Re: [RFC 1/2] ARM: OMAP2+: hwmod: Add refcounting for modulemode shared by multiple hwmods
Hi,
On Tuesday 27 May 2014 03:50 PM, Rajendra Nayak wrote:
On Monday 26 May 2014 04:14 PM, Archit Taneja wrote:
Generally, IP blocks/modules within a clock domain each have their own
CM_x_CLKCTRL register, each having it's own MODULEMODE field to manage the
module.
@@ -2751,6 +2820,13 @@ static int __init _register(struct omap_hwmod *oh)
if (_lookup(oh->name))
return -EEXIST;
+ if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED &&
+ !oh->prcm.omap4.modulemode_ref) {
You might also want to check for someone populating a modulemode_ref but
failing to populate the flag?
Alternatively, Since you expect a modulemode_ref to be always available for all
modules which
share modulemode, that in itself can be used to identify such modules without
the
need of an additional flag?
It does seem redundant to have a flag at the moment. But the flag make
things more visible. 'prcm.omap4.modulemode' seems to work without a
flag too, so I suppose I'll remove the flag.
+ pr_err("omap_hwmod: %s shares modulemode, but doesn't hold a ref to
it\n",
+ oh->name);
+ return -EINVAL;
+ }
+
list_add_tail(&oh->node, &omap_hwmod_list);
INIT_LIST_HEAD(&oh->master_ports);
@@ -2759,6 +2835,15 @@ static int __init _register(struct omap_hwmod *oh)
oh->_state = _HWMOD_STATE_REGISTERED;
+ if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED) {
+ struct modulemode_shared *mmode = oh->prcm.omap4.modulemode_ref;
+
+ if (!mmode->registered) {
+ spin_lock_init(&mmode->lock);
+ mmode->registered = true;
If this is only used to keep track of the spin_lock being initialized, maybe
it'll be
more readable if you just call it mmode->spin_lock_init = true.
Yes, I'll fix this.
Archit
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [RFC 1/2] ARM: OMAP2+: hwmod: Add refcounting for modulemode shared by multiple hwmods
On Monday 26 May 2014 04:14 PM, Archit Taneja wrote:
> Generally, IP blocks/modules within a clock domain each have their own
> CM_x_CLKCTRL register, each having it's own MODULEMODE field to manage the
> module.
>
> DSS clockdoain, however, has multiple modules in it, but only one register
> named CM_DSS_DSS_CLKCTRL, which contains one MODULEMODE register field.
>
> Until now, we defined '.prcm.omap4.modulemode' only for the top level DSS
> hwmod("dss_core") and didn't define it for other DSS hwmods(like "dss_dispc",
> "dss_dsi1" and so on). This made the omapdss driver work as the top level DSS
> platform device and the rest had a parent-child relationship. This ensured
> that
> the parent hwmod("dss_core") is enabled if any of the children hwmods are
> enabled while using omapdss.
>
> This method, however, doesn't work when each hwmod is enabled individually.
> This happens early in boot in omap_hwmod_setup_all, where each hwmod is
> enabled,
> and then reset and idled. All the 'children' DSS hwmods fail to enable and
> reset, since they don't enable modulemode.
>
> The way to make such modules work both during initialization and when used by
> pm runtime API in the driver would be to add refcounting for
> enabling/disabling
> the modulemode field.
>
> We add a new flag bit for the flag in omap_hwmod_omap4_prcm, which tells
> omap_hwmod that this hwmod uses a modulemode field shared by other hwmods.
>
> We create a struct called 'modulemode_shared'. The hwmod data file should
> define
> a static instance of this struct. Each hwmod that uses this modulemode field
> should hold a pointer to this instance.
>
> omap_hwmod's soc enable_module and disable_module ops set the MODULEMODE
> reigster bits only when the first module using it is enabled, or the last
> module
> using it is disabled. We serialize accesses to the struct with a spinlock.
