[PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLL detection

[PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLL detection

[Kevin Hilman]

In the clock init code, the DPLL value set by the bootloader is
queried, but always turns zero due it's parent clock (sys_ck) having
no default rate.  This results in the improper setting of the default
PRCM rate-table entry and any queries of virt_prcm_set rate to return 0.

Following the example of the TI kernel, set the default sys_ck rate to
13MHz.  Could then be overridden in board setup code.

Signed-off-by: Kevin Hilman <khilman@mvista.com>

---
 arch/arm/mach-omap2/clock24xx.h |    1 +
 1 file changed, 1 insertion(+)

Index: dev/arch/arm/mach-omap2/clock24xx.h
===================================================================
--- dev.orig/arch/arm/mach-omap2/clock24xx.h
+++ dev/arch/arm/mach-omap2/clock24xx.h
@@ -581,6 +581,7 @@ static struct clk osc_ck = {		/* (*12, *
 /* With out modem likely 12MHz, with modem likely 13MHz */
 static struct clk sys_ck = {		/* (*12, *13, 19.2, 26, 38.4)MHz */
 	.name		= "sys_ck",		/* ~ ref_clk also */
+	.rate           = 13000000,
 	.parent		= &osc_ck,
 	.flags		= CLOCK_IN_OMAP242X | CLOCK_IN_OMAP243X |
 				ALWAYS_ENABLED | RATE_PROPAGATES,
--

Re: [PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLL detection

[Tony Lindgren]

* Kevin Hilman <khilman@mvista.com> [071019 14:16]:
> In the clock init code, the DPLL value set by the bootloader is
> queried, but always turns zero due it's parent clock (sys_ck) having
> no default rate.  This results in the improper setting of the default
> PRCM rate-table entry and any queries of virt_prcm_set rate to return 0.
> 
> Following the example of the TI kernel, set the default sys_ck rate to
> 13MHz.  Could then be overridden in board setup code.
> 
> Signed-off-by: Kevin Hilman <khilman@mvista.com>
> 
> ---
>  arch/arm/mach-omap2/clock24xx.h |    1 +
>  1 file changed, 1 insertion(+)
> 
> Index: dev/arch/arm/mach-omap2/clock24xx.h
> ===================================================================
> --- dev.orig/arch/arm/mach-omap2/clock24xx.h
> +++ dev/arch/arm/mach-omap2/clock24xx.h
> @@ -581,6 +581,7 @@ static struct clk osc_ck = {		/* (*12, *
>  /* With out modem likely 12MHz, with modem likely 13MHz */
>  static struct clk sys_ck = {		/* (*12, *13, 19.2, 26, 38.4)MHz */
>  	.name		= "sys_ck",		/* ~ ref_clk also */
> +	.rate           = 13000000,
>  	.parent		= &osc_ck,
>  	.flags		= CLOCK_IN_OMAP242X | CLOCK_IN_OMAP243X |
>  				ALWAYS_ENABLED | RATE_PROPAGATES,

Pushing today.

Tony

Re: [PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLL detection

[Igor Stoppa]

Hi Kevin,
On Fri, 2007-10-19 at 14:14 -0700, ext Kevin Hilman wrote:
> In the clock init code, the DPLL value set by the bootloader is
> queried, but always turns zero due it's parent clock (sys_ck) having
> no default rate.  This results in the improper setting of the default
> PRCM rate-table entry and any queries of virt_prcm_set rate to return 0.
> 
> Following the example of the TI kernel, set the default sys_ck rate to
> 13MHz.  Could then be overridden in board setup code.

There should be an even cleaner way to handle that (but i have no code
to prove that it works =) since the boot rom already does auto-detection
of the oscillator to support serial flashing.

If it is possible to read the detected value then the code can be moved
to arch or even plat.

-- 
Cheers, Igor

Igor Stoppa <igor.stoppa@nokia.com>
(Nokia Multimedia - CP - OSSO / Helsinki, Finland)

RE: [PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLLdetection

[Woodruff, Richard]

The TI code does this with init_osc_sys_clk_rates() function.  The
preset bit in structure likely isn't needed.

The APLLS field which is setup by the bootloader is used to know osc and
sys clk's rates.

A little while back Paul had patched some of this and the initial go did
result in a bad value for this.  After this was pointed out a subsequent
patch was pushed to fix this.  Perhaps yet another patch broke this or
perhaps the version you are using was missing this update.

