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authorAlexander Graf <agraf@suse.de>2013-06-30 15:29:13 +0200
committerAlexander Graf <agraf@suse.de>2013-07-11 18:51:25 +0200
commitf35ea98cd9f75db9286f05bf3dc4b532f4cb5eaa (patch)
tree594b8455808884e8f28eee95570b9b0de0c54eb8 /hw/intc
parenta0f9fdfd98cc0571f9921a7eadd7316532e3e289 (diff)
downloadfocaccia-qemu-f35ea98cd9f75db9286f05bf3dc4b532f4cb5eaa.tar.gz
focaccia-qemu-f35ea98cd9f75db9286f05bf3dc4b532f4cb5eaa.zip
PPC: dbdma: Support more multi-issue DMA requests
A DMA request can happen for data that hasn't been completely been
provided by the IDE core yet. For example

  - DBDMA request for 0x1000 bytes
  - IDE request for 1 sector
  - DBDMA wants to read 0x1000 bytes (8 sectors) from bdrv
  - breakage

Instead, we should truncate our bdrv request to the maximum number
of sectors we're allowed to read at that given time. Once that transfer
is through, we will fall into our recently introduced waiting logic.

  - DBDMA requests for 0x1000 bytes
  - IDE request for 1 sector
  - DBDMA wants to read MIN(0x1000, 1 * 512) bytes
  - DBDMA finishes reading, indicates to IDE core that transfer is complete
  - IDE request for 7 sectors
  - DBDMA finishes the DMA

Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'hw/intc')
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