[PATCH 0/5] firewire: some simplifications in firewire-core + a fix

[PATCH 0/5] firewire: some simplifications in firewire-core + a fix

[Stefan Richter]

Next up:

 firewire: core: drop unused call parameters of close_transaction
 firewire: core: increase bus manager grace period
 firewire: core: simplify broadcast channel allocation
 firewire: core: optimize propagation of BROADCAST_CHANNEL

 drivers/firewire/fw-card.c        |  214 +++++-------------------------
 drivers/firewire/fw-device.c      |   45 +++++-
 drivers/firewire/fw-device.h      |    5
 drivers/firewire/fw-topology.c    |    1
 drivers/firewire/fw-transaction.c |   17 +-
 drivers/firewire/fw-transaction.h |    6
 6 files changed, 96 insertions(+), 192 deletions(-)
-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/

[PATCH 1/5] firewire: core: drop unused call parameters of close_transaction

[Stefan Richter]

All callers inserted NULL and 0 here.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/fw-transaction.c |   17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

Index: linux/drivers/firewire/fw-transaction.c
===================================================================
--- linux.orig/drivers/firewire/fw-transaction.c
+++ linux/drivers/firewire/fw-transaction.c
@@ -65,8 +65,7 @@
 #define PHY_IDENTIFIER(id)		((id) << 30)
 
 static int close_transaction(struct fw_transaction *transaction,
-			     struct fw_card *card, int rcode,
-			     u32 *payload, size_t length)
+			     struct fw_card *card, int rcode)
 {
 	struct fw_transaction *t;
 	unsigned long flags;
@@ -82,7 +81,7 @@ static int close_transaction(struct fw_t
 	spin_unlock_irqrestore(&card->lock, flags);
 
 	if (&t->link != &card->transaction_list) {
-		t->callback(card, rcode, payload, length, t->callback_data);
+		t->callback(card, rcode, NULL, 0, t->callback_data);
 		return 0;
 	}
 
@@ -110,7 +109,7 @@ int fw_cancel_transaction(struct fw_card
 	 * if the transaction is still pending and remove it in that case.
 	 */
 
-	return close_transaction(transaction, card, RCODE_CANCELLED, NULL, 0);
+	return close_transaction(transaction, card, RCODE_CANCELLED);
 }
 EXPORT_SYMBOL(fw_cancel_transaction);
 
@@ -122,7 +121,7 @@ static void transmit_complete_callback(s
 
 	switch (status) {
 	case ACK_COMPLETE:
-		close_transaction(t, card, RCODE_COMPLETE, NULL, 0);
+		close_transaction(t, card, RCODE_COMPLETE);
 		break;
 	case ACK_PENDING:
 		t->timestamp = packet->timestamp;
@@ -130,20 +129,20 @@ static void transmit_complete_callback(s
 	case ACK_BUSY_X:
 	case ACK_BUSY_A:
 	case ACK_BUSY_B:
-		close_transaction(t, card, RCODE_BUSY, NULL, 0);
+		close_transaction(t, card, RCODE_BUSY);
 		break;
 	case ACK_DATA_ERROR:
-		close_transaction(t, card, RCODE_DATA_ERROR, NULL, 0);
+		close_transaction(t, card, RCODE_DATA_ERROR);
 		break;
 	case ACK_TYPE_ERROR:
-		close_transaction(t, card, RCODE_TYPE_ERROR, NULL, 0);
+		close_transaction(t, card, RCODE_TYPE_ERROR);
 		break;
 	default:
 		/*
 		 * In this case the ack is really a juju specific
 		 * rcode, so just forward that to the callback.
 		 */
-		close_transaction(t, card, status, NULL, 0);
+		close_transaction(t, card, status);
 		break;
 	}
 }

-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/

[PATCH 2/5] firewire: core: increase bus manager grace period

[Stefan Richter]

Per IEEE 1394 clause 8.4.2.5, bus manager capable nodes which are not
incumbent shall wait at least 125ms before trying to establish
themselves as bus manager.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/fw-card.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

Index: linux/drivers/firewire/fw-card.c
===================================================================
--- linux.orig/drivers/firewire/fw-card.c
+++ linux/drivers/firewire/fw-card.c
@@ -368,9 +368,11 @@ static void fw_card_bm_work(struct work_
 			atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
 	root_device_is_cmc = root_device && root_device->cmc;
 	root_id = root_node->node_id;
-	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10));
 	irm_device = irm_node->data;
 	local_device = local_node->data;
+
+	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
+
 	if (is_next_generation(generation, card->bm_generation) ||
 	    (card->bm_generation != generation && grace)) {
 		/*
@@ -434,12 +436,11 @@ static void fw_card_bm_work(struct work_
 		}
 	} else if (card->bm_generation != generation) {
 		/*
-		 * OK, we weren't BM in the last generation, and it's
-		 * less than 100ms since last bus reset. Reschedule
-		 * this task 100ms from now.
+		 * We weren't BM in the last generation, and the last
+		 * bus reset is less than 125ms ago.  Reschedule this job.
 		 */
 		spin_unlock_irqrestore(&card->lock, flags);
-		fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 10));
+		fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
 		goto out;
 	}
 