>
> Signed-off-by: Archit Taneja
> ---
> arch/arm/mach-omap2/omap_hwmod.c | 123
> +--
> arch/arm/mach-omap2/omap_hwmod.h | 38 +---
> 2 files changed, 133 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c
> b/arch/arm/mach-omap2/omap_hwmod.c
> index 66c60fe..b42718d 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -973,17 +973,33 @@ static void _disable_optional_clocks(struct omap_hwmod
> *oh)
> */
> static void _omap4_enable_module(struct omap_hwmod *oh)
> {
> + unsigned long flags;
> + struct modulemode_shared *mmode = NULL;
> + bool enable = true;
> +
> if (!oh->clkdm || !oh->prcm.omap4.modulemode)
> return;
>
> pr_debug("omap_hwmod: %s: %s: %d\n",
>oh->name, __func__, oh->prcm.omap4.modulemode);
>
> - omap4_cminst_module_enable(oh->prcm.omap4.modulemode,
> -oh->clkdm->prcm_partition,
> -oh->clkdm->cm_inst,
> -oh->clkdm->clkdm_offs,
> -oh->prcm.omap4.clkctrl_offs);
> + if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED) {
> + mmode = oh->prcm.omap4.modulemode_ref;
> +
> + spin_lock_irqsave(&mmode->lock, flags);
> +
> + enable = mmode->refcnt++ == 0;
> + }
> +
> + if (enable)
> + omap4_cminst_module_enable(oh->prcm.omap4.modulemode,
> +oh->clkdm->prcm_partition,
> +oh->clkdm->cm_inst,
> +oh->clkdm->clkdm_offs,
> +oh->prcm.omap4.clkctrl_offs);
> +
> + if (mmode)
> + spin_unlock_irqrestore(&mmode->lock, flags);
> }
>
> /**
> @@ -995,15 +1011,32 @@ static void _omap4_enable_module(struct omap_hwmod *oh)
> */
> static void _am33xx_enable_module(struct omap_hwmod *oh)
> {
> + unsigned long flags;
> + struct modulemode_shared *mmode = NULL;
> + bool enable = true;
> +
> if (!oh->clkdm || !oh->prcm.omap4.modulemode)
> return;
>
> pr_debug("omap_hwmod: %s: %s: %d\n",
>oh->name, __func__, oh->prcm.omap4.modulemode);
>
> - am33xx_cm_module_enable(oh->prcm.omap4.modulemode, oh->clkdm->cm_inst,
> - oh->clkdm->clkdm_offs,
> - oh->prcm.omap4.clkctrl_offs);
> + if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED) {
> + mmode = oh->prcm.omap4.modulemode_ref;
> +
> + spin_lock_irqsave(&mmode->lock, flags);
> +
> + enable = mmode->refcnt++ == 0;
> + }
> +
> + if (enable)
> + am33xx_cm_module_enable(oh->prcm.omap4.modulemode,
> + oh->clkdm->cm_inst,
> + oh->clkdm->clkdm_offs,
> + oh->prcm.omap4.clkctrl_offs);
> +
> + if (mm
[RFC 1/2] ARM: OMAP2+: hwmod: Add refcounting for modulemode shared by multiple hwmods
Generally, IP blocks/modules within a clock domain each have their own
CM_x_CLKCTRL register, each having it's own MODULEMODE field to manage the
module.
DSS clockdoain, however, has multiple modules in it, but only one register
named CM_DSS_DSS_CLKCTRL, which contains one MODULEMODE register field.
Until now, we defined '.prcm.omap4.modulemode' only for the top level DSS
hwmod("dss_core") and didn't define it for other DSS hwmods(like "dss_dispc",
"dss_dsi1" and so on). This made the omapdss driver work as the top level DSS
platform device and the rest had a parent-child relationship. This ensured that
the parent hwmod("dss_core") is enabled if any of the children hwmods are
enabled while using omapdss.
This method, however, doesn't work when each hwmod is enabled individually.
This happens early in boot in omap_hwmod_setup_all, where each hwmod is enabled,
and then reset and idled. All the 'children' DSS hwmods fail to enable and
reset, since they don't enable modulemode.
