5 files changed, 85 insertions, 29 deletions

diff --git a/arch/sparc64/kernel/pci_iommu.c b/arch/sparc64/kernel/pci_iommu.c
index 33ca56c90da2..2803bc7c2c79 100644
--- a/arch/sparc64/kernel/pci_iommu.c
+++ b/arch/sparc64/kernel/pci_iommu.c
@@ -196,6 +196,34 @@ static iopte_t *alloc_consistent_cluster(struct pci_iommu *iommu, unsigned long
         return NULL;
 }
 
+static int iommu_alloc_ctx(struct pci_iommu *iommu)
+{
+        int lowest = iommu->ctx_lowest_free;
+        int sz = IOMMU_NUM_CTXS - lowest;
+        int n = find_next_zero_bit(iommu->ctx_bitmap, sz, lowest);
+
+        if (unlikely(n == sz)) {
+                n = find_next_zero_bit(iommu->ctx_bitmap, lowest, 1);
+                if (unlikely(n == lowest)) {
+                        printk(KERN_WARNING "IOMMU: Ran out of contexts.\n");
+                        n = 0;
+                }
+        }
+        if (n)
+                __set_bit(n, iommu->ctx_bitmap);
+
+        return n;
+}
+
+static inline void iommu_free_ctx(struct pci_iommu *iommu, int ctx)
+{
+        if (likely(ctx)) {
+                __clear_bit(ctx, iommu->ctx_bitmap);
+                if (ctx < iommu->ctx_lowest_free)
+                        iommu->ctx_lowest_free = ctx;
+        }
+}
+
 /* Allocate and map kernel buffer of size SIZE using consistent mode
  * DMA for PCI device PDEV.  Return non-NULL cpu-side address if
  * successful and set *DMA_ADDRP to the PCI side dma address.
@@ -236,7 +264,7 @@ void *pci_alloc_consistent(struct pci_dev *pdev, size_t size, dma_addr_t *dma_ad
         npages = size >> IO_PAGE_SHIFT;
         ctx = 0;
         if (iommu->iommu_ctxflush)
-                ctx = iommu->iommu_cur_ctx++;
+                ctx = iommu_alloc_ctx(iommu);
         first_page = __pa(first_page);
         while (npages--) {
                 iopte_val(*iopte) = (IOPTE_CONSISTENT(ctx) |
@@ -317,6 +345,8 @@ void pci_free_consistent(struct pci_dev *pdev, size_t size, void *cpu, dma_addr_
                 }
         }
 
+        iommu_free_ctx(iommu, ctx);
+
         spin_unlock_irqrestore(&iommu->lock, flags);
 
         order = get_order(size);
@@ -360,7 +390,7 @@ dma_addr_t pci_map_single(struct pci_dev *pdev, void *ptr, size_t sz, int direct
         base_paddr = __pa(oaddr & IO_PAGE_MASK);
         ctx = 0;
         if (iommu->iommu_ctxflush)
-                ctx = iommu->iommu_cur_ctx++;
+                ctx = iommu_alloc_ctx(iommu);
         if (strbuf->strbuf_enabled)
                 iopte_protection = IOPTE_STREAMING(ctx);
         else
@@ -380,39 +410,53 @@ bad:
         return PCI_DMA_ERROR_CODE;
 }
 
-static void pci_strbuf_flush(struct pci_strbuf *strbuf, struct pci_iommu *iommu, u32 vaddr, unsigned long ctx, unsigned long npages)
+static void pci_strbuf_flush(struct pci_strbuf *strbuf, struct pci_iommu *iommu, u32 vaddr, unsigned long ctx, unsigned long npages, int direction)
 {
         int limit;
 
-        PCI_STC_FLUSHFLAG_INIT(strbuf);
         if (strbuf->strbuf_ctxflush &&
             iommu->iommu_ctxflush) {
                 unsigned long matchreg, flushreg;
+                u64 val;
 
                 flushreg = strbuf->strbuf_ctxflush;
                 matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
 
