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block: extend generic driver API (Ref #750) 

* allow to handle a maximum of packets in parallel
  that fits free slots in the ack queue
* stop processing packets, when the driver can't handle
  more requests in parallel, and resume packet handling,
  when the driver is ready again
This commit is contained in:
Stefan Kalkowski 2013-12-09 12:02:54 +01:00 committed by Norman Feske
parent b10b9e20a2
commit 56a7d00a44
13 changed files with 211 additions and 102 deletions
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4
dde_linux/src/lib/usb/storage/storage.cc
View File

@ -45,7 +45,7 @@ class Storage_device : public Genode::List<Storage_device>::Element,
if (verbose)
PDBG("ACK packet for block: %llu status: %d", packet->block_number(), cmnd->result);
session->complete_packet(*packet);
session->ack_packet(*packet);
Genode::destroy(Genode::env()->heap(), packet);
_scsi_free_command(cmnd);
}
@ -129,7 +129,7 @@ class Storage_device : public Genode::List<Storage_device>::Element,
/* send command to host driver */
if (_sdev->host->hostt->queuecommand(_sdev->host, cmnd)) {
throw Io_error();
throw Request_congestion();
}
}

2
gems/src/server/http_blk/main.cc
View File

@ -56,7 +56,7 @@ class Driver : public Block::Driver
{
_http.cmd_get(block_nr * _block_size, block_count * _block_size,
(addr_t)buffer);
session->complete_packet(packet);
session->ack_packet(packet);
}
};

