sparc64: Add ATU (new IOMMU) support

ATU (Address Translation Unit) is a new IOMMU in SPARC supported with
Hypervisor IOMMU v2 APIs.

Current SPARC IOMMU supports only 32bit address ranges and one TSB
per PCIe root complex that has a 2GB per root complex DVMA space
limit. The limit has become a scalability bottleneck nowadays that
a typical 10G/40G NIC can consume 300MB-500MB DVMA space per
instance. When DVMA resource is exhausted, devices will not be usable
since the driver can't allocate DVMA.

ATU removes bottleneck by allowing guest os to create IOTSB of size
32G (or more) with 64bit address ranges available in ATU HW. 32G is
more than enough DVMA space to be shared by all PCIe devices under
root complex contrast to 2G space provided by legacy IOMMU.

ATU allows PCIe devices to use 64bit DMA addressing. Devices
which choose to use 32bit DMA mask will continue to work with the
existing legacy IOMMU.

Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Reviewed-by: chris hyser <chris.hyser@oracle.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 140 insertions, 0 deletions

diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
index db57d8acdc01..2afb86c73da9 100644
--- a/arch/sparc/kernel/pci_sun4v.c
+++ b/arch/sparc/kernel/pci_sun4v.c
@@ -44,6 +44,9 @@ static struct vpci_version vpci_versions[] = {
         { .major = 1, .minor = 1 },
 };
 
+static unsigned long vatu_major = 1;
+static unsigned long vatu_minor = 1;
+
 #define PGLIST_NENTS    (PAGE_SIZE / sizeof(u64))
 
 struct iommu_batch {
@@ -581,6 +584,107 @@ static unsigned long probe_existing_entries(struct pci_pbm_info *pbm,
         return cnt;
 }
 
+static int pci_sun4v_atu_alloc_iotsb(struct pci_pbm_info *pbm)
+{
+        struct atu *atu = pbm->iommu->atu;
+        struct atu_iotsb *iotsb;
+        void *table;
+        u64 table_size;
+        u64 iotsb_num;
+        unsigned long order;
+        unsigned long err;
+
+        iotsb = kzalloc(sizeof(*iotsb), GFP_KERNEL);
+        if (!iotsb) {
+                err = -ENOMEM;
+                goto out_err;
+        }
+        atu->iotsb = iotsb;
+
+        /* calculate size of IOTSB */
+        table_size = (atu->size / IO_PAGE_SIZE) * 8;
+        order = get_order(table_size);
+        table = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+        if (!table) {
+                err = -ENOMEM;
+                goto table_failed;
+        }
+        iotsb->table = table;
+        iotsb->ra = __pa(table);
+        iotsb->dvma_size = atu->size;
+        iotsb->dvma_base = atu->base;
+        iotsb->table_size = table_size;
+        iotsb->page_size = IO_PAGE_SIZE;
+
+        /* configure and register IOTSB with HV */
+        err = pci_sun4v_iotsb_conf(pbm->devhandle,
+                                   iotsb->ra,
+                                   iotsb->table_size,
+                                   iotsb->page_size,
+                                   iotsb->dvma_base,
+                                   &iotsb_num);
+        if (err) {
+                pr_err(PFX "pci_iotsb_conf failed error: %ld\n", err);
+                goto iotsb_conf_failed;
+        }
+        iotsb->iotsb_num = iotsb_num;
+
+        return 0;
+
+iotsb_conf_failed:
+        free_pages((unsigned long)table, order);
+table_failed:
+        kfree(iotsb);
+out_err:
+        return err;
+}
+
+static int pci_sun4v_atu_init(struct pci_pbm_info *pbm)
+{
+        struct atu *atu = pbm->iommu->atu;
+        unsigned long err;
+        const u64 *ranges;
+        const u32 *page_size;
+        int len;
+
+        ranges = of_get_property(pbm->op->dev.of_node, "iommu-address-ranges",
+                                 &len);
+        if (!ranges) {
+                pr_err(PFX "No iommu-address-ranges\n");
+                return -EINVAL;
+        }
+
+        page_size = of_get_property(pbm->op->dev.of_node, "iommu-pagesizes",
+                                    NULL);
+        if (!page_size) {
+                pr_err(PFX "No iommu-pagesizes\n");
+                return -EINVAL;
+        }
+
+        /* There are 4 iommu-address-ranges supported. Each range is pair of
+         * {base, size}. The ranges[0] and ranges[1] are 32bit address space
+         * while ranges[2] and ranges[3] are 64bit space.  We want to use 64bit
+         * address ranges to support 64bit addressing. Because 'size' for
+         * address ranges[2] and ranges[3] are same we can select either of
+         * ranges[2] or ranges[3] for mapping. However due to 'size' is too
+         * large for OS to allocate IOTSB we are using fix size 32G
+         * (ATU_64_SPACE_SIZE) which is more than enough for all PCIe devices
+         * to share.
+         */
+        atu->ranges = (struct atu_ranges *)ranges;
+        atu->base = atu->ranges[3].base;
+        atu->size = ATU_64_SPACE_SIZE;
+
+        /* Create IOTSB */
+        err = pci_sun4v_atu_alloc_iotsb(pbm);
+        if (err) {
+                pr_err(PFX "Error creating ATU IOTSB\n");
+                return err;
+        }
+
+        return 0;
+}
+
 static int pci_sun4v_iommu_init(struct pci_pbm_info *pbm)
 {
         static const u32 vdma_default[] = { 0x80000000, 0x80000000 };
@@ -918,6 +1022,18 @@ static int pci_sun4v_pbm_init(struct pci_pbm_info *pbm,
 
