firewire: add CSR NODE_IDS support

The NODE_IDS register, and especially its bus_id field, is quite
useless because 1394.1 requires that the bus_id field always stays
0x3ff.  However, the 1394 specification requires this register on all
transaction capable nodes, and the Base 1394 Test Suite tests for it,
so we better implement it.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

drivers/firewire/core-transaction.c

@@ -1023,6 +1023,17 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		}
 		break;
 
+	case CSR_NODE_IDS:
+		if (tcode == TCODE_READ_QUADLET_REQUEST)
+			*data = cpu_to_be32(card->driver->
+					read_csr_reg(card, CSR_NODE_IDS));
+		else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
+			card->driver->write_csr_reg(card, CSR_NODE_IDS,
+						    be32_to_cpu(*data));
+		else
+			rcode = RCODE_TYPE_ERROR;
+		break;
+
 	case CSR_CYCLE_TIME:
 		if (TCODE_IS_READ_REQUEST(tcode) && length == 4)
 			*data = cpu_to_be32(card->driver->

drivers/firewire/core.h

@@ -76,6 +76,7 @@ struct fw_card_driver {
 			       int node_id, int generation);
 
 	u32 (*read_csr_reg)(struct fw_card *card, int csr_offset);
+	void (*write_csr_reg)(struct fw_card *card, int csr_offset, u32 value);
 
 	struct fw_iso_context *
 	(*allocate_iso_context)(struct fw_card *card,

drivers/firewire/ohci.c

@@ -1974,6 +1974,9 @@ static u32 ohci_read_csr_reg(struct fw_card *card, int csr_offset)
 	struct fw_ohci *ohci = fw_ohci(card);
 
 	switch (csr_offset) {
+	case CSR_NODE_IDS:
+		return reg_read(ohci, OHCI1394_NodeID) << 16;
+
 	case CSR_CYCLE_TIME:
 		return get_cycle_time(ohci);
 
@@ -1983,6 +1986,22 @@ static u32 ohci_read_csr_reg(struct fw_card *card, int csr_offset)
 	}
 }
 
+static void ohci_write_csr_reg(struct fw_card *card, int csr_offset, u32 value)
+{
+	struct fw_ohci *ohci = fw_ohci(card);
+
+	switch (csr_offset) {
+	case CSR_NODE_IDS:
+		reg_write(ohci, OHCI1394_NodeID, value >> 16);
+		flush_writes(ohci);
+		break;
+
+	default:
+		WARN_ON(1);
+		break;
+	}
+}
+
 static void copy_iso_headers(struct iso_context *ctx, void *p)
 {
 	int i = ctx->header_length;
@@ -2421,6 +2440,7 @@ static const struct fw_card_driver ohci_driver = {
 	.cancel_packet		= ohci_cancel_packet,
 	.enable_phys_dma	= ohci_enable_phys_dma,
 	.read_csr_reg		= ohci_read_csr_reg,
+	.write_csr_reg		= ohci_write_csr_reg,
 
 	.allocate_iso_context	= ohci_allocate_iso_context,
 	.free_iso_context	= ohci_free_iso_context,