riscv_debug: provide abstraction for dtm dmi reads and writes

blackmagic-debug · Feb 23, 2023 · 29c1626 · 29c1626
1 parent a942708
commit 29c1626
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Showing 2 changed files with 28 additions and 8 deletions.
diff --git a/src/target/riscv_debug.c b/src/target/riscv_debug.c
@@ -208,8 +208,8 @@ static void riscv_dm_init(riscv_dm_s *dbg_module);
 static bool riscv_hart_init(riscv_hart_s *hart);
 static void riscv_hart_free(void *priv);
 static uint32_t riscv_shift_dtmcs(const riscv_dtm_s *dtm, uint32_t control);
-static bool riscv_dmi_read(riscv_dtm_s *dtm, uint32_t address, uint32_t *value);
-static bool riscv_dmi_write(riscv_dtm_s *dtm, uint32_t address, uint32_t value);
+static bool riscv_jtag_dmi_read(riscv_dtm_s *dtm, uint32_t address, uint32_t *value);
+static bool riscv_jtag_dmi_write(riscv_dtm_s *dtm, uint32_t address, uint32_t value);
 static void riscv_dm_ref(riscv_dm_s *dbg_module);
 static void riscv_dm_unref(riscv_dm_s *dbg_module);
 static riscv_debug_version_e riscv_dtmcs_version(uint32_t dtmcs);
@@ -229,6 +229,18 @@ static void riscv_halt_resume(target_s *target, bool step);
 static target_halt_reason_e riscv_halt_poll(target_s *target, target_addr_t *watch);
 static void riscv_reset(target_s *target);
 
+static bool riscv_dmi_read(riscv_dtm_s *dtm, uint32_t address, uint32_t *value)
+{
+	/* dereference dmi_read from abstracted struct, there is no NULL check */
+	return dtm->dmi_read(dtm, address, value);
+}
+
+static bool riscv_dmi_write(riscv_dtm_s *dtm, uint32_t address, uint32_t value)
+{
+	/* dereference dmi_write from abstracted struct, there is no NULL check */
+	return dtm->dmi_write(dtm, address, value);
+}
+
 void riscv_debug_dtm_handler(const uint8_t dev_index)
 {
 	riscv_dtm_s *dtm = calloc(1, sizeof(*dtm));
@@ -237,6 +249,9 @@ void riscv_debug_dtm_handler(const uint8_t dev_index)
 		return;
 	}
 
+	dtm->dmi_read = riscv_jtag_dmi_read;
+	dtm->dmi_write = riscv_jtag_dmi_write;
+
 	/* Setup and try to discover the DMI bus */
 	dtm->dev_index = dev_index;
 	/*
@@ -502,27 +517,27 @@ static bool riscv_shift_dmi(riscv_dtm_s *const dtm, const uint8_t operation, con
 	return status == RV_DMI_SUCCESS;
 }
 
-static bool riscv_dmi_read(riscv_dtm_s *const dtm, const uint32_t address, uint32_t *const value)
+static bool riscv_jtag_dmi_read(riscv_dtm_s *const dtm, const uint32_t address, uint32_t *const value)
 {
 	/* Setup the location to read from */
 	bool result = riscv_shift_dmi(dtm, RV_DMI_READ, address, 0, NULL);
 	if (result)
 		/* If that worked, read back the value and check the operation status */
 		result = riscv_shift_dmi(dtm, RV_DMI_NOOP, 0, 0, value);
 	if (!result)
-		DEBUG_WARN("DMI read at 0x%08" PRIx32 " failed with status %u\n", address, dtm->fault);
+		DEBUG_WARN("JTAG DMI read at 0x%08" PRIx32 " failed with status %u\n", address, dtm->fault);
 	return result;
 }
 
-static bool riscv_dmi_write(riscv_dtm_s *const dtm, const uint32_t address, const uint32_t value)
+static bool riscv_jtag_dmi_write(riscv_dtm_s *const dtm, const uint32_t address, const uint32_t value)
 {
 	/* Write a value to the requested register */
 	bool result = riscv_shift_dmi(dtm, RV_DMI_WRITE, address, value, NULL);
 	if (result)
 		/* If that worked, read back the operation status to ensure the write actually worked */
 		result = riscv_shift_dmi(dtm, RV_DMI_NOOP, 0, 0, NULL);
 	if (!result)
-		DEBUG_WARN("DMI write at 0x%08" PRIx32 " failed with status %u\n", address, dtm->fault);
+		DEBUG_WARN("JTAG DMI write at 0x%08" PRIx32 " failed with status %u\n", address, dtm->fault);
 	return result;
 }
 

diff --git a/src/target/riscv_debug.h b/src/target/riscv_debug.h
@@ -85,17 +85,22 @@ typedef enum riscv_match_size {
 } riscv_match_size_e;
 
 /* This structure represents a agnostic interface to a RISC-V Debug Transport Module */
-typedef struct riscv_dtm {
+typedef struct riscv_dtm riscv_dtm_s;
+
+struct riscv_dtm {
 	uint32_t ref_count;
 
 	uint16_t designer_code;
 	riscv_debug_version_e version;
 
+	bool (*dmi_read)(riscv_dtm_s *dtm, uint32_t address, uint32_t *value);
+	bool (*dmi_write)(riscv_dtm_s *dtm, uint32_t address, uint32_t value);
+
 	uint8_t dev_index;
 	uint8_t idle_cycles;
 	uint8_t dmi_address_bits;
 	uint8_t fault;
-} riscv_dtm_s;
+};
 
 /* This represents a specific Debug Module on the DMI bus */
 typedef struct riscv_dm {