On 09/28/2011 09:47 PM, Dan Williams wrote:
Based on original implementation from Jiangbi Liu and Maciej Trela. ATAPI transfers happen in two-to-three stages. The two stage atapi commands are those that include a dma data transfer. The data transfer portion of these operations is handled by the hardware packet-dma acceleration. The three-stage commands do not have a data transfer and are handled without hardware assistance in raw frame mode. stage1: transmit host-to-device fis to notify the device of an incoming atapi cdb. Upon reception of the pio-setup-fis repost the task_context to perform the dma transfer of the cdb+data (go to stage3), or repost the task_context to transmit the cdb as a raw frame (go to stage 2). stage2: wait for hardware notification of the cdb transmission and then go to stage 3. stage3: wait for the arrival of the terminating device-to-host fis and terminate the command. To keep the implementation simple we only support ATAPI packet-dma protocol (for commands with data) to avoid needing to handle the data transfer manually (like we do for SATA-PIO). This may affect compatibility for a small number of devices (see ATA_HORKAGE_ATAPI_MOD16_DMA). If the data-transfer underruns, or encounters an error the device-to-host fis is expected to arrive in the unsolicited frame queue to pass to libata for disposition. However, in the DONE_UNEXP_FIS (data underrun) case it appears we need to craft a response. In the DONE_REG_ERR case we do receive the UF and propagate it to libsas. Signed-off-by: Maciej Trela<maciej.trela@xxxxxxxxx> Signed-off-by: Dan Williams<dan.j.williams@xxxxxxxxx> --- drivers/scsi/isci/remote_device.c | 24 +++ drivers/scsi/isci/remote_device.h | 9 + drivers/scsi/isci/request.c | 327 ++++++++++++++++++++++++++++++++++- drivers/scsi/isci/request.h | 28 +++ drivers/scsi/libsas/sas_scsi_host.c | 2 include/scsi/libsas.h | 5 + 6 files changed, 379 insertions(+), 16 deletions(-)
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