[Patch v2 08/10] usb: chipidea: host: add quirk for ehci operation

[LW@KARO-electronics.de (Lothar Waßmann)]

Hi,

Peter Chen wrote:
> For chipidea controller, it does not follow ehci spec strictly.
> Taking resume signal as an example, it will stop resume signal about
> 20-21ms later automatically, but standard ehci spec says, the resume
> signal is controlled by software (clear portsc.PORT_RESUME).
> 
> This operation causes some remote wakeup problems for high speed
> devices due to host controller does not send SOF in time since
> software can't guarantee set run/stop bit in time (run/stop bit
> was cleared at the ehci suspend routine).
> 
> When software sets run/stop bit, it needs 1 SoF time to make it effect.
> If we close the PHY clock just after setting run/stop bit, it does
> not be set in practice, so a software delay is needed.
> 
> Signed-off-by: Peter Chen <peter.chen@freescale.com>
> ---
>  drivers/usb/chipidea/host.c |   51 +++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 51 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
> index 59e6020..283b385 100644
> --- a/drivers/usb/chipidea/host.c
> +++ b/drivers/usb/chipidea/host.c
> @@ -33,6 +33,53 @@
>  #include "host.h"
>  
>  static struct hc_driver __read_mostly ci_ehci_hc_driver;
> +static int (*orig_bus_suspend)(struct usb_hcd *hcd);
> +
> +static int ci_ehci_bus_suspend(struct usb_hcd *hcd)
> +{
> +	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
> +	int port;
> +	u32 tmp;
> +
> +	int ret = orig_bus_suspend(hcd);
> +
> +	if (ret)
> +		return ret;
> +
> +	port = HCS_N_PORTS(ehci->hcs_params);
> +	while (port--) {
> +		u32 __iomem *reg = &ehci->regs->port_status[port];
> +		u32 portsc = ehci_readl(ehci, reg);
> +
> +		if (portsc & PORT_CONNECT) {
> +			/*
> +			 * For chipidea, the resume signal will be ended
> +			 * automatically, so for remote wakeup case, the
> +			 * usbcmd.rs may not be set before the resume has
> +			 * ended if other resume path consumes too much
> +			 * time (~23ms-24ms), in that case, the SOF will not
> +			 * send out within 3ms after resume ends, then the
> +			 * device will enter suspend again.
> +			 */
> +			if (hcd->self.root_hub->do_remote_wakeup) {
> +				ehci_dbg(ehci,
> +					"Remote wakeup is enabled, "
> +					"and device is on the port\n");
>
Please don't line wrap message texts, since it makes it harder to grep
the kernel source for messages found in a logfile.


Lothar Wa?mann
-- 
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