utmi_width, thus dwc2_core_reset() is called every
time (usbcfg != usbcfg_old), which causes 2 issues:
1) The call to dwc2_core_reset() does another reset 300us after the initial
Chirp K of the first reset (which should last at least Tuch = 1ms), and
messes up the High-speed Detection Handshake: both hub and device drive
current into the D+ and D- lines at the same time.
2) GUSBCFG.USBTrdTim is cleared by the second reset, so its value is always
the default one (0x5).
Setting GUSBCFG.USBTrdTim after the potential call to dwc2_core_reset()
fixes both issues. It is now set even when select_phy is false because the
cost of the Core Soft Reset is removed.
Fixes: 1e868545f2bb ("usb: dwc2: gadget: Move gadget phy init into core phy init")
Signed-off-by: Clément Lassieur <clement@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210603155921.940651-1-clement@xxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index 6f70ab9577b4..272ae5722c86 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -1111,15 +1111,6 @@ static int dwc2_hs_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
usbcfg &= ~(GUSBCFG_ULPI_UTMI_SEL | GUSBCFG_PHYIF16);
if (hsotg->params.phy_utmi_width == 16)
usbcfg |= GUSBCFG_PHYIF16;
-
- /* Set turnaround time */
- if (dwc2_is_device_mode(hsotg)) {
- usbcfg &= ~GUSBCFG_USBTRDTIM_MASK;
- if (hsotg->params.phy_utmi_width == 16)
- usbcfg |= 5 << GUSBCFG_USBTRDTIM_SHIFT;
- else
- usbcfg |= 9 << GUSBCFG_USBTRDTIM_SHIFT;
- }
break;
default:
dev_err(hsotg->dev, "FS PHY selected at HS!\n");
@@ -1141,6 +1132,24 @@ static int dwc2_hs_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
return retval;
}
+static void dwc2_set_turnaround_time(struct dwc2_hsotg *hsotg)
+{
+ u32 usbcfg;
+
+ if (hsotg->params.phy_type != DWC2_PHY_TYPE_PARAM_UTMI)
+ return;
+
+ usbcfg = dwc2_readl(hsotg, GUSBCFG);
+
+ usbcfg &= ~GUSBCFG_USBTRDTIM_MASK;
+ if (hsotg->params.phy_utmi_width == 16)
+ usbcfg |= 5 << GUSBCFG_USBTRDTIM_SHIFT;
+ else
+ usbcfg |= 9 << GUSBCFG_USBTRDTIM_SHIFT;
+
+ dwc2_writel(hsotg, usbcfg, GUSBCFG);
+}
+
int dwc2_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
{
u32 usbcfg;
@@ -1158,6 +1167,9 @@ int dwc2_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
retval = dwc2_hs_phy_init(hsotg, select_phy);
if (retval)
return retval;
+
+ if (dwc2_is_device_mode(hsotg))
+ dwc2_set_turnaround_time(hsotg);
}
if (hsotg->hw_params.hs_phy_type == GHWCFG2_HS_PHY_TYPE_ULPI &&
