From: Yu Chen <chenyu56@xxxxxxxxxx> From: John Stultz <john.stultz@xxxxxxxxxx> According to the programming guide, to switch mode for DRD controller, the driver needs to do the following. To switch from device to host: 1. Reset controller with GCTL.CoreSoftReset 2. Set GCTL.PrtCapDir(host mode) 3. Reset the host with USBCMD.HCRESET 4. Then follow up with the initializing host registers sequence To switch from host to device: 1. Reset controller with GCTL.CoreSoftReset 2. Set GCTL.PrtCapDir(device mode) 3. Reset the device with DCTL.CSftRst 4. Then follow up with the initializing registers sequence Currently we're missing step 1) to do GCTL.CoreSoftReset and step 3) of switching from host to device. John Stult reported a lockup issue seen with HiKey960 platform without these steps[1]. Similar issue is observed with Ferry's testing platform[2]. So, apply the required steps along with some fixes to Yu Chen's and John Stultz's version. The main fixes to their versions are the missing wait for clocks synchronization before clearing GCTL.CoreSoftReset and only apply DCTL.CSftRst when switching from host to device. [1] https://lore.kernel.org/linux-usb/20210108015115.27920-1-john.stultz@xxxxxxxxxx/ [2] https://lore.kernel.org/linux-usb/0ba7a6ba-e6a7-9cd4-0695-64fc927e01f1@xxxxxxxxx/ Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Cc: Ferry Toth <fntoth@xxxxxxxxx> Cc: Wesley Cheng <wcheng@xxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Fixes: 41ce1456e1db ("usb: dwc3: core: make dwc3_set_mode() work properly") Signed-off-by: Yu Chen <chenyu56@xxxxxxxxxx> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> Signed-off-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> --- Note: Only some basic mode switching tests were done using our HAPS platform. It'd be great if we can have some "Tested-by" with some real hardwares. Thanks. drivers/usb/dwc3/core.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 5c25e6a72dbd..4ac2895331b7 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -14,6 +14,7 @@ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/spinlock.h> +#include <linux/mutex.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/interrupt.h> @@ -40,6 +41,8 @@ #define DWC3_DEFAULT_AUTOSUSPEND_DELAY 5000 /* ms */ +static DEFINE_MUTEX(mode_switch_lock); + /** * dwc3_get_dr_mode - Validates and sets dr_mode * @dwc: pointer to our context structure @@ -114,13 +117,20 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode) dwc->current_dr_role = mode; } +static int dwc3_core_soft_reset(struct dwc3 *dwc); + static void __dwc3_set_mode(struct work_struct *work) { struct dwc3 *dwc = work_to_dwc(work); unsigned long flags; + unsigned int hw_mode; int ret; u32 reg; + mutex_lock(&mode_switch_lock); + + hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0); + pm_runtime_get_sync(dwc->dev); if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG) @@ -154,6 +164,24 @@ static void __dwc3_set_mode(struct work_struct *work) break; } + if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD) { + reg = dwc3_readl(dwc->regs, DWC3_GCTL); + reg |= DWC3_GCTL_CORESOFTRESET; + dwc3_writel(dwc->regs, DWC3_GCTL, reg); + + /* + * Wait for internal clocks to synchronized. DWC_usb31 and + * DWC_usb32 may need at least 50ms (less for DWC_usb3). To + * keep it consistent across different IPs, let's wait up to + * 100ms before clearing GCTL.CORESOFTRESET. + */ + msleep(100); + + reg = dwc3_readl(dwc->regs, DWC3_GCTL); + reg &= ~DWC3_GCTL_CORESOFTRESET; + dwc3_writel(dwc->regs, DWC3_GCTL, reg); + } + spin_lock_irqsave(&dwc->lock, flags); dwc3_set_prtcap(dwc, dwc->desired_dr_role); @@ -178,6 +206,9 @@ static void __dwc3_set_mode(struct work_struct *work) } break; case DWC3_GCTL_PRTCAP_DEVICE: + if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD) + dwc3_core_soft_reset(dwc); + dwc3_event_buffers_setup(dwc); if (dwc->usb2_phy) @@ -200,6 +231,7 @@ static void __dwc3_set_mode(struct work_struct *work) out: pm_runtime_mark_last_busy(dwc->dev); pm_runtime_put_autosuspend(dwc->dev); + mutex_unlock(&mode_switch_lock); } void dwc3_set_mode(struct dwc3 *dwc, u32 mode) base-commit: 4b853c236c7b5161a2e444bd8b3c76fe5aa5ddcb -- 2.28.0
