From 83eed2cba32ad8c683bd42e0ad5426589f630bd2 Mon Sep 17 00:00:00 2001
From: Aswath Govindraju <a-govindraju@ti.com>
Date: Wed, 24 Apr 2024 13:09:11 +0530
Subject: [PATCH] usb: cdns3: gadget.c: Set fast access bit
When the device port is in a low power state [U3/L2/Not Connected],
accesses to usb device registers may take a long time. This could lead to
potential core hang when the controller registers are accessed after the
port is disabled by setting DEVDS field. Setting the fast register access
bit ensures that the PHY clock is keeping up in active state.
Therefore, set fast access bit to ensure the accesses to device registers
are quick even in low power states.
commit b5148d946f45 ("usb: cdns3: gadget: set fast access bit") in the
upstream kernel is taken as reference.
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20240424073911.1943-1-r-gunasekaran@ti.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
---
drivers/usb/cdns3/gadget.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 7aa0c6b2be..d11175dc5b 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2325,6 +2325,9 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
writel(USB_IEN_INIT, ®s->usb_ien);
writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, ®s->usb_conf);
+ /* Set the Fast access bit */
+ writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
+
cdns3_configure_dmult(priv_dev, NULL);
cdns3_gadget_pullup(&priv_dev->gadget, 1);
@@ -2383,6 +2386,7 @@ static int cdns3_gadget_udc_stop(struct usb_gadget *gadget)
/* disable interrupt for device */
writel(0, &priv_dev->regs->usb_ien);
+ writel(0, &priv_dev->regs->usb_pwr);
writel(USB_CONF_DEVDS, &priv_dev->regs->usb_conf);
return ret;
--
2.39.5