OMAP hwmod: add hwmod class support

Add support for categorizing and iterating over hardware IP blocks by
the "class" of the IP block.  The class is the type of the IP block:
e.g., "timer", "timer1ms", etc.  Move the OCP_SYSCONFIG/SYSSTATUS data
from the struct omap_hwmod into the struct omap_hwmod_class, since
it's expected to stay consistent for each class.  While here, fix some
comments.

The hwmod_class structures in this patch were designed and proposed by
Benoît Cousson <b-cousson@ti.com> and were refined in a discussion
between Thara Gopinath <thara@ti.com>, Kevin Hilman
<khilman@deeprootsystems.com>, and myself.

This patch uses WARN() lines that are longer than 80 characters, as
Kevin noted a broader lkml consensus to increase greppability by
keeping the messages all on one line.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Benoît Cousson <b-cousson@ti.com>
Cc: Thara Gopinath <thara@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

7 files changed, 206 insertions, 90 deletions

diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 7fa4dec2947e..d3984d34fd03 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -5,15 +5,16 @@
 # Common support
 obj-y := id.o io.o control.o mux.o devices.o serial.o gpmc.o timer-gp.o
 
-omap-2-3-common                         = irq.o sdrc.o omap_hwmod.o \
+omap-2-3-common                         = irq.o sdrc.o
+hwmod-common                            = omap_hwmod.o \
                                           omap_hwmod_common_data.o
 prcm-common                             = prcm.o powerdomain.o
 clock-common                            = clock.o clock_common_data.o \
                                           clockdomain.o clkt_dpll.o \
                                           clkt_clksel.o
 
-obj-$(CONFIG_ARCH_OMAP2) += $(omap-2-3-common) $(prcm-common)
-obj-$(CONFIG_ARCH_OMAP3) += $(omap-2-3-common) $(prcm-common)
+obj-$(CONFIG_ARCH_OMAP2) += $(omap-2-3-common) $(prcm-common) $(hwmod-common)
+obj-$(CONFIG_ARCH_OMAP3) += $(omap-2-3-common) $(prcm-common) $(hwmod-common)
 obj-$(CONFIG_ARCH_OMAP4) += $(prcm-common)
 
 obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 501660aae962..c6649472ce0d 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -84,17 +84,16 @@ static u8 inited;
  */
 static int _update_sysc_cache(struct omap_hwmod *oh)
 {
-        if (!oh->sysconfig) {
-                WARN(!oh->sysconfig, "omap_hwmod: %s: cannot read "
-                     "OCP_SYSCONFIG: not defined on hwmod\n", oh->name);
+        if (!oh->class->sysc) {
+                WARN(1, "omap_hwmod: %s: cannot read OCP_SYSCONFIG: not defined on hwmod's class\n", oh->name);
                 return -EINVAL;
         }
 
         /* XXX ensure module interface clock is up */
 
-        oh->_sysc_cache = omap_hwmod_readl(oh, oh->sysconfig->sysc_offs);
+        oh->_sysc_cache = omap_hwmod_readl(oh, oh->class->sysc->sysc_offs);
 
-        if (!(oh->sysconfig->sysc_flags & SYSC_NO_CACHE))
+        if (!(oh->class->sysc->sysc_flags & SYSC_NO_CACHE))
                 oh->_int_flags |= _HWMOD_SYSCONFIG_LOADED;
 
         return 0;
@@ -105,14 +104,13 @@ static int _update_sysc_cache(struct omap_hwmod *oh)
  * @v: OCP_SYSCONFIG value to write
  * @oh: struct omap_hwmod *
  *
- * Write @v into the module OCP_SYSCONFIG register, if it has one.  No
- * return value.
+ * Write @v into the module class' OCP_SYSCONFIG register, if it has
+ * one.  No return value.
  */
 static void _write_sysconfig(u32 v, struct omap_hwmod *oh)
 {
-        if (!oh->sysconfig) {
-                WARN(!oh->sysconfig, "omap_hwmod: %s: cannot write "
-                     "OCP_SYSCONFIG: not defined on hwmod\n", oh->name);
+        if (!oh->class->sysc) {
+                WARN(1, "omap_hwmod: %s: cannot write OCP_SYSCONFIG: not defined on hwmod's class\n", oh->name);
                 return;
         }
 
