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From 61d471c8da972c7ebbaf63779bf8100ee1ec54eb Mon Sep 17 00:00:00 2001
From: Ran Wang <ran.wang_1@nxp.com>
Date: Wed, 16 Jan 2019 13:23:17 +0800
Subject: [PATCH] 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.
Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
---
drivers/usb/dwc3/core.c | 3 +++
drivers/usb/dwc3/core.h | 3 +++
drivers/usb/dwc3/host.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 54 insertions(+)
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1355,6 +1355,9 @@ static void dwc3_get_properties(struct d
dwc->dis_metastability_quirk = device_property_read_bool(dev,
"snps,dis_metastability_quirk");
+ dwc->host_vbus_glitches = device_property_read_bool(dev,
+ "snps,host-vbus-glitches");
+
dwc->lpm_nyet_threshold = lpm_nyet_threshold;
dwc->tx_de_emphasis = tx_de_emphasis;
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1041,6 +1041,8 @@ struct dwc3_scratchpad_array {
* 2 - No de-emphasis
* 3 - Reserved
* @dis_metastability_quirk: set to disable metastability quirk.
+ * @host_vbus_glitches: set to avoid vbus glitch during
+ * xhci reset.
* @imod_interval: set the interrupt moderation interval in 250ns
* increments or 0 to disable.
*/
@@ -1233,6 +1235,7 @@ struct dwc3 {
unsigned tx_de_emphasis:2;
unsigned dis_metastability_quirk:1;
+ unsigned host_vbus_glitches:1;
u16 imod_interval;
};
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -9,8 +9,49 @@
#include <linux/platform_device.h>
+#include "../host/xhci.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
+ * @dwc3: Pointer to our controller context structure
+ */
+static void dwc3_power_off_all_roothub_ports(struct dwc3 *dwc)
+{
+ int i, port_num;
+ u32 reg, op_regs_base, offset;
+ void __iomem *xhci_regs;
+
+ /* 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 int dwc3_host_get_irq(struct dwc3 *dwc)
{
struct platform_device *dwc3_pdev = to_platform_device(dwc->dev);
@@ -50,6 +91,13 @@ int dwc3_host_init(struct dwc3 *dwc)
struct platform_device *dwc3_pdev = to_platform_device(dwc->dev);
int prop_idx = 0;
+ /*
+ * We have 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)
+ dwc3_power_off_all_roothub_ports(dwc);
+
irq = dwc3_host_get_irq(dwc);
if (irq < 0)
return irq;
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