ALSA: firewire: extend snd_fw_transaction()

Add a flag to snd_fw_transaction() to allow it to abort when a bus reset
happens.  This removes most of the duplicated error handling loops that
were required around calls to the low-level fw_run_transaction().

Also add a flag to suppress error messages; errors are expected when we
attempt to clean up after the device was unplugged.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

sound/firewire/cmp.c

@@ -48,9 +48,6 @@ static int pcr_modify(struct cmp_connection *c,
 		      int (*check)(struct cmp_connection *c, __be32 pcr),
 		      enum bus_reset_handling bus_reset_handling)
 {
-	struct fw_device *device = fw_parent_device(c->resources.unit);
-	int generation = c->resources.generation;
-	int rcode, errors = 0;
 	__be32 old_arg, buffer[2];
 	int err;
 
@@ -59,36 +56,31 @@ static int pcr_modify(struct cmp_connection *c,
 		old_arg = buffer[0];
 		buffer[1] = modify(c, buffer[0]);
 
-		rcode = fw_run_transaction(
-				device->card, TCODE_LOCK_COMPARE_SWAP,
-				device->node_id, generation, device->max_speed,
+		err = snd_fw_transaction(
+				c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
 				CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
-				buffer, 8);
-
-		if (rcode == RCODE_COMPLETE) {
-			if (buffer[0] == old_arg) /* success? */
-				break;
-
-			if (check) {
-				err = check(c, buffer[0]);
-				if (err < 0)
-					return err;
-			}
-		} else if (rcode == RCODE_GENERATION)
-			goto bus_reset;
-		else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
-			goto io_error;
+				buffer, 8,
+				FW_FIXED_GENERATION | c->resources.generation);
+
+		if (err < 0) {
+			if (err == -EAGAIN &&
+			    bus_reset_handling == SUCCEED_ON_BUS_RESET)
+				err = 0;
+			return err;
+		}
+
+		if (buffer[0] == old_arg) /* success? */
+			break;
+
+		if (check) {
+			err = check(c, buffer[0]);
+			if (err < 0)
+				return err;
+		}
 	}
 	c->last_pcr_value = buffer[1];
 
 	return 0;
-
-io_error:
-	cmp_error(c, "transaction failed: %s\n", fw_rcode_string(rcode));
-	return -EIO;
-
-bus_reset:
-	return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0;
 }
 
 
@@ -108,7 +100,7 @@ int cmp_connection_init(struct cmp_connection *c,
 
 	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
 				 CSR_REGISTER_BASE + CSR_IMPR,
-				 &impr_be, 4);
+				 &impr_be, 4, 0);
 	if (err < 0)
 		return err;
 	impr = be32_to_cpu(impr_be);

sound/firewire/fcp.c

@@ -90,7 +90,7 @@ int fcp_avc_transaction(struct fw_unit *unit,
 					  : TCODE_WRITE_BLOCK_REQUEST;
 		ret = snd_fw_transaction(t.unit, tcode,
 					 CSR_REGISTER_BASE + CSR_FCP_COMMAND,
-					 (void *)command, command_size);
+					 (void *)command, command_size, 0);
 		if (ret < 0)
 			break;
 

sound/firewire/isight.c

@@ -217,7 +217,7 @@ static void isight_packet(struct fw_iso_context *context, u32 cycle,
 
 static int isight_connect(struct isight *isight)
 {
-	int ch, err, rcode, errors = 0;
+	int ch, err;
 	__be32 value;
 
 retry_after_bus_reset:
@@ -230,27 +230,19 @@ static int isight_connect(struct isight *isight)
 	}
 
 	value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT));
-	for (;;) {
-		rcode = fw_run_transaction(
-				isight->device->card,
-				TCODE_WRITE_QUADLET_REQUEST,
-				isight->device->node_id,
-				isight->resources.generation,
-				isight->device->max_speed,
-				isight->audio_base + REG_ISO_TX_CONFIG,
-				&value, 4);
-		if (rcode == RCODE_COMPLETE) {
-			return 0;
-		} else if (rcode == RCODE_GENERATION) {
-			fw_iso_resources_free(&isight->resources);
-			goto retry_after_bus_reset;
-		} else if (rcode_is_permanent_error(rcode) || ++errors >= 3) {
-			err = -EIO;
-			goto err_resources;
-		}
-		msleep(5);
+	err = snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 isight->audio_base + REG_ISO_TX_CONFIG,
+				 &value, 4, FW_FIXED_GENERATION |
+				 isight->resources.generation);
+	if (err == -EAGAIN) {
+		fw_iso_resources_free(&isight->resources);
+		goto retry_after_bus_reset;
+	} else if (err < 0) {
+		goto err_resources;
 	}
 
+	return 0;
+
 err_resources:
 	fw_iso_resources_free(&isight->resources);
 error:
@@ -315,17 +307,19 @@ static int isight_hw_params(struct snd_pcm_substream *substream,
 static int reg_read(struct isight *isight, int offset, __be32 *value)
 {
 	return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST,
-				  isight->audio_base + offset, value, 4);
+				  isight->audio_base + offset, value, 4, 0);
 }
 
 static int reg_write(struct isight *isight, int offset, __be32 value)
 {
 	return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
-				  isight->audio_base + offset, &value, 4);
+				  isight->audio_base + offset, &value, 4, 0);
 }
 
 static void isight_stop_streaming(struct isight *isight)
 {
+	__be32 value;
+
 	if (!isight->context)
 		return;
 
