Date:	Wed, 5 Dec 2012 16:09:00 +0000
From:	James Hogan <james.hogan@...tec.com>
To:	<linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:	Arnd Bergmann <arnd@...db.de>, James Hogan <james.hogan@...tec.com>
Subject: [PATCH v2 42/44] metag: Add JTAG Debug Adapter (DA) support

Add basic JTAG Debug Adapter (DA) support so that drivers which
communicate with the DA can detect whether one is actually present
(otherwise the target will halt indefinitely).

Signed-off-by: James Hogan <james.hogan@...tec.com>
---
 arch/metag/Kconfig                     |    9 ++++++
 arch/metag/configs/meta1_defconfig     |    1 +
 arch/metag/configs/meta2_defconfig     |    1 +
 arch/metag/configs/meta2_smp_defconfig |    1 +
 arch/metag/include/asm/da.h            |   43 ++++++++++++++++++++++++++++++++
 arch/metag/kernel/Makefile             |    1 +
 arch/metag/kernel/da.c                 |   23 +++++++++++++++++
 arch/metag/kernel/setup.c              |    3 ++
 8 files changed, 82 insertions(+), 0 deletions(-)
 create mode 100644 arch/metag/include/asm/da.h
 create mode 100644 arch/metag/kernel/da.c

diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index d198c9b..5807964 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -213,6 +213,15 @@ config METAG_PERFCOUNTER_IRQS
 	  When disabled, Performance Counters information will be collected
 	  based on Timer Interrupt.
 
+config METAG_DA
+	bool "DA support"
+	help
+	  Say Y if you plan to use a DA debug adapter with Linux. The presence
+	  of the DA will be detected automatically at boot, so it is safe to say
+	  Y to this option even when booting without a DA.
+
+	  This enables support for services provided by DA JTAG debug adapters.
+
 menu "Boot options"
 
 config METAG_BUILTIN_DTB
diff --git a/arch/metag/configs/meta1_defconfig b/arch/metag/configs/meta1_defconfig
index 74cc490..76a2d5f 100644
--- a/arch/metag/configs/meta1_defconfig
+++ b/arch/metag/configs/meta1_defconfig
@@ -14,6 +14,7 @@ CONFIG_PARTITION_ADVANCED=y
 # CONFIG_IOSCHED_CFQ is not set
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_META12_FPGA=y
+CONFIG_METAG_DA=y
 CONFIG_HZ_100=y
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
diff --git a/arch/metag/configs/meta2_defconfig b/arch/metag/configs/meta2_defconfig
index ad4ee2b..0b46722 100644
--- a/arch/metag/configs/meta2_defconfig
+++ b/arch/metag/configs/meta2_defconfig
@@ -16,6 +16,7 @@ CONFIG_PARTITION_ADVANCED=y
 CONFIG_METAG_L2C=y
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_METAG_HALT_ON_PANIC=y
+CONFIG_METAG_DA=y
 CONFIG_HZ_100=y
 CONFIG_DEVTMPFS=y
 # CONFIG_STANDALONE is not set
diff --git a/arch/metag/configs/meta2_smp_defconfig b/arch/metag/configs/meta2_smp_defconfig
index d9349df..b254e6c 100644
--- a/arch/metag/configs/meta2_smp_defconfig
+++ b/arch/metag/configs/meta2_smp_defconfig
@@ -17,6 +17,7 @@ CONFIG_METAG_L2C=y
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_METAG_HALT_ON_PANIC=y
 CONFIG_SMP=y
+CONFIG_METAG_DA=y
 CONFIG_HZ_100=y
 CONFIG_DEVTMPFS=y
 # CONFIG_STANDALONE is not set
diff --git a/arch/metag/include/asm/da.h b/arch/metag/include/asm/da.h
new file mode 100644
index 0000000..81bd521
--- /dev/null
+++ b/arch/metag/include/asm/da.h
@@ -0,0 +1,43 @@
+/*
+ * Meta DA JTAG debugger control.
+ *
+ * Copyright 2012 Imagination Technologies Ltd.
+ */
+
+#ifndef _METAG_DA_H_
+#define _METAG_DA_H_
+
+#ifdef CONFIG_METAG_DA
+
+#include <linux/init.h>
+#include <linux/types.h>
+
+extern bool _metag_da_present;
+
+/**
+ * metag_da_enabled() - Find whether a DA is currently enabled.
+ *
+ * Returns:	true if a DA was detected, false if not.
+ */
+static inline bool metag_da_enabled(void)
+{
+	return _metag_da_present;
+}
+
+/**
+ * metag_da_probe() - Try and detect a connected DA.
+ *
+ * This is used at start up to detect whether a DA is active.
+ *
+ * Returns:	0 on detection, -err otherwise.
+ */
+int __init metag_da_probe(void);
+
+#else /* !CONFIG_METAG_DA */
+
+#define metag_da_enabled() false
+#define metag_da_probe() do {} while (0)
+
+#endif
+
+#endif /* _METAG_DA_H_ */
diff --git a/arch/metag/kernel/Makefile b/arch/metag/kernel/Makefile
index 01536f9..228607e 100644
--- a/arch/metag/kernel/Makefile
+++ b/arch/metag/kernel/Makefile
@@ -29,6 +29,7 @@ obj-y	+= user_gateway.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf/
 
 obj-$(CONFIG_METAG_COREMEM)		+= coremem.o
+obj-$(CONFIG_METAG_DA)			+= da.o
 obj-$(CONFIG_DYNAMIC_FTRACE)		+= ftrace.o
 obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace_stub.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq_internal.o
diff --git a/arch/metag/kernel/da.c b/arch/metag/kernel/da.c
new file mode 100644
index 0000000..52aabb6
--- /dev/null
+++ b/arch/metag/kernel/da.c
@@ -0,0 +1,23 @@
+/*
+ * Meta DA JTAG debugger control.
+ *
+ * Copyright 2012 Imagination Technologies Ltd.
+ */
+
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <asm/da.h>
+#include <asm/metag_mem.h>
+
+bool _metag_da_present;
+
+int __init metag_da_probe(void)
+{
+	_metag_da_present = (metag_in32(T0VECINT_BHALT) == 1);
+	if (_metag_da_present)
+		pr_info("DA present\n");
+	else
+		pr_info("DA not present\n");
+	return 0;
+}
diff --git a/arch/metag/kernel/setup.c b/arch/metag/kernel/setup.c
index 5d7d8a1..65e8641 100644
--- a/arch/metag/kernel/setup.c
+++ b/arch/metag/kernel/setup.c
@@ -37,6 +37,7 @@
 #include <asm/hwthread.h>
 #include <asm/mmzone.h>
 #include <asm/l2cache.h>
+#include <asm/da.h>
 #include <asm/prom.h>
 #include <asm/mach/arch.h>
 #include <asm/core_reg.h>
@@ -182,6 +183,8 @@ void __init setup_arch(char **cmdline_p)
 	PTBISEG p_heap;
 	int heap_id, i;
 
+	metag_da_probe();
+
 	/* try interpreting the argument as a device tree */
 	machine_desc = setup_machine_fdt(original_cmd_line);
 	/* if it doesn't look like a device tree it must be a command line */
-- 
1.7.7.6


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