-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/

[PATCH 3/5] firewire: core: simplify broadcast channel allocation

[Stefan Richter]

fw-iso.c has channel allocation code now, use it.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/fw-card.c |  124 +++++++++----------------------------
 1 file changed, 33 insertions(+), 91 deletions(-)

Index: linux/drivers/firewire/fw-card.c
===================================================================
--- linux.orig/drivers/firewire/fw-card.c
+++ linux/drivers/firewire/fw-card.c
@@ -181,10 +181,6 @@ void fw_core_remove_descriptor(struct fw
 	mutex_unlock(&card_mutex);
 }
 
-/* ------------------------------------------------------------------ */
-/* Code to handle 1394a broadcast channel */
-
-#define THIRTY_TWO_CHANNELS (0xFFFFFFFFU)
 #define IRM_RETRIES 2
 
 /*
@@ -265,62 +261,18 @@ tryagain_w:
 	return 0;
 }
 
-static void
-irm_allocate_broadcast(struct fw_device *irm_dev, struct device *locald)
+static void allocate_broadcast_channel(struct fw_card *card, int generation)
 {
-	u32 generation;
-	u32 node_id;
-	u32 max_speed;
-	u32 retries;
-	__be32 old_data;
-	__be32 lock_data[2];
-	int rcode;
+	int channel, bandwidth = 0;
 
-	/*
-	 * The device we are updating is the IRM, so we must do
-	 * some extra work.
-	 */
-	retries = IRM_RETRIES;
-	generation = irm_dev->generation;
-	/* FIXME: do we need locking here? */
-	smp_rmb();
-	node_id = irm_dev->node_id;
-	max_speed = irm_dev->max_speed;
-
-	lock_data[0] = cpu_to_be32(THIRTY_TWO_CHANNELS);
-	lock_data[1] = cpu_to_be32(THIRTY_TWO_CHANNELS & ~1);
-tryagain:
-	old_data = lock_data[0];
-	rcode = fw_run_transaction(irm_dev->card, TCODE_LOCK_COMPARE_SWAP,
-				   node_id, generation, max_speed,
-				   CSR_REGISTER_BASE+CSR_CHANNELS_AVAILABLE_HI,
-				   &lock_data[0], 8);
-	switch (rcode) {
-	case RCODE_BUSY:
-		if (retries--)
-			goto tryagain;
-		/* fallthrough */
-	default:
-		fw_error("node %x: allocate broadcast channel failed (%x)\n",
-			 node_id, rcode);
-		return;
-
-	case RCODE_COMPLETE:
-		if (lock_data[0] == old_data)
-			break;
-		if (retries--) {
-			lock_data[1] = cpu_to_be32(be32_to_cpu(lock_data[0])&~1);
-			goto tryagain;
-		}
-		fw_error("node %x: allocate broadcast channel failed: too many"
-			 " retries\n", node_id);
-		return;
+	fw_iso_resource_manage(card, generation, 1ULL << 31,
+			       &channel, &bandwidth, true);
+	if (channel == 31) {
+		card->is_irm = true;
+		device_for_each_child(card->device, NULL,
+				      fw_irm_set_broadcast_channel_register);
 	}
-	irm_dev->card->is_irm = true;
-	device_for_each_child(locald, NULL, fw_irm_set_broadcast_channel_register);
 }
-/* ------------------------------------------------------------------ */
-
 
 static const char gap_count_table[] = {
 	63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
@@ -339,10 +291,11 @@ void fw_schedule_bm_work(struct fw_card 
 static void fw_card_bm_work(struct work_struct *work)
 {
 	struct fw_card *card = container_of(work, struct fw_card, work.work);
-	struct fw_device *root_device, *irm_device, *local_device;
-	struct fw_node *root_node, *local_node, *irm_node;
+	struct fw_device *root_device;
+	struct fw_node *root_node;
 	unsigned long flags;
-	int root_id, new_root_id, irm_id, gap_count, generation, grace, rcode;
+	int root_id, new_root_id, irm_id, local_id;
+	int gap_count, generation, grace, rcode;
 	bool do_reset = false;
 	bool root_device_is_running;
 	bool root_device_is_cmc;
@@ -350,26 +303,22 @@ static void fw_card_bm_work(struct work_
 
 	spin_lock_irqsave(&card->lock, flags);
 	card->is_irm = false;
-	local_node = card->local_node;
-	root_node  = card->root_node;
-	irm_node = card->irm_node;
 
