Support for JTAG-PDI based Atmel parts

src/Makefile

@@ -20,6 +20,9 @@ SRC =			\
 	adiv5.c		\
 	adiv5_jtagdp.c	\
 	adiv5_swdp.c	\
+	atxmega.c \
+	avr_jtagdp.c \
+	avr_pdi.c \
 	command.c	\
 	cortexa.c	\
 	cortexm.c	\

src/platforms/hosted/platform.c

@@ -25,6 +25,7 @@
 #include "target.h"
 #include "target_internal.h"
 #include "adiv5.h"
+#include "avr.h"
 #include "timing.h"
 #include "cl_utils.h"
 #include "gdb_if.h"
@@ -252,6 +253,12 @@ int platform_jtag_dp_init(ADIv5_DP_t *dp)
 	return 0;
 }
 
+int platform_avr_jtag_pdi_init(avr_pdi_t *pdi)
+{
+	(void)pdi;
+	return 0;
+}
+
 char *platform_ident(void)
 {
 	switch (info.bmp_type) {

src/target/adiv5.c

@@ -683,9 +683,8 @@ void adiv5_dp_init(ADIv5_DP_t *dp)
 		return;
 	}
 	DEBUG_INFO("DPIDR 0x%08" PRIx32 " (v%d %srev%d)\n", dp->idcode,
-			   (uint8_t)((dp->idcode >> 12) & 0xf),
-			   (dp->idcode & ADIV5_MINDP) ? "MINDP " : "",
-			   (uint16_t)(dp->idcode >> 28));
+			   (uint8_t)((dp->idcode >> 12U) & 0xfU),
+			   (dp->idcode & ADIV5_MINDP) ? "MINDP " : "", (uint16_t)(dp->idcode >> 28U));
 	volatile uint32_t ctrlstat = 0;
 #if PC_HOSTED  == 1
 	platform_adiv5_dp_defaults(dp);

src/target/atxmega.c

@@ -0,0 +1,74 @@
+#include "general.h"
+#include "target.h"
+#include "target_internal.h"
+#include "avr.h"
+
+#define IDCODE_XMEGA256A3U	0x9842U
+
+static const char tdesc_xmega6[] =
+	"<?xml version=\"1.0\"?>"
+	"<!DOCTYPE target SYSTEM \"gdb-target.dtd\">"
+	"<target>"
+	"	<architecture>avr:106</architecture>"
+	/* As it turns out, GDB doesn't acctually support this (despite asking for it!) yet */
+#if 0
+	"	<feature name=\"org.gnu.gdb.avr.cpu\">"
+	"		<reg name=\"r0\" bitsize=\"8\" regnum=\"0\"/>"
+	"		<reg name=\"r1\" bitsize=\"8\"/>"
+	"		<reg name=\"r2\" bitsize=\"8\"/>"
+	"		<reg name=\"r3\" bitsize=\"8\"/>"
+	"		<reg name=\"r4\" bitsize=\"8\"/>"
+	"		<reg name=\"r5\" bitsize=\"8\"/>"
+	"		<reg name=\"r6\" bitsize=\"8\"/>"
+	"		<reg name=\"r7\" bitsize=\"8\"/>"
+	"		<reg name=\"r8\" bitsize=\"8\"/>"
+	"		<reg name=\"r9\" bitsize=\"8\"/>"
+	"		<reg name=\"r10\" bitsize=\"8\"/>"
+	"		<reg name=\"r11\" bitsize=\"8\"/>"
+	"		<reg name=\"r12\" bitsize=\"8\"/>"
+	"		<reg name=\"r13\" bitsize=\"8\"/>"
+	"		<reg name=\"r14\" bitsize=\"8\"/>"
+	"		<reg name=\"r15\" bitsize=\"8\"/>"
+	"		<reg name=\"r16\" bitsize=\"8\"/>"
+	"		<reg name=\"r17\" bitsize=\"8\"/>"
+	"		<reg name=\"r18\" bitsize=\"8\"/>"
+	"		<reg name=\"r19\" bitsize=\"8\"/>"
+	"		<reg name=\"r20\" bitsize=\"8\"/>"
+	"		<reg name=\"r21\" bitsize=\"8\"/>"
+	"		<reg name=\"r22\" bitsize=\"8\"/>"
+	"		<reg name=\"r23\" bitsize=\"8\"/>"
+	"		<reg name=\"r24\" bitsize=\"8\"/>"
+	"		<reg name=\"r25\" bitsize=\"8\"/>"
+	"		<reg name=\"r26\" bitsize=\"8\"/>"
+	"		<reg name=\"r27\" bitsize=\"8\"/>"
+	"		<reg name=\"r28\" bitsize=\"8\"/>"
+	"		<reg name=\"r29\" bitsize=\"8\"/>"
+	"		<reg name=\"r30\" bitsize=\"8\"/>"
+	"		<reg name=\"r31\" bitsize=\"8\"/>"
+	"		<reg name=\"sreg\" bitsize=\"8\"/>"
+	"		<reg name=\"sp\" bitsize=\"16\" type=\"data_ptr\"/>"
+	"		<reg name=\"pc\" bitsize=\"32\" type=\"code_ptr\"/>"
+	"	</feature>"
+#endif
+	"</target>";
+
+bool atxmega_probe(target *t)
+{
+	avr_pdi_t *pdi = t->priv;
+
+	switch (t->idcode) {
+		case IDCODE_XMEGA256A3U:
+			t->core = "ATXMega256A3U";
+			// RAM is actually at 0x01002000, but this is done to keep things right for GDB
+			// - internally we add 0x00800000 to get to the PDI mapped address.
+			target_add_ram(t, 0x00802000, 0x800);
+			// These are mapped here to make things make sense to GDB
+			// - internally we add 0x00800000 to get to the PDI mapped address.
+			avr_add_flash(t, 0x00000000, 0x40000);
+			avr_add_flash(t, 0x00040000, 0x2000);
+			t->tdesc = tdesc_xmega6;
+			pdi->hw_breakpoints_max = 2;
+			return true;
+	}
+	return false;
+}

