patch-2.4.0-test7 linux/arch/ia64/kernel/pci-dma.c

• Lines: 524
• Date: Fri Aug 11 19:09:06 2000
• Orig file: v2.4.0-test6/linux/arch/ia64/kernel/pci-dma.c
• Orig date: Fri Jun 23 21:55:07 2000

diff -u --recursive --new-file v2.4.0-test6/linux/arch/ia64/kernel/pci-dma.c linux/arch/ia64/kernel/pci-dma.c
@@ -3,34 +3,509 @@
  *
  * This implementation is for IA-64 platforms that do not support
  * I/O TLBs (aka DMA address translation hardware).
- *
- * XXX This doesn't do the right thing yet.  It appears we would have
- * to add additional zones so we can implement the various address
- * mask constraints that we might encounter.  A zone for memory < 32
- * bits is obviously necessary...
+ * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
+ * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
  */
 
-#include <linux/types.h>
+#include <linux/config.h>
+
 #include <linux/mm.h>
-#include <linux/string.h>
 #include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/types.h>
 
 #include <asm/io.h>
+#include <asm/pci.h>
+#include <asm/dma.h>
+
+#ifdef CONFIG_SWIOTLB
+
+#include <linux/init.h>
+#include <linux/bootmem.h>
+
+#define ALIGN(val, align) ((unsigned long) (((unsigned long) (val) + ((align) - 1)) & ~((align) - 1)))
+
+/*
+ * log of the size of each IO TLB slab.  The number of slabs is command line
+ * controllable.
+ */
+#define IO_TLB_SHIFT 11
+
+/*
+ * Used to do a quick range check in pci_unmap_single and pci_sync_single, to see if the 
+ * memory was in fact allocated by this API.
+ */
+static char *io_tlb_start, *io_tlb_end;
+
+/*
+ * The number of IO TLB blocks (in groups of 64) betweeen io_tlb_start and io_tlb_end.
+ * This is command line adjustable via setup_io_tlb_npages.
+ */
+unsigned long io_tlb_nslabs = 1024;
+
+/*
+ * This is a free list describing the number of free entries available from each index
+ */
+static unsigned int *io_tlb_list;
+static unsigned int io_tlb_index;
+
+/*
+ * We need to save away the original address corresponding to a mapped entry for the sync 
+ * operations.
+ */
+static unsigned char **io_tlb_orig_addr;
+
+/*
+ * Protect the above data structures in the map and unmap calls
+ */ 
+spinlock_t io_tlb_lock = SPIN_LOCK_UNLOCKED;
+
+static int __init
+setup_io_tlb_npages (char *str)
+{
+	io_tlb_nslabs = simple_strtoul(str, NULL, 0) << (PAGE_SHIFT - IO_TLB_SHIFT);
+	return 1;
+}
+__setup("swiotlb=", setup_io_tlb_npages);
+
+/*
+ * Statically reserve bounce buffer space and initialize bounce buffer
+ * data structures for the software IO TLB used to implement the PCI DMA API
+ */
+void
+setup_swiotlb (void)
+{
+	int i;
+
+	/*
+	 * Get IO TLB memory from the low pages
+	 */
+	io_tlb_start = alloc_bootmem_low_pages(io_tlb_nslabs * (1 << IO_TLB_SHIFT));
+	if (!io_tlb_start)
+		BUG();
+	io_tlb_end = io_tlb_start + io_tlb_nslabs * (1 << IO_TLB_SHIFT);
+
+	/*
+	 * Allocate and initialize the free list array.  This array is used
+	 * to find contiguous free memory regions of size 2^IO_TLB_SHIFT between
+	 * io_tlb_start and io_tlb_end.
+	 */
+	io_tlb_list = alloc_bootmem(io_tlb_nslabs * sizeof(int));
+	for (i = 0; i < io_tlb_nslabs; i++)
+		io_tlb_list[i] = io_tlb_nslabs - i;
+	io_tlb_index = 0;
+	io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
+
+	printk("Placing software IO TLB between 0x%p - 0x%p\n", io_tlb_start, io_tlb_end);
+}
+
+/*
+ * Allocates bounce buffer and returns its kernel virtual address.
+ */
+static void *
+__pci_map_single (struct pci_dev *hwdev, char *buffer, size_t size, int direction)
+{
+	unsigned long flags;
+	char *dma_addr;
+	unsigned int i, nslots, stride, index, wrap;
+
+	/*
+	 * For mappings greater than a page size, we limit the stride (and hence alignment)
+	 * to a page size.
+	 */
+	nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	if (size > (1 << PAGE_SHIFT))
+		stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
+	else
+		stride = nslots;
+
+	if (!nslots)
+		BUG();
+
+	/*
+	 * Find suitable number of IO TLB entries size that will fit this request and allocate a buffer
