From: Dave Jiang dave.jiang@intel.com
mainline inclusion from mainline-v5.1-rc1 commit 528314b503f855b268ae7861ea4e206fbbfb8356 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V CVE: NA
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commit 528314b503f855b268ae7861ea4e206fbbfb8356 upstream.
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 Signed-off-by: Lin Wang lin.x.wang@intel.com Signed-off-by: Jackie Liu liuyun01@kylinos.cn Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/dma/ioat/init.c | 27 +++++++++++++++++++++++++++ drivers/dma/ioat/registers.h | 14 ++++++++++++++ 2 files changed, 41 insertions(+)
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c index aaa904c08802..5d0ee7a30275 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_ */