firewire: core: add CSR abdicate support

Implement the abdicate bit, which is required for bus manager
capable nodes and tested by the Base 1394 Test Suite.

Finally, something to do at a command reset!  :-)
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

drivers/firewire/core-card.c

@@ -260,7 +260,8 @@ static void fw_card_bm_work(struct work_struct *work)
 
 	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
 
-	if (is_next_generation(generation, card->bm_generation) ||
+	if ((is_next_generation(generation, card->bm_generation) &&
+	     !card->bm_abdicate) ||
 	    (card->bm_generation != generation && grace)) {
 		/*
 		 * This first step is to figure out who is IRM and

drivers/firewire/core-topology.c

@@ -552,6 +552,8 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
 	smp_wmb();
 	card->generation = generation;
 	card->reset_jiffies = jiffies;
+	card->bm_abdicate = card->csr_abdicate;
+	card->csr_abdicate = false;
 	fw_schedule_bm_work(card, 0);
 
 	local_node = build_tree(card, self_ids, self_id_count);

drivers/firewire/core-transaction.c

@@ -1008,6 +1008,10 @@ static u32 read_state_register(struct fw_card *card)
 	/* Bit 8 (cmstr): */
 	value |= card->driver->read_csr_reg(card, CSR_STATE_CLEAR);
 
+	/* Bit 10 (abdicate): */
+	if (card->csr_abdicate)
+		value |= CSR_STATE_BIT_ABDICATE;
+
 	return value;
 }
 
@@ -1041,6 +1045,8 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
 			card->driver->write_csr_reg(card, CSR_STATE_CLEAR,
 						    be32_to_cpu(*data));
+			if (*data & cpu_to_be32(CSR_STATE_BIT_ABDICATE))
+				card->csr_abdicate = false;
 		} else {
 			rcode = RCODE_TYPE_ERROR;
 		}
@@ -1052,7 +1058,8 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
 			card->driver->write_csr_reg(card, CSR_STATE_SET,
 						    be32_to_cpu(*data));
-			/* FIXME: implement abdicate */
+			if (*data & cpu_to_be32(CSR_STATE_BIT_ABDICATE))
+				card->csr_abdicate = true;
 		} else {
 			rcode = RCODE_TYPE_ERROR;
 		}
@@ -1070,7 +1077,9 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		break;
 
 	case CSR_RESET_START:
-		if (tcode != TCODE_WRITE_QUADLET_REQUEST)
+		if (tcode == TCODE_WRITE_QUADLET_REQUEST)
+			card->csr_abdicate = false;
+		else
 			rcode = RCODE_TYPE_ERROR;
 		break;
 

drivers/firewire/core.h

@@ -41,6 +41,7 @@ struct fw_packet;
 #define FEATURE_PRIORITY_BUDGET		0x01
 
 #define CSR_STATE_BIT_CMSTR	(1 << 8)
+#define CSR_STATE_BIT_ABDICATE	(1 << 10)
 
 struct fw_card_driver {
 	/*

include/linux/firewire.h

@@ -119,6 +119,8 @@ struct fw_card {
 	int bm_retries;
 	int bm_generation;
 	__be32 bm_transaction_data[2];
+	bool bm_abdicate; /* value of csr_abdicate before last bus reset */
+	bool csr_abdicate; /* visible in CSR STATE_CLEAR/SET registers */
 
 	bool broadcast_channel_allocated;
 	u32 broadcast_channel;