+	 * from that IO TLB pool.
+	 */
+	spin_lock_irqsave(&io_tlb_lock, flags);
+	{
+		wrap = index = ALIGN(io_tlb_index, stride);
+		do {
+			/*
+			 * If we find a slot that indicates we have 'nslots' number of 
+			 * contiguous buffers, we allocate the buffers from that slot and mark the
+			 * entries as '0' indicating unavailable.
+			 */
+			if (io_tlb_list[index] >= nslots) {
+				for (i = index; i < index + nslots; i++)
+					io_tlb_list[i] = 0;
+				dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
+
+				/*
+				 * Update the indices to avoid searching in the next round.
+				 */
+				io_tlb_index = (index + nslots) < io_tlb_nslabs ? (index + nslots) : 0;
+
+				goto found;
+			}
+			index += stride;
+			if (index >= io_tlb_nslabs)
+				index = 0;
+		} while (index != wrap);
+
+		/*
+		 * XXX What is a suitable recovery mechanism here?  We cannot 
+		 * sleep because we are called from with in interrupts!
+		 */
+		panic("__pci_map_single: could not allocate software IO TLB (%ld bytes)", size);
+found:
+	}
+	spin_unlock_irqrestore(&io_tlb_lock, flags);
+
+	/*
+	 * Save away the mapping from the original address to the DMA address.  This is needed
+	 * when we sync the memory.  Then we sync the buffer if needed.
+	 */
+	io_tlb_orig_addr[index] = buffer;
+	if (direction == PCI_DMA_TODEVICE || direction == PCI_DMA_BIDIRECTIONAL)
+		memcpy(dma_addr, buffer, size);
+
+	return dma_addr;
+}
+
+/*
+ * dma_addr is the kernel virtual address of the bounce buffer to unmap.
+ */
+static void
+__pci_unmap_single (struct pci_dev *hwdev, char *dma_addr, size_t size, int direction)
+{
+	unsigned long flags;
+	int i, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
+	char *buffer = io_tlb_orig_addr[index];
+
+	/*
+	 * First, sync the memory before unmapping the entry
+	 */
+	if ((direction == PCI_DMA_FROMDEVICE) || (direction == PCI_DMA_BIDIRECTIONAL))
+		/*
+ 	 	 * bounce... copy the data back into the original buffer
+	  	 * and delete the bounce buffer.
+ 	 	 */
+		memcpy(buffer, dma_addr, size);
+
+	/*
+	 * Return the buffer to the free list by setting the corresponding entries to indicate
+	 * the number of contigous entries available.  
+	 * While returning the entries to the free list, we merge the entries with slots below
+	 * and above the pool being returned.
+	 */
+	spin_lock_irqsave(&io_tlb_lock, flags);
+	{
+		int count = ((index + nslots) < io_tlb_nslabs ? io_tlb_list[index + nslots] : 0);
+		/*
+		 * Step 1: return the slots to the free list, merging the slots with superceeding slots
+		 */
+		for (i = index + nslots - 1; i >= index; i--)
+			io_tlb_list[i] = ++count;
+		/*
+		 * Step 2: merge the returned slots with the preceeding slots, if available (non zero)
+		 */
+		for (i = index - 1; (i >= 0) && io_tlb_list[i]; i--)
+			io_tlb_list[i] += io_tlb_list[index];
+	}
+	spin_unlock_irqrestore(&io_tlb_lock, flags);
+}
+
+static void
+__pci_sync_single (struct pci_dev *hwdev, char *dma_addr, size_t size, int direction)
+{
+	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
+	char *buffer = io_tlb_orig_addr[index];
+
+	/*
+  	 * bounce... copy the data back into/from the original buffer
+	 * XXX How do you handle PCI_DMA_BIDIRECTIONAL here ?
+ 	 */
+	if (direction == PCI_DMA_FROMDEVICE)
+		memcpy(buffer, dma_addr, size);
+	else if (direction == PCI_DMA_TODEVICE)
+		memcpy(dma_addr, buffer, size);
+	else
+		BUG();
+}
+
+/*
+ * Map a single buffer of the indicated size for DMA in streaming mode.
+ * The PCI address to use is returned.
+ *
+ * Once the device is given the dma address, the device owns this memory
+ * until either pci_unmap_single or pci_dma_sync_single is performed.
+ */
+dma_addr_t
+pci_map_single (struct pci_dev *hwdev, void *ptr, size_t size, int direction)
+{
+	unsigned long pci_addr = virt_to_phys(ptr);
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+	/*
+	 * Check if the PCI device can DMA to ptr... if so, just return ptr
+	 */
+	if ((pci_addr & ~hwdev->dma_mask) == 0)
