target/arc: Introduce L1I,L1D,L2 caches support

With this commit we introduce L1 and L2 cache
flush and invalidate operations which are necessary for
getting/setting actual data during memory r/w operations.

We introduce L2 cache support, which is not presented
on currently support EMSK board. But L2 is presented
on HSDK board, which soon will be introduced.

Change-Id: I2fda505a47ecb8833cc9f5ffe24f6a4e22ab6eb0
Signed-off-by: Evgeniy Didin <didin@synopsys.com>
Reviewed-on: http://openocd.zylin.com/5688
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

4 files changed, 328 insertions, 5 deletions

diff --git a/src/target/arc.c b/src/target/arc.c
index 6cf0ec7..e9709f4 100644
--- a/src/target/arc.c
+++ b/src/target/arc.c
@@ -86,6 +86,26 @@ struct reg *arc_reg_get_by_name(struct reg_cache *first,
 	return NULL;
 }
 
+/**
+ * Reset internal states of caches. Must be called when entering debugging.
+ *
+ * @param target Target for which to reset caches states.
+ */
+int arc_reset_caches_states(struct target *target)
+{
+	struct arc_common *arc = target_to_arc(target);
+
+	LOG_DEBUG("Resetting internal variables of caches states");
+
+	/* Reset caches states. */
+	arc->dcache_flushed = false;
+	arc->l2cache_flushed = false;
+	arc->icache_invalidated = false;
+	arc->dcache_invalidated = false;
+	arc->l2cache_invalidated = false;
+
+	return ERROR_OK;
+}
 
 /* Initialize arc_common structure, which passes to openocd target instance */
 static int arc_init_arch_info(struct target *target, struct arc_common *arc,
@@ -102,6 +122,15 @@ static int arc_init_arch_info(struct target *target, struct arc_common *arc,
 		return ERROR_FAIL;
 	}
 
+	/* On most ARC targets there is a dcache, so we enable its flushing
+	 * by default. If there no dcache, there will be no error, just a slight
+	 * performance penalty from unnecessary JTAG operations. */
+	arc->has_dcache = true;
+	arc->has_icache = true;
+	/* L2$ is not available in a target by default. */
+	arc->has_l2cache = false;
+	arc_reset_caches_states(target);
+
 	/* Add standard GDB data types */
 	INIT_LIST_HEAD(&arc->reg_data_types);
 	struct arc_reg_data_type *std_types = calloc(ARRAY_SIZE(standard_gdb_types),
@@ -900,6 +929,7 @@ static int arc_debug_entry(struct target *target)
 
 	/* TODO: reset internal indicators of caches states, otherwise D$/I$
 	 * will not be flushed/invalidated when required. */
+	CHECK_RETVAL(arc_reset_caches_states(target));
 	CHECK_RETVAL(arc_examine_debug_reason(target));
 
 	return ERROR_OK;
@@ -1152,6 +1182,11 @@ static int arc_resume(struct target *target, int current, target_addr_t address,
 	LOG_DEBUG("current:%i, address:0x%08" TARGET_PRIxADDR ", handle_breakpoints(not supported yet):%i,"
 		" debug_execution:%i", current, address, handle_breakpoints, debug_execution);
 
+	/* We need to reset ARC cache variables so caches
+	 * would be invalidated and actual data
+	 * would be fetched from memory. */
+	CHECK_RETVAL(arc_reset_caches_states(target));
+
 	if (target->state != TARGET_HALTED) {
 		LOG_WARNING("target not halted");
 		return ERROR_TARGET_NOT_HALTED;
@@ -1396,8 +1431,9 @@ static int arc_set_breakpoint(struct target *target,
 		LOG_DEBUG("ERROR: setting unknown breakpoint type");
 		return ERROR_FAIL;
 	}
-	/* core instruction cache is now invalid,
-	 * TODO: add cache invalidation function here (when implemented). */
+
+	/* core instruction cache is now invalid. */
+	CHECK_RETVAL(arc_cache_invalidate(target));
 
 	return ERROR_OK;
 }
@@ -1462,8 +1498,8 @@ static int arc_unset_breakpoint(struct target *target,
 			return ERROR_FAIL;
 	}
 
-	/* core instruction cache is now invalid.
-	 * TODO: Add cache invalidation function */
+	/* core instruction cache is now invalid. */
+	CHECK_RETVAL(arc_cache_invalidate(target));
 
 	return retval;
 }
@@ -1596,6 +1632,176 @@ int arc_step(struct target *target, int current, target_addr_t address,
 }
 