-	if (local_node == NULL) {
+	if (card->local_node == NULL) {
 		spin_unlock_irqrestore(&card->lock, flags);
 		goto out_put_card;
 	}
-	fw_node_get(local_node);
-	fw_node_get(root_node);
-	fw_node_get(irm_node);
 
 	generation = card->generation;
+	root_node = card->root_node;
+	fw_node_get(root_node);
 	root_device = root_node->data;
 	root_device_is_running = root_device &&
 			atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
 	root_device_is_cmc = root_device && root_device->cmc;
-	root_id = root_node->node_id;
-	irm_device = irm_node->data;
-	local_device = local_node->data;
+	root_id  = root_node->node_id;
+	irm_id   = card->irm_node->node_id;
+	local_id = card->local_node->node_id;
 
 	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
 
@@ -387,16 +336,15 @@ static void fw_card_bm_work(struct work_
 		 * next generation.
 		 */
 
-		irm_id = irm_node->node_id;
-		if (!irm_node->link_on) {
-			new_root_id = local_node->node_id;
+		if (!card->irm_node->link_on) {
+			new_root_id = local_id;
 			fw_notify("IRM has link off, making local node (%02x) root.\n",
 				  new_root_id);
 			goto pick_me;
 		}
 
 		lock_data[0] = cpu_to_be32(0x3f);
-		lock_data[1] = cpu_to_be32(local_node->node_id);
+		lock_data[1] = cpu_to_be32(local_id);
 
 		spin_unlock_irqrestore(&card->lock, flags);
 
@@ -411,12 +359,11 @@ static void fw_card_bm_work(struct work_
 
 		if (rcode == RCODE_COMPLETE &&
 		    lock_data[0] != cpu_to_be32(0x3f)) {
-			/* Somebody else is BM, let them do the work. */
-			if (irm_id == local_node->node_id) {
-				/* But we are IRM, so do irm-y things */
-				irm_allocate_broadcast(irm_device,
-						       card->device);
-			}
+
+			/* Somebody else is BM.  Only act as IRM. */
+			if (local_id == irm_id)
+				allocate_broadcast_channel(card, generation);
+
 			goto out;
 		}
 
@@ -429,7 +376,7 @@ static void fw_card_bm_work(struct work_
 			 * do a bus reset and pick the local node as
 			 * root, and thus, IRM.
 			 */
-			new_root_id = local_node->node_id;
+			new_root_id = local_id;
 			fw_notify("BM lock failed, making local node (%02x) root.\n",
 				  new_root_id);
 			goto pick_me;
@@ -456,7 +403,7 @@ static void fw_card_bm_work(struct work_
 		 * Either link_on is false, or we failed to read the
 		 * config rom.  In either case, pick another root.
 		 */
-		new_root_id = local_node->node_id;
+		new_root_id = local_id;
 	} else if (!root_device_is_running) {
 		/*
 		 * If we haven't probed this device yet, bail out now
@@ -478,7 +425,7 @@ static void fw_card_bm_work(struct work_
 		 * successfully read the config rom, but it's not
 		 * cycle master capable.
 		 */
-		new_root_id = local_node->node_id;
+		new_root_id = local_id;
 	}
 
  pick_me:
@@ -509,19 +456,14 @@ static void fw_card_bm_work(struct work_
 			  card->index, new_root_id, gap_count);
 		fw_send_phy_config(card, new_root_id, generation, gap_count);
 		fw_core_initiate_bus_reset(card, 1);
-	} else if (irm_node->node_id == local_node->node_id) {
-		/*
-		 * We are IRM, so do irm-y things.
-		 * There's no reason to do this if we're doing a reset. . .
-		 * We'll be back.
-		 */
-		irm_allocate_broadcast(irm_device, card->device);
+		/* Will allocate broadcast channel after the reset. */
+	} else {
+		if (local_id == irm_id)
+			allocate_broadcast_channel(card, generation);
 	}
 
  out:
 	fw_node_put(root_node);
-	fw_node_put(local_node);
-	fw_node_put(irm_node);
  out_put_card:
 	fw_card_put(card);
 }

-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/

[PATCH 4/5] firewire: core: optimize propagation of BROADCAST_CHANNEL

[Stefan Richter]

Cache the test result of whether a device implements BROADCAST_CHANNEL.
This minimizes traffic on the bus after each bus reset.  A majority of
devices does not implement BROADCAST_CHANNEL.