Regards
Richard W.


> 
> Hi Kevin,
> On Fri, 2007-10-19 at 14:14 -0700, ext Kevin Hilman wrote:
> > In the clock init code, the DPLL value set by the bootloader is
> > queried, but always turns zero due it's parent clock (sys_ck) having
> > no default rate.  This results in the improper setting of the
default
> > PRCM rate-table entry and any queries of virt_prcm_set rate to
return 0.
> >
> > Following the example of the TI kernel, set the default sys_ck rate
to
> > 13MHz.  Could then be overridden in board setup code.
> 
> There should be an even cleaner way to handle that (but i have no code
> to prove that it works =) since the boot rom already does
auto-detection
> of the oscillator to support serial flashing.
> 
> If it is possible to read the detected value then the code can be
moved
> to arch or even plat.
> 
> --
> Cheers, Igor
> 
> Igor Stoppa <igor.stoppa@nokia.com>
> (Nokia Multimedia - CP - OSSO / Helsinki, Finland)
> _______________________________________________
> Linux-omap-open-source mailing list
> Linux-omap-open-source@linux.omap.com
> http://linux.omap.com/mailman/listinfo/linux-omap-open-source

Re: [PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLLdetection

[Kevin Hilman]

Woodruff, Richard wrote:
> The TI code does this with init_osc_sys_clk_rates() function.  The
> preset bit in structure likely isn't needed.
> 
> The APLLS field which is setup by the bootloader is used to know osc and
> sys clk's rates.
> 
> A little while back Paul had patched some of this and the initial go did
> result in a bad value for this.  After this was pointed out a subsequent
> patch was pushed to fix this.  Perhaps yet another patch broke this or
> perhaps the version you are using was missing this update.

I was working from the head of OMAP git, and it was broken there.

It looks like the git tree has the equivalent funtion to the one you
mentioned from the TI tree (see omap2_osc_clk_recalc), but it doesn't
work for sys_ck.  The osc_ck is correctly being set, but it's not
propagating to sys_ck because it uses propagate_rate() which doesn't
work since none of the clocks are registered yet.

The simple fix I tried was to move the osc_clk_recalc() after all the
clk_registers, but then it no longer boots (didn't investigate too deeply.)

The easier fix is to simply add omap2_sys_clk_recalc() as in the
following patch (which also reverts my previous patch.)  If that seems
reasonable, I'll submit it.

Kevin

Index: dev/arch/arm/mach-omap2/clock24xx.c
===================================================================
--- dev.orig/arch/arm/mach-omap2/clock24xx.c
+++ dev/arch/arm/mach-omap2/clock24xx.c
@@ -475,6 +475,7 @@ int __init omap2_clk_init(void)
 	clk_init(&omap2_clk_functions);

 	omap2_osc_clk_recalc(&osc_ck);
+	omap2_sys_clk_recalc(&sys_ck);

 	for (clkp = onchip_24xx_clks;
 	     clkp < onchip_24xx_clks + ARRAY_SIZE(onchip_24xx_clks);
Index: dev/arch/arm/mach-omap2/clock24xx.h
===================================================================
--- dev.orig/arch/arm/mach-omap2/clock24xx.h
+++ dev/arch/arm/mach-omap2/clock24xx.h
@@ -581,7 +581,6 @@ static struct clk osc_ck = {		/* (*12, *
 /* With out modem likely 12MHz, with modem likely 13MHz */
 static struct clk sys_ck = {		/* (*12, *13, 19.2, 26, 38.4)MHz */
 	.name		= "sys_ck",		/* ~ ref_clk also */
-	.rate           = 13000000,
 	.parent		= &osc_ck,
 	.flags		= CLOCK_IN_OMAP242X | CLOCK_IN_OMAP243X |
 				ALWAYS_ENABLED | RATE_PROPAGATES,

Re: [PATCH] ARM: OMAP: fix default sys_ck.rate for boot-time DPLLdetection

[Paul Walmsley]

On Mon, 22 Oct 2007, Kevin Hilman wrote:

> The easier fix is to simply add omap2_sys_clk_recalc() as in the
> following patch (which also reverts my previous patch.)  If that seems
> reasonable, I'll submit it.

I would prefer this second patch; it allows sys_ck to be calculated 
dynamically based on osc_ck.


- Paul