redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

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>
5.4-rM2-2.2.x-imx-squashed
Ran Wang 2019-01-16 13:23:17 +08:00 committed by Dong Aisheng
parent bca3c354c8
commit b30e41dc1e
3 changed files with 54 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/usb/dwc3/core.c
View File

@ -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;

3
drivers/usb/dwc3/core.h
View File

@ -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;
};

48
drivers/usb/dwc3/host.c
View File

@ -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;