diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2019-02-22 18:00:10 +0100 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2019-02-25 07:48:38 +0100 |
| commit | 528314b503f855b268ae7861ea4e206fbbfb8356 (patch) | |
| tree | 873bde942ff9be7959da78f4ac62cf6a1976f656 /drivers/dma/ioat | |
| parent | dmaengine: ioatdma: add descriptor pre-fetch support for v3.4 (diff) | |
| download | linux-528314b503f855b268ae7861ea4e206fbbfb8356.tar.xz linux-528314b503f855b268ae7861ea4e206fbbfb8356.zip | |
dmaengine: ioatdma: support latency tolerance report (LTR) for v3.4
IOATDMA 3.4 supports PCIe LTR mechanism. The registers are non-standard
PCIe LTR support. This needs to be setup in order to not suffer performance
impact and provide proper power management. The channel is set to active
when it is allocated, and to passive when it's freed.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/ioat')
| -rw-r--r-- | drivers/dma/ioat/init.c | 27 | ||||
| -rw-r--r-- | drivers/dma/ioat/registers.h | 14 |
2 files changed, 41 insertions, 0 deletions
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c index 020bcdecb3fb..d41dc9a9ff68 100644 --- a/drivers/dma/ioat/init.c +++ b/drivers/dma/ioat/init.c @@ -638,6 +638,11 @@ static void ioat_free_chan_resources(struct dma_chan *c) ioat_stop(ioat_chan); ioat_reset_hw(ioat_chan); + /* Put LTR to idle */ + if (ioat_dma->version >= IOAT_VER_3_4) + writeb(IOAT_CHAN_LTR_SWSEL_IDLE, + ioat_chan->reg_base + IOAT_CHAN_LTR_SWSEL_OFFSET); + spin_lock_bh(&ioat_chan->cleanup_lock); spin_lock_bh(&ioat_chan->prep_lock); descs = ioat_ring_space(ioat_chan); @@ -727,6 +732,28 @@ static int ioat_alloc_chan_resources(struct dma_chan *c) spin_unlock_bh(&ioat_chan->prep_lock); spin_unlock_bh(&ioat_chan->cleanup_lock); + /* Setting up LTR values for 3.4 or later */ + if (ioat_chan->ioat_dma->version >= IOAT_VER_3_4) { + u32 lat_val; + + lat_val = IOAT_CHAN_LTR_ACTIVE_SNVAL | + IOAT_CHAN_LTR_ACTIVE_SNLATSCALE | + IOAT_CHAN_LTR_ACTIVE_SNREQMNT; + writel(lat_val, ioat_chan->reg_base + + IOAT_CHAN_LTR_ACTIVE_OFFSET); + + lat_val = IOAT_CHAN_LTR_IDLE_SNVAL | + IOAT_CHAN_LTR_IDLE_SNLATSCALE | + IOAT_CHAN_LTR_IDLE_SNREQMNT; + writel(lat_val, ioat_chan->reg_base + + IOAT_CHAN_LTR_IDLE_OFFSET); + + /* Select to active */ + writeb(IOAT_CHAN_LTR_SWSEL_ACTIVE, + ioat_chan->reg_base + + IOAT_CHAN_LTR_SWSEL_OFFSET); + } + ioat_start_null_desc(ioat_chan); /* check that we got off the ground */ diff --git a/drivers/dma/ioat/registers.h b/drivers/dma/ioat/registers.h index 2b517d6db5fd..99c1c24d465d 100644 --- a/drivers/dma/ioat/registers.h +++ b/drivers/dma/ioat/registers.h @@ -253,4 +253,18 @@ #define IOAT_CHAN_DRS_EN 0x0100 #define IOAT_CHAN_DRS_AUTOWRAP 0x0200 +#define IOAT_CHAN_LTR_SWSEL_OFFSET 0xBC +#define IOAT_CHAN_LTR_SWSEL_ACTIVE 0x0 +#define IOAT_CHAN_LTR_SWSEL_IDLE 0x1 + +#define IOAT_CHAN_LTR_ACTIVE_OFFSET 0xC0 +#define IOAT_CHAN_LTR_ACTIVE_SNVAL 0x0000 /* 0 us */ +#define IOAT_CHAN_LTR_ACTIVE_SNLATSCALE 0x0800 /* 1us scale */ +#define IOAT_CHAN_LTR_ACTIVE_SNREQMNT 0x8000 /* snoop req enable */ + +#define IOAT_CHAN_LTR_IDLE_OFFSET 0xC4 +#define IOAT_CHAN_LTR_IDLE_SNVAL 0x0258 /* 600 us */ +#define IOAT_CHAN_LTR_IDLE_SNLATSCALE 0x0800 /* 1us scale */ +#define IOAT_CHAN_LTR_IDLE_SNREQMNT 0x8000 /* snoop req enable */ + #endif /* _IOAT_REGISTERS_H_ */ |