+		/*
+		 * Device is bit capable of DMA'ing to the
+		 * buffer... just return the PCI address of ptr
+		 */
+		return pci_addr;
+
+	/* 
+	 * get a bounce buffer: 
+	 */
+	pci_addr = virt_to_phys(__pci_map_single(hwdev, ptr, size, direction));
+
+	/*
+	 * Ensure that the address returned is DMA'ble:
+	 */
+	if ((pci_addr & ~hwdev->dma_mask) != 0)
+		panic("__pci_map_single: bounce buffer is not DMA'ble");
+
+	return pci_addr;
+}
+
+/*
+ * Unmap a single streaming mode DMA translation.  The dma_addr and size
+ * must match what was provided for in a previous pci_map_single call.  All
+ * other usages are undefined.
+ *
+ * After this call, reads by the cpu to the buffer are guarenteed to see
+ * whatever the device wrote there.
+ */
+void
+pci_unmap_single (struct pci_dev *hwdev, dma_addr_t pci_addr, size_t size, int direction)
+{
+	char *dma_addr = phys_to_virt(pci_addr);
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+	if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
+		__pci_unmap_single(hwdev, dma_addr, size, direction);
+}
+
+/*
+ * Make physical memory consistent for a single
+ * streaming mode DMA translation after a transfer.
+ *
+ * If you perform a pci_map_single() but wish to interrogate the
+ * buffer using the cpu, yet do not wish to teardown the PCI dma
+ * mapping, you must call this function before doing so.  At the
+ * next point you give the PCI dma address back to the card, the
+ * device again owns the buffer.
+ */
+void
+pci_dma_sync_single (struct pci_dev *hwdev, dma_addr_t pci_addr, size_t size, int direction)
+{
+	char *dma_addr = phys_to_virt(pci_addr);
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+	if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
+		__pci_sync_single(hwdev, dma_addr, size, direction);
+}
+
+/*
+ * Map a set of buffers described by scatterlist in streaming
+ * mode for DMA.  This is the scather-gather version of the
+ * above pci_map_single interface.  Here the scatter gather list
+ * elements are each tagged with the appropriate dma address
+ * and length.  They are obtained via sg_dma_{address,length}(SG).
+ *
+ * NOTE: An implementation may be able to use a smaller number of
+ *       DMA address/length pairs than there are SG table elements.
+ *       (for example via virtual mapping capabilities)
+ *       The routine returns the number of addr/length pairs actually
+ *       used, at most nents.
+ *
+ * Device ownership issues as mentioned above for pci_map_single are
+ * the same here.
+ */
+int
+pci_map_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nelems, int direction)
+{
+	int i;
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+
+	for (i = 0; i < nelems; i++, sg++) {
+		sg->orig_address = sg->address;
+		if ((virt_to_phys(sg->address) & ~hwdev->dma_mask) != 0) {
+			sg->address = __pci_map_single(hwdev, sg->address, sg->length, direction);
+		}
+	}
+	return nelems;
+}
+
+/*
+ * Unmap a set of streaming mode DMA translations.
+ * Again, cpu read rules concerning calls here are the same as for
+ * pci_unmap_single() above.
+ */
+void
+pci_unmap_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nelems, int direction)
+{
+	int i;
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+
+	for (i = 0; i < nelems; i++, sg++)
+		if (sg->orig_address != sg->address) {
+			__pci_unmap_single(hwdev, sg->address, sg->length, direction);
+			sg->address = sg->orig_address;
+		}
+}
+
+/*
+ * Make physical memory consistent for a set of streaming mode DMA
+ * translations after a transfer.
+ *
+ * The same as pci_dma_sync_single but for a scatter-gather list,
+ * same rules and usage.
+ */
+void
+pci_dma_sync_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nelems, int direction)
+{
+	int i;
+
+	if (direction == PCI_DMA_NONE)
+		BUG();
+
+	for (i = 0; i < nelems; i++, sg++)
+		if (sg->orig_address != sg->address)
+			__pci_sync_single(hwdev, sg->address, sg->length, direction);
+}
+
+#else
+/*