 
+/* This function invalidates icache. */
+static int arc_icache_invalidate(struct target *target)
+{
+	uint32_t value;
+
+	struct arc_common *arc = target_to_arc(target);
+
+	/* Don't waste time if already done. */
+	if (!arc->has_icache || arc->icache_invalidated)
+	    return ERROR_OK;
+
+	LOG_DEBUG("Invalidating I$.");
+
+	value = IC_IVIC_INVALIDATE;	/* invalidate I$ */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_IC_IVIC_REG, value));
+
+	arc->icache_invalidated = true;
+
+	return ERROR_OK;
+}
+
+/* This function invalidates dcache */
+static int arc_dcache_invalidate(struct target *target)
+{
+	uint32_t value, dc_ctrl_value;
+
+	struct arc_common *arc = target_to_arc(target);
+
+	if (!arc->has_dcache || arc->dcache_invalidated)
+	    return ERROR_OK;
+
+	LOG_DEBUG("Invalidating D$.");
+
+	CHECK_RETVAL(arc_jtag_read_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, &value));
+	dc_ctrl_value = value;
+	value &= ~DC_CTRL_IM;
+
+	/* set DC_CTRL invalidate mode to invalidate-only (no flushing!!) */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, value));
+	value = DC_IVDC_INVALIDATE;	/* invalidate D$ */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_IVDC_REG, value));
+
+	/* restore DC_CTRL invalidate mode */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, dc_ctrl_value));
+
+	arc->dcache_invalidated = true;
+
+	return ERROR_OK;
+}
+
+/* This function invalidates l2 cache. */
+static int arc_l2cache_invalidate(struct target *target)
+{
+	uint32_t value, slc_ctrl_value;
+
+	struct arc_common *arc = target_to_arc(target);
+
+	if (!arc->has_l2cache || arc->l2cache_invalidated)
+	    return ERROR_OK;
+
+	LOG_DEBUG("Invalidating L2$.");
+
+	CHECK_RETVAL(arc_jtag_read_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_CTRL, &value));
+	slc_ctrl_value = value;
+	value &= ~L2_CTRL_IM;
+
+	/* set L2_CTRL invalidate mode to invalidate-only (no flushing!!) */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_CTRL, value));
+	/* invalidate L2$ */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_INV, L2_INV_IV));
+
+	/* Wait until invalidate operation ends */
+	do {
+	    LOG_DEBUG("Waiting for invalidation end.");
+	    CHECK_RETVAL(arc_jtag_read_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_CTRL, &value));
+	} while (value & L2_CTRL_BS);
+
+	/* restore L2_CTRL invalidate mode */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_CTRL, slc_ctrl_value));
+
+	arc->l2cache_invalidated = true;
+
+	return ERROR_OK;
+}
+
+
+int arc_cache_invalidate(struct target *target)
+{
+	CHECK_RETVAL(arc_icache_invalidate(target));
+	CHECK_RETVAL(arc_dcache_invalidate(target));
+	CHECK_RETVAL(arc_l2cache_invalidate(target));
+
+	return ERROR_OK;
+}
+
+/* Flush data cache. This function is cheap to call and return quickly if D$
+ * already has been flushed since target had been halted. JTAG debugger reads
+ * values directly from memory, bypassing cache, so if there are unflushed
+ * lines debugger will read invalid values, which will cause a lot of troubles.
+ * */
+int arc_dcache_flush(struct target *target)
+{
+	uint32_t value, dc_ctrl_value;
+	bool has_to_set_dc_ctrl_im;
+
+	struct arc_common *arc = target_to_arc(target);
+
+	/* Don't waste time if already done. */
+	if (!arc->has_dcache || arc->dcache_flushed)
+	    return ERROR_OK;
+
+	LOG_DEBUG("Flushing D$.");
+
+	/* Store current value of DC_CTRL */
+	CHECK_RETVAL(arc_jtag_read_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, &dc_ctrl_value));
+
+	/* Set DC_CTRL invalidate mode to flush (if not already set) */
+	has_to_set_dc_ctrl_im = (dc_ctrl_value & DC_CTRL_IM) == 0;
+	if (has_to_set_dc_ctrl_im) {
+		value = dc_ctrl_value | DC_CTRL_IM;
+		CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, value));
+	}
+
+	/* Flush D$ */
+	value = DC_IVDC_INVALIDATE;
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_IVDC_REG, value));
+
+	/* Restore DC_CTRL invalidate mode (even of flush failed) */
+	if (has_to_set_dc_ctrl_im)
+	    CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, AUX_DC_CTRL_REG, dc_ctrl_value));
+
+	arc->dcache_flushed = true;
+
+	return ERROR_OK;
+}
+
+/* This function flushes l2cache. */
+static int arc_l2cache_flush(struct target *target)
+{
+	uint32_t value;
+
+	struct arc_common *arc = target_to_arc(target);
+
+	/* Don't waste time if already done. */
+	if (!arc->has_l2cache || arc->l2cache_flushed)
+	    return ERROR_OK;
+
+	LOG_DEBUG("Flushing L2$.");
+
+	/* Flush L2 cache */
+	CHECK_RETVAL(arc_jtag_write_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_FLUSH, L2_FLUSH_FL));
+
+	/* Wait until flush operation ends */
+	do {
+	    LOG_DEBUG("Waiting for flushing end.");
+	    CHECK_RETVAL(arc_jtag_read_aux_reg_one(&arc->jtag_info, SLC_AUX_CACHE_CTRL, &value));
+	} while (value & L2_CTRL_BS);
+
+	arc->l2cache_flushed = true;
+
+	return ERROR_OK;
+}
+
+int arc_cache_flush(struct target *target)
+{
+	CHECK_RETVAL(arc_dcache_flush(target));
+	CHECK_RETVAL(arc_l2cache_flush(target));
+
+	return ERROR_OK;
+}
 
