On Tue, Jan 23, 2024, Frank Li wrote: > 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: > Change from v2 to v3 > - reversed christmas tree > - please move major change hunk to the top > - Reword "We have to ..." to "Some platforms need to ... " > > Change from v1 to v2: > - split xhci.h > Last review at June 06, 2019. Fixed all review comments and sent again. > > https://urldefense.com/v3/__https://lore.kernel.org/linux-kernel/AM5PR0402MB2865979E26017BC5937DBBA5F1170@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/__;!!A4F2R9G_pg!YEsCyKK-dC7cMDJENYpU7xC2cfHhLa3SnXoedPYgtS3jP2bar4TF7hAcj2iHY1Mq1dqIXcshBWGmceo9fdjF$ > > drivers/usb/dwc3/core.c | 3 +++ > drivers/usb/dwc3/core.h | 2 ++ > drivers/usb/dwc3/host.c | 51 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 56 insertions(+) > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index 3e55838c00014..3b68e8e45b8b9 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -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; > > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h > index e3eea965e57bf..df544ec730d22 100644 > --- a/drivers/usb/dwc3/core.h > +++ b/drivers/usb/dwc3/core.h > @@ -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; > diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c > index 61f57fe5bb783..952d73d05dffa 100644 > --- a/drivers/usb/dwc3/host.c > +++ b/drivers/usb/dwc3/host.c > @@ -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 > + * @dwc3: Pointer to our controller context structure > + */ If you're trying to follow the kernel-doc style, then please do it properly with the kernel-doc comment style. /** * .. * .. */ > +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; > -- > 2.34.1 > Regardless whether you decided to update related the comment above: Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> Thanks, Thinh