Remove busy retries; just rely on the hardware to retry requests to busy
responders.  Remove unnecessary log messages.

Rename the flag is_irm to broadcast_channel_allocated to better reflect
its meaning.  Reset the flag earlier in fw_core_handle_bus_reset.

Pass the generation down as a call parameter; that way generation can't
be newer than card->broadcast_channel_allocated and device->node_id.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/fw-card.c        |   85 +-----------------------------
 drivers/firewire/fw-device.c      |   45 ++++++++++++++-
 drivers/firewire/fw-device.h      |    5 +
 drivers/firewire/fw-topology.c    |    1 
 drivers/firewire/fw-transaction.h |    6 --
 5 files changed, 52 insertions(+), 90 deletions(-)

Index: linux/drivers/firewire/fw-card.c
===================================================================
--- linux.orig/drivers/firewire/fw-card.c
+++ linux/drivers/firewire/fw-card.c
@@ -181,83 +181,9 @@ void fw_core_remove_descriptor(struct fw
 	mutex_unlock(&card_mutex);
 }
 
-#define IRM_RETRIES 2
-
-/*
- * The abi is set by device_for_each_child(), even though we have no use
- * for data, nor do we have a meaningful return value.
- */
-int fw_irm_set_broadcast_channel_register(struct device *dev, void *data)
+static int set_broadcast_channel(struct device *dev, void *data)
 {
-	struct fw_device *d;
-	int rcode;
-	int node_id;
-	int max_speed;
-	int retries;
-	int generation;
-	__be32 regval;
-	struct fw_card *card;
-
-	d = fw_device(dev);
-	/* FIXME: do we need locking here? */
-	generation = d->generation;
-	smp_rmb(); /* Ensure generation is at least as old as node_id */
-	node_id = d->node_id;
-	max_speed = d->max_speed;
-	retries = IRM_RETRIES;
-	card = d->card;
-tryagain_r:
-	rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
-				   node_id, generation, max_speed,
-				   CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
-				   &regval, 4);
-	switch (rcode) {
-	case RCODE_BUSY:
-		if (retries--)
-			goto tryagain_r;
-		fw_notify("node %x read broadcast channel busy\n",
-			  node_id);
-		return 0;
-
-	default:
-		fw_notify("node %x read broadcast channel failed %x\n",
-			  node_id, rcode);
-		return 0;
-
-	case RCODE_COMPLETE:
-		/*
-		 * Paranoid reporting of nonstandard broadcast channel
-		 * contents goes here
-		 */
-		if (regval != cpu_to_be32(BROADCAST_CHANNEL_INITIAL))
-			return 0;
-		break;
-	}
-	retries = IRM_RETRIES;
-	regval = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
-			     BROADCAST_CHANNEL_VALID);
-tryagain_w:
-	rcode = fw_run_transaction(card,
-			TCODE_WRITE_QUADLET_REQUEST, node_id,
-			generation, max_speed,
-			CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
-			&regval, 4);
-	switch (rcode) {
-	case RCODE_BUSY:
-		if (retries--)
-			goto tryagain_w;
-		fw_notify("node %x write broadcast channel busy\n",
-			  node_id);
-		return 0;
-
-	default:
-		fw_notify("node %x write broadcast channel failed %x\n",
-			  node_id, rcode);
-		return 0;
-
-	case RCODE_COMPLETE:
-		return 0;
-	}
+	fw_device_set_broadcast_channel(fw_device(dev), (long)data);
 	return 0;
 }
 
@@ -268,9 +194,9 @@ static void allocate_broadcast_channel(s
 	fw_iso_resource_manage(card, generation, 1ULL << 31,
 			       &channel, &bandwidth, true);
 	if (channel == 31) {
-		card->is_irm = true;
-		device_for_each_child(card->device, NULL,
-				      fw_irm_set_broadcast_channel_register);
+		card->broadcast_channel_allocated = true;
+		device_for_each_child(card->device, (void *)(long)generation,
+				      set_broadcast_channel);
 	}
 }
 
@@ -302,7 +228,6 @@ static void fw_card_bm_work(struct work_
 	__be32 lock_data[2];
 
 	spin_lock_irqsave(&card->lock, flags);
-	card->is_irm = false;
 
 	if (card->local_node == NULL) {
 		spin_unlock_irqrestore(&card->lock, flags);
Index: linux/drivers/firewire/fw-device.c
===================================================================
--- linux.orig/drivers/firewire/fw-device.c
+++ linux/drivers/firewire/fw-device.c
@@ -518,7 +518,7 @@ static int read_bus_info_block(struct fw
 
 	kfree(old_rom);
 	ret = 0;
-	device->cmc = rom[2] & 1 << 30;
+	device->cmc = rom[2] >> 30 & 1;
  out:
 	kfree(rom);
 
