Messages in this thread | | | Date | Mon, 05 Jan 2015 14:31:09 -0800 | From | "" <> | Subject | Re: [PATCH] ARM: OMAP2+: hwmod: Fix _wait_target_ready() for hwmods without sysc |
| |
On 1/5/15 2:19 PM, Paul Walmsley wrote: > + Santosh > > Hi Lokesh > > On Mon, 5 Jan 2015, Lokesh Vutla wrote: >> On Saturday 03 January 2015 02:40 AM, Paul Walmsley wrote: >>> On Thu, 18 Dec 2014, Roger Quadros wrote: >>> >>>> On 18/12/14 17:49, Roger Quadros wrote: >>>>> There are quite a few hwmods that don't have sysconfig register and so >>>>> _find_mpu_rt_port(oh) will return NULL thus preventing ready state check >>>>> on those modules after the module is enabled. >>> >>> Hmm. Any IP block that exposes registers that are accessible by the MPU >>> should have an MPU register target port, even if there's no SYSCONFIG >>> register. And if an IP block doesn't have registers that are accessible >>> from the MPU, then there shouldn't be much point to waiting for the module >>> to become ready. >>> >>> Looks like the real problem is the test for oh->class->sysc before the >>> call to _init_mpu_rt_base(). That was introduced by commit 6423d6df1440 >>> ("ARM: OMAP2+: hwmod: check for module address space during init"). It's >>> not clear to me why that test was added, since _init_mpu_rt_base() doesn't >>> do anything with oh->class->sysc or SYSCONFIG registers. >> This was introduced by commit >> 97597b962529 (ARM: OMAP2+: hwmod: Don't call _init_mpu_rt_base if no sysc) > > Yes, you're right. I misread commit 6423d6df1440. > >> Patch description states that "there are few hwmod which doesn't have sysconfig registers and hence >> no need to ioremap() them in early init code". > > The MPU register target port code doesn't only determine whether the > hwmod code should map the IP block's address space. It also determines > whether or not the hwmod code needs to wait for the IP block to become > ready after being enabled, so register accesses by non-hwmod code can > succeed. > IIRC, Yes the intention was to skip the ioremap o.w there were some crashes seen. I am fine if that check is actually moved closer to iormap as it should have been first place.
Regards, Santosh seen
| |