From 4fb9b9e8d55880523db550043dfb204696dd0422 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 8 Sep 2009 12:01:04 -0700 Subject: ioat: cleanup completion status reads The cleanup path makes an effort to only perform an atomic read of the 64-bit completion address. However in the 32-bit case it does not matter if we read the upper-32 and lower-32 non-atomically because the upper-32 will always be zero. Signed-off-by: Maciej Sosnowski Signed-off-by: Dan Williams diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c index edf4f5e..08417ad 100644 --- a/drivers/dma/ioat/dma.c +++ b/drivers/dma/ioat/dma.c @@ -201,8 +201,7 @@ static void ioat1_reset_part2(struct work_struct *work) spin_lock_bh(&chan->cleanup_lock); spin_lock_bh(&ioat->desc_lock); - chan->completion_virt->low = 0; - chan->completion_virt->high = 0; + *chan->completion = 0; ioat->pending = 0; /* count the descriptors waiting */ @@ -256,8 +255,7 @@ static void ioat1_reset_channel(struct ioat_dma_chan *ioat) dev_dbg(to_dev(chan), "%s\n", __func__); chanerr = readl(reg_base + IOAT_CHANERR_OFFSET); - chansts = (chan->completion_virt->low - & IOAT_CHANSTS_DMA_TRANSFER_STATUS); + chansts = *chan->completion & IOAT_CHANSTS_DMA_TRANSFER_STATUS; if (chanerr) { dev_err(to_dev(chan), "chan%d, CHANSTS = 0x%08x CHANERR = 0x%04x, clearing\n", @@ -293,14 +291,8 @@ static void ioat1_chan_watchdog(struct work_struct *work) struct ioat_dma_chan *ioat; struct ioat_chan_common *chan; int i; - - union { - u64 full; - struct { - u32 low; - u32 high; - }; - } completion_hw; + u64 completion; + u32 completion_low; unsigned long compl_desc_addr_hw; for (i = 0; i < device->common.chancnt; i++) { @@ -334,25 +326,24 @@ static void ioat1_chan_watchdog(struct work_struct *work) * try resetting the channel */ - completion_hw.low = readl(chan->reg_base + + /* we need to read the low address first as this + * causes the chipset to latch the upper bits + * for the subsequent read + */ + completion_low = readl(chan->reg_base + IOAT_CHANSTS_OFFSET_LOW(chan->device->version)); - completion_hw.high = readl(chan->reg_base + + completion = readl(chan->reg_base + IOAT_CHANSTS_OFFSET_HIGH(chan->device->version)); -#if (BITS_PER_LONG == 64) - compl_desc_addr_hw = - completion_hw.full - & IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR; -#else - compl_desc_addr_hw = - completion_hw.low & IOAT_LOW_COMPLETION_MASK; -#endif + completion <<= 32; + completion |= completion_low; + compl_desc_addr_hw = completion & + IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR; if ((compl_desc_addr_hw != 0) && (compl_desc_addr_hw != chan->watchdog_completion) && (compl_desc_addr_hw != chan->last_compl_desc_addr_hw)) { chan->last_compl_desc_addr_hw = compl_desc_addr_hw; - chan->completion_virt->low = completion_hw.low; - chan->completion_virt->high = completion_hw.high; + *chan->completion = completion; } else { ioat1_reset_channel(ioat); chan->watchdog_completion = 0; @@ -492,14 +483,12 @@ static int ioat1_dma_alloc_chan_resources(struct dma_chan *c) /* allocate a completion writeback area */ /* doing 2 32bit writes to mmio since 1 64b write doesn't work */ - chan->completion_virt = pci_pool_alloc(chan->device->completion_pool, - GFP_KERNEL, - &chan->completion_addr); - memset(chan->completion_virt, 0, - sizeof(*chan->completion_virt)); - writel(((u64) chan->completion_addr) & 0x00000000FFFFFFFF, + chan->completion = pci_pool_alloc(chan->device->completion_pool, + GFP_KERNEL, &chan->completion_dma); + memset(chan->completion, 0, sizeof(*chan->completion)); + writel(((u64) chan->completion_dma) & 0x00000000FFFFFFFF, chan->reg_base + IOAT_CHANCMP_OFFSET_LOW); - writel(((u64) chan->completion_addr) >> 32, + writel(((u64) chan->completion_dma) >> 32, chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH); tasklet_enable(&chan->cleanup_task); @@ -558,15 +547,16 @@ static void ioat1_dma_free_chan_resources(struct dma_chan *c) spin_unlock_bh(&ioat->desc_lock); pci_pool_free(ioatdma_device->completion_pool, - chan->completion_virt, - chan->completion_addr); + chan->completion, + chan->completion_dma); /* one is ok since we left it on there on purpose */ if (in_use_descs > 1) dev_err(to_dev(chan), "Freeing %d in use descriptors!