s390/pci: DMA support

Add DMA IOMMU support using 4K page table entries. Implement dma_map_ops.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 505 insertions, 0 deletions

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
new file mode 100644
index 000000000000..de48625b3590
--- /dev/null
+++ b/arch/s390/pci/pci_dma.c
@@ -0,0 +1,505 @@
+/*
+ * Copyright IBM Corp. 2012
+ *
+ * Author(s):
+ *   Jan Glauber <jang@linux.vnet.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/iommu-helper.h>
+#include <linux/dma-mapping.h>
+#include <linux/pci.h>
+#include <asm/pci_dma.h>
+
+static enum zpci_ioat_dtype zpci_ioat_dt = ZPCI_IOTA_RTTO;
+
+static struct kmem_cache *dma_region_table_cache;
+static struct kmem_cache *dma_page_table_cache;
+
+static unsigned long *dma_alloc_cpu_table(void)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
+	if (!table)
+		return NULL;
+
+	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
+		*entry = ZPCI_TABLE_INVALID | ZPCI_TABLE_PROTECTED;
+	return table;
+}
+
+static void dma_free_cpu_table(void *table)
+{
+	kmem_cache_free(dma_region_table_cache, table);
+}
+
+static unsigned long *dma_alloc_page_table(void)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
+	if (!table)
+		return NULL;
+
+	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
+		*entry = ZPCI_PTE_INVALID | ZPCI_TABLE_PROTECTED;
+	return table;
+}
+
+static void dma_free_page_table(void *table)
+{
+	kmem_cache_free(dma_page_table_cache, table);
+}
+
+static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
+{
+	unsigned long *sto;
+
+	if (reg_entry_isvalid(*entry))
+		sto = get_rt_sto(*entry);
+	else {
+		sto = dma_alloc_cpu_table();
+		if (!sto)
+			return NULL;
+
+		set_rt_sto(entry, sto);
+		validate_rt_entry(entry);
+		entry_clr_protected(entry);
+	}
+	return sto;
+}
+
+static unsigned long *dma_get_page_table_origin(unsigned long *entry)
+{
+	unsigned long *pto;
+
+	if (reg_entry_isvalid(*entry))
+		pto = get_st_pto(*entry);
+	else {
+		pto = dma_alloc_page_table();
+		if (!pto)
+			return NULL;
+		set_st_pto(entry, pto);
+		validate_st_entry(entry);
+		entry_clr_protected(entry);
+	}
+	return pto;
+}
+
+static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
+{
+	unsigned long *sto, *pto;
+	unsigned int rtx, sx, px;
+
+	rtx = calc_rtx(dma_addr);
+	sto = dma_get_seg_table_origin(&rto[rtx]);
+	if (!sto)
+		return NULL;
+
+	sx = calc_sx(dma_addr);
+	pto = dma_get_page_table_origin(&sto[sx]);
+	if (!pto)
+		return NULL;
+
+	px = calc_px(dma_addr);
+	return &pto[px];
+}
+
+static void dma_update_cpu_trans(struct zpci_dev *zdev, void *page_addr,
+				 dma_addr_t dma_addr, int flags)
+{
+	unsigned long *entry;
+
+	entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
+	if (!entry) {
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	if (flags & ZPCI_PTE_INVALID) {
+		invalidate_pt_entry(entry);
+		return;
+	} else {
+		set_pt_pfaa(entry, page_addr);
+		validate_pt_entry(entry);
+	}
+
+	if (flags & ZPCI_TABLE_PROTECTED)
+		entry_set_protected(entry);
+	else
+		entry_clr_protected(entry);
+}
+
+static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
+			    dma_addr_t dma_addr, size_t size, int flags)
+{
+	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	u8 *page_addr = (u8 *) (pa & PAGE_MASK);
+	dma_addr_t start_dma_addr = dma_addr;
+	unsigned long irq_flags;
+	int i, rc = 0;
+
+	if (!nr_pages)
+		return -EINVAL;
+
+	spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
+	if (!zdev->dma_table) {
+		dev_err(&zdev->pdev->dev, "Missing DMA table\n");
+		goto no_refresh;
+	}
+
+	for (i = 0; i < nr_pages; i++) {
+		dma_update_cpu_trans(zdev, page_addr, dma_addr, flags);
+		page_addr += PAGE_SIZE;
+		dma_addr += PAGE_SIZE;
+	}
+
+	/*
+	 * rpcit is not required to establish new translations when previously
+	 * invalid translation-table entries are validated, however it is
+	 * required when altering previously valid entries.
+	 */
+	if (!zdev->tlb_refresh &&
+	    ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
+		/*
+		 * TODO: also need to check that the old entry is indeed INVALID
+		 * and not only for one page but for the whole range...
+		 * -> now we WARN_ON in that case but with lazy unmap that
+		 * needs to be redone!
