blackfin architecture

[~andy/linux] / Documentation / blackfin / cache-lock.txt

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+/*
+ * File:         Documentation/blackfin/cache-lock.txt
+ * Based on:
+ * Author:
+ *
+ * Created:
+ * Description:  This file contains the simple DMA Implementation for Blackfin
+ *
+ * Rev:          $Id: cache-lock.txt 2384 2006-11-01 04:12:43Z magicyang $
+ *
+ * Modified:
+ *               Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ */
+
+How to lock your code in cache in uClinux/blackfin
+--------------------------------------------------
+
+There are only a few steps required to lock your code into the cache.
+Currently you can lock the code by Way.
+
+Below are the interface provided for locking the cache.
+
+
+1. cache_grab_lock(int Ways);
+
+This function grab the lock for locking your code into the cache specified
+by Ways.
+
+
+2. cache_lock(int Ways);
+
+This function should be called after your critical code has been executed.
+Once the critical code exits, the code is now loaded into the cache. This
+function locks the code into the cache.
+
+
+So, the example sequence will be:
+
+       cache_grab_lock(WAY0_L);        /* Grab the lock */
+
+       critical_code();                /* Execute the code of interest */
+
+       cache_lock(WAY0_L);             /* Lock the cache */
+
+Where WAY0_L signifies WAY0 locking.