211
os/include/block/component.h
View File

@ -30,21 +30,6 @@ namespace Block {
class Block::Session_component : public Block::Session_rpc_object
{
public:
void complete_packet(Packet_descriptor &packet, bool success = true)
{
packet.succeeded(success);
/* acknowledge packet to the client */
if (!tx_sink()->ready_to_ack()) {
PWRN("need to wait until ready-for-ack");
return;
}
tx_sink()->acknowledge_packet(packet);
}
private:
Driver_factory &_driver_factory;
@ -53,80 +38,127 @@ class Block::Session_component : public Block::Session_rpc_object
addr_t _rq_phys;
Signal_dispatcher<Session_component> _sink_ack;
Signal_dispatcher<Session_component> _sink_submit;
bool _req_queue_full;
Packet_descriptor _p_to_handle;
unsigned _p_in_fly;
void _ready_to_submit(unsigned)
/**
* Acknowledge a packet already handled
*/
inline void _ack_packet(Packet_descriptor &packet)
{
/* handle requests */
while (tx_sink()->packet_avail()) {
if (!tx_sink()->ready_to_ack())
PERR("Not ready to ack!");
/* blocking-get packet from client */
Packet_descriptor packet = tx_sink()->get_packet();
if (!packet.valid()) {
PWRN("received invalid packet");
continue;
}
packet.succeeded(true);
try {
switch (packet.operation()) {
case Block::Packet_descriptor::READ:
if (_driver.dma_enabled())
_driver.read_dma(packet.block_number(),
packet.block_count(),
_rq_phys + packet.offset(),
packet);
else
_driver.read(packet.block_number(),
packet.block_count(),
tx_sink()->packet_content(packet),
packet);
break;
case Block::Packet_descriptor::WRITE:
if (_driver.dma_enabled())
_driver.write_dma(packet.block_number(),
packet.block_count(),
_rq_phys + packet.offset(),
packet);
else
_driver.write(packet.block_number(),
packet.block_count(),
tx_sink()->packet_content(packet),
packet);
break;
default:
throw Driver::Io_error();
}
} catch (Driver::Io_error) {
complete_packet(packet, false);
tx_sink()->acknowledge_packet(packet);
_p_in_fly--;
}
/**
* Range check packet request
*/
inline bool _range_check(Packet_descriptor &p) {
return p.block_number() + p.block_count() - 1
< _driver.block_count(); }
/**
* Handle a single request
*/
void _handle_packet(Packet_descriptor packet)
{
_p_to_handle = packet;
_p_to_handle.succeeded(false);
/* ignore invalid packets */
if (!packet.valid() || !_range_check(_p_to_handle)) {
_ack_packet(_p_to_handle);
return;
}
try {
switch (_p_to_handle.operation()) {
case Block::Packet_descriptor::READ:
if (_driver.dma_enabled())
_driver.read_dma(packet.block_number(),
packet.block_count(),
_rq_phys + packet.offset(),
_p_to_handle);
else
_driver.read(packet.block_number(),
packet.block_count(),
tx_sink()->packet_content(packet),
_p_to_handle);
break;
case Block::Packet_descriptor::WRITE:
if (_driver.dma_enabled())
_driver.write_dma(packet.block_number(),
packet.block_count(),
_rq_phys + packet.offset(),
_p_to_handle);
else
_driver.write(packet.block_number(),
packet.block_count(),
tx_sink()->packet_content(packet),
_p_to_handle);
break;
default:
throw Driver::Io_error();
}
} catch (Driver::Request_congestion) {
_req_queue_full = true;
} catch (Driver::Io_error) {
_ack_packet(_p_to_handle);
}
}
void _ack_avail(unsigned) { }
/**
* Triggered when a packet was placed into the empty submit queue
*/
void _packet_avail(unsigned)
{
/*
* as long as more packets are available, and we're able to ack
* them, and the driver's request queue isn't full,
* direct the packet request to the driver backend
*/
for (; !_req_queue_full && tx_sink()->packet_avail() &&
!(_p_in_fly >= tx_sink()->ack_slots_free()); _p_in_fly++)
_handle_packet(tx_sink()->get_packet());
}
/**
* Triggered when an ack got removed from the full ack queue
*/
void _ready_to_ack(unsigned) { _packet_avail(0); }
public:
/**
* Constructor
*
* \param rq_ds shared dataspace for packet stream
* \param driver block driver backend
* \param driver_factory factory to create and destroy driver objects
* \param ep entrypoint handling this session component
* \param receiver signal receiver managing signals of the client
*/
Session_component(Ram_dataspace_capability rq_ds,
Driver &driver,
Driver_factory &driver_factory,
Rpc_entrypoint &ep,
Signal_receiver &receiver)
:
Session_rpc_object(rq_ds, ep),
_driver_factory(driver_factory),
_driver(driver),
_rq_ds(rq_ds),
_rq_phys(Dataspace_client(_rq_ds).phys_addr()),
_sink_ack(receiver, *this, &Session_component::_ack_avail),
_sink_submit(receiver, *this,
&Session_component::_ready_to_submit)
: Session_rpc_object(rq_ds, ep),
_driver_factory(driver_factory),
_driver(driver),
_rq_ds(rq_ds),
_rq_phys(Dataspace_client(_rq_ds).phys_addr()),
_sink_ack(receiver, *this, &Session_component::_ready_to_ack),
_sink_submit(receiver, *this, &Session_component::_packet_avail),
_req_queue_full(false),
_p_in_fly(0)
{
_tx.sigh_ready_to_ack(_sink_ack);
_tx.sigh_packet_avail(_sink_submit);
@ -135,11 +167,34 @@ class Block::Session_component : public Block::Session_rpc_object
}
/**
* Destructor
* Acknowledges a packet processed by the driver to the client
*
* \param packet the packet to acknowledge
* \param success indicated whether the processing was successful
*
* \throw Ack_congestion
*/
~Session_component()
void ack_packet(Packet_descriptor &packet, bool success = true)
{
_driver_factory.destroy(&_driver);
bool ack_queue_full = _p_in_fly >= tx_sink()->ack_slots_free();
packet.succeeded(success);
_ack_packet(packet);
if (!_req_queue_full && !ack_queue_full)
return;
/*
* when the driver's request queue was full,
* handle last unprocessed packet taken out of submit queue
*/
if (_req_queue_full) {
_req_queue_full = false;
_handle_packet(_p_to_handle);
}
/* resume packet processing */
_packet_avail(0);
}
/**
@ -217,6 +272,14 @@ class Block::Root :
public:
/**
* Constructor
*
* \param session_ep entrypoint handling this root component
* \param md_alloc allocator to allocate session components
* \param driver_factory factory to create and destroy driver backend
* \param receiver signal receiver managing signals of the client
*/
Root(Rpc_entrypoint *session_ep, Allocator *md_alloc,
Driver_factory &driver_factory, Signal_receiver &receiver)
:

