[SPARC64]: Add timeouts to streaming buffer synchronization.
David S. Miller [Wed, 11 May 2005 18:37:00 +0000 (11:37 -0700)]
If some hardware error occurs and the flush flag never updates,
we will hang forever in these routines.  Add a timeout, and
print out a diagnostic if it is reached.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/pci_iommu.c
arch/sparc64/kernel/sbus.c

index 2929834..f009b1b 100644 (file)
@@ -8,6 +8,7 @@
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
+#include <linux/delay.h>
 
 #include <asm/pbm.h>
 
@@ -379,6 +380,54 @@ 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)
+{
+       int limit;
+
+       PCI_STC_FLUSHFLAG_INIT(strbuf);
+       if (strbuf->strbuf_ctxflush &&
+           iommu->iommu_ctxflush) {
+               unsigned long matchreg, flushreg;
+
+               flushreg = strbuf->strbuf_ctxflush;
+               matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
+
+               limit = 10000;
+               do {
+                       pci_iommu_write(flushreg, ctx);
+                       udelay(10);
+                       limit--;
+                       if (!limit)
+                               break;
+               } while(((long)pci_iommu_read(matchreg)) < 0L);
+               if (!limit)
+                       printk(KERN_WARNING "pci_strbuf_flush: ctx flush "
+                              "timeout vaddr[%08x] ctx[%lx]\n",
+                              vaddr, ctx);
+       } else {
+               unsigned long i;
+
+               for (i = 0; i < npages; i++, vaddr += IO_PAGE_SIZE)
+                       pci_iommu_write(strbuf->strbuf_pflush, vaddr);
+       }
+
+       pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
+       (void) pci_iommu_read(iommu->write_complete_reg);
+
+       limit = 10000;
+       while (!PCI_STC_FLUSHFLAG_SET(strbuf)) {
+               limit--;
+               if (!limit)
+                       break;
+               udelay(10);
+               membar("#LoadLoad");
+       }
+       if (!limit)
+               printk(KERN_WARNING "pci_strbuf_flush: flushflag timeout "
+                      "vaddr[%08x] ctx[%lx] npages[%ld]\n",
+                      vaddr, ctx, npages);
+}
+
 /* Unmap a single streaming mode DMA translation. */
 void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int direction)
 {
@@ -386,7 +435,7 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
        struct pci_iommu *iommu;
        struct pci_strbuf *strbuf;
        iopte_t *base;
-       unsigned long flags, npages, i, ctx;
+       unsigned long flags, npages, ctx;
 
        if (direction == PCI_DMA_NONE)
                BUG();
@@ -414,29 +463,8 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
                ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
 
        /* Step 1: Kick data out of streaming buffers if necessary. */
-       if (strbuf->strbuf_enabled) {
-               u32 vaddr = bus_addr;
-
-               PCI_STC_FLUSHFLAG_INIT(strbuf);
-               if (strbuf->strbuf_ctxflush &&
-                   iommu->iommu_ctxflush) {
-                       unsigned long matchreg, flushreg;
-
-                       flushreg = strbuf->strbuf_ctxflush;
-                       matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
-                       do {
-                               pci_iommu_write(flushreg, ctx);
-                       } while(((long)pci_iommu_read(matchreg)) < 0L);
-               } else {
-                       for (i = 0; i < npages; i++, vaddr += IO_PAGE_SIZE)
-                               pci_iommu_write(strbuf->strbuf_pflush, vaddr);
-               }
-
-               pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
-               (void) pci_iommu_read(iommu->write_complete_reg);
-               while (!PCI_STC_FLUSHFLAG_SET(strbuf))
-                       membar("#LoadLoad");
-       }
+       if (strbuf->strbuf_enabled)
+               pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
 
        /* Step 2: Clear out first TSB entry. */
        iopte_make_dummy(iommu, base);
@@ -647,29 +675,8 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
                ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
 
        /* Step 1: Kick data out of streaming buffers if necessary. */
-       if (strbuf->strbuf_enabled) {
-               u32 vaddr = (u32) bus_addr;
-
-               PCI_STC_FLUSHFLAG_INIT(strbuf);
-               if (strbuf->strbuf_ctxflush &&
-                   iommu->iommu_ctxflush) {
-                       unsigned long matchreg, flushreg;
-
-                       flushreg = strbuf->strbuf_ctxflush;
-                       matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
-                       do {
-                               pci_iommu_write(flushreg, ctx);
-                       } while(((long)pci_iommu_read(matchreg)) < 0L);
-               } else {
-                       for (i = 0; i < npages; i++, vaddr += IO_PAGE_SIZE)
-                               pci_iommu_write(strbuf->strbuf_pflush, vaddr);
-               }
-
-               pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
-               (void) pci_iommu_read(iommu->write_complete_reg);
-               while (!PCI_STC_FLUSHFLAG_SET(strbuf))
-                       membar("#LoadLoad");
-       }
+       if (strbuf->strbuf_enabled)
+               pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
 
        /* Step 2: Clear out first TSB entry. */
        iopte_make_dummy(iommu, base);
@@ -715,28 +722,7 @@ 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_STC_FLUSHFLAG_INIT(strbuf);
-       if (iommu->iommu_ctxflush &&
-           strbuf->strbuf_ctxflush) {
-               unsigned long matchreg, flushreg;
-
-               flushreg = strbuf->strbuf_ctxflush;
-               matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
-               do {
-                       pci_iommu_write(flushreg, ctx);
-               } while(((long)pci_iommu_read(matchreg)) < 0L);
-       } else {
-               unsigned long i;
-
-               for (i = 0; i < npages; i++, bus_addr += IO_PAGE_SIZE)
-                       pci_iommu_write(strbuf->strbuf_pflush, bus_addr);
-       }
-
-       /* Step 3: Perform flush synchronization sequence. */
-       pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
-       (void) pci_iommu_read(iommu->write_complete_reg);
-       while (!PCI_STC_FLUSHFLAG_SET(strbuf))
-               membar("#LoadLoad");
+       pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages);
 
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
@@ -749,7 +735,8 @@ void pci_dma_sync_sg_for_cpu(struct pci_dev *pdev, struct scatterlist *sglist, i
        struct pcidev_cookie *pcp;
        struct pci_iommu *iommu;
        struct pci_strbuf *strbuf;
-       unsigned long flags, ctx;
+       unsigned long flags, ctx, npages, i;
+       u32 bus_addr;
 
        pcp = pdev->sysdata;
        iommu = pcp->pbm->iommu;
@@ -772,36 +759,14 @@ void pci_dma_sync_sg_for_cpu(struct pci_dev *pdev, struct scatterlist *sglist, i
        }
 
        /* Step 2: Kick data out of streaming buffers. */
-       PCI_STC_FLUSHFLAG_INIT(strbuf);
-       if (iommu->iommu_ctxflush &&
-           strbuf->strbuf_ctxflush) {
-               unsigned long matchreg, flushreg;
-
-               flushreg = strbuf->strbuf_ctxflush;
-               matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
-               do {
-                       pci_iommu_write(flushreg, ctx);
-               } while (((long)pci_iommu_read(matchreg)) < 0L);
-       } else {
-               unsigned long i, npages;
-               u32 bus_addr;
-
-               bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
-
-               for(i = 1; i < nelems; i++)
-                       if (!sglist[i].dma_length)
-                               break;
-               i--;
-               npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) - bus_addr) >> IO_PAGE_SHIFT;
-               for (i = 0; i < npages; i++, bus_addr += IO_PAGE_SIZE)
-                       pci_iommu_write(strbuf->strbuf_pflush, bus_addr);
-       }
-
-       /* Step 3: Perform flush synchronization sequence. */
-       pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
-       (void) pci_iommu_read(iommu->write_complete_reg);
-       while (!PCI_STC_FLUSHFLAG_SET(strbuf))
-               membar("#LoadLoad");
+       bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
+       for(i = 1; i < nelems; i++)
+               if (!sglist[i].dma_length)
+                       break;
+       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);
 
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
index 14d9c3a..d3eca98 100644 (file)
@@ -117,19 +117,34 @@ static void iommu_flush(struct sbus_iommu *iommu, u32 base, unsigned long npages
 
 #define STRBUF_TAG_VALID       0x02UL
 
-static void 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)
 {
+       unsigned long n;
+       int limit;
+
        iommu->strbuf_flushflag = 0UL;
-       while (npages--)
-               upa_writeq(base + (npages << IO_PAGE_SHIFT),
+       n = npages;
+       while (n--)
+               upa_writeq(base + (n << IO_PAGE_SHIFT),
                           iommu->strbuf_regs + STRBUF_PFLUSH);
 
        /* Whoopee cushion! */
        upa_writeq(__pa(&iommu->strbuf_flushflag),
                   iommu->strbuf_regs + STRBUF_FSYNC);
        upa_readq(iommu->sbus_control_reg);
-       while (iommu->strbuf_flushflag == 0UL)
+
+       limit = 10000;
+       while (iommu->strbuf_flushflag == 0UL) {
+               limit--;
+               if (!limit)
+                       break;
+               udelay(10);
                membar("#LoadLoad");
+       }
+       if (!limit)
+               printk(KERN_WARNING "sbus_strbuf_flush: flushflag timeout "
+                      "vaddr[%08x] npages[%ld]\n",
+                      base, npages);
 }
 
 static iopte_t *alloc_streaming_cluster(struct sbus_iommu *iommu, unsigned long npages)
@@ -406,7 +421,7 @@ 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);
-       strbuf_flush(iommu, dma_base, size >> IO_PAGE_SHIFT);
+       sbus_strbuf_flush(iommu, dma_base, size >> IO_PAGE_SHIFT);
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -569,7 +584,7 @@ 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);
-       strbuf_flush(iommu, dvma_base, size >> IO_PAGE_SHIFT);
+       sbus_strbuf_flush(iommu, dvma_base, size >> IO_PAGE_SHIFT);
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -581,7 +596,7 @@ 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);
-       strbuf_flush(iommu, base & IO_PAGE_MASK, size >> IO_PAGE_SHIFT);
+       sbus_strbuf_flush(iommu, base & IO_PAGE_MASK, size >> IO_PAGE_SHIFT);
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
@@ -605,7 +620,7 @@ 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);
-       strbuf_flush(iommu, base, size >> IO_PAGE_SHIFT);
+       sbus_strbuf_flush(iommu, base, size >> IO_PAGE_SHIFT);
        spin_unlock_irqrestore(&iommu->lock, flags);
 }