From: Ran Wang <ran.wang_1@xxxxxxx>
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@xxxxxxx>
Reviewed-by: Peter Chen <peter.chen@xxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Notes:
Last review at June 06, 2019. Fixed all review comments and sent again.
https://lore.kernel.org/linux-kernel/AM5PR0402MB2865979E26017BC5937DBBA5F1170@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
drivers/usb/dwc3/core.c | 2 ++
drivers/usb/dwc3/core.h | 2 ++
drivers/usb/dwc3/host.c | 46 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 50 insertions(+)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 3e55838c00014..a57adf0c11dd1 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1626,6 +1626,8 @@ 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 = device_property_read_bool(dev, "snps,host-vbus-glitches");
+
dwc->lpm_nyet_threshold = lpm_nyet_threshold;
dwc->tx_de_emphasis = tx_de_emphasis;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index e3eea965e57bf..0269bacbbf6bd 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1135,6 +1135,7 @@ struct dwc3_scratchpad_array {
* @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.
+ * @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.
* @max_cfg_eps: current max number of IN eps used across all USB configs.
@@ -1353,6 +1354,7 @@ struct dwc3 {
unsigned tx_de_emphasis:2;
unsigned dis_metastability_quirk:1;
+ unsigned host_vbus_glitches:1;
unsigned dis_split_quirk:1;
unsigned async_callbacks:1;
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index 61f57fe5bb783..af8903ee37c20 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -11,6 +11,7 @@
#include <linux/of.h>
#include <linux/platform_device.h>
+#include "../host/xhci.h"
#include "core.h"
static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
@@ -28,6 +29,44 @@ static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
dwc->xhci_resources[1].name = name;
}
+#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);
@@ -66,6 +105,13 @@ int dwc3_host_init(struct dwc3 *dwc)
int ret, irq;
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;
--
2.34.1