+		 */
+		goto no_refresh;
+	rc = rpcit_instr((u64) zdev->fh << 32, start_dma_addr,
+			  nr_pages * PAGE_SIZE);
+
+no_refresh:
+	spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
+	return rc;
+}
+
+static void dma_free_seg_table(unsigned long entry)
+{
+	unsigned long *sto = get_rt_sto(entry);
+	int sx;
+
+	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
+		if (reg_entry_isvalid(sto[sx]))
+			dma_free_page_table(get_st_pto(sto[sx]));
+
+	dma_free_cpu_table(sto);
+}
+
+static void dma_cleanup_tables(struct zpci_dev *zdev)
+{
+	unsigned long *table = zdev->dma_table;
+	int rtx;
+
+	if (!zdev || !zdev->dma_table)
+		return;
+
+	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
+		if (reg_entry_isvalid(table[rtx]))
+			dma_free_seg_table(table[rtx]);
+
+	dma_free_cpu_table(table);
+	zdev->dma_table = NULL;
+}
+
+static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev, unsigned long start,
+				   int size)
+{
+	unsigned long boundary_size = 0x1000000;
+
+	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
+				start, size, 0, boundary_size, 0);
+}
+
+static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size)
+{
+	unsigned long offset, flags;
+
+	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
+	offset = __dma_alloc_iommu(zdev, zdev->next_bit, size);
+	if (offset == -1)
+		offset = __dma_alloc_iommu(zdev, 0, size);
+
+	if (offset != -1) {
+		zdev->next_bit = offset + size;
+		if (zdev->next_bit >= zdev->iommu_pages)
+			zdev->next_bit = 0;
+	}
+	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
+	return offset;
+}
+
+static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
+	if (!zdev->iommu_bitmap)
+		goto out;
+	bitmap_clear(zdev->iommu_bitmap, offset, size);
+	if (offset >= zdev->next_bit)
+		zdev->next_bit = offset + size;
+out:
+	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
+}
+
+int dma_set_mask(struct device *dev, u64 mask)
+{
+	if (!dev->dma_mask || !dma_supported(dev, mask))
+		return -EIO;
+
+	*dev->dma_mask = mask;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dma_set_mask);
+
+static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction direction,
+				     struct dma_attrs *attrs)
+{
+	struct zpci_dev *zdev = get_zdev(container_of(dev, struct pci_dev, dev));
+	unsigned long nr_pages, iommu_page_index;
+	unsigned long pa = page_to_phys(page) + offset;
+	int flags = ZPCI_PTE_VALID;
+	dma_addr_t dma_addr;
+
+	WARN_ON_ONCE(offset > PAGE_SIZE);
+
+	/* This rounds up number of pages based on size and offset */
+	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
+	iommu_page_index = dma_alloc_iommu(zdev, nr_pages);
+	if (iommu_page_index == -1)
+		goto out_err;
+
+	/* Use rounded up size */
+	size = nr_pages * PAGE_SIZE;
+
+	dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
+	if (dma_addr + size > zdev->end_dma) {
+		dev_err(dev, "(dma_addr: 0x%16.16LX + size: 0x%16.16lx) > end_dma: 0x%16.16Lx\n",
+			 dma_addr, size, zdev->end_dma);
+		goto out_free;
+	}
+
+	if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
+		flags |= ZPCI_TABLE_PROTECTED;
+
+	if (!dma_update_trans(zdev, pa, dma_addr, size, flags))
+		return dma_addr + offset;
+
+out_free:
+	dma_free_iommu(zdev, iommu_page_index, nr_pages);
+out_err:
+	dev_err(dev, "Failed to map addr: %lx\n", pa);
+	return DMA_ERROR_CODE;
+}
+
+static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
+				 size_t size, enum dma_data_direction direction,
+				 struct dma_attrs *attrs)
+{
+	struct zpci_dev *zdev = get_zdev(container_of(dev, struct pci_dev, dev));
+	unsigned long iommu_page_index;
+	int npages;
+
+	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
+	dma_addr = dma_addr & PAGE_MASK;
+	if (dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
+			     ZPCI_TABLE_PROTECTED | ZPCI_PTE_INVALID))
+		dev_err(dev, "Failed to unmap addr: %Lx\n", dma_addr);
+
+	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
+	dma_free_iommu(zdev, iommu_page_index, npages);
+}
+
+static void *s390_dma_alloc(struct device *dev, size_t size,
+			    dma_addr_t *dma_handle, gfp_t flag,
+			    struct dma_attrs *attrs)
+{
+	struct page *page;
+	unsigned long pa;
+	dma_addr_t map;
+
+	size = PAGE_ALIGN(size);
+	page = alloc_pages(flag, get_order(size));
+	if (!page)
+		return NULL;
+	pa = page_to_phys(page);
