On Tuesday 16 July 2013 12:53 AM, Suman Anna wrote: > On 07/15/2013 05:01 AM, Rajendra Nayak wrote: >> On Monday 15 July 2013 12:14 PM, Rajendra Nayak wrote: >>> On Friday 12 July 2013 06:10 AM, Suman Anna wrote: >>>> On 07/11/2013 04:59 AM, Grygorii Strashko wrote: >>>>> Hi, >>>>> >>>>> On 07/11/2013 09:32 AM, Tony Lindgren wrote: >>>>>> * Felipe Balbi <balbi@xxxxxx> [130710 09:18]: >>>>>>> >>>>>>> On Wed, Jul 10, 2013 at 07:07:04PM +0300, Felipe Balbi wrote: >>>>>>>> how about something like below ? It makes omap_device/hwmod and >>>>>>>> pm_runtime agree on the initial state of the device and will prevent >>>>>>>> ->runtime_resume() from being called on first pm_runtime_get*() done >>>>>>>> during probe. >>>>>>>> >>>>>>>> This is similar to what PCI bus does (if you look at pci_pm_init()). >>>>>>>> >>>>>>>> commit 59108a500b4ab4b1a5102648a3360276dbf7df6f >>>>>>>> Author: Felipe Balbi <balbi@xxxxxx> >>>>>>>> Date: Wed Jul 10 18:50:16 2013 +0300 >>>>>>>> >>>>>>>> arm: omap2plus: unidle devices which are about to probe >>>>>>>> >>>>>>>> in order to make HWMOD and pm_runtime agree on the >>>>>>>> initial state of the device, we will unidle the device >>>>>>>> and call pm_runtime_set_active() to tell pm_runtime >>>>>>>> that the device is really active. >>>>> Don't think that it's good idea ( >>>>> I've checked some driver's and think this patch will enable some devices >>>>> unpredictably: >>>>> - hwspinlock >>>>> - mailbox >>>>> - iommu >>>>> - ipu >>>>> All above devices need to be enabled on demand only (no >>>>> pm_runtime_get*() calls in probe). More over, some of them have very >>>>> specific enabling sequence - like ipu). >>>>> >>>>> May be Summan can say more on that. >>>> >>>> Indeed, this is a problem for any of the slave processor devices. >>>> mailbox and iommu would be slaves to the remoteproc and the drivers have >>>> a specific sequence of bringing up a processor. The current >>>> hwmod/omap_device code is such that these devices will be left in reset >>>> and the driver code use the omap_device_(de)assert_hardreset API >>>> together with omap_device_enable code to bring up the devices. The >>>> remoteproc driver also needs to assert the resets (there are other >>>> problems associated with using omap_device_idle for remoteproc and >>>> iommu) for bringing up the devices after a suspend sequence. hwspinlock >>>> and mailbox may get away since they are in CORE domain, but definitely >>>> an issue for iommu and remoteproc. I would think that this would also >>>> affect other compute devices like IVAHD, ISS, SGX. >>> >>> Today, for these IPs I guess hwmod waits for the resets to be de-asserted, right? > > Yes, the omap_device_enable bails out if the reset lines are still > asserted, and the driver code deals with the resets currently. This code > essentially achieves the same as if a HWMOD_INIT_NO_RESET flag is > added to the corresponding hwmods - we do not want the hwmod/omap_device > code to enable the processor IPs and leave the enabling/device > management to the driver. > >>> >>> /* >>> * If an IP block contains HW reset lines and all of them are >>> * asserted, we let integration code associated with that >>> * block handle the enable. We've received very little >>> * information on what those driver authors need, and until >>> * detailed information is provided and the driver code is >>> * posted to the public lists, this is probably the best we >>> * can do. >>> */ >>> if (_are_all_hardreset_lines_asserted(oh)) >>> return 0; >>> >>> What if this information is send back to omap_device() through a return value >>> so omap_device() knows about this too, so it avoids marking the omap device as >>> enabled? Wouldn't that fix the issue? >> >> I meant something like this.. >> >> From 2fbea0dde0f72897089ef2e8e441b5e5bd6ea967 Mon Sep 17 00:00:00 2001 >> From: Rajendra Nayak <rnayak@xxxxxx> >> Date: Mon, 15 Jul 2013 15:23:07 +0530 >> Subject: [PATCH] ARM: OMAP2+: Make omap_device aware of hwmod failing to >> enable/idle/shutdown the hwmods >> >> For IP blocks (mainly processors) which have hard reset lines, hwmod avoids >> enable/idle/shutdown operations as long as all the hard reset lines are >> kept asserted. However it does not return an error back to the caller (in some >> cases the omap_device layer) to communicate back the failure to operate on the >> hwmod. >> >> Fix this by making _enable()/_idle()/_shutdown() all return an error in such >> cases, and also fix the omap_device layer to look at the return values coming >> from hwmod operations before doing a omap_device level state transition. >> >> Signed-off-by: Rajendra Nayak <rnayak@xxxxxx> > > Let me test this and get back to you if there are any issues. Great, thanks for testing. > > regards > Suman > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