35
os/include/block/driver.h
View File

@ -35,17 +35,19 @@ namespace Block {
*/
struct Block::Driver
{
Session_component *session;
Session_component * session; /* single session component of the driver
* might get used to acknowledge requests */
/**
* Exceptions
*/
class Io_error : public ::Genode::Exception { };
class Io_error : public ::Genode::Exception { };
class Request_congestion : public ::Genode::Exception { };
/**
* Request block size for driver and medium
*/
virtual Genode::size_t block_size() = 0;
virtual Genode::size_t block_size() = 0;
/**
* Request capacity of medium in blocks
@ -63,6 +65,11 @@ struct Block::Driver
* \param block_number number of first block to read
* \param block_count number of blocks to read
* \param buffer output buffer for read request
* \param packet packet descriptor from the client
*
* \throw Request_congestion
*
* Note: should be overridden by DMA non-capable devices
*/
virtual void read(sector_t block_number,
Genode::size_t block_count,
@ -76,6 +83,11 @@ struct Block::Driver
* \param block_number number of first block to write
* \param block_count number of blocks to write
* \param buffer buffer for write request
* \param packet packet descriptor from the client
*
* \throw Request_congestion
*
* Note: should be overridden by DMA non-capable, non-ROM devices
*/
virtual void write(sector_t block_number,
Genode::size_t block_count,
@ -89,6 +101,11 @@ struct Block::Driver
* \param block_number number of first block to read
* \param block_count number of blocks to read
* \param phys phyiscal address of read buffer
* \param packet packet descriptor from the client
*
* \throw Request_congestion
*
* Note: should be overridden by DMA capable devices
*/
virtual void read_dma(sector_t block_number,
Genode::size_t block_count,
@ -102,6 +119,11 @@ struct Block::Driver
* \param block_number number of first block to write
* \param block_count number of blocks to write
* \param phys physical address of write buffer
* \param packet packet descriptor from the client
*
* \throw Request_congestion
*
* Note: should be overridden by DMA capable, non-ROM devices
*/
virtual void write_dma(sector_t block_number,
Genode::size_t block_count,
@ -113,6 +135,8 @@ struct Block::Driver
* Check if DMA is enabled for driver
*
* \return true if DMA is enabled, false otherwise
*
* Note: has to be overriden by DMA-capable devices
*/
virtual bool dma_enabled() { return false; }
@ -124,7 +148,10 @@ struct Block::Driver
return Genode::env()->ram_session()->alloc(size, false); }
/**
* Synchronize with with device.
* Synchronize with device.
*
* Note: should be overriden by (e.g. intermediate) components,
* which cache data
*/
virtual void sync() {}
};

23
os/include/os/packet_stream.h
View File

@ -131,8 +131,8 @@ class Packet_descriptor_queue
{
private:
int _head;
int _tail;
unsigned _head;
unsigned _tail;
PACKET_DESCRIPTOR _queue[QUEUE_SIZE];
public:
@ -200,10 +200,18 @@ class Packet_descriptor_queue
*/
bool single_element() { return (_tail + 1)%QUEUE_SIZE == _head; }
/**
* Return true if a single slot is left to be put into the queue
*/
bool single_slot_free() { return (_head + 2)%QUEUE_SIZE == _tail; }
/**
* Return number of slots left to be put into the queue
*/
unsigned slots_free() {
return ((_tail > _head) ? _tail - _head
: QUEUE_SIZE - _head + _tail) - 1; }
};
@ -280,6 +288,11 @@ class Packet_descriptor_transmitter
if (_tx_queue->single_element())
_rx_ready.submit();
}
/**
* Return number of slots left to be put into the tx queue
*/
unsigned tx_slots_free() { return _tx_queue->slots_free(); }
};
@ -775,6 +788,12 @@ class Packet_stream_sink : private Packet_stream_base
*/
bool ready_to_ack() { return _ack_transmitter.ready_for_tx(); }
/**
* Returns number of slots left in the the ack queue
*/
unsigned ack_slots_free() {
return _ack_transmitter.tx_slots_free(); }
/**
* Tell the source that the processing of the specified packet is completed
*

4
os/src/drivers/ahci/exynos5/ahci_driver.h
View File

@ -61,7 +61,7 @@ class Ahci_driver : public Block::Driver
{
if (_ncq_command(block_nr, block_cnt, phys, 0))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
void write_dma(Block::sector_t block_nr, size_t block_cnt, addr_t phys,
@ -69,7 +69,7 @@ class Ahci_driver : public Block::Driver
{
if (_ncq_command(block_nr, block_cnt, phys, 1))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
};

4
os/src/drivers/ahci/include/ahci_driver_base.h
View File

@ -66,7 +66,7 @@ class Ahci_driver_base : public Block::Driver
{
_sanity_check(block_number, block_count);
_device->read(block_number, block_count, phys);
if (session) session->complete_packet(packet);
if (session) session->ack_packet(packet);
}
void write_dma(Block::sector_t block_number,
@ -76,7 +76,7 @@ class Ahci_driver_base : public Block::Driver
{
_sanity_check(block_number, block_count);
_device->write(block_number, block_count, phys);
if (session) session->complete_packet(packet);
if (session) session->ack_packet(packet);
}
Ram_dataspace_capability alloc_dma_buffer(size_t size) {