@@ -333,7 +327,10 @@ static void isight_stop_streaming(struct isight *isight)
 	fw_iso_context_destroy(isight->context);
 	isight->context = NULL;
 	fw_iso_resources_free(&isight->resources);
-	reg_write(isight, REG_AUDIO_ENABLE, 0);
+	value = 0;
+	snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
+			   isight->audio_base + REG_AUDIO_ENABLE,
+			   &value, 4, FW_QUIET);
 }
 
 static int isight_hw_free(struct snd_pcm_substream *substream)

sound/firewire/lib.c

@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include "lib.h"
 
-#define ERROR_RETRY_DELAY_MS	5
+#define ERROR_RETRY_DELAY_MS	20
 
 /**
  * snd_fw_transaction - send a request and wait for its completion
@@ -20,6 +20,9 @@
  * @offset: the address in the target's address space
  * @buffer: input/output data
  * @length: length of @buffer
+ * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
+ *         request only in that generation; use %FW_QUIET to suppress error
+ *         messages
  *
  * Submits an asynchronous request to the target device, and waits for the
  * response.  The node ID and the current generation are derived from @unit.
@@ -27,14 +30,18 @@
  * Returns zero on success, or a negative error code.
  */
 int snd_fw_transaction(struct fw_unit *unit, int tcode,
-		       u64 offset, void *buffer, size_t length)
+		       u64 offset, void *buffer, size_t length,
+		       unsigned int flags)
 {
 	struct fw_device *device = fw_parent_device(unit);
 	int generation, rcode, tries = 0;
 
+	generation = flags & FW_GENERATION_MASK;
 	for (;;) {
-		generation = device->generation;
-		smp_rmb(); /* node_id vs. generation */
+		if (!(flags & FW_FIXED_GENERATION)) {
+			generation = device->generation;
+			smp_rmb(); /* node_id vs. generation */
+		}
 		rcode = fw_run_transaction(device->card, tcode,
 					   device->node_id, generation,
 					   device->max_speed, offset,
@@ -43,9 +50,14 @@ int snd_fw_transaction(struct fw_unit *unit, int tcode,
 		if (rcode == RCODE_COMPLETE)
 			return 0;
 
+		if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
+			return -EAGAIN;
+
 		if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
-			dev_err(&unit->device, "transaction failed: %s\n",
-				fw_rcode_string(rcode));
+			if (!(flags & FW_QUIET))
+				dev_err(&unit->device,
+					"transaction failed: %s\n",
+					fw_rcode_string(rcode));
 			return -EIO;
 		}
 

sound/firewire/lib.h

@@ -6,8 +6,13 @@
 
 struct fw_unit;
 
+#define FW_GENERATION_MASK	0x00ff
+#define FW_FIXED_GENERATION	0x0100
+#define FW_QUIET		0x0200
+
 int snd_fw_transaction(struct fw_unit *unit, int tcode,
-		       u64 offset, void *buffer, size_t length);
+		       u64 offset, void *buffer, size_t length,
+		       unsigned int flags);
 
 /* returns true if retrying the transaction would not make sense */
 static inline bool rcode_is_permanent_error(int rcode)

sound/firewire/scs1x.c

@@ -369,7 +369,7 @@ static int scs_init_hss_address(struct scs *scs)
 	data = cpu_to_be64(((u64)HSS1394_TAG_CHANGE_ADDRESS << 56) |
 			   scs->hss_handler.offset);
 	err = snd_fw_transaction(scs->unit, TCODE_WRITE_BLOCK_REQUEST,
-				 HSS1394_ADDRESS, &data, 8);
+				 HSS1394_ADDRESS, &data, 8, 0);
 	if (err < 0)
 		dev_err(&scs->unit->device, "HSS1394 communication failed\n");
 
@@ -455,12 +455,16 @@ static int scs_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
 static void scs_update(struct fw_unit *unit)
 {
 	struct scs *scs = dev_get_drvdata(&unit->device);
+	int generation;
 	__be64 data;
 
 	data = cpu_to_be64(((u64)HSS1394_TAG_CHANGE_ADDRESS << 56) |
 			   scs->hss_handler.offset);
+	generation = fw_parent_device(unit)->generation;
+	smp_rmb(); /* node_id vs. generation */
 	snd_fw_transaction(scs->unit, TCODE_WRITE_BLOCK_REQUEST,
-			   HSS1394_ADDRESS, &data, 8);
+			   HSS1394_ADDRESS, &data, 8,
+			   FW_FIXED_GENERATION | generation);
 }
 
 static void scs_remove(struct fw_unit *unit)

sound/firewire/speakers.c

@@ -647,7 +647,7 @@ static u32 fwspk_read_firmware_version(struct fw_unit *unit)
 	int err;
 
 	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
-				 OXFORD_FIRMWARE_ID_ADDRESS, &data, 4);
+				 OXFORD_FIRMWARE_ID_ADDRESS, &data, 4, 0);
 	return err >= 0 ? be32_to_cpu(data) : 0;
 }