mips32: add fastdata loader working area

Add a working area that is preserved between calls to
mips_m4k_bulk_write_memory - this gives us a speed increase
of approx 3kb/sec during flash writes to the pic32mx.

This area is released during a resume/reset.

Signed-off-by: Spencer Oliver <ntfreak@users.sourceforge.net>

6 files changed, 29 insertions, 11 deletions

diff --git a/src/target/mips32.c b/src/target/mips32.c
index 533701aa..e48a040c 100644
--- a/src/target/mips32.c
+++ b/src/target/mips32.c
@@ -309,6 +309,7 @@ int mips32_init_arch_info(struct target *target, struct mips32_common *mips32, s
 {
 	target->arch_info = mips32;
 	mips32->common_magic = MIPS32_COMMON_MAGIC;
+	mips32->fast_data_area = NULL;
 
 	/* has breakpoint/watchpint unit been scanned */
 	mips32->bp_scanned = 0;
diff --git a/src/target/mips32.h b/src/target/mips32.h
index 7ffe95fc..0d544a40 100644
--- a/src/target/mips32.h
+++ b/src/target/mips32.h
@@ -57,6 +57,9 @@ struct mips32_common
 	uint32_t core_regs[MIPS32NUMCOREREGS];
 	enum mips32_isa_mode isa_mode;
 
+	/* working area for fastdata access */
+	struct working_area *fast_data_area;
+
 	int bp_scanned;
 	int num_inst_bpoints;
 	int num_data_bpoints;
diff --git a/src/target/mips32_pracc.c b/src/target/mips32_pracc.c
index 236f3894..a4ea2d36 100644
--- a/src/target/mips32_pracc.c
+++ b/src/target/mips32_pracc.c
@@ -985,7 +985,12 @@ int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_are
 	}
 
 	/* write program into RAM */
-	mips32_pracc_write_mem32(ejtag_info, source->address, ARRAY_SIZE(handler_code), handler_code);
+	if (write_t != ejtag_info->fast_access_save)
+	{
+		mips32_pracc_write_mem32(ejtag_info, source->address, ARRAY_SIZE(handler_code), handler_code);
+		/* save previous operation to speed to any consecutive read/writes */
+		ejtag_info->fast_access_save = write_t;
+	}
 
 	LOG_DEBUG("%s using 0x%.8" PRIx32 " for write handler", __func__, source->address);
 
diff --git a/src/target/mips_ejtag.c b/src/target/mips_ejtag.c
index 33507b55..e3810639 100644
--- a/src/target/mips_ejtag.c
+++ b/src/target/mips_ejtag.c
@@ -300,6 +300,7 @@ int mips_ejtag_init(struct mips_ejtag *ejtag_info)
 
 	/* set initial state for ejtag control reg */
 	ejtag_info->ejtag_ctrl = EJTAG_CTRL_ROCC | EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_SETDEV;
+	ejtag_info->fast_access_save = -1;
 
 	return ERROR_OK;
 }
diff --git a/src/target/mips_ejtag.h b/src/target/mips_ejtag.h
index a4430b6e..0db0504a 100644
--- a/src/target/mips_ejtag.h
+++ b/src/target/mips_ejtag.h
@@ -128,6 +128,7 @@ struct mips_ejtag
 	uint32_t impcode;
 	uint32_t idcode;
 	uint32_t ejtag_ctrl;
+	int fast_access_save;
 };
 
 int mips_ejtag_set_instr(struct mips_ejtag *ejtag_info,
diff --git a/src/target/mips_m4k.c b/src/target/mips_m4k.c
index c0adc066..8afee9cd 100644
--- a/src/target/mips_m4k.c
+++ b/src/target/mips_m4k.c
@@ -964,7 +964,6 @@ static int mips_m4k_bulk_write_memory(struct target *target, uint32_t address,
 {
 	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
-	struct working_area *source;
 	int retval;
 	int write_t = 1;
 
@@ -980,12 +979,23 @@ static int mips_m4k_bulk_write_memory(struct target *target, uint32_t address,
 	if (address & 0x3u)
 		return ERROR_TARGET_UNALIGNED_ACCESS;
 
-	/* Get memory for block write handler */
-	retval = target_alloc_working_area(target, MIPS32_FASTDATA_HANDLER_SIZE, &source);
-	if (retval != ERROR_OK)
+	if (mips32->fast_data_area == NULL)
 	{
-		LOG_WARNING("No working area available, falling back to non-bulk write");
-		return mips_m4k_write_memory(target, address, 4, count, buffer);
+		/* Get memory for block write handler
+		 * we preserve this area between calls and gain a speed increase
+		 * of about 3kb/sec when writing flash
+		 * this will be released/nulled by the system when the target is resumed or reset */
+		retval = target_alloc_working_area(target,
+				MIPS32_FASTDATA_HANDLER_SIZE,
+				&mips32->fast_data_area);
+		if (retval != ERROR_OK)
+		{
+			LOG_WARNING("No working area available, falling back to non-bulk write");
+			return mips_m4k_write_memory(target, address, 4, count, buffer);
+		}
+
+		/* reset fastadata state so the algo get reloaded */
+		ejtag_info->fast_access_save = -1;
 	}
 
 	/* TAP data register is loaded LSB first (little endian) */
@@ -999,7 +1009,7 @@ static int mips_m4k_bulk_write_memory(struct target *target, uint32_t address,
 		}
 	}
 
-	retval = mips32_pracc_fastdata_xfer(ejtag_info, source, write_t, address,
+	retval = mips32_pracc_fastdata_xfer(ejtag_info, mips32->fast_data_area, write_t, address,
 			count, (uint32_t*) (void *)buffer);
 	if (retval != ERROR_OK)
 	{
@@ -1008,9 +1018,6 @@ static int mips_m4k_bulk_write_memory(struct target *target, uint32_t address,
 		retval = mips_m4k_write_memory(target, address, 4, count, buffer);
 	}
 
-	if (source)
-		target_free_working_area(target, source);
-
 	return retval;
 }