diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2019-02-22 10:00:05 -0700 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2019-02-25 12:18:38 +0530 |
| commit | e0100d40906d5dbe6d09d31083c1a5aaccc947fa (patch) | |
| tree | 5589211aa08cbc8d9c8987e3a8c5b1190c19fd32 | |
| parent | 11e31e281bd8f482a9277268f7b0d9c213584271 (diff) | |
dmaengine: ioatdma: add descriptor pre-fetch support for v3.4
Adding support for new feature on ioatdma 3.4 hardware that provides
descriptor pre-fetching in order to reduce small DMA latencies.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
| -rw-r--r-- | drivers/dma/ioat/dma.c | 12 | ||||
| -rw-r--r-- | drivers/dma/ioat/init.c | 8 | ||||
| -rw-r--r-- | drivers/dma/ioat/registers.h | 10 |
3 files changed, 28 insertions, 2 deletions
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c index 23fb2fa04000..f373a139e0c3 100644 --- a/drivers/dma/ioat/dma.c +++ b/drivers/dma/ioat/dma.c @@ -372,6 +372,7 @@ struct ioat_ring_ent ** ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags) { struct ioatdma_chan *ioat_chan = to_ioat_chan(c); + struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma; struct ioat_ring_ent **ring; int total_descs = 1 << order; int i, chunks; @@ -437,6 +438,17 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags) } ring[i]->hw->next = ring[0]->txd.phys; + /* setup descriptor pre-fetching for v3.4 */ + if (ioat_dma->cap & IOAT_CAP_DPS) { + u16 drsctl = IOAT_CHAN_DRSZ_2MB | IOAT_CHAN_DRS_EN; + + if (chunks == 1) + drsctl |= IOAT_CHAN_DRS_AUTOWRAP; + + writew(drsctl, ioat_chan->reg_base + IOAT_CHAN_DRSCTL_OFFSET); + + } + return ring; } diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c index 58dd1bfd3edd..020bcdecb3fb 100644 --- a/drivers/dma/ioat/init.c +++ b/drivers/dma/ioat/init.c @@ -138,10 +138,10 @@ static int ioat3_dma_self_test(struct ioatdma_device *ioat_dma); static int ioat_dca_enabled = 1; module_param(ioat_dca_enabled, int, 0644); MODULE_PARM_DESC(ioat_dca_enabled, "control support of dca service (default: 1)"); -int ioat_pending_level = 4; +int ioat_pending_level = 7; module_param(ioat_pending_level, int, 0644); MODULE_PARM_DESC(ioat_pending_level, - "high-water mark for pushing ioat descriptors (default: 4)"); + "high-water mark for pushing ioat descriptors (default: 7)"); static char ioat_interrupt_style[32] = "msix"; module_param_string(ioat_interrupt_style, ioat_interrupt_style, sizeof(ioat_interrupt_style), 0644); @@ -1188,6 +1188,10 @@ static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca) if (err) return err; + if (ioat_dma->cap & IOAT_CAP_DPS) + writeb(ioat_pending_level + 1, + ioat_dma->reg_base + IOAT_PREFETCH_LIMIT_OFFSET); + return 0; } diff --git a/drivers/dma/ioat/registers.h b/drivers/dma/ioat/registers.h index 2f3bbc88ff2a..2b517d6db5fd 100644 --- a/drivers/dma/ioat/registers.h +++ b/drivers/dma/ioat/registers.h @@ -84,6 +84,9 @@ #define IOAT_CAP_PQ 0x00000200 #define IOAT_CAP_DWBES 0x00002000 #define IOAT_CAP_RAID16SS 0x00020000 +#define IOAT_CAP_DPS 0x00800000 + +#define IOAT_PREFETCH_LIMIT_OFFSET 0x4C /* CHWPREFLMT */ #define IOAT_CHANNEL_MMIO_SIZE 0x80 /* Each Channel MMIO space is this size */ @@ -243,4 +246,11 @@ #define IOAT_CHANERR_MASK_OFFSET 0x2C /* 32-bit Channel Error Register */ +#define IOAT_CHAN_DRSCTL_OFFSET 0xB6 +#define IOAT_CHAN_DRSZ_4KB 0x0000 +#define IOAT_CHAN_DRSZ_8KB 0x0001 +#define IOAT_CHAN_DRSZ_2MB 0x0009 +#define IOAT_CHAN_DRS_EN 0x0100 +#define IOAT_CHAN_DRS_AUTOWRAP 0x0200 + #endif /* _IOAT_REGISTERS_H_ */ |