 /* ARC v2 target */
 struct target_type arcv2_target = {
diff --git a/src/target/arc.h b/src/target/arc.h
index defa3fa..6641411 100644
--- a/src/target/arc.h
+++ b/src/target/arc.h
@@ -60,6 +60,24 @@
 /* ARC 16bits opcodes */
 #define ARC_SDBBP_16 0x7FFF      /* BRK_S */
 
+/* Cache registers */
+#define AUX_IC_IVIC_REG			0X10
+#define IC_IVIC_INVALIDATE		0XFFFFFFFF
+
+#define AUX_DC_IVDC_REG			0X47
+#define DC_IVDC_INVALIDATE		BIT(0)
+#define AUX_DC_CTRL_REG			0X48
+#define DC_CTRL_IM			BIT(6)
+
+/* L2 cache registers */
+#define SLC_AUX_CACHE_CTRL		0x903
+#define L2_CTRL_IM			BIT(6)
+#define L2_CTRL_BS			BIT(8)		/* Busy flag */
+#define SLC_AUX_CACHE_FLUSH		0x904
+#define L2_FLUSH_FL			BIT(0)
+#define SLC_AUX_CACHE_INV		0x905
+#define L2_INV_IV			BIT(0)
+
 struct arc_reg_bitfield {
 	struct reg_data_type_bitfield bitfield;
 	char name[REG_TYPE_MAX_NAME_LENGTH];
@@ -109,6 +127,22 @@ struct arc_common {
 	struct reg_cache *core_and_aux_cache;
 	struct reg_cache *bcr_cache;
 
+	/* Cache control */
+	bool has_dcache;
+	bool has_icache;
+	bool has_l2cache;
+	/* If true, then D$ has been already flushed since core has been
+	 * halted. */
+	bool dcache_flushed;
+	/* If true, then L2 has been already flushed since core has been
+	 * halted. */
+	bool l2cache_flushed;
+	/* If true, then caches have been already flushed since core has been
+	 * halted. */
+	bool icache_invalidated;
+	bool dcache_invalidated;
+	bool l2cache_invalidated;
+
 	/* Indicate if cach was built (for deinit function) */
 	bool core_aux_cache_built;
 	bool bcr_cache_built;
@@ -247,4 +281,7 @@ struct reg *arc_reg_get_by_name(struct reg_cache *first,
 int arc_reg_get_field(struct target *target, const char *reg_name,
 		const char *field_name, uint32_t *value_ptr);
 
+int arc_cache_flush(struct target *target);
+int arc_cache_invalidate(struct target *target);
+
 #endif /* OPENOCD_TARGET_ARC_H */
diff --git a/src/target/arc_cmd.c b/src/target/arc_cmd.c
index fad8ca9..59e1645 100644
--- a/src/target/arc_cmd.c
+++ b/src/target/arc_cmd.c
@@ -909,10 +909,60 @@ static int jim_arc_get_reg_field(Jim_Interp *interp, int argc, Jim_Obj * const *
 	return JIM_OK;
 }
 
+COMMAND_HANDLER(arc_l1_cache_disable_auto_cmd)
+{
+	bool value;
+	int retval = 0;
+	struct arc_common *arc = target_to_arc(get_current_target(CMD_CTX));
+	retval = CALL_COMMAND_HANDLER(handle_command_parse_bool,
+		&value, "target has caches enabled");
+	arc->has_l2cache = value;
+	arc->has_dcache = value;
+	arc->has_icache = value;
+	return retval;
+}
+
+COMMAND_HANDLER(arc_l2_cache_disable_auto_cmd)
+{
+	struct arc_common *arc = target_to_arc(get_current_target(CMD_CTX));
+	return CALL_COMMAND_HANDLER(handle_command_parse_bool,
+		&arc->has_l2cache, "target has l2 cache enabled");
+}
+
 /* ----- Exported target commands ------------------------------------------ */
 