@@ -120,7 +118,7 @@ static void _write_sysconfig(u32 v, struct omap_hwmod *oh)
 
         if (oh->_sysc_cache != v) {
                 oh->_sysc_cache = v;
-                omap_hwmod_writel(v, oh, oh->sysconfig->sysc_offs);
+                omap_hwmod_writel(v, oh, oh->class->sysc->sysc_offs);
         }
 }
 
@@ -140,17 +138,16 @@ static int _set_master_standbymode(struct omap_hwmod *oh, u8 standbymode,
         u32 mstandby_mask;
         u8 mstandby_shift;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_MIDLEMODE))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_MIDLEMODE))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        mstandby_shift = oh->sysconfig->sysc_fields->midle_shift;
+        mstandby_shift = oh->class->sysc->sysc_fields->midle_shift;
         mstandby_mask = (0x3 << mstandby_shift);
 
         *v &= ~mstandby_mask;
@@ -174,17 +171,16 @@ static int _set_slave_idlemode(struct omap_hwmod *oh, u8 idlemode, u32 *v)
         u32 sidle_mask;
         u8 sidle_shift;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_SIDLEMODE))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_SIDLEMODE))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        sidle_shift = oh->sysconfig->sysc_fields->sidle_shift;
+        sidle_shift = oh->class->sysc->sysc_fields->sidle_shift;
         sidle_mask = (0x3 << sidle_shift);
 
         *v &= ~sidle_mask;
@@ -209,17 +205,16 @@ static int _set_clockactivity(struct omap_hwmod *oh, u8 clockact, u32 *v)
         u32 clkact_mask;
         u8  clkact_shift;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_CLOCKACTIVITY))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_CLOCKACTIVITY))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        clkact_shift = oh->sysconfig->sysc_fields->clkact_shift;
+        clkact_shift = oh->class->sysc->sysc_fields->clkact_shift;
         clkact_mask = (0x3 << clkact_shift);
 
         *v &= ~clkact_mask;
@@ -240,17 +235,16 @@ static int _set_softreset(struct omap_hwmod *oh, u32 *v)
 {
         u32 softrst_mask;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_SOFTRESET))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_SOFTRESET))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        softrst_mask = (0x1 << oh->sysconfig->sysc_fields->srst_shift);
+        softrst_mask = (0x1 << oh->class->sysc->sysc_fields->srst_shift);
 
         *v |= softrst_mask;
 
@@ -276,17 +270,16 @@ static int _set_module_autoidle(struct omap_hwmod *oh, u8 autoidle,
         u32 autoidle_mask;
         u8 autoidle_shift;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_AUTOIDLE))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_AUTOIDLE))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        autoidle_shift = oh->sysconfig->sysc_fields->autoidle_shift;
+        autoidle_shift = oh->class->sysc->sysc_fields->autoidle_shift;
         autoidle_mask = (0x3 << autoidle_shift);
 
         *v &= ~autoidle_mask;
@@ -306,17 +299,16 @@ static int _enable_wakeup(struct omap_hwmod *oh)
 {
         u32 v, wakeup_mask;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_ENAWAKEUP))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        wakeup_mask = (0x1 << oh->sysconfig->sysc_fields->enwkup_shift);
+        wakeup_mask = (0x1 << oh->class->sysc->sysc_fields->enwkup_shift);
 
         v = oh->_sysc_cache;
         v |= wakeup_mask;
@@ -340,17 +332,16 @@ static int _disable_wakeup(struct omap_hwmod *oh)
 {
         u32 v, wakeup_mask;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_ENAWAKEUP))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
                 return -EINVAL;
 
-        if (!oh->sysconfig->sysc_fields) {
-                WARN(!oh->sysconfig->sysc_fields, "offset struct for "
-                        "sysconfig not provided!\n");
+        if (!oh->class->sysc->sysc_fields) {
+                WARN(1, "omap_hwmod: %s: offset struct for sysconfig not provided in class\n", oh->name);
                 return -EINVAL;
         }
 
-        wakeup_mask = (0x1 << oh->sysconfig->sysc_fields->enwkup_shift);
+        wakeup_mask = (0x1 << oh->class->sysc->sysc_fields->enwkup_shift);
 
         v = oh->_sysc_cache;
         v &= ~wakeup_mask;
@@ -638,27 +629,28 @@ static void __iomem *_find_mpu_rt_base(struct omap_hwmod *oh, u8 index)
  */
 static void _sysc_enable(struct omap_hwmod *oh)
 {
-        u8 idlemode;
+        u8 idlemode, sf;
         u32 v;
 
