ARM: OMAP: Add function to request timer by node

Add a function so that OMAP dmtimers can be requested by device-tree
node. This allows for devices, such as the internal DSP, or drivers,
such as PWM, to reference a specific dmtimer node via the device-tree.

Given that there are several APIs available for requesting dmtimers
(by ID, by capability or by node) consolidate the code for all these
functions into a single helper function that can be used by these
request functions.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>

2 files changed, 94 insertions, 74 deletions

diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
index 725d9720dd2b..05efb370a2bd 100644
--- a/arch/arm/plat-omap/dmtimer.c
+++ b/arch/arm/plat-omap/dmtimer.c
@@ -52,6 +52,13 @@ static u32 omap_reserved_systimers;
 static LIST_HEAD(omap_timer_list);
 static DEFINE_SPINLOCK(dm_timer_lock);
 
+enum {
+        REQUEST_ANY = 0,
+        REQUEST_BY_ID,
+        REQUEST_BY_CAP,
+        REQUEST_BY_NODE,
+};
+
 /**
  * omap_dm_timer_read_reg - read timer registers in posted and non-posted mode
  * @timer:      timer pointer over which read operation to perform
@@ -178,29 +185,82 @@ int omap_dm_timer_reserve_systimer(int id)
         return 0;
 }
 
-struct omap_dm_timer *omap_dm_timer_request(void)
+static struct omap_dm_timer *_omap_dm_timer_request(int req_type, void *data)
 {
         struct omap_dm_timer *timer = NULL, *t;
+        struct device_node *np = NULL;
         unsigned long flags;
-        int ret = 0;
+        u32 cap = 0;
+        int id = 0;
+
+        switch (req_type) {
+        case REQUEST_BY_ID:
+                id = *(int *)data;
+                break;
+        case REQUEST_BY_CAP:
+                cap = *(u32 *)data;
+                break;
+        case REQUEST_BY_NODE:
+                np = (struct device_node *)data;
+                break;
+        default:
+                /* REQUEST_ANY */
+                break;
+        }
 
         spin_lock_irqsave(&dm_timer_lock, flags);
         list_for_each_entry(t, &omap_timer_list, node) {
                 if (t->reserved)
                         continue;
 
-                timer = t;
-                timer->reserved = 1;
-                break;
+                switch (req_type) {
+                case REQUEST_BY_ID:
+                        if (id == t->pdev->id) {
+                                timer = t;
+                                timer->reserved = 1;
+                                goto found;
+                        }
+                        break;
+                case REQUEST_BY_CAP:
+                        if (cap == (t->capability & cap)) {
+                                /*
+                                 * If timer is not NULL, we have already found
+                                 * one timer but it was not an exact match
+                                 * because it had more capabilites that what
+                                 * was required. Therefore, unreserve the last
+                                 * timer found and see if this one is a better
+                                 * match.
+                                 */
+                                if (timer)
+                                        timer->reserved = 0;
+                                timer = t;
+                                timer->reserved = 1;
+
+                                /* Exit loop early if we find an exact match */
+                                if (t->capability == cap)
+                                        goto found;
+                        }
+                        break;
+                case REQUEST_BY_NODE:
+                        if (np == t->pdev->dev.of_node) {
+                                timer = t;
+                                timer->reserved = 1;
+                                goto found;
+                        }
+                        break;
+                default:
+                        /* REQUEST_ANY */
+                        timer = t;
+                        timer->reserved = 1;
+                        goto found;
+                }
         }
+found:
         spin_unlock_irqrestore(&dm_timer_lock, flags);
 
-        if (timer) {
-                ret = omap_dm_timer_prepare(timer);
-                if (ret) {
-                        timer->reserved = 0;
-                        timer = NULL;
-                }
+        if (timer && omap_dm_timer_prepare(timer)) {
+                timer->reserved = 0;
+                timer = NULL;
         }
 
         if (!timer)
@@ -208,43 +268,23 @@ struct omap_dm_timer *omap_dm_timer_request(void)
 
         return timer;
 }
+
+struct omap_dm_timer *omap_dm_timer_request(void)
+{
+        return _omap_dm_timer_request(REQUEST_ANY, NULL);
+}
 EXPORT_SYMBOL_GPL(omap_dm_timer_request);
 
 struct omap_dm_timer *omap_dm_timer_request_specific(int id)
 {
-        struct omap_dm_timer *timer = NULL, *t;
-        unsigned long flags;
-        int ret = 0;
-
         /* Requesting timer by ID is not supported when device tree is used */
         if (of_have_populated_dt()) {
-                pr_warn("%s: Please use omap_dm_timer_request_by_cap()\n",
+                pr_warn("%s: Please use omap_dm_timer_request_by_cap/node()\n",
                         __func__);
                 return NULL;
         }
 
