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diff --git a/Documentation/dvb/README.flexcop b/Documentation/dvb/README.flexcop new file mode 100644 index 000000000000..a50c70f9ca72 --- /dev/null +++ b/Documentation/dvb/README.flexcop @@ -0,0 +1,205 @@ +This README escorted the skystar2-driver rewriting procedure. It describes the +state of the new flexcop-driver set and some internals are written down here +too. + +This document hopefully describes things about the flexcop and its +device-offsprings. Goal was to write an easy-to-write and easy-to-read set of +drivers based on the skystar2.c and other information. + +Remark: flexcop-pci.c was a copy of skystar2.c, but every line has been +touched and rewritten. + +History & News +============== + 2005-04-01 - correct USB ISOC transfers (thanks to Vadim Catana) + + + + +General coding processing +========================= + +We should proceed as follows (as long as no one complains): + +0) Think before start writing code! + +1) rewriting the skystar2.c with the help of the flexcop register descriptions +and splitting up the files to a pci-bus-part and a flexcop-part. +The new driver will be called b2c2-flexcop-pci.ko/b2c2-flexcop-usb.ko for the +device-specific part and b2c2-flexcop.ko for the common flexcop-functions. + +2) Search for errors in the leftover of flexcop-pci.c (compare with pluto2.c +and other pci drivers) + +3) make some beautification (see 'Improvements when rewriting (refactoring) is +done') + +4) Testing the new driver and maybe substitute the skystar2.c with it, to reach +a wider tester audience. + +5) creating an usb-bus-part using the already written flexcop code for the pci +card. + +Idea: create a kernel-object for the flexcop and export all important +functions. This option saves kernel-memory, but maybe a lot of functions have +to be exported to kernel namespace. + + +Current situation +================= + +0) Done :) +1) Done (some minor issues left) +2) Done +3) Not ready yet, more information is necessary +4) next to be done (see the table below) +5) USB driver is working (yes, there are some minor issues) + +What seems to be ready? +----------------------- + +1) Rewriting +1a) i2c is cut off from the flexcop-pci.c and seems to work +1b) moved tuner and demod stuff from flexcop-pci.c to flexcop-tuner-fe.c +1c) moved lnb and diseqc stuff from flexcop-pci.c to flexcop-tuner-fe.c +1e) eeprom (reading MAC address) +1d) sram (no dynamic sll size detection (commented out) (using default as JJ told me)) +1f) misc. register accesses for reading parameters (e.g. resetting, revision) +1g) pid/mac filter (flexcop-hw-filter.c) +1i) dvb-stuff initialization in flexcop.c (done) +1h) dma stuff (now just using the size-irq, instead of all-together, to be done) +1j) remove flexcop initialization from flexcop-pci.c completely (done) +1l) use a well working dma IRQ method (done, see 'Known bugs and problems and TODO') +1k) cleanup flexcop-files (remove unused EXPORT_SYMBOLs, make static from +non-static where possible, moved code to proper places) + +2) Search for errors in the leftover of flexcop-pci.c (partially done) +5a) add MAC address reading +5c) feeding of ISOC data to the software demux (format of the isochronous data +and speed optimization, no real error) (thanks to Vadim Catana) + +What to do in the near future? +-------------------------------------- +(no special order here) + +5) USB driver +5b) optimize isoc-transfer (submitting/killing isoc URBs when transfer is starting) + +Testing changes +--------------- + +O = item is working +P = item is partially working +X = item is not working +N = item does not apply here +<empty field> = item need to be examined + + | PCI | USB +item | mt352 | nxt2002 | stv0299 | mt312 | mt352 | nxt2002 | stv0299 | mt312 +-------+-------+---------+---------+-------+-------+---------+---------+------- +1a) | O | | | | N | N | N | N +1b) | O | | | | | | O | +1c) | N | N | | | N | N | O | +1d) | O | O +1e) | O | O +1f) | P +1g) | O +1h) | P | +1i) | O | N +1j) | O | N +1l) | O | N +2) | O | N +5a) | N | O +5b)* | N | +5c) | N | O + +* - not done yet + +Known bugs and problems and TODO +-------------------------------- + +1g/h/l) when pid filtering is enabled on the pci card + +DMA usage currently: + The DMA is splitted in 2 equal-sized subbuffers. The Flexcop writes to first + address and triggers an IRQ when it's full and starts writing to the second + address. When the second address is full, the IRQ is triggered again, and + the flexcop writes to first address again, and so on. + The buffersize of each address is currently 640*188 bytes. + + Problem is, when using hw-pid-filtering and doing some low-bandwidth + operation (like scanning) the buffers won't be filled enough to trigger + the IRQ. That's why: + + When PID filtering is activated, the timer IRQ is used. Every 1.97 ms the IRQ + is triggered. Is the current write address of DMA1 different to the one + during the last IRQ, then the data is passed to the demuxer. + + There is an additional DMA-IRQ-method: packet count IRQ. This isn't + implemented correctly yet. + + The solution is to disable HW PID filtering, but I don't know how the DVB + API software demux behaves on slow systems with 45MBit/s TS. + +Solved bugs :) +-------------- +1g) pid-filtering (somehow pid index 4 and 5 (EMM_PID and ECM_PID) aren't +working) +SOLUTION: also index 0 was affected, because net_translation is done for +these indexes by default + +5b) isochronous transfer does only work in the first attempt (for the Sky2PC +USB, Air2PC is working) SOLUTION: the flexcop was going asleep and never really +woke up again (don't know if this need fixes, see +flexcop-fe-tuner.c:flexcop_sleep) + +NEWS: when the driver is loaded and unloaded and loaded again (w/o doing +anything in the while the driver is loaded the first time), no transfers take +place anymore. + +Improvements when rewriting (refactoring) is done +================================================= + +- split sleeping of the flexcop (misc_204.ACPI3_sig = 1;) from lnb_control + (enable sleeping for other demods than dvb-s) +- add support for CableStar (stv0297 Microtune 203x/ALPS) (almost done, incompatibilities with the Nexus-CA) + +Debugging +--------- +- add verbose debugging to skystar2.c (dump the reg_dw_data) and compare it + with this flexcop, this is important, because i2c is now using the + flexcop_ibi_value union from flexcop-reg.h (do you have a better idea for + that, please tell us so). + +Everything which is identical in the following table, can be put into a common +flexcop-module. + + PCI USB +------------------------------------------------------------------------------- +Different: +Register access: accessing IO memory USB control message +I2C bus: I2C bus of the FC USB control message +Data transfer: DMA isochronous transfer +EEPROM transfer: through i2c bus not clear yet + +Identical: +Streaming: accessing registers +PID Filtering: accessing registers +Sram destinations: accessing registers +Tuner/Demod: I2C bus +DVB-stuff: can be written for common use + +Acknowledgements (just for the rewriting part) +================ + +Bjarne Steinsbo thought a lot in the first place of the pci part for this code +sharing idea. + +Andreas Oberritter for providing a recent PCI initialization template +(pluto2.c). + +Boleslaw Ciesielski for pointing out a problem with firmware loader. + +Vadim Catana for correcting the USB transfer. + +comments, critics and ideas to linux-dvb@linuxtv.org. |
