linux-kernel - Re: [PATCH] ARM: OMAP2+: hwmod: Fix _wait_target

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Message-ID: <alpine.DEB.2.02.1501132345220.28034@utopia.booyaka.com>
Date:	Tue, 13 Jan 2015 23:46:55 +0000 (UTC)
From:	Paul Walmsley <paul@...an.com>
To:	Roger Quadros <rogerq@...com>
cc:	Lokesh Vutla <lokeshvutla@...com>, tony@...mide.com,
	santosh.shilimkar@...cle.com, t-kristo@...com, nm@...com,
	nsekhar@...com, bcousson@...libre.com, linux-omap@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	s-anna@...com
Subject: Re: [PATCH] ARM: OMAP2+: hwmod: Fix _wait_target_ready() for hwmods
 without sysc

On Wed, 7 Jan 2015, Roger Quadros wrote:

> > From: Paul Walmsley <paul@...an.com>
> > Date: Mon, 5 Jan 2015 15:49:57 -0700
> > Subject: [PATCH] Only skip ioremap() if IP block does not have OCP header
> >  registers. Experimental.
> > 
> > ---
> >  arch/arm/mach-omap2/omap_hwmod.c | 33 +++++++++++++++++++++------------
> >  1 file changed, 21 insertions(+), 12 deletions(-)
> > 
> > diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> > index cbb908dc5cf0..03df8833d399 100644
> > --- a/arch/arm/mach-omap2/omap_hwmod.c
> > +++ b/arch/arm/mach-omap2/omap_hwmod.c
> > @@ -1938,6 +1938,8 @@ static int _reset(struct omap_hwmod *oh)
> >  	pr_debug("omap_hwmod: %s: resetting\n", oh->name);
> >  
> >  	if (oh->class->reset) {
> > +		WARN(!oh->_mpu_rt_va, "Attempt to call custom reset with no MPU register target ioremapped: %s",
> > +		     oh->name);
> 
> Not part of $subject.

Hmm, how do you mean?  If we skip the ioremap(), wouldn't you like to know 
before some custom reset code gets called that pretty much always depends 
on the ioremap() succeeding? :-)

> >  		r = oh->class->reset(oh);
> >  	} else {
> >  		if (oh->rst_lines_cnt > 0) {
> > @@ -2358,15 +2360,19 @@ static int of_dev_hwmod_lookup(struct device_node *np,
> >  }
> >  
> >  /**
> > - * _init_mpu_rt_base - populate the virtual address for a hwmod
> > + * _init_mpu_rt_base - populate the MPU port and virtual address
> >   * @oh: struct omap_hwmod * to locate the virtual address
> >   * @data: (unused, caller should pass NULL)
> >   * @index: index of the reg entry iospace in device tree
> >   * @np: struct device_node * of the IP block's device node in the DT data
> >   *
> > - * Cache the virtual address used by the MPU to access this IP block's
> > - * registers.  This address is needed early so the OCP registers that
> > - * are part of the device's address space can be ioremapped properly.
> > + * Cache the interconnect target port and the virtual address used by
> > + * the MPU to access this IP block's registers.  The address is needed
> > + * early so the OCP registers that are part of the device's address
> > + * space can be ioremapped properly.  The presence or absence of the
> > + * interconnect target port also indicates whether the hwmod code
> > + * should wait for the IP block to indicate readiness after it is
> > + * enabled.
> >   *
> >   * Returns 0 on success, -EINVAL if an invalid hwmod is passed, and
> >   * -ENXIO on absent or invalid register target address space.
> > @@ -2385,6 +2391,13 @@ static int __init _init_mpu_rt_base(struct omap_hwmod *oh, void *data,
> >  	if (oh->_int_flags & _HWMOD_NO_MPU_PORT)
> >  		return -ENXIO;
> >  
> > +	/*
> > +	 * If there's no need for the hwmod code to read or write to
> > +	 * the IP block registers, bail out early before the ioremap()
> > +	 */
> > +	if (!oh->class->sysc)
> > +		return 0;
> > +
> >  	mem = _find_mpu_rt_addr_space(oh);
> >  	if (!mem) {
> >  		pr_debug("omap_hwmod: %s: no MPU register target found\n",
> > @@ -2451,14 +2464,10 @@ static int __init _init(struct omap_hwmod *oh, void *data)
> >  				oh->name, np->name);
> >  	}
> >  
> > -	if (oh->class->sysc) {
> > -		r = _init_mpu_rt_base(oh, NULL, index, np);
> > -		if (r < 0) {
> > -			WARN(1, "omap_hwmod: %s: doesn't have mpu register target base\n",
> > -			     oh->name);
> > -			return 0;
> > -		}
> > -	}
> > +	r = _init_mpu_rt_base(oh, NULL, index, np);
> > +	if (r < 0)
> > +		pr_debug("omap_hwmod: %s: doesn't have mpu register target base\n",
> > +			 oh->name);
> 
> This is the real piece that fixes the issue.
> 
> >  
> >  	r = _init_clocks(oh, NULL);
> >  	if (r < 0) {
> > 
> 
> I've tested this patch on am43x-gp-evm, and it seems to fix the issue 
> although with some unpleasant warning messages.

Could you paste those in?


- Paul
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