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>

4 files changed, 546 insertions, 1 deletions

diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile
index 628be7bc006c..4590596d8b25 100644
--- a/arch/s390/pci/Makefile
+++ b/arch/s390/pci/Makefile
@@ -2,4 +2,4 @@
 # Makefile for the s390 PCI subsystem.
 #
 
-obj-$(CONFIG_PCI)       += pci.o pci_clp.o pci_msi.o
+obj-$(CONFIG_PCI)       += pci.o pci_dma.o pci_clp.o pci_msi.o
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index d11dc8a25f34..5a2ef9e75c97 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -34,6 +34,7 @@
 #include <asm/facility.h>
 #include <asm/pci_insn.h>
 #include <asm/pci_clp.h>
+#include <asm/pci_dma.h>
 
 #define DEBUG                           /* enable pr_debug */
 
@@ -232,6 +233,25 @@ static int mod_pci(struct zpci_dev *zdev, int fn, u8 dmaas, struct mod_pci_args
         return rc;
 }
 
+/* Modify PCI: Register I/O address translation parameters */
+int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
+                       u64 base, u64 limit, u64 iota)
+{
+        struct mod_pci_args args = { base, limit, iota };
+
+        WARN_ON_ONCE(iota & 0x3fff);
+        args.iota |= ZPCI_IOTA_RTTO_FLAG;
+        return mod_pci(zdev, ZPCI_MOD_FC_REG_IOAT, dmaas, &args);
+}
+
+/* Modify PCI: Unregister I/O address translation parameters */
+int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
+{
+        struct mod_pci_args args = { 0, 0, 0 };
+
+        return mod_pci(zdev, ZPCI_MOD_FC_DEREG_IOAT, dmaas, &args);
+}
+
 /* Modify PCI: Unregister adapter interruptions */
 static int zpci_unregister_airq(struct zpci_dev *zdev)
 {
@@ -602,6 +622,7 @@ static void zpci_remove_device(struct pci_dev *pdev)
 
         dev_info(&pdev->dev, "Removing device %u\n", zdev->domain);
         zdev->state = ZPCI_FN_STATE_CONFIGURED;
+        zpci_dma_exit_device(zdev);
         zpci_unmap_resources(pdev);
         list_del(&zdev->entry);         /* can be called from init */
         zdev->pdev = NULL;
@@ -887,7 +908,14 @@ int zpci_enable_device(struct zpci_dev *zdev)
         if (rc)
                 goto out;
         pr_info("Enabled fh: 0x%x fid: 0x%x\n", zdev->fh, zdev->fid);
+
+        rc = zpci_dma_init_device(zdev);
+        if (rc)
+                goto out_dma;
         return 0;
+
+out_dma:
+        clp_disable_fh(zdev);
 out:
         return rc;
 }
@@ -929,6 +957,7 @@ out:
 
 void zpci_stop_device(struct zpci_dev *zdev)
 {
+        zpci_dma_exit_device(zdev);
         /*
          * Note: SCLP disables fh via set-pci-fn so don't
          * do that here.
@@ -953,6 +982,7 @@ int zpci_scan_device(struct zpci_dev *zdev)
         return 0;
 
 out:
+        zpci_dma_exit_device(zdev);
         clp_disable_fh(zdev);
         return -EIO;
 }
@@ -1028,6 +1058,10 @@ static int __init pci_base_init(void)
         if (rc)
                 goto out_irq;
 
+        rc = zpci_dma_init();
+        if (rc)
+                goto out_dma;
+
         rc = clp_find_pci_devices();
         if (rc)
                 goto out_find;
@@ -1036,6 +1070,8 @@ static int __init pci_base_init(void)
         return 0;
 
 out_find:
+        zpci_dma_exit();
+out_dma:
         zpci_irq_exit();
 out_irq:
         zpci_msihash_exit();
diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
index 72694fb6d525..7f4ce8d874a4 100644
--- a/arch/s390/pci/pci_clp.c
+++ b/arch/s390/pci/pci_clp.c
@@ -48,6 +48,8 @@ static void clp_free_block(void *ptr)
 static void clp_store_query_pci_fngrp(struct zpci_dev *zdev,
                                       struct clp_rsp_query_pci_grp *response)
 {
+        zdev->tlb_refresh = response->refresh;
+        zdev->dma_mask = response->dasm;
         zdev->msi_addr = response->msia;
 
         pr_debug("Supported number of MSI vectors: %u\n", response->noi);
@@ -97,6 +99,8 @@ static int clp_store_query_pci_fn(struct zpci_dev *zdev,
                 zdev->bars[i].val = le32_to_cpu(response->bar[i]);
                 zdev->bars[i].size = response->bar_size[i];
         }
+        zdev->start_dma = response->sdma;
+        zdev->end_dma = response->edma;
         zdev->pchid = response->pchid;
         zdev->pfgid = response->pfgid;
         return 0;
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);