+	memset((void *) pa, 0, size);
+
+	map = s390_dma_map_pages(dev, page, pa % PAGE_SIZE,
+				 size, DMA_BIDIRECTIONAL, NULL);
+	if (dma_mapping_error(dev, map)) {
+		free_pages(pa, get_order(size));
+		return NULL;
+	}
+
+	if (dma_handle)
+		*dma_handle = map;
+	return (void *) pa;
+}
+
+static void s390_dma_free(struct device *dev, size_t size,
+			  void *pa, dma_addr_t dma_handle,
+			  struct dma_attrs *attrs)
+{
+	s390_dma_unmap_pages(dev, dma_handle, PAGE_ALIGN(size),
+			     DMA_BIDIRECTIONAL, NULL);
+	free_pages((unsigned long) pa, get_order(size));
+}
+
+static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
+			   int nr_elements, enum dma_data_direction dir,
+			   struct dma_attrs *attrs)
+{
+	int mapped_elements = 0;
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nr_elements, i) {
+		struct page *page = sg_page(s);
+		s->dma_address = s390_dma_map_pages(dev, page, s->offset,
+						    s->length, dir, NULL);
+		if (!dma_mapping_error(dev, s->dma_address)) {
+			s->dma_length = s->length;
+			mapped_elements++;
+		} else
+			goto unmap;
+	}
+out:
+	return mapped_elements;
+
+unmap:
+	for_each_sg(sg, s, mapped_elements, i) {
+		if (s->dma_address)
+			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
+					     dir, NULL);
+		s->dma_address = 0;
+		s->dma_length = 0;
+	}
+	mapped_elements = 0;
+	goto out;
+}
+
+static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+			      int nr_elements, enum dma_data_direction dir,
+			      struct dma_attrs *attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nr_elements, i) {
+		s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL);
+		s->dma_address = 0;
+		s->dma_length = 0;
+	}
+}
+
+int zpci_dma_init_device(struct zpci_dev *zdev)
+{
+	unsigned int bitmap_order;
+	int rc;
+
+	spin_lock_init(&zdev->iommu_bitmap_lock);
+	spin_lock_init(&zdev->dma_table_lock);
+
+	zdev->dma_table = dma_alloc_cpu_table();
+	if (!zdev->dma_table) {
+		rc = -ENOMEM;
+		goto out_clean;
+	}
+
+	zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET;
+	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
+	bitmap_order = get_order(zdev->iommu_pages / 8);
+	pr_info("iommu_size: 0x%lx  iommu_pages: 0x%lx  bitmap_order: %i\n",
+		 zdev->iommu_size, zdev->iommu_pages, bitmap_order);
+
+	zdev->iommu_bitmap = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+						       bitmap_order);
+	if (!zdev->iommu_bitmap) {
+		rc = -ENOMEM;
+		goto out_reg;
+	}
+
+	rc = zpci_register_ioat(zdev,
+				0,
+				zdev->start_dma + PAGE_OFFSET,
+				zdev->start_dma + zdev->iommu_size - 1,
+				(u64) zdev->dma_table);
+	if (rc)
+		goto out_reg;
+	return 0;
+
+out_reg:
+	dma_free_cpu_table(zdev->dma_table);
+out_clean:
+	return rc;
+}
+
+void zpci_dma_exit_device(struct zpci_dev *zdev)
+{
+	zpci_unregister_ioat(zdev, 0);
+	dma_cleanup_tables(zdev);
+	free_pages((unsigned long) zdev->iommu_bitmap,
+		   get_order(zdev->iommu_pages / 8));
+	zdev->iommu_bitmap = NULL;
+	zdev->next_bit = 0;
+}
+
+static int __init dma_alloc_cpu_table_caches(void)
+{
+	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
+					ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
+					0, NULL);
+	if (!dma_region_table_cache)
+		return -ENOMEM;
+
+	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
+					ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
+					0, NULL);
+	if (!dma_page_table_cache) {
+		kmem_cache_destroy(dma_region_table_cache);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+int __init zpci_dma_init(void)
+{
+	return dma_alloc_cpu_table_caches();
+}
+
+void zpci_dma_exit(void)
+{
+	kmem_cache_destroy(dma_page_table_cache);
+	kmem_cache_destroy(dma_region_table_cache);
+}
+
+#define PREALLOC_DMA_DEBUG_ENTRIES	(1 << 16)
+
+static int __init dma_debug_do_init(void)
+{
+	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
+	return 0;
+}
+fs_initcall(dma_debug_do_init);
+
+struct dma_map_ops s390_dma_ops = {
+	.alloc		= s390_dma_alloc,
+	.free		= s390_dma_free,
+	.map_sg		= s390_dma_map_sg,
+	.unmap_sg	= s390_dma_unmap_sg,
+	.map_page	= s390_dma_map_pages,
+	.unmap_page	= s390_dma_unmap_pages,
+	/* if we support direct DMA this must be conditional */
+	.is_phys	= 0,
+	/* dma_supported is unconditionally true without a callback */
+};
+EXPORT_SYMBOL_GPL(s390_dma_ops);