[PATCH v2 1/5] ioatdma: Removing hw bug workaround for CB3.x .2 andearlier

From: Dave Jiang
Date: Wed Apr 10 2013 - 19:44:27 EST


CB3.2 and earlier hardware has silicon bugs that are no longer needed with
the new hardware. We don't have to use a NULL op to signal interrupt for
RAID ops any longer. This code make sure the legacy workarounds only happen on
legacy hardware.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
drivers/dma/ioat/dma_v3.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index cf97e3f..6393115 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -837,6 +837,7 @@ __ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
{
struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
struct ioat_chan_common *chan = &ioat->base;
+ struct ioatdma_device *device = chan->device;
struct ioat_ring_ent *compl_desc;
struct ioat_ring_ent *desc;
struct ioat_ring_ent *ext;
@@ -847,6 +848,7 @@ __ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
u32 offset = 0;
u8 op = result ? IOAT_OP_PQ_VAL : IOAT_OP_PQ;
int i, s, idx, with_ext, num_descs;
+ int cb32 = (device->version < IOAT_VER_3_3) ? 1 : 0;

dev_dbg(to_dev(chan), "%s\n", __func__);
/* the engine requires at least two sources (we provide
@@ -872,7 +874,7 @@ __ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
* order.
*/
if (likely(num_descs) &&
- ioat2_check_space_lock(ioat, num_descs+1) == 0)
+ ioat2_check_space_lock(ioat, num_descs + cb32) == 0)
idx = ioat->head;
else
return NULL;
@@ -926,16 +928,23 @@ __ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
dump_pq_desc_dbg(ioat, desc, ext);

- /* completion descriptor carries interrupt bit */
- compl_desc = ioat2_get_ring_ent(ioat, idx + i);
- compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
- hw = compl_desc->hw;
- hw->ctl = 0;
- hw->ctl_f.null = 1;
- hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
- hw->ctl_f.compl_write = 1;
- hw->size = NULL_DESC_BUFFER_SIZE;
- dump_desc_dbg(ioat, compl_desc);
+ if (!cb32) {
+ pq->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+ pq->ctl_f.compl_write = 1;
+ compl_desc = desc;
+ } else {
+ /* completion descriptor carries interrupt bit */
+ compl_desc = ioat2_get_ring_ent(ioat, idx + i);
+ compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
+ hw = compl_desc->hw;
+ hw->ctl = 0;
+ hw->ctl_f.null = 1;
+ hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+ hw->ctl_f.compl_write = 1;
+ hw->size = NULL_DESC_BUFFER_SIZE;
+ dump_desc_dbg(ioat, compl_desc);
+ }
+

/* we leave the channel locked to ensure in order submission */
return &compl_desc->txd;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/