[PATCH] intel_reg_dumper: Add a single register decode mode

[damien.lespiau at gmail.com (Damien Lespiau)]

From: Damien Lespiau <damien.lespiau at intel.com>

>From time to time, one would like to decode a register value that have
been captured at a certain point in time (and say printed out with a
printk). intel_reg_dumper has all the knowledge to do that and this
patch adds a -r option to use the tool in that mode.

Example usage:

$ ./tools/intel_reg_dumper -r PCH_PP_CONTROL 0xabcd0002
       PCH_PP_CONTROL: 0xabcd0002 (blacklight disabled, power...

Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
 tools/intel_reg_dumper.c | 102 ++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 88 insertions(+), 14 deletions(-)

diff --git a/tools/intel_reg_dumper.c b/tools/intel_reg_dumper.c
index b49d967..88d7216 100644
--- a/tools/intel_reg_dumper.c
+++ b/tools/intel_reg_dumper.c
@@ -1911,26 +1911,33 @@ static struct reg_debug i945gm_mi_regs[] = {
 	DEFINEREG(ECOSKPD),
 };
 
+static void
+_intel_dump_reg(struct reg_debug *reg, uint32_t val)
+{
+	char debug[1024];
+
+	if (reg->debug_output != NULL) {
+		reg->debug_output(debug, sizeof(debug), reg->reg, val);
+		printf("%30.30s: 0x%08x (%s)\n",
+		       reg->name,
+		       (unsigned int)val, debug);
+	} else {
+		printf("%30.30s: 0x%08x\n", reg->name,
+		       (unsigned int)val);
+	}
+}
+
 #define intel_dump_regs(regs) _intel_dump_regs(regs, ARRAY_SIZE(regs))
 
 static void
 _intel_dump_regs(struct reg_debug *regs, int count)
 {
-	char debug[1024];
 	int i;
 
 	for (i = 0; i < count; i++) {
 		uint32_t val = INREG(regs[i].reg);
 
-		if (regs[i].debug_output != NULL) {
-			regs[i].debug_output(debug, sizeof(debug), regs[i].reg, val);
-			printf("%30.30s: 0x%08x (%s)\n",
-			       regs[i].name,
-			       (unsigned int)val, debug);
-		} else {
-			printf("%30.30s: 0x%08x\n", regs[i].name,
-			       (unsigned int)val);
-		}
+		_intel_dump_reg(&regs[i], val);
 	}
 }
 
@@ -1964,6 +1971,54 @@ static struct reg_debug gen6_rp_debug_regs[] = {
 	DEFINEREG(GEN6_PMINTRMSK),
 };
 
+#define DECLARE_REGS(r)	{ .regs = r, .count = ARRAY_SIZE(r) }
+static struct {
+	struct reg_debug *regs;
+	int count;
+}known_registers[] = {
+	DECLARE_REGS(ironlake_debug_regs),
+	DECLARE_REGS(i945gm_mi_regs),
+	DECLARE_REGS(intel_debug_regs),
+	DECLARE_REGS(gen6_rp_debug_regs),
+	DECLARE_REGS(haswell_debug_regs)
+};
+#undef DECLARE_REGS
+
+static struct reg_debug *
+find_register_by_name(struct reg_debug *regs, int count,
+		      const char *name)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		if (strcmp(name, regs[i].name) == 0)
+			return &regs[i];
+
+	return NULL;
+}
+
+static void
+decode_register(const char *name, uint32_t val)
+{
+	int i;
+	struct reg_debug *reg = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(known_registers); i++) {
+		reg = find_register_by_name(known_registers[i].regs,
+					    known_registers[i].count,
+					    name);
+		if (reg)
+			break;
+	}
+
+	if (!reg) {
+		fprintf(stderr, "Unknown register: %s\n", name);
+		return;
+	}
+
+	_intel_dump_reg(reg, val);
+}
+
 static void
 intel_dump_other_regs(void)
 {
@@ -2171,10 +2226,11 @@ intel_dump_other_regs(void)
 
 static void print_usage(void)
 {
-	printf("Usage: intel_reg_dumper [options] [file]\n"
+	printf("Usage: intel_reg_dumper [options] [file|value]\n"
 	       "Options:\n"
 	       "  -d id   when a dump file is used, use 'id' as device id (in "
 	       "hex)\n"
+	       "  -r name name of the register to decode\n"
 	       "  -h      prints this help\n");
 }
 
@@ -2182,13 +2238,17 @@ int main(int argc, char** argv)
 {
 	struct pci_device *pci_dev;
 	int opt;
-	char *file = NULL;
+	char *reg_name = NULL;
+	char *arg = NULL, *file = NULL;
 
-	while ((opt = getopt(argc, argv, "d:h")) != -1) {
+	while ((opt = getopt(argc, argv, "d:r:h")) != -1) {
 		switch (opt) {
 		case 'd':
 			devid = strtol(optarg, NULL, 16);
 			break;
+		case 'r':
+			reg_name = optarg;
+			break;
 		case 'h':
 			print_usage();
 			return 0;
@@ -2198,8 +2258,22 @@ int main(int argc, char** argv)
 		}
 	}
 	if (optind < argc)
-		file = argv[optind];
+		arg = argv[optind];
+
+	if (reg_name && !arg) {
+		fprintf (stderr, "-r needs a value to decode\n");
+		return 2;
+	}
+
+	/* the tool operates in "single" mode, decode a single register given
+	 * on the command line: -r PCH_PP_CONTROL 0xabcd0002 */
+	if (reg_name) {
+		uint32_t reg_val = strtoul(arg, NULL, 0);
+		decode_register(reg_name, reg_val);
+		return 0;
+	}
 
+	file = arg;
 	if (file) {
 		intel_map_file(file);
 		if (devid) {
-- 
1.7.11.4