iommu/s390: Add iommu api for s390 pci devices

This adds an IOMMU API implementation for s390 PCI devices.

Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

4 files changed, 34 insertions, 13 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 1d57000b1b24..74db332c59b8 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -582,6 +582,7 @@ menuconfig PCI
         bool "PCI support"
         select HAVE_DMA_ATTRS
         select PCI_MSI
+        select IOMMU_SUPPORT
         help
           Enable PCI support.
 
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 34d960353a08..c873e682b67f 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -62,6 +62,8 @@ struct zpci_bar_struct {
         u8              size;           /* order 2 exponent */
 };
 
+struct s390_domain;
+
 /* Private data per function */
 struct zpci_dev {
         struct pci_dev  *pdev;
@@ -118,6 +120,8 @@ struct zpci_dev {
 
         struct dentry   *debugfs_dev;
         struct dentry   *debugfs_perf;
+
+        struct s390_domain *s390_domain; /* s390 IOMMU domain data */
 };
 
 static inline bool zdev_enabled(struct zpci_dev *zdev)
diff --git a/arch/s390/include/asm/pci_dma.h b/arch/s390/include/asm/pci_dma.h
index 30b4c179c38c..7a7abf1a5537 100644
--- a/arch/s390/include/asm/pci_dma.h
+++ b/arch/s390/include/asm/pci_dma.h
@@ -192,5 +192,8 @@ static inline unsigned long *get_st_pto(unsigned long entry)
 /* Prototypes */
 int zpci_dma_init_device(struct zpci_dev *);
 void zpci_dma_exit_device(struct zpci_dev *);
-
+void dma_free_seg_table(unsigned long);
+unsigned long *dma_alloc_cpu_table(void);
+void dma_cleanup_tables(unsigned long *);
+void dma_update_cpu_trans(unsigned long *, void *, dma_addr_t, int);
 #endif
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 37505b8b4093..37d10f74425a 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -24,7 +24,7 @@ static int zpci_refresh_global(struct zpci_dev *zdev)
                                   zdev->iommu_pages * PAGE_SIZE);
 }
 
-static unsigned long *dma_alloc_cpu_table(void)
+unsigned long *dma_alloc_cpu_table(void)
 {
         unsigned long *table, *entry;
 
@@ -114,12 +114,12 @@ static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t 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)
+void dma_update_cpu_trans(unsigned long *dma_table, void *page_addr,
+                          dma_addr_t dma_addr, int flags)
 {
         unsigned long *entry;
 
-        entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
+        entry = dma_walk_cpu_trans(dma_table, dma_addr);
         if (!entry) {
                 WARN_ON_ONCE(1);
                 return;
@@ -156,7 +156,8 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
                 goto no_refresh;
 
         for (i = 0; i < nr_pages; i++) {
-                dma_update_cpu_trans(zdev, page_addr, dma_addr, flags);
+                dma_update_cpu_trans(zdev->dma_table, page_addr, dma_addr,
+                                     flags);
                 page_addr += PAGE_SIZE;
                 dma_addr += PAGE_SIZE;
         }
@@ -181,7 +182,7 @@ no_refresh:
         return rc;
 }
 
-static void dma_free_seg_table(unsigned long entry)
+void dma_free_seg_table(unsigned long entry)
 {
         unsigned long *sto = get_rt_sto(entry);
         int sx;
@@ -193,21 +194,18 @@ static void dma_free_seg_table(unsigned long entry)
         dma_free_cpu_table(sto);
 }
 
-static void dma_cleanup_tables(struct zpci_dev *zdev)
+void dma_cleanup_tables(unsigned long *table)
 {
-        unsigned long *table;
         int rtx;
 
-        if (!zdev || !zdev->dma_table)
+        if (!table)
                 return;
 
-        table = zdev->dma_table;
         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,
@@ -416,6 +414,13 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
 {
         int rc;
 
+        /*
+         * At this point, if the device is part of an IOMMU domain, this would
+         * be a strong hint towards a bug in the IOMMU API (common) code and/or
+         * simultaneous access via IOMMU and DMA API. So let's issue a warning.
+         */
+        WARN_ON(zdev->s390_domain);
+
         spin_lock_init(&zdev->iommu_bitmap_lock);
         spin_lock_init(&zdev->dma_table_lock);
 
@@ -450,8 +455,16 @@ out_clean:
 
 void zpci_dma_exit_device(struct zpci_dev *zdev)
 {
+        /*
+         * At this point, if the device is part of an IOMMU domain, this would
+         * be a strong hint towards a bug in the IOMMU API (common) code and/or
+         * simultaneous access via IOMMU and DMA API. So let's issue a warning.
+         */
+        WARN_ON(zdev->s390_domain);
+
         zpci_unregister_ioat(zdev, 0);
-        dma_cleanup_tables(zdev);
+        dma_cleanup_tables(zdev->dma_table);
+        zdev->dma_table = NULL;
         vfree(zdev->iommu_bitmap);
         zdev->iommu_bitmap = NULL;
         zdev->next_bit = 0;