[PATCH 1/1] ehci-mxc: Fix mx31 OTG host initialisation

[Philippe Rétornaz]

>  -----Original Message-----
> From: Philippe Rétornaz [mailto:philippe.retornaz at epfl.ch]
> Sent: Monday, May 10, 2010 1:14 PM
> To: linux-arm-kernel at lists.infradead.org; linux-usb at vger.kernel.org
> Cc: s.hauer at pengutronix.de; valentin.longchamp at epfl.ch; daniel at caiaq.de;
>  Nguyen Dinh-R00091; gregkh at suse.de; Philippe Rétornaz Subject: [PATCH 1/1]
>  ehci-mxc: Fix mx31 OTG host initialisation
> 
> On mx31 the OTG host initialisation fail if you need to have an ULPI
>  transfert to initialize the PHY.
> 
> In order to be able to communicate with the PHY a complete reset of the usb
>  host is needed. After the PHY initialization the host usb configuration
>  registers need to be rewritten to avoid a host controller lockup.
> 
> Signed-off-by: Philippe Rétornaz <philippe.retornaz at epfl.ch>
> ---
>  drivers/usb/host/ehci-mxc.c |   68
>  +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 68
>  insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-mxc.c b/drivers/usb/host/ehci-mxc.c
>  index 544ccfd..39d28da 100644 --- a/drivers/usb/host/ehci-mxc.c
> +++ b/drivers/usb/host/ehci-mxc.c
> @@ -29,6 +29,11 @@
>  #define PORTSC_OFFSET		0x184
>  #define USBMODE_OFFSET		0x1a8
>  #define USBMODE_CM_HOST		3
> +#define USBCMD_OFFSET		0x140
> +#define USBCMD_RS		(1 << 0)
> +#define USBCMD_RST		(1 << 1)
> +#define USBSTS_OFFSET		0x144
> +#define USBSTS_HCH		(1 << 12)
> 
>  struct ehci_mxc_priv {
>  	struct clk *usbclk, *ahbclk;
> @@ -120,6 +125,7 @@ static int ehci_mxc_drv_probe(struct platform_device
>  *pdev) int irq, ret, temp;
>  	struct ehci_mxc_priv *priv;
>  	struct device *dev = &pdev->dev;
> +	int i;
> 
>  	dev_info(&pdev->dev, "initializing i.MX USB Controller\n");
> 
> @@ -204,6 +210,51 @@ static int ehci_mxc_drv_probe(struct platform_device
>  *pdev) if (ret < 0)
>  		goto err_init;
> 
> +	/* i.Mx31 OTG host has a bug, if you don't do a reset, then ULPI
> +	 * transfert timeout. */
> +	if (cpu_is_mx31() && pdev->id == 0) {
> +		/* Wait for the controller to go idle */
> +		for (i = 0; i < 10000; i++) {
> +			if (readl(hcd->regs + USBSTS_OFFSET) & USBSTS_HCH)
> +				break;
> +			udelay(1);
> +		}
> +		if (i == 10000) {
> +			dev_err(dev, "Timeout while stopping USB controller\n");
> +			goto err_init;
> +		}
> +
> +		/* Stop the usb controller */
> +		temp = readl(hcd->regs + USBCMD_OFFSET);
> +		writel(temp & (~USBCMD_RS), hcd->regs + USBCMD_OFFSET);
> +
> +		for (i = 0; i < 10000; i++) {
> +			if (!(readl(hcd->regs + USBCMD_OFFSET) & USBCMD_RS))
> +				break;
> +			udelay(1);
> +		}
> +
> +		if (i == 10000) {
> +			dev_err(dev, "Timeout while stopping USB controller\n");
> +			goto err_init;
> +		}
> +
> +		/* Reset the usb controller */
> +		temp = readl(hcd->regs + USBCMD_OFFSET);
> +		writel(temp | USBCMD_RST, hcd->regs + USBCMD_OFFSET);
> +
> +		for (i = 0; i < 10000; i++) {
> +			if (!(readl(hcd->regs + USBCMD_OFFSET) & USBCMD_RST))
> +				break;
> +			udelay(1);
> +		}
> +
> +		if (i == 10000) {
> +			dev_err(dev, "Timeout while reseting USB controller\n");
> +			goto err_init;
> +		}
> +	}
> +
>  	/* Initialize the transceiver */
>  	if (pdata->otg) {
>  		pdata->otg->io_priv = hcd->regs + ULPI_VIEWPORT_OFFSET; @@ -213,6
>  +264,23 @@ static int ehci_mxc_drv_probe(struct platform_device *pdev)
>  dev_err(dev, "unable to enable vbus on transceiver\n");
>  	}
> 
> +	/* i.Mx31 OTG host has a bug, if you do an ULPI transfert then the host
> +	 * controller stay busy. Rewriting the register is enough to make it
> +	 * working */
> +	if (cpu_is_mx31() && pdev->id == 0) {
> +		/* set USBMODE to host mode */
> +		temp = readl(hcd->regs + USBMODE_OFFSET);
> +		writel(temp | USBMODE_CM_HOST, hcd->regs + USBMODE_OFFSET);
> +
> +		/* set up the PORTSCx register */
> +		writel(pdata->portsc, hcd->regs + PORTSC_OFFSET);
> +
> +		/* setup USBCONTROL. */
> +		ret = mxc_initialize_usb_hw(pdev->id, pdata->flags);
> +		if (ret < 0)
> +			goto err_init;
> +	}
> +
> 
> [Dinh Nguyen] - Should this be done in mxc_initialize_usb_hw() in ehci.c?
>  The probe function gets kinda of ugly with this.

I cannot do this is mxc_initialize_usb_hw() because I really need to do the 
reset before initializing the PHY which is done inside 
otg_init()/otg_set_vbus().
And the registers needs to be rewritten after the PHY initialisation. The 
whole patch is a single fix for one problem.

This is only needed on the usb OTG port, and I really suspect a hardware bug.
Since you work at freescale, maybe you could get some information about why 
the OTG port has a such strange behavior.

I will repost a patch soon addressing all the feedback I got.


Philippe