src/target/avr.h

@@ -0,0 +1,41 @@
+#ifndef ATMEL___H
+#define ATMEL___H
+
+#include "jtag_scan.h"
+#include "target.h"
+
+enum avr_error_e
+{
+	pdi_ok,
+	pdi_failure,
+};
+
+#define AVR_MAX_BREAKPOINTS 2
+
+typedef struct avr_pdi_s {
+	uint32_t idcode;
+
+	uint8_t dp_jd_index;
+	enum target_halt_reason halt_reason;
+	enum avr_error_e error_state;
+	target_addr programCounter;
+
+	target_addr hw_breakpoint[AVR_MAX_BREAKPOINTS];
+	uint32_t hw_breakpoints_enabled;
+	uint32_t hw_breakpoints_max;
+} avr_pdi_t;
+
+bool avr_pdi_init(avr_pdi_t *pdi);
+
+void avr_jtag_pdi_handler(uint8_t jd_index);
+int platform_avr_jtag_pdi_init(avr_pdi_t *pdi);
+
+bool avr_jtag_shift_dr(jtag_proc_t *jp, uint8_t jd_index, uint8_t *dout, const uint8_t din);
+bool avr_pdi_reg_write(avr_pdi_t *pdi, uint8_t reg, uint8_t value);
+uint8_t avr_pdi_reg_read(avr_pdi_t *pdi, uint8_t reg);
+
+bool avr_attach(target *t);
+void avr_detach(target *t);
+void avr_add_flash(target *t, uint32_t start, size_t length);
+
+#endif /*ATMEL___H*/

src/target/avr_jtagdp.c

@@ -0,0 +1,55 @@
+#include "general.h"
+#include "exception.h"
+#include "avr.h"
+#include "jtag_scan.h"
+#include "jtagtap.h"
+
+#define PDI_DELAY	0xDBU
+
+void avr_jtag_pdi_handler(uint8_t jd_index)
+{
+	avr_pdi_t *pdi = calloc(1, sizeof(*pdi));
+	if (!pdi) {			/* calloc failed: heap exhaustion */
+		DEBUG_WARN("calloc: failed in %s\n", __func__);
+		return;
+	}
+	pdi->dp_jd_index = jd_index;
+	pdi->idcode = jtag_devs[jd_index].jd_idcode;
+	pdi->error_state = pdi_ok;
+	pdi->hw_breakpoints_enabled = 0;
+	if ((PC_HOSTED == 0) || (!platform_avr_jtag_pdi_init(pdi))) {
+		//
+	}
+	avr_pdi_init(pdi);
+}
+
+bool avr_jtag_shift_dr(jtag_proc_t *jp, uint8_t jd_index, uint8_t *dout, const uint8_t din)
+{
+	jtag_dev_t *d = &jtag_devs[jd_index];
+	uint8_t result = 0;
+	uint16_t request = 0, response = 0;
+	uint8_t *data;
+	if (!dout)
+		return false;
+	do
+	{
+		data = (uint8_t *)&request;
+		jtagtap_shift_dr();
+		jp->jtagtap_tdi_seq(0, ones, d->dr_prescan);
+		data[0] = din;
+		// Calculate the parity bit
+		for (uint8_t i = 0; i < 8; ++i)
+			data[1] ^= (din >> i) & 1U;
+		jp->jtagtap_tdi_tdo_seq((uint8_t *)&response, 1, (uint8_t *)&request, 9);
+		jp->jtagtap_tdi_seq(1, ones, d->dr_postscan);
+		jtagtap_return_idle();
+		data = (uint8_t *)&response;
+	}
+	while (data[0] == PDI_DELAY && data[1] == 1);
+	// Calculate the parity bit
+	for (uint8_t i = 0; i < 8; ++i)
+		result ^= (data[0] >> i) & 1U;
+	*dout = data[0];
+	DEBUG_INFO("Sent 0x%02x to target, response was 0x%02x (0x%x)\n", din, data[0], data[1]);
+	return result == data[1];
+}