ARM: new DPM interface

First version of interface for sharing code between ARMv6 and ARMv7a
debug modules ... now the architecture includes debug support.  (Not
the same as for the trimmed-down v7m or v6m though!)  This is a first
version of an interface that will let the ARM11 and Cortex-A8 support
share code, features, and bugfixes.  Based on existing code from both
of those cores.

The ARM v7-AR architecture specification calls this commonality the
"Debug Programmer's Model (DPM)", which seemed to be an appropriate
acronym -- a TLA even! -- for use in our code.  Made it so.  :)

The initial scope of this just supports register access, and is geared
towards supporting top level "struct arm" mechanisms.  Later, things
like breakpoint and watchpoint support should be included.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

1 files changed, 87 insertions, 0 deletions

diff --git a/src/target/arm_dpm.h b/src/target/arm_dpm.h
new file mode 100644
index 00000000..06b548ec
--- /dev/null
+++ b/src/target/arm_dpm.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2009 by David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef __ARM_DPM_H
+#define __ARM_DPM_H
+
+/**
+ * @file
+ * This is the interface to the Debug Programmers Model for ARMv6 and
+ * ARMv7 processors.  ARMv6 processors (such as ARM11xx implementations)
+ * introduced a model which became part of the ARMv7-AR architecture
+ * which is most familiar through the Cortex-A series parts.  While
+ * specific details differ (like how to write the instruction register),
+ * the high level models easily support shared code because those
+ * registers are compatible.
+ */
+
+/**
+ * This wraps an implementation of DPM primitives.  Each interface
+ * provider supplies a structure like this, which is the glue between
+ * upper level code and the lower level hardware access.
+ *
+ * It is a PRELIMINARY AND INCOMPLETE set of primitives, starting with
+ * support for CPU register access.
+ */
+struct arm_dpm {
+	struct arm *arm;
+
+	/** Cache of DIDR */
+	uint32_t didr;
+
+	/** Invoke before a series of instruction operations */
+	int (*prepare)(struct arm_dpm *);
+
+	/** Invoke after a series of instruction operations */
+	int (*finish)(struct arm_dpm *);
+
+	/* WRITE TO CPU */
+
+	/** Runs one instruction, writing data to DCC before execution. */
+	int (*instr_write_data_dcc)(struct arm_dpm *,
+			uint32_t opcode, uint32_t data);
+
+	/** Runs one instruction, writing data to R0 before execution. */
+	int (*instr_write_data_r0)(struct arm_dpm *,
+			uint32_t opcode, uint32_t data);
+
+	/* READ FROM CPU */
+
+	/** Runs one instruction, reading data from dcc after execution. */
+	int (*instr_read_data_dcc)(struct arm_dpm *,
+			uint32_t opcode, uint32_t *data);
+
+	/** Runs one instruction, reading data from r0 after execution. */
+	int (*instr_read_data_r0)(struct arm_dpm *,
+			uint32_t opcode, uint32_t *data);
+
+	// FIXME -- add breakpoint support
+
+	// FIXME -- add watchpoint support (including context-sensitive ones)
+
+	// FIXME -- read/write DCSR methods and symbols
+};
+
+int arm_dpm_setup(struct arm_dpm *dpm);
+int arm_dpm_reinitialize(struct arm_dpm *dpm);
+
+int arm_dpm_read_current_registers(struct arm_dpm *);
+int arm_dpm_write_dirty_registers(struct arm_dpm *);
+
+#endif /* __ARM_DPM_H */