linux-kernel - [PATCH 1/3] ARM: omap2+: omap_hwmod: introduce hwmod flag for custom reset handling

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Date:	Mon, 8 Feb 2016 16:42:19 +0530
From:	Kishon Vijay Abraham I <kishon@...com>
To:	Paul Walmsley <paul@...an.com>, Tony Lindgren <tony@...mide.com>,
	<bhelgaas@...gle.com>, <richardcochran@...il.com>, <s-anna@...com>
CC:	Russell King <linux@....linux.org.uk>,
	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <bcousson@...libre.com>,
	<kishon@...com>, <nsekhar@...com>
Subject: [PATCH 1/3] ARM: omap2+: omap_hwmod: introduce hwmod flag for custom reset handling

From: Paul Walmsley <paul@...an.com>

Many of the IP blocks with PRM hardreset lines are processor IP blocks
and need special reset handling to ensure that WFI/HLT-like
instructions are executed after reset. Introduce a new hwmod flag
_HWMOD_CUSTOM_HARDRESET_ to indicate if the IP block requires
special reset handling.

Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
---
 arch/arm/mach-omap2/omap_hwmod.h |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h
index 76bce11..4198829 100644
--- a/arch/arm/mach-omap2/omap_hwmod.h
+++ b/arch/arm/mach-omap2/omap_hwmod.h
@@ -525,6 +525,17 @@ struct omap_hwmod_omap4_prcm {
  *     or idled.
  * HWMOD_OPT_CLKS_NEEDED: The optional clocks are needed for the module to
  *     operate and they need to be handled at the same time as the main_clk.
+ * HWMOD_CUSTOM_HARDRESET: By default, if a hwmod has PRCM hardreset
+ *     lines associated with it (i.e., a populated .rst_lines field in
+ *     the hwmod), the hwmod code will assert the hardreset lines when
+ *     the IP block is initially reset, deassert the hardreset lines
+ *     in _enable(), and reassert them in _shutdown().  If this flag
+ *     is set, the hwmod code will not deassert the hardreset lines in
+ *     _enable(), leaving this responsibility to the driver code.  This flag may
+ *     be needed for processor IP blocks that must be put into a WFI/HLT
+ *     state after reset is deasserted, lest the processor leave its MSTANDBY
+ *     signal deasserted, thus blocking the chip from entering a system-wide
+ *     low power state.
  */
 #define HWMOD_SWSUP_SIDLE			(1 << 0)
 #define HWMOD_SWSUP_MSTANDBY			(1 << 1)
@@ -541,6 +552,7 @@ struct omap_hwmod_omap4_prcm {
 #define HWMOD_SWSUP_SIDLE_ACT			(1 << 12)
 #define HWMOD_RECONFIG_IO_CHAIN			(1 << 13)
 #define HWMOD_OPT_CLKS_NEEDED			(1 << 14)
+#define HWMOD_CUSTOM_HARDRESET			(1 << 15)
 
 /*
  * omap_hwmod._int_flags definitions
-- 
1.7.9.5