Niilo Minkkinen <ext-niilo.1.minkkinen@xxxxxxxxx> writes:
> 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 <mikechan@xxxxxxxxxx>
>>
>> Tested-by: Mike Chan <mikechan@xxxxxxxxxx>
>> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
>> ---
>> 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;
I thought about waiting for reset, but I decided that it wasn't
necessary to wait since I wasn't going to write any other values
after. Why hold up the boot process when nothing else will be
writing?
Kevin
> SOFTRST & RESETDONE already defined in omap2430.h
>
>> +
>> + clk_disable(iclk);
>> + clk_put(iclk);
>> }
>>
>> #ifdef CONFIG_USB_MUSB_SOC
--
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