libata: Add a drivers/ide style DMA disable

This is useful when debugging, handling problem systems, or for
distributions just to get the system installed so it can be sorted
out later.

This is a bit smarter than the old IDE one and lets you do

libata.dma=0	Disable all PATA DMA like old IDE
libata.dma=1	Disk DMA only
libata.dma=2	ATAPI DMA only
libata.dma=4	CF DMA only

(or combinations thereof - 0,1,3 being the useful ones I suspect)

(I've split CF as it seems to be a seperate case of pain and suffering
different to the others and caused by assorted PIO wired adapters etc)

Signed-off-by: Alan Cox <alan@redhat.com>

[edited to work on SATA too, changing name from 'pata_dma' to 'dma']
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index ca296a575c4a..84dfc23b9d31 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -331,6 +331,12 @@ enum {
         ATA_HORKAGE_BROKEN_HPA  = (1 << 4),     /* Broken HPA */
         ATA_HORKAGE_SKIP_PM     = (1 << 5),     /* Skip PM operations */
         ATA_HORKAGE_HPA_SIZE    = (1 << 6),     /* native size off by one */
+
+         /* DMA mask for user DMA control: User visible values; DO NOT 
+            renumber */
+        ATA_DMA_MASK_ATA        = (1 << 0),     /* DMA on ATA Disk */
+        ATA_DMA_MASK_ATAPI      = (1 << 1),     /* DMA on ATAPI */
+        ATA_DMA_MASK_CFA        = (1 << 2),     /* DMA on CF Card */
 };
 
 enum hsm_task_states {