-        if (!oh->sysconfig)
+        if (!oh->class->sysc)
                 return;
 
         v = oh->_sysc_cache;
+        sf = oh->class->sysc->sysc_flags;
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_SIDLEMODE) {
+        if (sf & SYSC_HAS_SIDLEMODE) {
                 idlemode = (oh->flags & HWMOD_SWSUP_SIDLE) ?
                         HWMOD_IDLEMODE_NO : HWMOD_IDLEMODE_SMART;
                 _set_slave_idlemode(oh, idlemode, &v);
         }
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_MIDLEMODE) {
+        if (sf & SYSC_HAS_MIDLEMODE) {
                 idlemode = (oh->flags & HWMOD_SWSUP_MSTANDBY) ?
                         HWMOD_IDLEMODE_NO : HWMOD_IDLEMODE_SMART;
                 _set_master_standbymode(oh, idlemode, &v);
         }
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_AUTOIDLE) {
+        if (sf & SYSC_HAS_AUTOIDLE) {
                 idlemode = (oh->flags & HWMOD_NO_OCP_AUTOIDLE) ?
                         0 : 1;
                 _set_module_autoidle(oh, idlemode, &v);
@@ -671,9 +663,9 @@ static void _sysc_enable(struct omap_hwmod *oh)
          * calling into this code.  But this must wait until the
          * clock structures are tagged with omap_hwmod entries
          */
-        if (oh->flags & HWMOD_SET_DEFAULT_CLOCKACT &&
-            oh->sysconfig->sysc_flags & SYSC_HAS_CLOCKACTIVITY)
-                _set_clockactivity(oh, oh->sysconfig->clockact, &v);
+        if ((oh->flags & HWMOD_SET_DEFAULT_CLOCKACT) &&
+            (sf & SYSC_HAS_CLOCKACTIVITY))
+                _set_clockactivity(oh, oh->class->sysc->clockact, &v);
 
         _write_sysconfig(v, oh);
 }
@@ -689,21 +681,22 @@ static void _sysc_enable(struct omap_hwmod *oh)
  */
 static void _sysc_idle(struct omap_hwmod *oh)
 {
-        u8 idlemode;
+        u8 idlemode, sf;
         u32 v;
 
-        if (!oh->sysconfig)
+        if (!oh->class->sysc)
                 return;
 
         v = oh->_sysc_cache;
+        sf = oh->class->sysc->sysc_flags;
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_SIDLEMODE) {
+        if (sf & SYSC_HAS_SIDLEMODE) {
                 idlemode = (oh->flags & HWMOD_SWSUP_SIDLE) ?
                         HWMOD_IDLEMODE_FORCE : HWMOD_IDLEMODE_SMART;
                 _set_slave_idlemode(oh, idlemode, &v);
         }
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_MIDLEMODE) {
+        if (sf & SYSC_HAS_MIDLEMODE) {
                 idlemode = (oh->flags & HWMOD_SWSUP_MSTANDBY) ?
                         HWMOD_IDLEMODE_FORCE : HWMOD_IDLEMODE_SMART;
                 _set_master_standbymode(oh, idlemode, &v);
@@ -722,19 +715,21 @@ static void _sysc_idle(struct omap_hwmod *oh)
 static void _sysc_shutdown(struct omap_hwmod *oh)
 {
         u32 v;
+        u8 sf;
 
-        if (!oh->sysconfig)
+        if (!oh->class->sysc)
                 return;
 
         v = oh->_sysc_cache;
+        sf = oh->class->sysc->sysc_flags;
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_SIDLEMODE)
+        if (sf & SYSC_HAS_SIDLEMODE)
                 _set_slave_idlemode(oh, HWMOD_IDLEMODE_FORCE, &v);
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_MIDLEMODE)
+        if (sf & SYSC_HAS_MIDLEMODE)
                 _set_master_standbymode(oh, HWMOD_IDLEMODE_FORCE, &v);
 
-        if (oh->sysconfig->sysc_flags & SYSC_HAS_AUTOIDLE)
+        if (sf & SYSC_HAS_AUTOIDLE)
                 _set_module_autoidle(oh, 1, &v);
 
         _write_sysconfig(v, oh);
@@ -851,9 +846,9 @@ static int _reset(struct omap_hwmod *oh)
         u32 r, v;
         int c = 0;
 
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_SOFTRESET) ||
-            (oh->sysconfig->sysc_flags & SYSS_MISSING))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_SOFTRESET) ||
+            (oh->class->sysc->sysc_flags & SYSS_MISSING))
                 return -EINVAL;
 
         /* clocks must be on for this operation */
@@ -871,7 +866,7 @@ static int _reset(struct omap_hwmod *oh)
                 return r;
         _write_sysconfig(v, oh);
 
-        omap_test_timeout((omap_hwmod_readl(oh, oh->sysconfig->syss_offs) &
+        omap_test_timeout((omap_hwmod_readl(oh, oh->class->sysc->syss_offs) &
                            SYSS_RESETDONE_MASK),
                           MAX_MODULE_RESET_WAIT, c);
 
@@ -917,7 +912,7 @@ static int _enable(struct omap_hwmod *oh)
         _add_initiator_dep(oh, mpu_oh);
         _enable_clocks(oh);
 
-        if (oh->sysconfig) {
+        if (oh->class->sysc) {
                 if (!(oh->_int_flags & _HWMOD_SYSCONFIG_LOADED))
                         _update_sysc_cache(oh);
                 _sysc_enable(oh);
@@ -948,7 +943,7 @@ static int _idle(struct omap_hwmod *oh)
 
         pr_debug("omap_hwmod: %s: idling\n", oh->name);
 
-        if (oh->sysconfig)
+        if (oh->class->sysc)
                 _sysc_idle(oh);
         _del_initiator_dep(oh, mpu_oh);
         _disable_clocks(oh);
@@ -978,7 +973,7 @@ static int _shutdown(struct omap_hwmod *oh)
 
         pr_debug("omap_hwmod: %s: disabling\n", oh->name);
 
-        if (oh->sysconfig)
+        if (oh->class->sysc)
                 _sysc_shutdown(oh);
         _del_initiator_dep(oh, mpu_oh);
         /* XXX what about the other system initiators here? DMA, tesla, d2d */
@@ -1038,7 +1033,7 @@ static int _setup(struct omap_hwmod *oh)
                  * _enable() function should be split to avoid the
                  * rewrite of the OCP_SYSCONFIG register.
                  */
-                if (oh->sysconfig) {
+                if (oh->class->sysc) {
                         _update_sysc_cache(oh);
                         _sysc_enable(oh);
                 }
@@ -1085,9 +1080,12 @@ int omap_hwmod_set_slave_idlemode(struct omap_hwmod *oh, u8 idlemode)
  * omap_hwmod_register - register a struct omap_hwmod
  * @oh: struct omap_hwmod *
  *
- * Registers the omap_hwmod @oh.  Returns -EEXIST if an omap_hwmod already
- * has been registered by the same name; -EINVAL if the omap_hwmod is in the
- * wrong state, or 0 on success.
+ * Registers the omap_hwmod @oh.  Returns -EEXIST if an omap_hwmod
+ * already has been registered by the same name; -EINVAL if the
+ * omap_hwmod is in the wrong state, if @oh is NULL, if the
+ * omap_hwmod's class field is NULL; if the omap_hwmod is missing a
+ * name, or if the omap_hwmod's class is missing a name; or 0 upon
+ * success.
  *
  * XXX The data should be copied into bootmem, so the original data
  * should be marked __initdata and freed after init.  This would allow
@@ -1099,7 +1097,8 @@ int omap_hwmod_register(struct omap_hwmod *oh)
 {
         int ret, ms_id;
 
-        if (!oh || (oh->_state != _HWMOD_STATE_UNKNOWN))
+        if (!oh || !oh->name || !oh->class || !oh->class->name ||
+            (oh->_state != _HWMOD_STATE_UNKNOWN))
                 return -EINVAL;
 
         mutex_lock(&omap_hwmod_mutex);
@@ -1372,7 +1371,7 @@ void omap_hwmod_ocp_barrier(struct omap_hwmod *oh)
 {
         BUG_ON(!oh);
 
