OMAP4: hwmod & CM: Implement the omap4_cm_wait_module_ready function

The return of the omap4_cm_wait_module_ready function is checked
in order to avoid accessing the sysconfig register if the module is
not in the correct state.
In that case the _setup will exit without trying to reset
using sysconfig.
For the moment a warning is printed. A proper management of fclk
and module reset will have to be done in order to init correctly
the problematic IPs listed below.

  <4>omap_hwmod: ivahd: cannot be enabled (3)
  <4>omap_hwmod: iss: cannot be enabled (3)
  <4>omap_hwmod: tesla: cannot be enabled (3)
  <4>omap_hwmod: sdma: cannot be enabled (3)
  <4>omap_hwmod: sl2: cannot be enabled (3)
  <4>omap_hwmod: sad2d: cannot be enabled (3)
  <4>omap_hwmod: ducati: cannot be enabled (3)

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

3 files changed, 50 insertions, 21 deletions

diff --git a/arch/arm/mach-omap2/cm.h b/arch/arm/mach-omap2/cm.h
index bbc69df3bf3..a02ca30423d 100644
--- a/arch/arm/mach-omap2/cm.h
+++ b/arch/arm/mach-omap2/cm.h
@@ -112,7 +112,7 @@ extern u32 cm_rmw_mod_reg_bits(u32 mask, u32 bits, s16 module, s16 idx);
 
 extern int omap2_cm_wait_module_ready(s16 prcm_mod, u8 idlest_id,
                                       u8 idlest_shift);
-extern int omap4_cm_wait_module_ready(u32 prcm_mod, u8 prcm_dev_offs);
+extern int omap4_cm_wait_module_ready(void __iomem *clkctrl_reg);
 
 static inline u32 cm_set_mod_reg_bits(u32 bits, s16 module, s16 idx)
 {
diff --git a/arch/arm/mach-omap2/cm4xxx.c b/arch/arm/mach-omap2/cm4xxx.c
index af32a457a46..b101091e95d 100644
--- a/arch/arm/mach-omap2/cm4xxx.c
+++ b/arch/arm/mach-omap2/cm4xxx.c
@@ -21,19 +21,41 @@
 
 #include <asm/atomic.h>
 
+#include <plat/common.h>
+
 #include "cm.h"
 #include "cm-regbits-44xx.h"
 
 /**
- * omap4_cm_wait_idlest_ready - wait for a module to leave idle or standby
- * @prcm_mod: PRCM module offset (XXX example)
- * @prcm_dev_offs: PRCM device offset (e.g. MCASP XXX example)
+ * omap4_cm_wait_module_ready - wait for a module to be in 'func' state
+ * @clkctrl_reg: CLKCTRL module address
+ *
+ * Wait for the module IDLEST to be functional. If the idle state is in any
+ * the non functional state (trans, idle or disabled), module and thus the
+ * sysconfig cannot be accessed and will probably lead to an "imprecise
+ * external abort"
+ *
+ * Module idle state:
+ *   0x0 func:     Module is fully functional, including OCP
+ *   0x1 trans:    Module is performing transition: wakeup, or sleep, or sleep
+ *                 abortion
+ *   0x2 idle:     Module is in Idle mode (only OCP part). It is functional if
+ *                 using separate functional clock
+ *   0x3 disabled: Module is disabled and cannot be accessed
  *
- * XXX document
+ * TODO: Need to handle module accessible in idle state
  */
-int omap4_cm_wait_idlest_ready(u32 prcm_mod, u8 prcm_dev_offs)
+int omap4_cm_wait_module_ready(void __iomem *clkctrl_reg)
 {
-        /* FIXME: Add clock manager related code */
-        return 0;
+        int i = 0;
+
+        if (!clkctrl_reg)
+                return 0;
+
+        omap_test_timeout(((__raw_readl(clkctrl_reg) &
+                            OMAP4430_IDLEST_MASK) == 0),
+                          MAX_MODULE_READY_TIME, i);
+
+        return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
 }
 
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index e436dcb1979..4a134c4d227 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -819,11 +819,8 @@ static int _wait_target_ready(struct omap_hwmod *oh)
                 ret = omap2_cm_wait_module_ready(oh->prcm.omap2.module_offs,
                                                  oh->prcm.omap2.idlest_reg_id,
                                                  oh->prcm.omap2.idlest_idle_bit);
-#if 0
         } else if (cpu_is_omap44xx()) {
-                ret = omap4_cm_wait_module_ready(oh->prcm.omap4.module_offs,
-                                                 oh->prcm.omap4.device_offs);
-#endif
+                ret = omap4_cm_wait_module_ready(oh->prcm.omap4.clkctrl_reg);
         } else {
                 BUG();
         };
@@ -912,16 +909,21 @@ static int _enable(struct omap_hwmod *oh)
         _add_initiator_dep(oh, mpu_oh);
         _enable_clocks(oh);
 
-        if (oh->class->sysc) {
-                if (!(oh->_int_flags & _HWMOD_SYSCONFIG_LOADED))
-                        _update_sysc_cache(oh);
-                _sysc_enable(oh);
-        }
-
         r = _wait_target_ready(oh);
-        if (!r)
+        if (!r) {
                 oh->_state = _HWMOD_STATE_ENABLED;
 
+                /* Access the sysconfig only if the target is ready */
+                if (oh->class->sysc) {
+                        if (!(oh->_int_flags & _HWMOD_SYSCONFIG_LOADED))
+                                _update_sysc_cache(oh);
+                        _sysc_enable(oh);
+                }
+        } else {
+                pr_debug("omap_hwmod: %s: _wait_target_ready: %d\n",
+                         oh->name, r);
+        }
+
         return r;
 }
 
@@ -999,7 +1001,7 @@ static int _shutdown(struct omap_hwmod *oh)
 static int _setup(struct omap_hwmod *oh)
 {
         struct omap_hwmod_ocp_if *os;
-        int i;
+        int i, r;
 
         if (!oh)
                 return -EINVAL;
@@ -1023,7 +1025,12 @@ static int _setup(struct omap_hwmod *oh)
 
         oh->_state = _HWMOD_STATE_INITIALIZED;
 
-        _enable(oh);
+        r = _enable(oh);
+        if (r) {
+                pr_warning("omap_hwmod: %s: cannot be enabled (%d)\n",
+                           oh->name, oh->_state);
+                return 0;
+        }
 
         if (!(oh->flags & HWMOD_INIT_NO_RESET)) {
                 /*