-                limit = 100000;
                 pci_iommu_write(flushreg, ctx);
-                for(;;) {
-                        if (((long)pci_iommu_read(matchreg)) >= 0L)
-                                break;
-                        limit--;
-                        if (!limit)
-                                break;
-                        udelay(1);
+                val = pci_iommu_read(matchreg);
+                val &= 0xffff;
+                if (!val)
+                        goto do_flush_sync;
+
+                while (val) {
+                        if (val & 0x1)
+                                pci_iommu_write(flushreg, ctx);
+                        val >>= 1;
                 }
-                if (!limit)
+                val = pci_iommu_read(matchreg);
+                if (unlikely(val)) {
                         printk(KERN_WARNING "pci_strbuf_flush: ctx flush "
-                               "timeout vaddr[%08x] ctx[%lx]\n",
-                               vaddr, ctx);
+                               "timeout matchreg[%lx] ctx[%lx]\n",
+                               val, ctx);
+                        goto do_page_flush;
+                }
         } else {
                 unsigned long i;
 
+        do_page_flush:
                 for (i = 0; i < npages; i++, vaddr += IO_PAGE_SIZE)
                         pci_iommu_write(strbuf->strbuf_pflush, vaddr);
         }
 
+do_flush_sync:
+        /* If the device could not have possibly put dirty data into
+         * the streaming cache, no flush-flag synchronization needs
+         * to be performed.
+         */
+        if (direction == PCI_DMA_TODEVICE)
+                return;
+
+        PCI_STC_FLUSHFLAG_INIT(strbuf);
         pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
         (void) pci_iommu_read(iommu->write_complete_reg);
 
@@ -466,7 +510,7 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
 
         /* Step 1: Kick data out of streaming buffers if necessary. */
         if (strbuf->strbuf_enabled)
-                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
+                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
         /* Step 2: Clear out first TSB entry. */
         iopte_make_dummy(iommu, base);
@@ -474,6 +518,8 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
         free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base,
                                npages, ctx);
 
+        iommu_free_ctx(iommu, ctx);
+
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -613,7 +659,7 @@ int pci_map_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems, int
         /* Step 4: Choose a context if necessary. */
         ctx = 0;
         if (iommu->iommu_ctxflush)
-                ctx = iommu->iommu_cur_ctx++;
+                ctx = iommu_alloc_ctx(iommu);
 
         /* Step 5: Create the mappings. */
         if (strbuf->strbuf_enabled)
@@ -678,7 +724,7 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
 
         /* Step 1: Kick data out of streaming buffers if necessary. */
         if (strbuf->strbuf_enabled)
-                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
+                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
         /* Step 2: Clear out first TSB entry. */
         iopte_make_dummy(iommu, base);
@@ -686,6 +732,8 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
         free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base,
                                npages, ctx);
 
+        iommu_free_ctx(iommu, ctx);
+
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -724,7 +772,7 @@ void pci_dma_sync_single_for_cpu(struct pci_dev *pdev, dma_addr_t bus_addr, size
         }
 
         /* Step 2: Kick data out of streaming buffers. */
-        pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
+        pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
@@ -768,7 +816,7 @@ void pci_dma_sync_sg_for_cpu(struct pci_dev *pdev, struct scatterlist *sglist, i
         i--;
         npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length)
                   - bus_addr) >> IO_PAGE_SHIFT;
-        pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
+        pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
diff --git a/arch/sparc64/kernel/pci_psycho.c b/arch/sparc64/kernel/pci_psycho.c
index 3567fa879e1f..534320ef0db2 100644
--- a/arch/sparc64/kernel/pci_psycho.c
+++ b/arch/sparc64/kernel/pci_psycho.c
@@ -1212,7 +1212,7 @@ static void __init psycho_iommu_init(struct pci_controller_info *p)
 
         /* Setup initial software IOMMU state. */
         spin_lock_init(&iommu->lock);
-        iommu->iommu_cur_ctx = 0;
+        iommu->ctx_lowest_free = 1;
 
         /* Register addresses. */
         iommu->iommu_control  = p->pbm_A.controller_regs + PSYCHO_IOMMU_CONTROL;
diff --git a/arch/sparc64/kernel/pci_sabre.c b/arch/sparc64/kernel/pci_sabre.c
index 5525d1ec4af8..53d333b4a4e8 100644
--- a/arch/sparc64/kernel/pci_sabre.c
+++ b/arch/sparc64/kernel/pci_sabre.c
@@ -1265,7 +1265,7 @@ static void __init sabre_iommu_init(struct pci_controller_info *p,
 
         /* Setup initial software IOMMU state. */
         spin_lock_init(&iommu->lock);
-        iommu->iommu_cur_ctx = 0;
+        iommu->ctx_lowest_free = 1;
 