         pci_sun4v_scan_bus(pbm, &op->dev);
 
+        /* if atu_init fails its not complete failure.
+         * we can still continue using legacy iommu.
+         */
+        if (pbm->iommu->atu) {
+                err = pci_sun4v_atu_init(pbm);
+                if (err) {
+                        kfree(pbm->iommu->atu);
+                        pbm->iommu->atu = NULL;
+                        pr_err(PFX "ATU init failed, err=%d\n", err);
+                }
+        }
+
         pbm->next = pci_pbm_root;
         pci_pbm_root = pbm;
 
@@ -931,8 +1047,10 @@ static int pci_sun4v_probe(struct platform_device *op)
         struct pci_pbm_info *pbm;
         struct device_node *dp;
         struct iommu *iommu;
+        struct atu *atu;
         u32 devhandle;
         int i, err = -ENODEV;
+        static bool hv_atu = true;
 
         dp = op->dev.of_node;
 
@@ -954,6 +1072,19 @@ static int pci_sun4v_probe(struct platform_device *op)
                 pr_info(PFX "Registered hvapi major[%lu] minor[%lu]\n",
                         vpci_major, vpci_minor);
 
+                err = sun4v_hvapi_register(HV_GRP_ATU, vatu_major, &vatu_minor);
+                if (err) {
+                        /* don't return an error if we fail to register the
+                         * ATU group, but ATU hcalls won't be available.
+                         */
+                        hv_atu = false;
+                        pr_err(PFX "Could not register hvapi ATU err=%d\n",
+                               err);
+                } else {
+                        pr_info(PFX "Registered hvapi ATU major[%lu] minor[%lu]\n",
+                                vatu_major, vatu_minor);
+                }
+
                 dma_ops = &sun4v_dma_ops;
         }
 
@@ -991,6 +1122,14 @@ static int pci_sun4v_probe(struct platform_device *op)
         }
 
         pbm->iommu = iommu;
+        iommu->atu = NULL;
+        if (hv_atu) {
+                atu = kzalloc(sizeof(*atu), GFP_KERNEL);
+                if (!atu)
+                        pr_err(PFX "Could not allocate atu\n");
+                else
+                        iommu->atu = atu;
+        }
 
         err = pci_sun4v_pbm_init(pbm, op, devhandle);
         if (err)
@@ -1001,6 +1140,7 @@ static int pci_sun4v_probe(struct platform_device *op)
         return 0;
 
 out_free_iommu:
+        kfree(iommu->atu);
         kfree(pbm->iommu);
 
 out_free_controller: