omap: iommu: migrate to the generic IOMMU API

Migrate OMAP's iommu driver to the generic IOMMU API, so users can stay
generic, and any generic IOMMU functionality can be developed once
in the generic framework.

Migrate omap's iovmm (virtual memory manager) to the generic IOMMU API,
and adapt omap3isp as needed, so the latter won't break.

The plan is to eventually remove iovmm completely by replacing it
with the (upcoming) IOMMU-based DMA-API.

Tested on OMAP3 (with omap3isp) and OMAP4 (with rpmsg/remoteproc).

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 266 insertions, 42 deletions

diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index 34fc31ee9081..51aa008d8223 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -18,6 +18,9 @@
 #include <linux/ioport.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
+#include <linux/iommu.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
 
 #include <asm/cacheflush.h>
 
@@ -30,6 +33,19 @@
              (__i < (n)) && (cr = __iotlb_read_cr((obj), __i), true);   \
              __i++)
 
+/**
+ * struct omap_iommu_domain - omap iommu domain
+ * @pgtable:    the page table
+ * @iommu_dev:  an omap iommu device attached to this domain. only a single
+ *              iommu device can be attached for now.
+ * @lock:       domain lock, should be taken when attaching/detaching
+ */
+struct omap_iommu_domain {
+        u32 *pgtable;
+        struct iommu *iommu_dev;
+        spinlock_t lock;
+};
+
 /* accommodate the difference between omap1 and omap2/3 */
 static const struct iommu_functions *arch_iommu;
 
@@ -852,35 +868,55 @@ int iommu_set_da_range(struct iommu *obj, u32 start, u32 end)
 EXPORT_SYMBOL_GPL(iommu_set_da_range);
 
 /**
- * iommu_get - Get iommu handler
- * @name:       target iommu name
+ * omap_find_iommu_device() - find an omap iommu device by name
+ * @name:       name of the iommu device
+ *
+ * The generic iommu API requires the caller to provide the device
+ * he wishes to attach to a certain iommu domain.
+ *
+ * Drivers generally should not bother with this as it should just
+ * be taken care of by the DMA-API using dev_archdata.
+ *
+ * This function is provided as an interim solution until the latter
+ * materializes, and omap3isp is fully migrated to the DMA-API.
+ */
+struct device *omap_find_iommu_device(const char *name)
+{
+        return driver_find_device(&omap_iommu_driver.driver, NULL,
+                                (void *)name,
+                                device_match_by_alias);
+}
+EXPORT_SYMBOL_GPL(omap_find_iommu_device);
+
+/**
+ * omap_iommu_attach() - attach iommu device to an iommu domain
+ * @dev:        target omap iommu device
+ * @iopgd:      page table
  **/
-struct iommu *iommu_get(const char *name)
+static struct iommu *omap_iommu_attach(struct device *dev, u32 *iopgd)
 {
         int err = -ENOMEM;
-        struct device *dev;
-        struct iommu *obj;
-
-        dev = driver_find_device(&omap_iommu_driver.driver, NULL, (void *)name,
-                                 device_match_by_alias);
-        if (!dev)
-                return ERR_PTR(-ENODEV);
-
-        obj = to_iommu(dev);
+        struct iommu *obj = to_iommu(dev);
 
-        mutex_lock(&obj->iommu_lock);
+        spin_lock(&obj->iommu_lock);
 
-        if (obj->refcount++ == 0) {
-                err = iommu_enable(obj);
-                if (err)
-                        goto err_enable;
-                flush_iotlb_all(obj);
+        /* an iommu device can only be attached once */
+        if (++obj->refcount > 1) {
+                dev_err(dev, "%s: already attached!\n", obj->name);
+                err = -EBUSY;
+                goto err_enable;
         }
 
+        obj->iopgd = iopgd;
+        err = iommu_enable(obj);
+        if (err)
+                goto err_enable;
+        flush_iotlb_all(obj);
+
         if (!try_module_get(obj->owner))
                 goto err_module;
 
-        mutex_unlock(&obj->iommu_lock);
+        spin_unlock(&obj->iommu_lock);
 
         dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
         return obj;
@@ -890,32 +926,32 @@ err_module:
                 iommu_disable(obj);
 err_enable:
         obj->refcount--;
-        mutex_unlock(&obj->iommu_lock);
+        spin_unlock(&obj->iommu_lock);
         return ERR_PTR(err);
 }
-EXPORT_SYMBOL_GPL(iommu_get);
 
 /**
- * iommu_put - Put back iommu handler
+ * omap_iommu_detach - release iommu device
  * @obj:        target iommu
  **/
-void iommu_put(struct iommu *obj)
+static void omap_iommu_detach(struct iommu *obj)
 {
         if (!obj || IS_ERR(obj))
                 return;
 