         /* Register addresses. */
         iommu->iommu_control  = p->pbm_A.controller_regs + SABRE_IOMMU_CONTROL;
diff --git a/arch/sparc64/kernel/pci_schizo.c b/arch/sparc64/kernel/pci_schizo.c
index e93fcadc3722..5753175b94e6 100644
--- a/arch/sparc64/kernel/pci_schizo.c
+++ b/arch/sparc64/kernel/pci_schizo.c
@@ -1753,7 +1753,7 @@ static void schizo_pbm_iommu_init(struct pci_pbm_info *pbm)
 
         /* Setup initial software IOMMU state. */
         spin_lock_init(&iommu->lock);
-        iommu->iommu_cur_ctx = 0;
+        iommu->ctx_lowest_free = 1;
 
         /* Register addresses, SCHIZO has iommu ctx flushing. */
         iommu->iommu_control  = pbm->pbm_regs + SCHIZO_IOMMU_CONTROL;
diff --git a/arch/sparc64/kernel/sbus.c b/arch/sparc64/kernel/sbus.c
index 76ea6455433f..89f5e019f24c 100644
--- a/arch/sparc64/kernel/sbus.c
+++ b/arch/sparc64/kernel/sbus.c
@@ -117,17 +117,25 @@ static void iommu_flush(struct sbus_iommu *iommu, u32 base, unsigned long npages
 
 #define STRBUF_TAG_VALID        0x02UL
 
-static void sbus_strbuf_flush(struct sbus_iommu *iommu, u32 base, unsigned long npages)
+static void sbus_strbuf_flush(struct sbus_iommu *iommu, u32 base, unsigned long npages, int direction)
 {
         unsigned long n;
         int limit;
 
-        iommu->strbuf_flushflag = 0UL;
         n = npages;
         while (n--)
                 upa_writeq(base + (n << IO_PAGE_SHIFT),
                            iommu->strbuf_regs + STRBUF_PFLUSH);
 
+        /* If the device could not have possibly put dirty data into
+         * the streaming cache, no flush-flag synchronization needs
+         * to be performed.
+         */
+        if (direction == SBUS_DMA_TODEVICE)
+                return;
+
+        iommu->strbuf_flushflag = 0UL;
+
         /* Whoopee cushion! */
         upa_writeq(__pa(&iommu->strbuf_flushflag),
                    iommu->strbuf_regs + STRBUF_FSYNC);
@@ -421,7 +429,7 @@ void sbus_unmap_single(struct sbus_dev *sdev, dma_addr_t dma_addr, size_t size,
 
         spin_lock_irqsave(&iommu->lock, flags);
         free_streaming_cluster(iommu, dma_base, size >> IO_PAGE_SHIFT);
-        sbus_strbuf_flush(iommu, dma_base, size >> IO_PAGE_SHIFT);
+        sbus_strbuf_flush(iommu, dma_base, size >> IO_PAGE_SHIFT, direction);
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -584,7 +592,7 @@ void sbus_unmap_sg(struct sbus_dev *sdev, struct scatterlist *sg, int nents, int
         iommu = sdev->bus->iommu;
         spin_lock_irqsave(&iommu->lock, flags);
         free_streaming_cluster(iommu, dvma_base, size >> IO_PAGE_SHIFT);
-        sbus_strbuf_flush(iommu, dvma_base, size >> IO_PAGE_SHIFT);
+        sbus_strbuf_flush(iommu, dvma_base, size >> IO_PAGE_SHIFT, direction);
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -596,7 +604,7 @@ void sbus_dma_sync_single_for_cpu(struct sbus_dev *sdev, dma_addr_t base, size_t
         size = (IO_PAGE_ALIGN(base + size) - (base & IO_PAGE_MASK));
 
         spin_lock_irqsave(&iommu->lock, flags);
-        sbus_strbuf_flush(iommu, base & IO_PAGE_MASK, size >> IO_PAGE_SHIFT);
+        sbus_strbuf_flush(iommu, base & IO_PAGE_MASK, size >> IO_PAGE_SHIFT, direction);
         spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -620,7 +628,7 @@ void sbus_dma_sync_sg_for_cpu(struct sbus_dev *sdev, struct scatterlist *sg, int
         size = IO_PAGE_ALIGN(sg[i].dma_address + sg[i].dma_length) - base;
 
         spin_lock_irqsave(&iommu->lock, flags);
-        sbus_strbuf_flush(iommu, base, size >> IO_PAGE_SHIFT);
+        sbus_strbuf_flush(iommu, base, size >> IO_PAGE_SHIFT, direction);
         spin_unlock_irqrestore(&iommu->lock, flags);
 }