The way to make such modules work both during initialization and when used by
pm runtime API in the driver would be to add refcounting for enabling/disabling
the modulemode field.
We add a new flag bit for the flag in omap_hwmod_omap4_prcm, which tells
omap_hwmod that this hwmod uses a modulemode field shared by other hwmods.
We create a struct called 'modulemode_shared'. The hwmod data file should define
a static instance of this struct. Each hwmod that uses this modulemode field
should hold a pointer to this instance.
omap_hwmod's soc enable_module and disable_module ops set the MODULEMODE
reigster bits only when the first module using it is enabled, or the last module
using it is disabled. We serialize accesses to the struct with a spinlock.
Signed-off-by: Archit Taneja
---
arch/arm/mach-omap2/omap_hwmod.c | 123 +--
arch/arm/mach-omap2/omap_hwmod.h | 38 +---
2 files changed, 133 insertions(+), 28 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 66c60fe..b42718d 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -973,17 +973,33 @@ static void _disable_optional_clocks(struct omap_hwmod
*oh)
*/
static void _omap4_enable_module(struct omap_hwmod *oh)
{
+ unsigned long flags;
+ struct modulemode_shared *mmode = NULL;
+ bool enable = true;
+
if (!oh->clkdm || !oh->prcm.omap4.modulemode)
return;
pr_debug("omap_hwmod: %s: %s: %d\n",
oh->name, __func__, oh->prcm.omap4.modulemode);
- omap4_cminst_module_enable(oh->prcm.omap4.modulemode,
- oh->clkdm->prcm_partition,
- oh->clkdm->cm_inst,
- oh->clkdm->clkdm_offs,
- oh->prcm.omap4.clkctrl_offs);
+ if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED) {
+ mmode = oh->prcm.omap4.modulemode_ref;
+
+ spin_lock_irqsave(&mmode->lock, flags);
+
+ enable = mmode->refcnt++ == 0;
+ }
+
+ if (enable)
+ omap4_cminst_module_enable(oh->prcm.omap4.modulemode,
+ oh->clkdm->prcm_partition,
+ oh->clkdm->cm_inst,
+ oh->clkdm->clkdm_offs,
+ oh->prcm.omap4.clkctrl_offs);
+
+ if (mmode)
+ spin_unlock_irqrestore(&mmode->lock, flags);
}
/**
@@ -995,15 +1011,32 @@ static void _omap4_enable_module(struct omap_hwmod *oh)
*/
static void _am33xx_enable_module(struct omap_hwmod *oh)
{
+ unsigned long flags;
+ struct modulemode_shared *mmode = NULL;
+ bool enable = true;
+
if (!oh->clkdm || !oh->prcm.omap4.modulemode)
return;
pr_debug("omap_hwmod: %s: %s: %d\n",
oh->name, __func__, oh->prcm.omap4.modulemode);
- am33xx_cm_module_enable(oh->prcm.omap4.modulemode, oh->clkdm->cm_inst,
- oh->clkdm->clkdm_offs,
- oh->prcm.omap4.clkctrl_offs);
+ if (oh->prcm.omap4.flags & HWMOD_OMAP4_MODULEMODE_SHARED) {
+ mmode = oh->prcm.omap4.modulemode_ref;
+
+ spin_lock_irqsave(&mmode->lock, flags);
+
+ enable = mmode->refcnt++ == 0;
+ }
+
+ if (enable)
+ am33xx_cm_module_enable(oh->prcm.omap4.modulemode,
+ oh->clkdm->cm_inst,
+ oh->clkdm->clkdm_offs,
+ oh->prcm.omap4.clkctrl_offs);
+
+ if (mmode)
+ spin_unlock_irqrestore(&mmode->lock, flags);
}
/**
@@ -1846,6 +1879,9 @@ static bool _are_any_hardreset_lines_asserted(struct
omap_hwmod *oh)
static int _omap4_disable_module(struct omap_
