cc Vaibhav due to the AM33xx change
Hi
On Thu, 4 Oct 2012, Archit Taneja wrote:
> I was trying out the linux-next kernel, and I noticed that DSS MODULEMODE bits
> are never cleared.
>
> In _omap4_disable_module(), there is a check:
>
> ...
>
> if (!_are_all_hardreset_lines_asserted(oh))
> return 0;
>
> /* MODULEMODE bits cleared here */
> ...
> ...
> ...
>
> The function _are_all_hardreset_lines_asserted() returns false if
> 'oh->rst_lines_cnt == 0', so we bail out from _omap4_disable_module() before
> clearing the MODULEMODE bits.
>
> Is this correct behavior? This would prevent all hwmods who have rst_lines_cnt
> as 0 to not get their MODULEMODE bits cleared.
You're right, that looks bogus. What do you think about the following
patch?
- Paul
From: Paul Walmsley <paul@xxxxxxxxx>
Date: Mon, 8 Oct 2012 23:08:15 -0600
Subject: [PATCH] ARM: OMAP4/AM335x: hwmod: fix disable_module regression in
hardreset handling
Commit eb05f691290e99ee0bd1672317d6add789523c1e ("ARM: OMAP: hwmod:
partially un-reset hwmods might not be properly enabled") added code
to skip the IP block disable sequence if any hardreset lines were left
unasserted. But this did not handle the case when no hardreset lines
were associated with a module, which is the general case. In that
situation, the IP block would be skipped, which is likely to cause PM
regressions.
So, modify _omap4_disable_module() and _am33xx_disable_module() to
only bail out early if there are any hardreset lines asserted. And
move the AM33xx test above the actual module disable code to ensure
that the behavior is consistent.
Reported-by: Archit Taneja <a0393947@xxxxxx>
Cc: Omar Ramirez Luna <omar.luna@xxxxxxxxxx>
Cc: Vaibhav Hiremath <hvaibhav@xxxxxx>
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/mach-omap2/omap_hwmod.c | 31 +++++++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 299ca28..b969ab1 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1698,6 +1698,29 @@ static bool _are_all_hardreset_lines_asserted(struct omap_hwmod *oh)
}
/**
+ * _are_any_hardreset_lines_asserted - return true if any part of @oh is
+ * hard-reset
+ * @oh: struct omap_hwmod *
+ *
+ * If any hardreset lines associated with @oh are asserted, then
+ * return true. Otherwise, if no hardreset lines associated with @oh
+ * are asserted, or if @oh has no hardreset lines, then return false.
+ * This function is used to avoid executing some parts of the IP block
+ * enable/disable sequence if any hardreset line is set.
+ */
+static bool _are_any_hardreset_lines_asserted(struct omap_hwmod *oh)
+{
+ int rst_cnt = 0;
+ int i;
+
+ for (i = 0; i < oh->rst_lines_cnt && rst_cnt == 0; i++)
+ if (_read_hardreset(oh, oh->rst_lines[i].name) > 0)
+ rst_cnt++;
+
+ return (rst_cnt) ? true : false;
+}
+
+/**
* _omap4_disable_module - enable CLKCTRL modulemode on OMAP4
* @oh: struct omap_hwmod *
*
@@ -1715,7 +1738,7 @@ static int _omap4_disable_module(struct omap_hwmod *oh)
* Since integration code might still be doing something, only
* disable if all lines are under hardreset.
*/
- if (!_are_all_hardreset_lines_asserted(oh))
+ if (_are_any_hardreset_lines_asserted(oh))
return 0;
pr_debug("omap_hwmod: %s: %s\n", oh->name, __func__);
@@ -1749,12 +1772,12 @@ static int _am33xx_disable_module(struct omap_hwmod *oh)
pr_debug("omap_hwmod: %s: %s\n", oh->name, __func__);
+ if (_are_any_hardreset_lines_asserted(oh))
+ return 0;
+
am33xx_cm_module_disable(oh->clkdm->cm_inst, oh->clkdm->clkdm_offs,
oh->prcm.omap4.clkctrl_offs);
- if (_are_all_hardreset_lines_asserted(oh))
- return 0;
-
v = _am33xx_wait_target_disable(oh);
if (v)
pr_warn("omap_hwmod: %s: _wait_target_disable failed\n",
--
1.7.10.4
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