-        spin_lock_irqsave(&dm_timer_lock, flags);
-        list_for_each_entry(t, &omap_timer_list, node) {
-                if (t->pdev->id == id && !t->reserved) {
-                        timer = t;
-                        timer->reserved = 1;
-                        break;
-                }
-        }
-        spin_unlock_irqrestore(&dm_timer_lock, flags);
-
-        if (timer) {
-                ret = omap_dm_timer_prepare(timer);
-                if (ret) {
-                        timer->reserved = 0;
-                        timer = NULL;
-                }
-        }
-
-        if (!timer)
-                pr_debug("%s: timer%d request failed!\n", __func__, id);
-
-        return timer;
+        return _omap_dm_timer_request(REQUEST_BY_ID, &id);
 }
 EXPORT_SYMBOL_GPL(omap_dm_timer_request_specific);
 
@@ -259,46 +299,25 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_request_specific);
  */
 struct omap_dm_timer *omap_dm_timer_request_by_cap(u32 cap)
 {
-        struct omap_dm_timer *timer = NULL, *t;
-        unsigned long flags;
+        return _omap_dm_timer_request(REQUEST_BY_CAP, &cap);
+}
+EXPORT_SYMBOL_GPL(omap_dm_timer_request_by_cap);
 
-        if (!cap)
+/**
+ * omap_dm_timer_request_by_node - Request a timer by device-tree node
+ * @np:         Pointer to device-tree timer node
+ *
+ * Request a timer based upon a device node pointer. Returns pointer to
+ * timer handle on success and a NULL pointer on failure.
+ */
+struct omap_dm_timer *omap_dm_timer_request_by_node(struct device_node *np)
+{
+        if (!np)
                 return NULL;
 
-        spin_lock_irqsave(&dm_timer_lock, flags);
-        list_for_each_entry(t, &omap_timer_list, node) {
-                if ((!t->reserved) && ((t->capability & cap) == cap)) {
-                        /*
-                         * If timer is not NULL, we have already found one timer
-                         * but it was not an exact match because it had more
-                         * capabilites that what was required. Therefore,
-                         * unreserve the last timer found and see if this one
-                         * is a better match.
-                         */
-                        if (timer)
-                                timer->reserved = 0;
-
-                        timer = t;
-                        timer->reserved = 1;
-
-                        /* Exit loop early if we find an exact match */
-                        if (t->capability == cap)
-                                break;
-                }
-        }
-        spin_unlock_irqrestore(&dm_timer_lock, flags);
-
-        if (timer && omap_dm_timer_prepare(timer)) {
-                timer->reserved = 0;
-                timer = NULL;
-        }
-
-        if (!timer)
-                pr_debug("%s: timer request failed!\n", __func__);
-
-        return timer;
+        return _omap_dm_timer_request(REQUEST_BY_NODE, np);
 }
-EXPORT_SYMBOL_GPL(omap_dm_timer_request_by_cap);
+EXPORT_SYMBOL_GPL(omap_dm_timer_request_by_node);
 
 int omap_dm_timer_free(struct omap_dm_timer *timer)
 {
diff --git a/arch/arm/plat-omap/include/plat/dmtimer.h b/arch/arm/plat-omap/include/plat/dmtimer.h
index a3fbc48c332e..fb92abb91628 100644
--- a/arch/arm/plat-omap/include/plat/dmtimer.h
+++ b/arch/arm/plat-omap/include/plat/dmtimer.h
@@ -128,6 +128,7 @@ int omap_dm_timer_reserve_systimer(int id);
 struct omap_dm_timer *omap_dm_timer_request(void);
 struct omap_dm_timer *omap_dm_timer_request_specific(int timer_id);
 struct omap_dm_timer *omap_dm_timer_request_by_cap(u32 cap);
+struct omap_dm_timer *omap_dm_timer_request_by_node(struct device_node *np);
 int omap_dm_timer_free(struct omap_dm_timer *timer);
 void omap_dm_timer_enable(struct omap_dm_timer *timer);
 void omap_dm_timer_disable(struct omap_dm_timer *timer);