Hello Benoît
On Tue, 29 May 2012, Cousson, Benoit wrote:
> On 5/25/2012 11:56 PM, Paul Walmsley wrote:
>
> > This patch is effectively a workaround for a hardware oversight. A
> > better hardware approach would have been to implement a smart-idle
> > target idle mode for this IP block. The smart-idle mode in this case
> > would behave identically to the force-idle mode.
>
> I'm not sure to follow you here :-)
I should rewrite that paragraph. It is not as clear as it could be.
> force-idle is almost equivalent to smart-idle, so it is the right
> workaround when smart-idle is not implemented.
>
> In force-idle idleack = idlereq. Whereas in smart-idle idleack = idlereq
> if internal /OCP activity is completed.
It would be nice if the hardware people just implemented smart-idle on
all IP blocks. Section 3.1.1.1.2 "Module-Level Clock Management" of The
OMAP4430 TRM Rev. vAA states:
"Smart-idle mode is the preferred mode of operation, while forced-idle and
no-idle modes are intended for debugging purposes."
Then no flags or software workarounds would be needed, except for
debugging.
> So in fact, I'm wondering if a new flag is needed. We can potentially apply that if
> idlemodes == (SIDLE_FORCE | SIDLE_NO).
>
> We need to check which IP will have that to ensure that does not add any side-effects.
I guess that means me :-)
> BTW, please note that the current idlemodes flags are wrong for the
> counter 32k. I've just figured out that fixing the STANDBY flags for
> some OMAP5 IPs. I'll add that fix in my WIP OMAP4 hwmod data cleanup for
> 3.6.
>
> Something like that:
Okay will queue up a fix for 3.5-rc.
> > .context_offs = OMAP4_RM_WKUP_SYNCTIMER_CONTEXT_OFFSET,
> > },
> > },
> > + .flags = HWMOD_ALWAYS_FORCE_SIDLE,
>
> I'm confused by the location and the value, both linus/master and
> lo/master branches does already have a flag for the counter_32k:
>
> /* counter_32k */
> static struct omap_hwmod omap44xx_counter_32k_hwmod = {
> .name = "counter_32k",
> .class = &omap44xx_counter_hwmod_class,
> .clkdm_name = "l4_wkup_clkdm",
> .flags = HWMOD_SWSUP_SIDLE,
> .main_clk = "sys_32k_ck",
> .prcm = {
> .omap4 = {
> .clkctrl_offs = OMAP4_CM_WKUP_SYNCTIMER_CLKCTRL_OFFSET,
> .context_offs = OMAP4_RM_WKUP_SYNCTIMER_CONTEXT_OFFSET,
> },
> },
> };
>
> So the patch should be slightly different, I guess ?
>
> .class = &omap44xx_counter_hwmod_class,
> .clkdm_name = "l4_wkup_clkdm",
> - .flags = HWMOD_SWSUP_SIDLE,
> + .flags = HWMOD_ALWAYS_FORCE_SIDLE,
> .main_clk = "sys_32k_ck",
> .prcm = {
>
>
> This is the same issue for OMAP3 data.
>
> What base branch are you using?
The wrong one, evidently. Will ensure this is fixed.
- Paul