+const struct command_registration arc_l2_cache_group_handlers[] = {
+	{
+		.name = "auto",
+		.handler = arc_l2_cache_disable_auto_cmd,
+		.mode = COMMAND_ANY,
+		.usage = "(1|0)",
+		.help = "Disable or enable L2",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+const struct command_registration arc_cache_group_handlers[] = {
+	{
+		.name = "auto",
+		.handler = arc_l1_cache_disable_auto_cmd,
+		.mode = COMMAND_ANY,
+		.help = "Disable or enable L1",
+		.usage = "(1|0)",
+	},
+	{
+		.name = "l2",
+		.mode = COMMAND_ANY,
+		.help = "L2 cache command group",
+		.usage = "",
+		.chain = arc_l2_cache_group_handlers,
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+
 static const struct command_registration arc_core_command_handlers[] = {
-{
+	{
 		.name = "add-reg-type-flags",
 		.jim_handler = jim_arc_add_reg_type_flags,
 		.mode = COMMAND_CONFIG,
@@ -967,6 +1017,13 @@ static const struct command_registration arc_core_command_handlers[] = {
 		.usage = "",
 		.chain = arc_jtag_command_group,
 	},
+	{
+		.name = "cache",
+		.mode = COMMAND_ANY,
+		.help = "cache command group",
+		.usage = "",
+		.chain = arc_cache_group_handlers,
+	},
 	COMMAND_REGISTRATION_DONE
 };
 
diff --git a/src/target/arc_mem.c b/src/target/arc_mem.c
index e80bfb4..866c71f 100644
--- a/src/target/arc_mem.c
+++ b/src/target/arc_mem.c
@@ -41,10 +41,18 @@ static int arc_mem_write_block32(struct target *target, uint32_t addr,
 	/* Check arguments */
 	assert(!(addr & 3));
 
+	/* We need to flush the cache since it might contain dirty
+	 * lines, so the cache invalidation may cause data inconsistency. */
+	CHECK_RETVAL(arc_cache_flush(target));
+
+
 	/* No need to flush cache, because we don't read values from memory. */
 	CHECK_RETVAL(arc_jtag_write_memory(&arc->jtag_info, addr, count,
 				(uint32_t *)buf));
 
+	/* Invalidate caches. */
+	CHECK_RETVAL(arc_cache_invalidate(target));
+
 	return ERROR_OK;
 }
 
@@ -64,6 +72,9 @@ static int arc_mem_write_block16(struct target *target, uint32_t addr,
 	/* Check arguments */
 	assert(!(addr & 1));
 
+	/* We will read data from memory, so we need to flush the cache. */
+	CHECK_RETVAL(arc_cache_flush(target));
+
 	/* non-word writes are less common, than 4-byte writes, so I suppose we can
 	 * allowe ourselves to write this in a cycle, instead of calling arc_jtag
 	 * with count > 1. */
@@ -97,6 +108,9 @@ static int arc_mem_write_block16(struct target *target, uint32_t addr,
 			(addr + i * sizeof(uint16_t)) & ~3u, 1, &buffer_he));
 	}
 
+	/* Invalidate caches. */
+	CHECK_RETVAL(arc_cache_invalidate(target));
+
 	return ERROR_OK;
 }
 
@@ -113,6 +127,9 @@ static int arc_mem_write_block8(struct target *target, uint32_t addr,
 	LOG_DEBUG("Write 1-byte memory block: addr=0x%08" PRIx32 ", count=%" PRIu32,
 			addr, count);
 
+	/* We will read data from memory, so we need to flush the cache. */
+	CHECK_RETVAL(arc_cache_flush(target));
+
 	/* non-word writes are less common, than 4-byte writes, so I suppose we can
 	 * allowe ourselves to write this in a cycle, instead of calling arc_jtag
 	 * with count > 1. */
@@ -128,6 +145,9 @@ static int arc_mem_write_block8(struct target *target, uint32_t addr,
 		CHECK_RETVAL(arc_jtag_write_memory(&arc->jtag_info, (addr + i) & ~3, 1, &buffer_he));
 	}
 
+	/* Invalidate caches. */
+	CHECK_RETVAL(arc_cache_invalidate(target));
+
 	return ERROR_OK;
 }
 
@@ -205,6 +225,9 @@ static int arc_mem_read_block(struct target *target, target_addr_t addr,
 	assert(!(addr & 3));
 	assert(size == 4);
 
+	/* Flush cache before memory access */
+	CHECK_RETVAL(arc_cache_flush(target));
+
 	CHECK_RETVAL(arc_jtag_read_memory(&arc->jtag_info, addr, count, buf,
 		    arc_mem_is_slow_memory(arc, addr, size, count)));