firewire: add CSR BUSY_TIMEOUT support

Implement the BUSY_TIMEOUT register, which is required for nodes that
support retries.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

drivers/firewire/core-transaction.c

@@ -1115,6 +1115,17 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 			rcode = RCODE_TYPE_ERROR;
 		break;
 
+	case CSR_BUSY_TIMEOUT:
+		if (tcode == TCODE_READ_QUADLET_REQUEST)
+			*data = cpu_to_be32(card->driver->
+					read_csr_reg(card, CSR_BUSY_TIMEOUT));
+		else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
+			card->driver->write_csr_reg(card, CSR_BUSY_TIMEOUT,
+						    be32_to_cpu(*data));
+		else
+			rcode = RCODE_TYPE_ERROR;
+		break;
+
 	case CSR_BROADCAST_CHANNEL:
 		if (tcode == TCODE_READ_QUADLET_REQUEST)
 			*data = cpu_to_be32(card->broadcast_channel);
@@ -1140,9 +1151,6 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		BUG();
 		break;
 
-	case CSR_BUSY_TIMEOUT:
-		/* FIXME: Implement this. */
-
 	default:
 		rcode = RCODE_ADDRESS_ERROR;
 		break;

drivers/firewire/ohci.c

@@ -1731,7 +1731,8 @@ static int ohci_enable(struct fw_card *card,
 	reg_write(ohci, OHCI1394_ATRetries,
 		  OHCI1394_MAX_AT_REQ_RETRIES |
 		  (OHCI1394_MAX_AT_RESP_RETRIES << 4) |
-		  (OHCI1394_MAX_PHYS_RESP_RETRIES << 8));
+		  (OHCI1394_MAX_PHYS_RESP_RETRIES << 8) |
+		  (200 << 16));
 
 	seconds = lower_32_bits(get_seconds());
 	reg_write(ohci, OHCI1394_IsochronousCycleTimer, seconds << 25);
@@ -2023,6 +2024,10 @@ static u32 ohci_read_csr_reg(struct fw_card *card, int csr_offset)
 		spin_unlock_irqrestore(&ohci->lock, flags);
 		return value;
 
+	case CSR_BUSY_TIMEOUT:
+		value = reg_read(ohci, OHCI1394_ATRetries);
+		return (value >> 4) & 0x0ffff00f;
+
 	default:
 		WARN_ON(1);
 		return 0;
@@ -2053,6 +2058,13 @@ static void ohci_write_csr_reg(struct fw_card *card, int csr_offset, u32 value)
 		spin_unlock_irqrestore(&ohci->lock, flags);
 		break;
 
+	case CSR_BUSY_TIMEOUT:
+		value = (value & 0xf) | ((value & 0xf) << 4) |
+			((value & 0xf) << 8) | ((value & 0x0ffff000) << 4);
+		reg_write(ohci, OHCI1394_ATRetries, value);
+		flush_writes(ohci);
+		break;
+
 	default:
 		WARN_ON(1);
 		break;