armv7a: cache ttbcr and ttb0/1 on debug state entry

Instead of re-reading ttbcr and ttb0/1 whenever a virt2phys translation
is done, cache the values once when entering debug state. Use the cached
values in armv7a_mmu_translate_va().

Change-Id: I1bc5349ad2f19b2dd75bdd48468a2c1f1e028699
Signed-off-by: Matthias Welwarsky <matthias@welwarsky.de>
Reviewed-on: http://openocd.zylin.com/3112
Tested-by: jenkins

diff --git a/src/target/armv7a.c b/src/target/armv7a.c
index db72afd2128dced727c0789226d038c75b93a0a3..183fde1bf6fcdb1706f022473a8dd7a0ca51bbf2 100644 (file)
--- a/src/target/armv7a.c
+++ b/src/target/armv7a.c
@@ -129,9 +129,13 @@ static int armv7a_read_ttbcr(struct target *target)
        struct armv7a_common *armv7a = target_to_armv7a(target);
        struct arm_dpm *dpm = armv7a->arm.dpm;
        uint32_t ttbcr, ttbcr_n;
-       int retval = dpm->prepare(dpm);
+       int ttbidx;
+       int retval;
+
+       retval = dpm->prepare(dpm);
        if (retval != ERROR_OK)
                goto done;
+
        /*  MRC p15,0,<Rt>,c2,c0,2 ; Read CP15 Translation Table Base Control Register*/
        retval = dpm->instr_read_data_r0(dpm,
                        ARMV4_5_MRC(15, 0, 0, 2, 0, 2),
@@ -145,6 +149,15 @@ static int armv7a_read_ttbcr(struct target *target)
        armv7a->armv7a_mmu.ttbcr = ttbcr;
        armv7a->armv7a_mmu.cached = 1;
 
+       for (ttbidx = 0; ttbidx < 2; ttbidx++) {
+               /*  MRC p15,0,<Rt>,c2,c0,ttbidx */
+               retval = dpm->instr_read_data_r0(dpm,
+                               ARMV4_5_MRC(15, 0, 0, 2, 0, ttbidx),
+                               &armv7a->armv7a_mmu.ttbr[ttbidx]);
+               if (retval != ERROR_OK)
+                       goto done;
+       }
+
        /*
         * ARM Architecture Reference Manual (ARMv7-A and ARMv7-Redition),
         * document # ARM DDI 0406C
@@ -182,42 +195,21 @@ int armv7a_mmu_translate_va(struct target *target,  uint32_t va, uint32_t *val)
        uint32_t second_lvl_descriptor = 0x0;
        int retval;
        struct armv7a_common *armv7a = target_to_armv7a(target);
-       struct arm_dpm *dpm = armv7a->arm.dpm;
        uint32_t ttbidx = 0;    /*  default to ttbr0 */
        uint32_t ttb_mask;
        uint32_t va_mask;
-       uint32_t ttbcr;
        uint32_t ttb;
 
-       retval = dpm->prepare(dpm);
-       if (retval != ERROR_OK)
-               goto done;
-
-       /*  MRC p15,0,<Rt>,c2,c0,2 ; Read CP15 Translation Table Base Control Register*/
-       retval = dpm->instr_read_data_r0(dpm,
-                       ARMV4_5_MRC(15, 0, 0, 2, 0, 2),
-                       &ttbcr);
-       if (retval != ERROR_OK)
-               goto done;
-
-       /* if ttbcr has changed or was not read before, re-read the information */
-       if ((armv7a->armv7a_mmu.cached == 0) ||
-               (armv7a->armv7a_mmu.ttbcr != ttbcr)) {
-               armv7a_read_ttbcr(target);
-       }
+       if (target->state != TARGET_HALTED)
+               LOG_INFO("target not halted, using cached values for translation table!");
 
        /* if va is above the range handled by ttbr0, select ttbr1 */
        if (va > armv7a->armv7a_mmu.ttbr_range[0]) {
                /*  select ttb 1 */
                ttbidx = 1;
        }
-       /*  MRC p15,0,<Rt>,c2,c0,ttbidx */
-       retval = dpm->instr_read_data_r0(dpm,
-                       ARMV4_5_MRC(15, 0, 0, 2, 0, ttbidx),
-                       &ttb);
-       if (retval != ERROR_OK)
-               return retval;
 
+       ttb = armv7a->armv7a_mmu.ttbr[ttbidx];
        ttb_mask = armv7a->armv7a_mmu.ttbr_mask[ttbidx];
        va_mask = 0xfff00000 & armv7a->armv7a_mmu.ttbr_range[ttbidx];
 
@@ -279,9 +271,6 @@ int armv7a_mmu_translate_va(struct target *target,  uint32_t va, uint32_t *val)
        }
 
        return ERROR_OK;
-
-done:
-       return retval;
 }
 
 /*  V7 method VA TO PA  */
@@ -740,6 +729,8 @@ int armv7a_arch_state(struct target *target)
 
        arm_arch_state(target);
 
+       armv7a_read_ttbcr(target);
+
        if (armv7a->is_armv7r) {
                LOG_USER("D-Cache: %s, I-Cache: %s",
                        state[armv7a->armv7a_mmu.armv7a_cache.d_u_cache_enabled],

diff --git a/src/target/armv7a.h b/src/target/armv7a.h
index 14112e4ed0267958f2ce392f0044e2dbf83b9078..33f6f5dbea15c75aa23a110e7b9e8d5689db6e7d 100644 (file)
--- a/src/target/armv7a.h
+++ b/src/target/armv7a.h
@@ -87,6 +87,7 @@ struct armv7a_mmu_common {
        /* following field mmu working way */
        int32_t cached;     /* 0: not initialized, 1: initialized */
        uint32_t ttbcr;     /* cache for ttbcr register */
+       uint32_t ttbr[2];
        uint32_t ttbr_mask[2];
        uint32_t ttbr_range[2];