OMAP2+: hwmod: add support for per-class custom device reset functions

The standard omap_hwmod.c _reset() code relies on an IP block's
OCP_SYSCONFIG.SOFTRESET register bit to reset the IP block.  This
works for most IP blocks on the chip, but unfortunately not all.  For
example, initiator-only IP blocks often don't have any MPU-accessible
OCP-header registers, and therefore the MPU can't write to any
OCP_SYSCONFIG registers in that block.  Other IP blocks, such as the
IVA and I2C, require a specialized reset sequence.

Since we need to be able to reset these IP blocks as well, allow
custom IP block reset functions to be passed into the hwmod code via a
per-hwmod-class reset function pointer, struct omap_hwmod_class.reset.
If .reset is non-null, then the hwmod _reset() code will call the custom
function instead of the standard OCP SOFTRESET-based code.

As part of this change, rename most of the existing _reset() function
code to _ocp_softreset(), to indicate more clearly that it does not work
for all cases.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Paul Hunt <hunt@ti.com>
Cc: Stanley Liu <stanley_liu@ti.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index b445ecdb95b8..e4c4fd4cc1ed 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -364,7 +364,7 @@ struct omap_hwmod_omap4_prcm {
  *     when module is enabled, rather than the default, which is to
  *     enable autoidle
  * HWMOD_SET_DEFAULT_CLOCKACT: program CLOCKACTIVITY bits at startup
- * HWMOD_NO_IDLEST : this module does not have idle status - this is the case
+ * HWMOD_NO_IDLEST: this module does not have idle status - this is the case
  *     only for few initiator modules on OMAP2 & 3.
  * HWMOD_CONTROL_OPT_CLKS_IN_RESET: Enable all optional clocks during reset.
  *     This is needed for devices like DSS that require optional clocks enabled
@@ -416,6 +416,7 @@ struct omap_hwmod_omap4_prcm {
  * @sysc: device SYSCONFIG/SYSSTATUS register data
  * @rev: revision of the IP class
  * @pre_shutdown: ptr to fn to be executed immediately prior to device shutdown
+ * @reset: ptr to fn to be executed in place of the standard hwmod reset fn
  *
  * Represent the class of a OMAP hardware "modules" (e.g. timer,
  * smartreflex, gpio, uart...)
@@ -427,12 +428,18 @@ struct omap_hwmod_omap4_prcm {
  * or some negative error upon failure.  Returning an error will cause
  * omap_hwmod_shutdown() to abort the device shutdown and return an
  * error.
+ *
+ * If @reset is defined, then the function it points to will be
+ * executed in place of the standard hwmod _reset() code in
+ * mach-omap2/omap_hwmod.c.  This is needed for IP blocks which have
+ * unusual reset sequences - usually processor IP blocks like the IVA.
  */
 struct omap_hwmod_class {
         const char                              *name;
         struct omap_hwmod_class_sysconfig       *sysc;
         u32                                     rev;
         int                                     (*pre_shutdown)(struct omap_hwmod *oh);
+        int                                     (*reset)(struct omap_hwmod *oh);
 };
 
 /**