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Commit 7889b60e authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: core: optimize propagation of BROADCAST_CHANNEL 



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: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent cbae787c

drivers/firewire/fw-card.c

+5 −80
Original line number Diff line number Diff line
@@ -181,83 +181,9 @@ void fw_core_remove_descriptor(struct fw_descriptor *desc) 
	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(struct fw_card *card, int generation) 
	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_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);

drivers/firewire/fw-device.c

+41 −4
Original line number Diff line number Diff line
@@ -518,7 +518,7 @@ static int read_bus_info_block(struct fw_device *device, int generation) 


	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 device *dev, void *data) 
	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_struct *work) 
				  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);

	}



	/*

drivers/firewire/fw-device.h

+4 −1
Original line number Diff line number Diff line
@@ -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 fw_device *device) 


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);

drivers/firewire/fw-topology.c

+1 −0
Original line number Diff line number Diff line
@@ -526,6 +526,7 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation, 


	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

drivers/firewire/fw-transaction.h

+1 −5
Original line number Diff line number Diff line
@@ -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];

};