PPC: dbdma: Support more multi-issue DMA requests

Enterprise / Virtualization / QEMU - Alexander Graf [suse.de] - 11 July 2013 11:51 UTC

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

f35ea98 PPC: dbdma: Support more multi-issue DMA requests
hw/ide/macio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Upstream: git.qemu.org

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