arm946e: cleanup C0.C cache type reg access

Cache type register C0.C is read-only, and display
hard core configuration information.
This information is unlikely be changed in runtime.

 - removed C0.C access when result is not used in
   arm946e_invalidate_dcache()
 - access C0.C only once per target, store result
   in cp15_cache_info field of target structure
 - fix cache index count calculation

Change-Id: I12bc4c967fdf07f54d755f2f2f42406c0ababc1a
Signed-off-by: Alexander Osipenko <sipych@gmail.com>
Reviewed-on: http://openocd.zylin.com/693
Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

diff --git a/src/target/arm946e.c b/src/target/arm946e.c
index bd3eceb5951ef480c10a596b55e204c5269c48e4..2a71f2d3501d6011190cb316acbe04c120008ea4 100644 (file)
--- a/src/target/arm946e.c
+++ b/src/target/arm946e.c
@@ -210,43 +210,55 @@ int arm946e_write_cp15(struct target *target, int reg_addr, uint32_t value)
        return ERROR_OK;
 }
 
-uint32_t arm946e_invalidate_whole_dcache(struct target *target)
-{
-
-       uint32_t csize = 0;
-       uint32_t shift = 0;
-       uint32_t cp15_idx, seg, dtag;
-       int nb_idx, idx = 0;
-       int retval;
-
-       /* Get cache type */
-       arm946e_read_cp15(target, 0x01, (uint32_t *) &csize);
+#define GET_ICACHE_SIZE  6
+#define GET_DCACHE_SIZE 18
 
-       csize = (csize >> 18) & 0x0F;
+/*
+ * \param target struct target pointer
+ * \param idsel  select GET_ICACHE_SIZE or GET_DCACHE_SIZE
+ * \returns      cache size, given in bytes
+ */
+static uint32_t arm946e_cp15_get_csize(struct target *target, int idsel)
+{
+       struct arm946e_common *arm946e = target_to_arm946(target);
+       uint32_t csize = arm946e->cp15_cache_info;
+       if (csize == 0) {
+               if (arm946e_read_cp15(target, 0x01, &csize) == ERROR_OK)
+                       arm946e->cp15_cache_info = csize;
+       }
+       if (csize & (1<<(idsel-4)))     /* cache absent */
+               return 0;
+       csize = (csize >> idsel) & 0x0F;
+       return csize ? 1 << (12 + (csize-3)) : 0;
+}
 
+uint32_t arm946e_invalidate_whole_dcache(struct target *target)
+{
+       uint32_t csize = arm946e_cp15_get_csize(target, GET_DCACHE_SIZE);
        if (csize == 0)
-               shift = 0;
-       else
-               shift = csize - 0x3;    /* Now 0 = 4KB, 1 = 8KB, ... */
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 
-       /* Cache size, given in bytes */
-       csize = 1 << (12 + shift);
-       /* One line (index) is 32 bytes (8 words) long */
-       nb_idx = (csize / 32);  /* gives nb of lines (indexes) in the cache */
+       /* One line (index) is 32 bytes (8 words) long, 4-way assoc
+        * ARM DDI 0201D, Section 3.3.5
+        */
+       int nb_idx = (csize / (4*8*NB_CACHE_WAYS));     /* gives nb of lines (indexes) in the cache */
 
        /* Loop for all segmentde (i.e. ways) */
+       uint32_t seg;
        for (seg = 0; seg < NB_CACHE_WAYS; seg++) {
                /* Loop for all indexes */
+               int idx;
                for (idx = 0; idx < nb_idx; idx++) {
                        /* Form and write cp15 index (segment + line idx) */
-                       cp15_idx = seg << 30 | idx << 5;
-                       retval = arm946e_write_cp15(target, 0x3a, cp15_idx);
+                       uint32_t cp15_idx = seg << 30 | idx << 5;
+                       int retval = arm946e_write_cp15(target, 0x3a, cp15_idx);
                        if (retval != ERROR_OK) {
                                LOG_DEBUG("ERROR writing index");
                                return retval;
                        }
 
                        /* Read dtag */
+                       uint32_t dtag;
                        arm946e_read_cp15(target, 0x16, (uint32_t *) &dtag);
 
                        /* Check cache line VALID bit */
@@ -274,15 +286,17 @@ uint32_t arm946e_invalidate_whole_dcache(struct target *target)
 
 uint32_t arm946e_invalidate_whole_icache(struct target *target)
 {
-       int retval;
+       /* Check cache presence before flushing - avoid undefined behavior */
+       uint32_t csize = arm946e_cp15_get_csize(target, GET_ICACHE_SIZE);
+       if (csize == 0)
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 
        LOG_DEBUG("FLUSHING I$");
-
        /**
         *  Invalidate (flush) I$
         *  mcr 15, 0, r0, cr7, cr5, {0}
         */
-       retval = arm946e_write_cp15(target, 0x0f, 0x1);
+       int retval = arm946e_write_cp15(target, 0x0f, 0x1);
        if (retval != ERROR_OK) {
                LOG_DEBUG("ERROR flushing I$");
                return retval;
@@ -360,8 +374,6 @@ void arm946e_pre_restore_context(struct target *target)
 uint32_t arm946e_invalidate_dcache(struct target *target, uint32_t address,
        uint32_t size, uint32_t count)
 {
-       uint32_t csize = 0x0;
-       uint32_t shift = 0;
        uint32_t cur_addr = 0x0;
        uint32_t cp15_idx, set, way, dtag;
        uint32_t i = 0;
@@ -370,18 +382,6 @@ uint32_t arm946e_invalidate_dcache(struct target *target, uint32_t address,
        for (i = 0; i < count*size; i++) {
                cur_addr = address + i;
 
-               /* Get cache type */
-               arm946e_read_cp15(target, 0x01, (uint32_t *) &csize);
-
-               /* Conclude cache size to find number of lines */
-               csize = (csize >> 18) & 0x0F;
-
-               if (csize == 0)
-                       shift = 0;
-               else
-                       shift = csize - 0x3;    /* Now 0 = 4KB, 1 = 8KB, ... */
-
-               csize = 1 << (12 + shift);
 
                set = (cur_addr >> 5) & 0xff;   /* set field is 8 bits long */
 

diff --git a/src/target/arm946e.h b/src/target/arm946e.h
index 1837bad77b5b1422438c72f709b76280a4be4a17..64750af19ed642f37fbed548afe3b5c3b90c1f3a 100644 (file)
--- a/src/target/arm946e.h
+++ b/src/target/arm946e.h
@@ -35,6 +35,7 @@ struct arm946e_common {
        struct arm7_9_common arm7_9_common;
        int common_magic;
        uint32_t cp15_control_reg;
+       uint32_t cp15_cache_info;
 };
 
 static inline struct arm946e_common *target_to_arm946(struct target *target)