-        mutex_lock(&obj->iommu_lock);
+        spin_lock(&obj->iommu_lock);
 
         if (--obj->refcount == 0)
                 iommu_disable(obj);
 
         module_put(obj->owner);
 
-        mutex_unlock(&obj->iommu_lock);
+        obj->iopgd = NULL;
+
+        spin_unlock(&obj->iommu_lock);
 
         dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
 }
-EXPORT_SYMBOL_GPL(iommu_put);
 
 int iommu_set_isr(const char *name,
                   int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs,
@@ -950,7 +986,6 @@ EXPORT_SYMBOL_GPL(iommu_set_isr);
 static int __devinit omap_iommu_probe(struct platform_device *pdev)
 {
         int err = -ENODEV;
-        void *p;
         int irq;
         struct iommu *obj;
         struct resource *res;
@@ -974,7 +1009,7 @@ static int __devinit omap_iommu_probe(struct platform_device *pdev)
         obj->da_start = pdata->da_start;
         obj->da_end = pdata->da_end;
 
-        mutex_init(&obj->iommu_lock);
+        spin_lock_init(&obj->iommu_lock);
         mutex_init(&obj->mmap_lock);
         spin_lock_init(&obj->page_table_lock);
         INIT_LIST_HEAD(&obj->mmap);
@@ -1009,22 +1044,9 @@ static int __devinit omap_iommu_probe(struct platform_device *pdev)
                 goto err_irq;
         platform_set_drvdata(pdev, obj);
 
-        p = (void *)__get_free_pages(GFP_KERNEL, get_order(IOPGD_TABLE_SIZE));
-        if (!p) {
-                err = -ENOMEM;
-                goto err_pgd;
-        }
-        memset(p, 0, IOPGD_TABLE_SIZE);
-        clean_dcache_area(p, IOPGD_TABLE_SIZE);
-        obj->iopgd = p;
-
-        BUG_ON(!IS_ALIGNED((unsigned long)obj->iopgd, IOPGD_TABLE_SIZE));
-
         dev_info(&pdev->dev, "%s registered\n", obj->name);
         return 0;
 
-err_pgd:
-        free_irq(irq, obj);
 err_irq:
         iounmap(obj->regbase);
 err_ioremap:
@@ -1045,7 +1067,6 @@ static int __devexit omap_iommu_remove(struct platform_device *pdev)
         platform_set_drvdata(pdev, NULL);
 
         iopgtable_clear_entry_all(obj);
-        free_pages((unsigned long)obj->iopgd, get_order(IOPGD_TABLE_SIZE));
 
         irq = platform_get_irq(pdev, 0);
         free_irq(irq, obj);
@@ -1072,6 +1093,207 @@ static void iopte_cachep_ctor(void *iopte)
         clean_dcache_area(iopte, IOPTE_TABLE_SIZE);
 }
 