@@ -756,6 +756,44 @@ static int lookup_existing_device(struct
 	return match;
 }
 
+enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
+
+void fw_device_set_broadcast_channel(struct fw_device *device, int generation)
+{
+	struct fw_card *card = device->card;
+	__be32 data;
+	int rcode;
+
+	if (!card->broadcast_channel_allocated)
+		return;
+
+	if (device->bc_implemented == BC_UNKNOWN) {
+		rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
+				device->node_id, generation, device->max_speed,
+				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
+				&data, 4);
+		switch (rcode) {
+		case RCODE_COMPLETE:
+			if (data & cpu_to_be32(1 << 31)) {
+				device->bc_implemented = BC_IMPLEMENTED;
+				break;
+			}
+			/* else fall through to case address error */
+		case RCODE_ADDRESS_ERROR:
+			device->bc_implemented = BC_UNIMPLEMENTED;
+		}
+	}
+
+	if (device->bc_implemented == BC_IMPLEMENTED) {
+		data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
+				   BROADCAST_CHANNEL_VALID);
+		fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
+				device->node_id, generation, device->max_speed,
+				CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
+				&data, 4);
+	}
+}
+
 static void fw_device_init(struct work_struct *work)
 {
 	struct fw_device *device =
@@ -849,9 +887,8 @@ static void fw_device_init(struct work_s
 				  device->config_rom[3], device->config_rom[4],
 				  1 << device->max_speed);
 		device->config_rom_retries = 0;
-		if (device->card->is_irm)
-			fw_irm_set_broadcast_channel_register(&device->device,
-							      NULL);
+
+		fw_device_set_broadcast_channel(device, device->generation);
 	}
 
 	/*
Index: linux/drivers/firewire/fw-device.h
===================================================================
--- linux.orig/drivers/firewire/fw-device.h
+++ linux/drivers/firewire/fw-device.h
@@ -71,7 +71,6 @@ struct fw_device {
 	int node_id;
 	int generation;
 	unsigned max_speed;
-	bool cmc;
 	struct fw_card *card;
 	struct device device;
 
@@ -81,6 +80,9 @@ struct fw_device {
 	u32 *config_rom;
 	size_t config_rom_length;
 	int config_rom_retries;
+	unsigned cmc:1;
+	unsigned bc_implemented:2;
+
 	struct delayed_work work;
 	struct fw_attribute_group attribute_group;
 };
@@ -109,6 +111,7 @@ static inline void fw_device_put(struct 
 
 struct fw_device *fw_device_get_by_devt(dev_t devt);
 int fw_device_enable_phys_dma(struct fw_device *device);
+void fw_device_set_broadcast_channel(struct fw_device *device, int generation);
 
 void fw_device_cdev_update(struct fw_device *device);
 void fw_device_cdev_remove(struct fw_device *device);
Index: linux/drivers/firewire/fw-topology.c
===================================================================
--- linux.orig/drivers/firewire/fw-topology.c
+++ linux/drivers/firewire/fw-topology.c
@@ -526,6 +526,7 @@ void fw_core_handle_bus_reset(struct fw_
 
 	spin_lock_irqsave(&card->lock, flags);
 
+	card->broadcast_channel_allocated = false;
 	card->node_id = node_id;
 	/*
 	 * Update node_id before generation to prevent anybody from using
Index: linux/drivers/firewire/fw-transaction.h
===================================================================
--- linux.orig/drivers/firewire/fw-transaction.h
+++ linux/drivers/firewire/fw-transaction.h
@@ -230,11 +230,6 @@ struct fw_card {
 	u8 color; /* must be u8 to match the definition in struct fw_node */
 	int gap_count;
 	bool beta_repeaters_present;
-	/*
-	 * Set if the local device is the IRM and the broadcast channel
-	 * was allocated.
-	 */
-	bool is_irm;
 
 	int index;
 
@@ -245,6 +240,7 @@ struct fw_card {
 	int bm_retries;
 	int bm_generation;
 
+	bool broadcast_channel_allocated;
 	u32 broadcast_channel;
 	u32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4];
 };

-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/

[PATCH 5/5] firewire: some simplifications in firewire-core + a fix

[Stefan Richter]

There is no 5th patch.  I can't count.
-- 
Stefan Richter
-=====-==--= --== -=-=-
http://arcgraph.de/sr/