-        if (!oh->sysconfig || !oh->sysconfig->sysc_flags) {
+        if (!oh->class->sysc || !oh->class->sysc->sysc_flags) {
                 WARN(1, "omap_device: %s: OCP barrier impossible due to "
                       "device configuration\n", oh->name);
                 return;
@@ -1382,7 +1381,7 @@ void omap_hwmod_ocp_barrier(struct omap_hwmod *oh)
          * Forces posted writes to complete on the OCP thread handling
          * register writes
          */
-        omap_hwmod_readl(oh, oh->sysconfig->sysc_offs);
+        omap_hwmod_readl(oh, oh->class->sysc->sysc_offs);
 }
 
 /**
@@ -1575,8 +1574,8 @@ int omap_hwmod_del_initiator_dep(struct omap_hwmod *oh,
  */
 int omap_hwmod_enable_wakeup(struct omap_hwmod *oh)
 {
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_ENAWAKEUP))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
                 return -EINVAL;
 
         mutex_lock(&omap_hwmod_mutex);
@@ -1600,8 +1599,8 @@ int omap_hwmod_enable_wakeup(struct omap_hwmod *oh)
  */
 int omap_hwmod_disable_wakeup(struct omap_hwmod *oh)
 {
-        if (!oh->sysconfig ||
-            !(oh->sysconfig->sysc_flags & SYSC_HAS_ENAWAKEUP))
+        if (!oh->class->sysc ||
+            !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
                 return -EINVAL;
 
         mutex_lock(&omap_hwmod_mutex);
@@ -1610,3 +1609,52 @@ int omap_hwmod_disable_wakeup(struct omap_hwmod *oh)
 
         return 0;
 }
+
+/**
+ * omap_hwmod_for_each_by_class - call @fn for each hwmod of class @classname
+ * @classname: struct omap_hwmod_class name to search for
+ * @fn: callback function pointer to call for each hwmod in class @classname
+ * @user: arbitrary context data to pass to the callback function
+ *
+ * For each omap_hwmod of class @classname, call @fn.  Takes
+ * omap_hwmod_mutex to prevent the hwmod list from changing during the
+ * iteration.  If the callback function returns something other than
+ * zero, the iterator is terminated, and the callback function's return
+ * value is passed back to the caller.  Returns 0 upon success, -EINVAL
+ * if @classname or @fn are NULL, or passes back the error code from @fn.
+ */
+int omap_hwmod_for_each_by_class(const char *classname,
+                                 int (*fn)(struct omap_hwmod *oh,
+                                           void *user),
+                                 void *user)
+{
+        struct omap_hwmod *temp_oh;
+        int ret = 0;
+
+        if (!classname || !fn)
+                return -EINVAL;
+
+        pr_debug("omap_hwmod: %s: looking for modules of class %s\n",
+                 __func__, classname);
+
+        mutex_lock(&omap_hwmod_mutex);
+
+        list_for_each_entry(temp_oh, &omap_hwmod_list, node) {
+                if (!strcmp(temp_oh->class->name, classname)) {
+                        pr_debug("omap_hwmod: %s: %s: calling callback fn\n",
+                                 __func__, temp_oh->name);
+                        ret = (*fn)(temp_oh, user);
+                        if (ret)
+                                break;
+                }
+        }
+
+        mutex_unlock(&omap_hwmod_mutex);
+
+        if (ret)
+                pr_debug("omap_hwmod: %s: iterator terminated early: %d\n",
+                         __func__, ret);
+
+        return ret;
+}
+
diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index a1c5839fc52d..eb7ee2453b24 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -16,6 +16,8 @@
 #include <plat/cpu.h>
 #include <plat/dma.h>
 
+#include "omap_hwmod_common_data.h"
+
 #include "prm-regbits-24xx.h"
 