+static int omap_iommu_map(struct iommu_domain *domain, unsigned long da,
+                         phys_addr_t pa, int order, int prot)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+        struct iommu *oiommu = omap_domain->iommu_dev;
+        struct device *dev = oiommu->dev;
+        size_t bytes = PAGE_SIZE << order;
+        struct iotlb_entry e;
+        int omap_pgsz;
+        u32 ret, flags;
+
+        /* we only support mapping a single iommu page for now */
+        omap_pgsz = bytes_to_iopgsz(bytes);
+        if (omap_pgsz < 0) {
+                dev_err(dev, "invalid size to map: %d\n", bytes);
+                return -EINVAL;
+        }
+
+        dev_dbg(dev, "mapping da 0x%lx to pa 0x%x size 0x%x\n", da, pa, bytes);
+
+        flags = omap_pgsz | prot;
+
+        iotlb_init_entry(&e, da, pa, flags);
+
+        ret = iopgtable_store_entry(oiommu, &e);
+        if (ret) {
+                dev_err(dev, "iopgtable_store_entry failed: %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int omap_iommu_unmap(struct iommu_domain *domain, unsigned long da,
+                            int order)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+        struct iommu *oiommu = omap_domain->iommu_dev;
+        struct device *dev = oiommu->dev;
+        size_t bytes = PAGE_SIZE << order;
+        size_t ret;
+
+        dev_dbg(dev, "unmapping da 0x%lx size 0x%x\n", da, bytes);
+
+        ret = iopgtable_clear_entry(oiommu, da);
+        if (ret != bytes) {
+                dev_err(dev, "entry @ 0x%lx was %d; not %d\n", da, ret, bytes);
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static int
+omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+        struct iommu *oiommu;
+        int ret = 0;
+
+        spin_lock(&omap_domain->lock);
+
+        /* only a single device is supported per domain for now */
+        if (omap_domain->iommu_dev) {
+                dev_err(dev, "iommu domain is already attached\n");
+                ret = -EBUSY;
+                goto out;
+        }
+
+        /* get a handle to and enable the omap iommu */
+        oiommu = omap_iommu_attach(dev, omap_domain->pgtable);
+        if (IS_ERR(oiommu)) {
+                ret = PTR_ERR(oiommu);
+                dev_err(dev, "can't get omap iommu: %d\n", ret);
+                goto out;
+        }
+
+        omap_domain->iommu_dev = oiommu;
+
+out:
+        spin_unlock(&omap_domain->lock);
+        return ret;
+}
+
+static void omap_iommu_detach_dev(struct iommu_domain *domain,
+                                 struct device *dev)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+        struct iommu *oiommu = to_iommu(dev);
+
+        spin_lock(&omap_domain->lock);
+
+        /* only a single device is supported per domain for now */
+        if (omap_domain->iommu_dev != oiommu) {
+                dev_err(dev, "invalid iommu device\n");
+                goto out;
+        }
+
+        iopgtable_clear_entry_all(oiommu);
+
+        omap_iommu_detach(oiommu);
+
+        omap_domain->iommu_dev = NULL;
+
+out:
+        spin_unlock(&omap_domain->lock);
+}
+
+static int omap_iommu_domain_init(struct iommu_domain *domain)
+{
+        struct omap_iommu_domain *omap_domain;
+
+        omap_domain = kzalloc(sizeof(*omap_domain), GFP_KERNEL);
+        if (!omap_domain) {
+                pr_err("kzalloc failed\n");
+                goto out;
+        }
+
+        omap_domain->pgtable = kzalloc(IOPGD_TABLE_SIZE, GFP_KERNEL);
+        if (!omap_domain->pgtable) {
+                pr_err("kzalloc failed\n");
+                goto fail_nomem;
+        }
+
+        /*
+         * should never fail, but please keep this around to ensure
+         * we keep the hardware happy
+         */
+        BUG_ON(!IS_ALIGNED((long)omap_domain->pgtable, IOPGD_TABLE_SIZE));
+
+        clean_dcache_area(omap_domain->pgtable, IOPGD_TABLE_SIZE);
+        spin_lock_init(&omap_domain->lock);
+
+        domain->priv = omap_domain;
+
+        return 0;
+
+fail_nomem:
+        kfree(omap_domain);
+out:
+        return -ENOMEM;
+}
+
+/* assume device was already detached */
+static void omap_iommu_domain_destroy(struct iommu_domain *domain)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+
+        domain->priv = NULL;
+
+        kfree(omap_domain->pgtable);
+        kfree(omap_domain);
+}
+
+static phys_addr_t omap_iommu_iova_to_phys(struct iommu_domain *domain,
+                                          unsigned long da)
+{
+        struct omap_iommu_domain *omap_domain = domain->priv;
+        struct iommu *oiommu = omap_domain->iommu_dev;
+        struct device *dev = oiommu->dev;
+        u32 *pgd, *pte;
+        phys_addr_t ret = 0;
+
+        iopgtable_lookup_entry(oiommu, da, &pgd, &pte);
+
+        if (pte) {
+                if (iopte_is_small(*pte))
+                        ret = omap_iommu_translate(*pte, da, IOPTE_MASK);
+                else if (iopte_is_large(*pte))
+                        ret = omap_iommu_translate(*pte, da, IOLARGE_MASK);
+                else
+                        dev_err(dev, "bogus pte 0x%x", *pte);
+        } else {
+                if (iopgd_is_section(*pgd))
+                        ret = omap_iommu_translate(*pgd, da, IOSECTION_MASK);
+                else if (iopgd_is_super(*pgd))
+                        ret = omap_iommu_translate(*pgd, da, IOSUPER_MASK);
+                else
+                        dev_err(dev, "bogus pgd 0x%x", *pgd);
+        }
+
+        return ret;
+}
+
+static int omap_iommu_domain_has_cap(struct iommu_domain *domain,
+                                    unsigned long cap)
+{
+        return 0;
+}
+
+static struct iommu_ops omap_iommu_ops = {
+        .domain_init    = omap_iommu_domain_init,
+        .domain_destroy = omap_iommu_domain_destroy,
+        .attach_dev     = omap_iommu_attach_dev,
+        .detach_dev     = omap_iommu_detach_dev,
+        .map            = omap_iommu_map,
+        .unmap          = omap_iommu_unmap,
+        .iova_to_phys   = omap_iommu_iova_to_phys,
+        .domain_has_cap = omap_iommu_domain_has_cap,
+};
+
 static int __init omap_iommu_init(void)
 {
         struct kmem_cache *p;
@@ -1084,6 +1306,8 @@ static int __init omap_iommu_init(void)
                 return -ENOMEM;
         iopte_cachep = p;
 
+        register_iommu(&omap_iommu_ops);
+
         return platform_driver_register(&omap_iommu_driver);
 }
 module_init(omap_iommu_init);