+ * Map a single buffer of the indicated size for DMA in streaming mode.
+ * The 32-bit bus address to use is returned.
+ *
+ * Once the device is given the dma address, the device owns this memory
+ * until either pci_unmap_single or pci_dma_sync_single is performed.
+ */
+extern inline dma_addr_t
+pci_map_single (struct pci_dev *hwdev, void *ptr, size_t size, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        return virt_to_bus(ptr);
+}
+
+/*
+ * Unmap a single streaming mode DMA translation.  The dma_addr and size
+ * must match what was provided for in a previous pci_map_single call.  All
+ * other usages are undefined.
+ *
+ * After this call, reads by the cpu to the buffer are guarenteed to see
+ * whatever the device wrote there.
+ */
+extern inline void
+pci_unmap_single (struct pci_dev *hwdev, dma_addr_t dma_addr, size_t size, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        /* Nothing to do */
+}
+/*
+ * Map a set of buffers described by scatterlist in streaming
+ * mode for DMA.  This is the scather-gather version of the
+ * above pci_map_single interface.  Here the scatter gather list
+ * elements are each tagged with the appropriate dma address
+ * and length.  They are obtained via sg_dma_{address,length}(SG).
+ *
+ * NOTE: An implementation may be able to use a smaller number of
+ *       DMA address/length pairs than there are SG table elements.
+ *       (for example via virtual mapping capabilities)
+ *       The routine returns the number of addr/length pairs actually
+ *       used, at most nents.
+ *
+ * Device ownership issues as mentioned above for pci_map_single are
+ * the same here.
+ */
+extern inline int
+pci_map_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nents, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        return nents;
+}
+
+/*
+ * Unmap a set of streaming mode DMA translations.
+ * Again, cpu read rules concerning calls here are the same as for
+ * pci_unmap_single() above.
+ */
+extern inline void
+pci_unmap_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nents, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        /* Nothing to do */
+}
+/*
+ * Make physical memory consistent for a single
+ * streaming mode DMA translation after a transfer.
+ *
+ * If you perform a pci_map_single() but wish to interrogate the
+ * buffer using the cpu, yet do not wish to teardown the PCI dma
+ * mapping, you must call this function before doing so.  At the
+ * next point you give the PCI dma address back to the card, the
+ * device again owns the buffer.
+ */
+extern inline void
+pci_dma_sync_single (struct pci_dev *hwdev, dma_addr_t dma_handle, size_t size, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        /* Nothing to do */
+}
+
+/*
+ * Make physical memory consistent for a set of streaming mode DMA
+ * translations after a transfer.
+ *
+ * The same as pci_dma_sync_single but for a scatter-gather list,
+ * same rules and usage.
+ */
+extern inline void
+pci_dma_sync_sg (struct pci_dev *hwdev, struct scatterlist *sg, int nelems, int direction)
+{
+        if (direction == PCI_DMA_NONE)
+                BUG();
+        /* Nothing to do */
+}
+
+#endif /* CONFIG_SWIOTLB */
 
 void *
 pci_alloc_consistent (struct pci_dev *hwdev, size_t size, dma_addr_t *dma_handle)
 {
-	void *ret;
+	unsigned long pci_addr;
 	int gfp = GFP_ATOMIC;
+	void *ret;
 
-	if (!hwdev || hwdev->dma_mask == 0xffffffff)
-		gfp |= GFP_DMA;	/* XXX fix me: should change this to GFP_32BIT or ZONE_32BIT */
+	if (!hwdev || hwdev->dma_mask <= 0xffffffff)
+		gfp |= GFP_DMA; /* XXX fix me: should change this to GFP_32BIT or ZONE_32BIT */
 	ret = (void *)__get_free_pages(gfp, get_order(size));
+	if (!ret)
+		return NULL;
 
-	if (ret) {
-		memset(ret, 0, size);
-		*dma_handle = virt_to_bus(ret);
-	}
+	memset(ret, 0, size);
+	pci_addr = virt_to_phys(ret);
+	if ((pci_addr & ~hwdev->dma_mask) != 0)
+		panic("pci_alloc_consistent: allocated memory is out of range for PCI device");
+	*dma_handle = pci_addr;
 	return ret;
 }