 /*
@@ -58,6 +60,7 @@ static struct omap_hwmod_ocp_if *omap2420_l3_masters[] = {
 /* L3 */
 static struct omap_hwmod omap2420_l3_hwmod = {
         .name           = "l3_hwmod",
+        .class          = &l3_hwmod_class,
         .masters        = omap2420_l3_masters,
         .masters_cnt    = ARRAY_SIZE(omap2420_l3_masters),
         .slaves         = omap2420_l3_slaves,
@@ -87,6 +90,7 @@ static struct omap_hwmod_ocp_if *omap2420_l4_core_masters[] = {
 /* L4 CORE */
 static struct omap_hwmod omap2420_l4_core_hwmod = {
         .name           = "l4_core_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap2420_l4_core_masters,
         .masters_cnt    = ARRAY_SIZE(omap2420_l4_core_masters),
         .slaves         = omap2420_l4_core_slaves,
@@ -106,6 +110,7 @@ static struct omap_hwmod_ocp_if *omap2420_l4_wkup_masters[] = {
 /* L4 WKUP */
 static struct omap_hwmod omap2420_l4_wkup_hwmod = {
         .name           = "l4_wkup_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap2420_l4_wkup_masters,
         .masters_cnt    = ARRAY_SIZE(omap2420_l4_wkup_masters),
         .slaves         = omap2420_l4_wkup_slaves,
@@ -121,6 +126,7 @@ static struct omap_hwmod_ocp_if *omap2420_mpu_masters[] = {
 /* MPU */
 static struct omap_hwmod omap2420_mpu_hwmod = {
         .name           = "mpu_hwmod",
+        .class          = &mpu_hwmod_class,
         .main_clk       = "mpu_ck",
         .masters        = omap2420_mpu_masters,
         .masters_cnt    = ARRAY_SIZE(omap2420_mpu_masters),
diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
index ed2de7936c10..241bd8230729 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2430_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
@@ -16,6 +16,8 @@
 #include <plat/cpu.h>
 #include <plat/dma.h>
 
+#include "omap_hwmod_common_data.h"
+
 #include "prm-regbits-24xx.h"
 
 /*
@@ -58,6 +60,7 @@ static struct omap_hwmod_ocp_if *omap2430_l3_masters[] = {
 /* L3 */
 static struct omap_hwmod omap2430_l3_hwmod = {
         .name           = "l3_hwmod",
+        .class          = &l3_hwmod_class,
         .masters        = omap2430_l3_masters,
         .masters_cnt    = ARRAY_SIZE(omap2430_l3_masters),
         .slaves         = omap2430_l3_slaves,
@@ -89,6 +92,7 @@ static struct omap_hwmod_ocp_if *omap2430_l4_core_masters[] = {
 /* L4 CORE */
 static struct omap_hwmod omap2430_l4_core_hwmod = {
         .name           = "l4_core_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap2430_l4_core_masters,
         .masters_cnt    = ARRAY_SIZE(omap2430_l4_core_masters),
         .slaves         = omap2430_l4_core_slaves,
@@ -108,6 +112,7 @@ static struct omap_hwmod_ocp_if *omap2430_l4_wkup_masters[] = {
 /* L4 WKUP */
 static struct omap_hwmod omap2430_l4_wkup_hwmod = {
         .name           = "l4_wkup_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap2430_l4_wkup_masters,
         .masters_cnt    = ARRAY_SIZE(omap2430_l4_wkup_masters),
         .slaves         = omap2430_l4_wkup_slaves,
@@ -123,6 +128,7 @@ static struct omap_hwmod_ocp_if *omap2430_mpu_masters[] = {
 /* MPU */
 static struct omap_hwmod omap2430_mpu_hwmod = {
         .name           = "mpu_hwmod",
+        .class          = &mpu_hwmod_class,
         .main_clk       = "mpu_ck",
         .masters        = omap2430_mpu_masters,
         .masters_cnt    = ARRAY_SIZE(omap2430_mpu_masters),
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 8d4b686a5e04..ed6084004260 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -18,6 +18,8 @@
 #include <plat/cpu.h>
 #include <plat/dma.h>
 
+#include "omap_hwmod_common_data.h"
+
 #include "prm-regbits-34xx.h"
 
