On Wed, 2009-06-24 at 02:27 +0200, ext Kevin Hilman wrote:
> Rather than simply setting force-idle mode on boot, do a reset of the
> OTG module. This really ensures that any bootloader/bootstrap code
> that leaves it active will not prevent future retention. After reset,
> OTG module will be in force-idle, force-standby mode.
>
> In addition, ensure that the iclk is enabled before attempting a write
> to the module SYSCONFIG register.
>
> Problem reported by Mike Chan <mikec...@google.com>
>
> Tested-by: Mike Chan <mikec...@google.com>
> Signed-off-by: Kevin Hilman <khil...@deeprootsystems.com>
> ---
> If no comments/issues, this will be applied to PM branch and
> backported to pm-2.6.29.
>
> arch/arm/mach-omap2/usb-musb.c | 21 ++++++++++++++++++---
> 1 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/usb-musb.c b/arch/arm/mach-omap2/usb-musb.c
> index d85296d..85731b8 100644
> --- a/arch/arm/mach-omap2/usb-musb.c
> +++ b/arch/arm/mach-omap2/usb-musb.c
> @@ -32,12 +32,27 @@
> #include <mach/usb.h>
>
> #define OTG_SYSCONFIG (OMAP34XX_HSUSB_OTG_BASE + 0x404)
> +#define OTG_SYSC_SOFTRESET BIT(1)
>
> static void __init usb_musb_pm_init(void)
> {
> - /* Ensure force-idle mode for OTG controller */
> - if (cpu_is_omap34xx())
> - omap_writel(0, OTG_SYSCONFIG);
> + struct clk *iclk;
> +
> + if (!cpu_is_omap34xx())
> + return;
> +
> + iclk = clk_get(NULL, "hsotgusb_ick");
> + if (WARN_ON(!iclk))
> + return;
> +
> + clk_enable(iclk);
> +
> + /* Reset OTG controller. After reset, it will be in
> + * force-idle, force-standby mode. */
> + omap_writel(OTG_SYSC_SOFTRESET, OTG_SYSCONFIG);
Do you think, this is safe to do w/o waiting reset to be finished
like : ?
+ omap_writel( SOFTRST, OTG_SYSCONFIG ); /* acquire RESET */
+ start = jiffies;
+ timeout = start + msecs_to_jiffies(10); /* max 10 ms */
+ while (!time_after(jiffies, timeout)) /* wait until RESET OK */
+ if ( omap_readl(OTG_SYSSTATUS) & RESETDONE )
+ break;
SOFTRST & RESETDONE already defined in omap2430.h
> +
> + clk_disable(iclk);
> + clk_put(iclk);
> }
>
> #ifdef CONFIG_USB_MUSB_SOC
--
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