Commit 2d2a3349 authored by Ran Wang's avatar Ran Wang Committed by Greg Kroah-Hartman
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usb: dwc3: Add workaround for host mode VBUS glitch when boot 



When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS
(or its control signal) will be turned on immediately on related Root Hub
ports. Then, the VBUS is turned off for a little while(15us) when do xhci
reset (conducted by xhci driver) and back to normal finally, we can
observe a negative glitch of related signal happen.

This VBUS glitch might cause some USB devices enumeration fail if kernel
boot with them connected. Such as LS1012AFWRY/LS1043ARDB/LX2160AQDS
/LS1088ARDB with Kingston 16GB USB2.0/Kingston USB3.0/JetFlash Transcend
4GB USB2.0 drives. The fail cases include enumerated as full-speed device
or report wrong device descriptor, etc.

One SW workaround which can fix this is by programing all xhci PORTSC[PP]
to 0 to turn off VBUS immediately after setting host mode in DWC3 driver
(per signal measurement result, it will be too late to do it in
xhci-plat.c or xhci.c). Then, after xhci reset complete in xhci driver,
PORTSC[PP]s' value will back to 1 automatically and VBUS on at that time,
no glitch happen and normal enumeration process has no impact.

Acked-by: default avatarThinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: default avatarRan Wang <ran.wang_1@nxp.com>
Reviewed-by: default avatarPeter Chen <peter.chen@nxp.com>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240124152525.3910311-4-Frank.Li@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bc83a877

drivers/usb/dwc3/core.c

+3 −0
Original line number Diff line number Diff line
@@ -1626,6 +1626,9 @@ static void dwc3_get_properties(struct dwc3 *dwc) 
	dwc->dis_split_quirk = device_property_read_bool(dev,

				"snps,dis-split-quirk");



	dwc->host_vbus_glitches_quirk = device_property_read_bool(dev,

				"snps,host-vbus-glitches-quirk");



	dwc->lpm_nyet_threshold = lpm_nyet_threshold;

	dwc->tx_de_emphasis = tx_de_emphasis;

drivers/usb/dwc3/core.h

+2 −0
Original line number Diff line number Diff line
@@ -1132,6 +1132,7 @@ struct dwc3_scratchpad_array { 
 *	2	- No de-emphasis

 *	3	- Reserved

 * @dis_metastability_quirk: set to disable metastability quirk.

 * @host_vbus_glitches_quirk: set to avoid vbus glitch during xhci reset.

 * @dis_split_quirk: set to disable split boundary.

 * @wakeup_configured: set if the device is configured for remote wakeup.

 * @suspended: set to track suspend event due to U3/L2.
@@ -1353,6 +1354,7 @@ struct dwc3 { 
	unsigned		tx_de_emphasis:2;



	unsigned		dis_metastability_quirk:1;

	unsigned		host_vbus_glitches_quirk:1;



	unsigned		dis_split_quirk:1;

	unsigned		async_callbacks:1;

drivers/usb/dwc3/host.c

+51 −0
Original line number Diff line number Diff line
@@ -11,8 +11,52 @@ 
#include <linux/of.h>

#include <linux/platform_device.h>



#include "../host/xhci-port.h"

#include "../host/xhci-ext-caps.h"

#include "../host/xhci-caps.h"

#include "core.h"



#define XHCI_HCSPARAMS1		0x4

#define XHCI_PORTSC_BASE	0x400



/**

 * dwc3_power_off_all_roothub_ports - Power off all Root hub ports

 * @dwc: Pointer to our controller context structure

 */

static void dwc3_power_off_all_roothub_ports(struct dwc3 *dwc)

{

	void __iomem *xhci_regs;

	u32 op_regs_base;

	int port_num;

	u32 offset;

	u32 reg;

	int i;



	/* xhci regs is not mapped yet, do it temperary here */

	if (dwc->xhci_resources[0].start) {

		xhci_regs = ioremap(dwc->xhci_resources[0].start, DWC3_XHCI_REGS_END);

		if (IS_ERR(xhci_regs)) {

			dev_err(dwc->dev, "Failed to ioremap xhci_regs\n");

			return;

		}



		op_regs_base = HC_LENGTH(readl(xhci_regs));

		reg = readl(xhci_regs + XHCI_HCSPARAMS1);

		port_num = HCS_MAX_PORTS(reg);



		for (i = 1; i <= port_num; i++) {

			offset = op_regs_base + XHCI_PORTSC_BASE + 0x10 * (i - 1);

			reg = readl(xhci_regs + offset);

			reg &= ~PORT_POWER;

			writel(reg, xhci_regs + offset);

		}



		iounmap(xhci_regs);

	} else {

		dev_err(dwc->dev, "xhci base reg invalid\n");

	}

}



static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,

					int irq, char *name)

{
@@ -66,6 +110,13 @@ int dwc3_host_init(struct dwc3 *dwc) 
	int			ret, irq;

	int			prop_idx = 0;



	/*

	 * Some platforms need to power off all Root hub ports immediately after DWC3 set to host

	 * mode to avoid VBUS glitch happen when xhci get reset later.

	 */

	if (dwc->host_vbus_glitches_quirk)

		dwc3_power_off_all_roothub_ports(dwc);



	irq = dwc3_host_get_irq(dwc);

	if (irq < 0)

		return irq;