\n", in_use_descs - 1); - chan->last_completion = chan->completion_addr = 0; + chan->last_completion = 0; + chan->completion_dma = 0; chan->watchdog_completion = 0; chan->last_compl_desc_addr_hw = 0; chan->watchdog_tcp_cookie = chan->watchdog_last_tcp_cookie = 0; @@ -709,25 +699,15 @@ void ioat_dma_unmap(struct ioat_chan_common *chan, enum dma_ctrl_flags flags, unsigned long ioat_get_current_completion(struct ioat_chan_common *chan) { unsigned long phys_complete; + u64 completion; - /* The completion writeback can happen at any time, - so reads by the driver need to be atomic operations - The descriptor physical addresses are limited to 32-bits - when the CPU can only do a 32-bit mov */ - -#if (BITS_PER_LONG == 64) - phys_complete = - chan->completion_virt->full - & IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR; -#else - phys_complete = chan->completion_virt->low & IOAT_LOW_COMPLETION_MASK; -#endif + completion = *chan->completion; + phys_complete = completion & IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR; dev_dbg(to_dev(chan), "%s: phys_complete: %#llx\n", __func__, (unsigned long long) phys_complete); - if ((chan->completion_virt->full - & IOAT_CHANSTS_DMA_TRANSFER_STATUS) == + if ((completion & IOAT_CHANSTS_DMA_TRANSFER_STATUS) == IOAT_CHANSTS_DMA_TRANSFER_STATUS_HALTED) { dev_err(to_dev(chan), "Channel halted, chanerr = %x\n", readl(chan->reg_base + IOAT_CHANERR_OFFSET)); @@ -750,7 +730,7 @@ static void ioat1_cleanup(struct ioat_dma_chan *ioat) dma_cookie_t cookie = 0; struct dma_async_tx_descriptor *tx; - prefetch(chan->completion_virt); + prefetch(chan->completion); if (!spin_trylock_bh(&chan->cleanup_lock)) return; diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h index 9f9edc2c..5fd6e2d 100644 --- a/drivers/dma/ioat/dma.h +++ b/drivers/dma/ioat/dma.h @@ -96,14 +96,8 @@ struct ioat_chan_common { struct ioatdma_device *device; struct dma_chan common; - dma_addr_t completion_addr; - union { - u64 full; /* HW completion writeback */ - struct { - u32 low; - u32 high; - }; - } *completion_virt; + dma_addr_t completion_dma; + u64 *completion; unsigned long last_compl_desc_addr_hw; struct tasklet_struct cleanup_task; }; diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c index 5888186..ca11342 100644 --- a/drivers/dma/ioat/dma_v2.c +++ b/drivers/dma/ioat/dma_v2.c @@ -200,8 +200,7 @@ static void ioat2_reset_channel(struct ioat2_dma_chan *ioat) return; chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET); - chansts = (chan->completion_virt->low - & IOAT_CHANSTS_DMA_TRANSFER_STATUS); + chansts = *chan->completion & IOAT_CHANSTS_DMA_TRANSFER_STATUS; if (chanerr) { dev_err(to_dev(chan), "chan%d, CHANSTS = 0x%08x CHANERR = 0x%04x, clearing\n", @@ -281,7 +280,7 @@ static void ioat2_cleanup(struct ioat2_dma_chan *ioat) int i; struct dma_async_tx_descriptor *tx; - prefetch(chan->completion_virt); + prefetch(chan->completion); spin_lock_bh(&chan->cleanup_lock); phys_complete = ioat_get_current_completion(chan); @@ -470,17 +469,15 @@ static int ioat2_alloc_chan_resources(struct dma_chan *c) /* allocate a completion writeback area */ /* doing 2 32bit writes to mmio since 1 64b write doesn't work */ - chan->completion_virt = pci_pool_alloc(chan->device->completion_pool, - GFP_KERNEL, - &chan->completion_addr); - if (!chan->completion_virt) + chan->completion = pci_pool_alloc(chan->device->completion_pool, + GFP_KERNEL, &chan->completion_dma); + if (!chan->completion) return -ENOMEM; - memset(chan->completion_virt, 0, - sizeof(*chan->completion_virt)); - writel(((u64) chan->completion_addr) & 0x00000000FFFFFFFF, + memset(chan->completion, 0, sizeof(*chan->completion)); + writel(((u64) chan->completion_dma) & 0x00000000FFFFFFFF, chan->reg_base + IOAT_CHANCMP_OFFSET_LOW); - writel(((u64) chan->completion_addr) >> 32, + writel(((u64) chan->completion_dma) >> 32, chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH); ioat->alloc_order = ioat_get_alloc_order(); @@ -655,12 +652,12 @@ static void ioat2_free_chan_resources(struct dma_chan *c) ioat->ring = NULL; ioat->alloc_order = 0; pci_pool_free(ioatdma_device->completion_pool, - chan->completion_virt, - chan->completion_addr); + chan->completion, + chan->completion_dma); spin_unlock_bh(&ioat->ring_lock); chan->last_completion = 0; - chan->completion_addr = 0; + chan->completion_dma = 0; ioat->pending = 0; ioat->dmacount = 0; chan->watchdog_completion = 0; diff --git a/drivers/dma/ioat/registers.h b/drivers/dma/ioat/registers.h index 49bc277..a83c733 100644 --- a/drivers/dma/ioat/registers.h +++ b/drivers/dma/ioat/registers.h @@ -94,10 +94,10 @@ #define IOAT2_CHANSTS_OFFSET_HIGH 0x0C #define IOAT_CHANSTS_OFFSET_HIGH(ver) ((ver) < IOAT_VER_2_0 \ ? IOAT1_CHANSTS_OFFSET_HIGH : IOAT2_CHANSTS_OFFSET_HIGH) -#define IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR ~0x3F -#define IOAT_CHANSTS_SOFT_ERR 0x0000000000000010 -#define IOAT_CHANSTS_UNAFFILIATED_ERR 0x0000000000000008 -#define IOAT_CHANSTS_DMA_TRANSFER_STATUS 0x0000000000000007 +#define IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR (~0x3fULL) +#define IOAT_CHANSTS_SOFT_ERR 0x10ULL +#define IOAT_CHANSTS_UNAFFILIATED_ERR 0x8ULL +#define IOAT_CHANSTS_DMA_TRANSFER_STATUS 0x7ULL #define IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE 0x0 #define IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE 0x1 #define IOAT_CHANSTS_DMA_TRANSFER_STATUS_SUSPENDED 0x2 -- cgit v0.10.2