8
os/src/drivers/atapi/ata_device.h
View File

@ -124,7 +124,7 @@ namespace Ata {
Block::Packet_descriptor &packet)
{
_read(block_number, block_count, buffer, false);
session->complete_packet(packet);
session->ack_packet(packet);
}
void write(Block::sector_t block_number,
@ -133,7 +133,7 @@ namespace Ata {
Block::Packet_descriptor &packet)
{
_write(block_number, block_count, buffer, false);
session->complete_packet(packet);
session->ack_packet(packet);
}
void read_dma(Block::sector_t block_number,
@ -142,7 +142,7 @@ namespace Ata {
Block::Packet_descriptor &packet)
{
_read(block_number, block_count, (char*)phys, true);
session->complete_packet(packet);
session->ack_packet(packet);
}
void write_dma(Block::sector_t block_number,
@ -151,7 +151,7 @@ namespace Ata {
Block::Packet_descriptor &packet)
{
_write(block_number, block_count, (char*)phys, true);
session->complete_packet(packet);
session->ack_packet(packet);
}
bool dma_enabled() { return _dma; }

4
os/src/drivers/sd_card/exynos5/driver.h
View File

@ -104,7 +104,7 @@ class Block::Exynos5_driver : public Block::Driver
{
if (!_controller.read_blocks_dma(block_number, block_count, phys))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
void write_dma(Block::sector_t block_number,
@ -114,7 +114,7 @@ class Block::Exynos5_driver : public Block::Driver
{
if (!_controller.write_blocks_dma(block_number, block_count, phys))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
bool dma_enabled() { return _use_dma; }

8
os/src/drivers/sd_card/omap4/driver.h
View File

@ -97,7 +97,7 @@ class Block::Omap4_driver : public Block::Driver
{
if (!_controller.read_blocks(block_number, block_count, out_buffer))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
void write(Block::sector_t block_number,
@ -107,7 +107,7 @@ class Block::Omap4_driver : public Block::Driver
{
if (!_controller.write_blocks(block_number, block_count, buffer))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
void read_dma(Block::sector_t block_number,
@ -117,7 +117,7 @@ class Block::Omap4_driver : public Block::Driver
{
if (!_controller.read_blocks_dma(block_number, block_count, phys))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
void write_dma(Block::sector_t block_number,
@ -127,7 +127,7 @@ class Block::Omap4_driver : public Block::Driver
{
if (!_controller.write_blocks_dma(block_number, block_count, phys))
throw Io_error();
session->complete_packet(packet);
session->ack_packet(packet);
}
bool dma_enabled() { return _use_dma; }

4
os/src/drivers/sd_card/pl180/sd_card.h
View File

@ -107,7 +107,7 @@ class Sd_card : public Block::Driver
length, &resp);
_hd.read_data(length, out_buffer + (i * BLOCK_SIZE));
}
session->complete_packet(packet);
session->ack_packet(packet);
}
void write(Block::sector_t block_number,
@ -129,7 +129,7 @@ class Sd_card : public Block::Driver
length, &resp);
_hd.write_data(length, buffer + (i * BLOCK_SIZE));
}
session->complete_packet(packet);
session->ack_packet(packet);
}
};

2
os/src/server/rom_blk/main.cc
View File

@ -76,7 +76,7 @@ class Rom_blk : public Block::Driver
/* copy file content to packet payload */
memcpy((void*)buffer, (void*)(_file_addr + offset), size);
session->complete_packet(packet);
session->ack_packet(packet);
}
};

4
os/src/test/fb_block_adapter/main.cc
View File

@ -74,7 +74,7 @@ class Driver : public Block::Driver
Genode::size_t size = block_count * BLOCK_SIZE;
Genode::memcpy((void*)buffer, (void*)(_fb_addr + offset), size);
session->complete_packet(packet);
session->ack_packet(packet);
}
void write(Block::sector_t block_number,
@ -94,7 +94,7 @@ class Driver : public Block::Driver
Genode::memcpy((void*)(_fb_addr + offset), (void*)buffer, size);
_fb.refresh(0, 0, _fb_mode.width(), _fb_mode.height());
session->complete_packet(packet);
session->ack_packet(packet);
}
};