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. 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
