diff mbox series

[v2] usb: cdns3: gadget.c: Set fast access bit

Message ID 20240423082420.32336-1-r-gunasekaran@ti.com
State Superseded
Delegated to: Marek Vasut
Headers show
Series [v2] usb: cdns3: gadget.c: Set fast access bit | expand

Commit Message

Ravi Gunasekaran April 23, 2024, 8:24 a.m. UTC 
From: Aswath Govindraju <a-govindraju@ti.com>

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.

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>
---
v1 was posted and was reviewed as well. But it did not get merged.
This change is present in upstream linux kernel as well.
Upstream Linux kernel commit: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")

Changes since v1:
----------------
* Rebased to tip of -next
* Added Reviewed-by tag

v1: https://lore.kernel.org/u-boot/20230505121353.23486-1-r-gunasekaran@ti.com/

 drivers/usb/cdns3/gadget.c | 4 ++++
 1 file changed, 4 insertions(+)


base-commit: bc39e06778168a34bb4e0a34fbee4edbde4414d8

Comments

Marek Vasut April 23, 2024, 12:53 p.m. UTC | #1 
On 4/23/24 10:24 AM, Ravi Gunasekaran wrote:
> From: Aswath Govindraju <a-govindraju@ti.com>
> 
> 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.
> 
> 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>
> ---
> v1 was posted and was reviewed as well. But it did not get merged.
> This change is present in upstream linux kernel as well.
> Upstream Linux kernel commit: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")

This commit ^ should be mentioned in the commit message.

With that fixed:

Reviewed-by: Marek Vasut <marex@denx.de>

Thanks !
diff mbox series

Patch

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, &regs->usb_ien);
 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->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;