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 all of the block's hardreset
lines weren't asserted.  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 disable would be skipped.  This
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@ti.com>
Tested-by: Archit Taneja <a0393947@ti.com> # DSS
Cc: Omar Ramirez Luna <omar.luna@linaro.org>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Acked-by: Vaibhav Hiremath <hvaibhav@ti.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com> # AM335x
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 27 insertions, 4 deletions

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 299ca2821ad1..b969ab1d258b 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",