 /*
@@ -69,6 +71,7 @@ static struct omap_hwmod_ocp_if *omap3xxx_l3_masters[] = {
 /* L3 */
 static struct omap_hwmod omap3xxx_l3_hwmod = {
         .name           = "l3_hwmod",
+        .class          = &l3_hwmod_class,
         .masters        = omap3xxx_l3_masters,
         .masters_cnt    = ARRAY_SIZE(omap3xxx_l3_masters),
         .slaves         = omap3xxx_l3_slaves,
@@ -98,6 +101,7 @@ static struct omap_hwmod_ocp_if *omap3xxx_l4_core_masters[] = {
 /* L4 CORE */
 static struct omap_hwmod omap3xxx_l4_core_hwmod = {
         .name           = "l4_core_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap3xxx_l4_core_masters,
         .masters_cnt    = ARRAY_SIZE(omap3xxx_l4_core_masters),
         .slaves         = omap3xxx_l4_core_slaves,
@@ -117,6 +121,7 @@ static struct omap_hwmod_ocp_if *omap3xxx_l4_per_masters[] = {
 /* L4 PER */
 static struct omap_hwmod omap3xxx_l4_per_hwmod = {
         .name           = "l4_per_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap3xxx_l4_per_masters,
         .masters_cnt    = ARRAY_SIZE(omap3xxx_l4_per_masters),
         .slaves         = omap3xxx_l4_per_slaves,
@@ -136,6 +141,7 @@ static struct omap_hwmod_ocp_if *omap3xxx_l4_wkup_masters[] = {
 /* L4 WKUP */
 static struct omap_hwmod omap3xxx_l4_wkup_hwmod = {
         .name           = "l4_wkup_hwmod",
+        .class          = &l4_hwmod_class,
         .masters        = omap3xxx_l4_wkup_masters,
         .masters_cnt    = ARRAY_SIZE(omap3xxx_l4_wkup_masters),
         .slaves         = omap3xxx_l4_wkup_slaves,
@@ -151,6 +157,7 @@ static struct omap_hwmod_ocp_if *omap3xxx_mpu_masters[] = {
 /* MPU */
 static struct omap_hwmod omap3xxx_mpu_hwmod = {
         .name           = "mpu_hwmod",
+        .class          = &mpu_hwmod_class,
         .main_clk       = "arm_fck",
         .masters        = omap3xxx_mpu_masters,
         .masters_cnt    = ARRAY_SIZE(omap3xxx_mpu_masters),
diff --git a/arch/arm/mach-omap2/omap_hwmod_common_data.c b/arch/arm/mach-omap2/omap_hwmod_common_data.c
index 2567c6edc6af..1e80b914fa1a 100644
--- a/arch/arm/mach-omap2/omap_hwmod_common_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_common_data.c
@@ -3,6 +3,10 @@
  *
  * Copyright (C) 2010 Texas Instruments, Inc.
  * Thara Gopinath <thara@ti.com>
+ * Benoît Cousson
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ * Paul Walmsley
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -14,6 +18,8 @@
 
 #include <plat/omap_hwmod.h>
 
+#include "omap_hwmod_common_data.h"
+
 /**
  * struct omap_hwmod_sysc_type1 - TYPE1 sysconfig scheme.
  *
@@ -42,3 +48,21 @@ struct omap_hwmod_sysc_fields omap_hwmod_sysc_type2 = {
         .sidle_shift    = SYSC_TYPE2_SIDLEMODE_SHIFT,
         .srst_shift     = SYSC_TYPE2_SOFTRESET_SHIFT,
 };
+
+
+/*
+ * omap_hwmod class data
+ */
+
+struct omap_hwmod_class l3_hwmod_class = {
+        .name = "l3"
+};
+
+struct omap_hwmod_class l4_hwmod_class = {
+        .name = "l4"
+};
+
+struct omap_hwmod_class mpu_hwmod_class = {
+        .name = "mpu"
+};
+
diff --git a/arch/arm/mach-omap2/omap_hwmod_common_data.h b/arch/arm/mach-omap2/omap_hwmod_common_data.h
new file mode 100644
index 000000000000..3645a28c7c27
--- /dev/null
+++ b/arch/arm/mach-omap2/omap_hwmod_common_data.h
@@ -0,0 +1,24 @@
+/*
+ * omap_hwmod_common_data.h - OMAP hwmod common macros and declarations
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ * Paul Walmsley
+ *
+ * Copyright (C) 2010 Texas Instruments, Inc.
+ * Benoît Cousson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __ARCH_ARM_MACH_OMAP2_OMAP_HWMOD_COMMON_DATA_H
+#define __ARCH_ARM_MACH_OMAP2_OMAP_HWMOD_COMMON_DATA_H
+
+#include <plat/omap_hwmod.h>
+
+/* OMAP hwmod classes - forward declarations */
+extern struct omap_hwmod_class l3_hwmod_class;
+extern struct omap_hwmod_class l4_hwmod_class;
+extern struct omap_hwmod_class mpu_hwmod_class;
+
+#endif