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