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Date: Thu, 29 Jan 2009 00:40:09 -0700 (MST)
From: Paul Walmsley <paul@...an.com>
To: Russell King - ARM Linux <linux@....linux.org.uk>
cc: linux-arm-kernel@...ts.arm.linux.org.uk,
linux-kernel@...r.kernel.org, Tony Lindgren <tony@...mide.com>,
linux-omap@...r.kernel.org
Subject: Re: [PATCH A 09/10] OMAP2/3: Remove OMAP_PRM_REGADDR,
OMAP_CM_REGADDR
Hi Russell,
On Wed, 28 Jan 2009, Russell King - ARM Linux wrote:
> On Tue, Jan 27, 2009 at 07:13:16PM -0700, Paul Walmsley wrote:
> > diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
> > index c4b80a4..55c5d67 100644
> > --- a/arch/arm/mach-omap2/clock.c
> > +++ b/arch/arm/mach-omap2/clock.c
> > @@ -27,6 +27,7 @@
> > #include <mach/clock.h>
> > #include <mach/clockdomain.h>
> > #include <mach/cpu.h>
> > +#include <mach/prcm.h>
> > #include <asm/div64.h>
> >
> > #include "memory.h"
> > @@ -247,9 +248,9 @@ static void omap2_clk_wait_ready(struct clk *clk)
> > /* REVISIT: What are the appropriate exclusions for 34XX? */
> > /* OMAP3: ignore DSS-mod clocks */
> > if (cpu_is_omap34xx() &&
> > - (((u32)reg & ~0xff) == (u32)OMAP_CM_REGADDR(OMAP3430_DSS_MOD, 0) ||
> > - ((((u32)reg & ~0xff) == (u32)OMAP_CM_REGADDR(CORE_MOD, 0)) &&
> > - clk->enable_bit == OMAP3430_EN_SSI_SHIFT)))
> > + (((u32)reg & ~0xff) == cm_read_mod_reg(OMAP3430_DSS_MOD, 0) ||
> > + ((((u32)reg & ~0xff) == cm_read_mod_reg(CORE_MOD, 0)) &&
> > + clk->enable_bit == OMAP3430_EN_SSI_SHIFT)))
> > return;
>
> As suggested in patch 2, I hate this approach. It's far better to deal
> with this by changing the way we handle enabling and disabling clocks,
> hence my
>
> "[ARM] omap: eliminate unnecessary conditionals in omap2_clk_wait_ready"
This function is radically cleaned up in a following patch, patch D 10. I
regret that I wasn't able to compress the above patch with D 10, but the
change delta between the two patches was quite large.
> > @@ -476,6 +466,37 @@ static int __init omap2_clk_arch_init(void)
> > }
> > arch_initcall(omap2_clk_arch_init);
> >
> > +static u32 prm_base;
> > +static u32 cm_base;
> > +
> > +/*
> > + * Since we share clock data for 242x and 243x, we need to rewrite some
> > + * some register base offsets. Assume offset is at prm_base if flagged,
> > + * else assume it's cm_base.
> > + */
> > +static inline void omap2_clk_check_reg(u32 flags, void __iomem **reg)
> > +{
> > + u32 tmp = (__force u32)*reg;
> > +
> > + if ((tmp >> 24) != 0)
> > + return;
> > +
> > + if (flags & OFFSET_GR_MOD)
> > + tmp += prm_base;
> > + else
> > + tmp += cm_base;
> > +
> > + *reg = (__force void __iomem *)tmp;
> > +}
> > +
> > +void __init omap2_clk_rewrite_base(struct clk *clk)
> > +{
> > + omap2_clk_check_reg(clk->flags, &clk->clksel_reg);
> > + omap2_clk_check_reg(clk->flags, &clk->enable_reg);
> > + if (clk->dpll_data)
> > + omap2_clk_check_reg(0, &clk->dpll_data->mult_div1_reg);
> > +}
> > +
> > int __init omap2_clk_init(void)
> > {
> > struct prcm_config *prcm;
> > @@ -487,6 +508,12 @@ int __init omap2_clk_init(void)
> > else if (cpu_is_omap2430())
> > cpu_mask = RATE_IN_243X;
> >
> > + for (clkp = onchip_24xx_clks;
> > + clkp < onchip_24xx_clks + ARRAY_SIZE(onchip_24xx_clks);
> > + clkp++) {
> > + omap2_clk_rewrite_base(*clkp);
> > + }
> > +
>
> I'm afraid this also fails to satisfy my decency filter. Let's summarise
> what's going on here.
>
> - the structure initializers are setup to cast integer register offsets
> to void __iomem *.
> - the code above walks all clock structures, looking for what could be
> considered an offset (iow, bits 31-24 of the pointer being zero).
> - it looks at the OFFSET_GR_MOD flag to determine which base to add in
> - the base address is not 'void __iomem *' but 'u32'.
> - we update the void __iomem * pointers in the structure.
>
> So, we have a base address which is an integer, and an offset which is
> an void __iomem *.
>
> I can see why you want to do this, but I think it needs more thought.
> I'll sit on this patch for a while.
I agree with your decency filter. I believe that patch was written for
expediency. It turns out that all of the register rewriting code is
ultimately unnecessary, and is wiped out in patch D 08.
> In the mean time, I've fixed up patches 1-8,10 to apply on top of my
> patch set.
>
> However, still waiting for a few to come through: D6, E2 and F2. No,
> these aren't suck in any of my mail spools or list admin queues.
The patches did make it to linux-kernel and linux-omap, but these three
patches were bounced by the linux-arm-kernel mailing list manager with the
following error message:
---
Remote host said: 550-Subjects containing xxx are taboo to many list
subscribers; we have no
550 option but to reject your message. Sorry.
---
The subject lines of these patches contain words like 'OMAP2xxx'.
Would you like me to resend these patches to your list with the subject
lines changed?
- Paul
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