From b30e41dc1e494033fc1b4ad4a4fd61378d6aceef Mon Sep 17 00:00:00 2001 From: Ran Wang 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 Reviewed-by: Peter Chen --- drivers/usb/dwc3/core.c | 3 +++ drivers/usb/dwc3/core.h | 3 +++ drivers/usb/dwc3/host.c | 48 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 83936edb0924..895344d3d0a0 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1347,6 +1347,9 @@ static void dwc3_get_properties(struct dwc3 *dwc) 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; diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index 8143c7981b69..fa1470ecaae2 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -1032,6 +1032,8 @@ 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. */ @@ -1223,6 +1225,7 @@ struct dwc3 { unsigned tx_de_emphasis:2; unsigned dis_metastability_quirk:1; + unsigned host_vbus_glitches:1; u16 imod_interval; }; diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c index 5567ed2cddbe..cbadceae92e7 100644 --- a/drivers/usb/dwc3/host.c +++ b/drivers/usb/dwc3/host.c @@ -9,8 +9,49 @@ #include +#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;