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

[Valentin Longchamp]

On 05/10/2010 08:58 PM, Nguyen Dinh-R00091 wrote:
>   -----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.
>
>   	priv->hcd = hcd;
>   	platform_set_drvdata(pdev, priv);

 From what I seen in arch/arm/plat-mxc/ehci.c (at least for mx31 for 
which we have the documentation), we do not write the hcd->regs. I think 
it is clearer to write all the hcd->regs at the same place, and 
ehci-mxc.c looks the correct place to do it.

Now the code could be cleaner with the help of a few additionnal 
functions maybe, as already suggested by Sascha and Mark.

Val

-- 
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1
valentin.longchamp at epfl.ch, Phone: +41216937827
http://people.epfl.ch/valentin.longchamp
MEB3494, Station 9, CH-1015 Lausanne