[RFC 1/6] omap: iommu: generic iommu api migration

Ohad Ben-Cohen
2011-06-02T22:31:08Z

Migrate OMAP's iommu to the generic iommu api, so users can stay
generic, and non-omap-specific code can be removed and eventually
consolidated into a generic framework.

Tested on both OMAP3 and OMAP4.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
---
arch/arm/plat-omap/Kconfig | 7 +-
arch/arm/plat-omap/include/plat/iommu.h | 3 +-
arch/arm/plat-omap/iommu.c | 288 +++++++++++++++++++++++++++----
arch/arm/plat-omap/iopgtable.h | 18 ++
4 files changed, 278 insertions(+), 38 deletions(-)

diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index 49a4c75..1c3acb5 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -131,8 +131,13 @@ config OMAP_MBOX_KFIFO_SIZE
This can also be changed at runtime (via the mbox_kfifo_size
module parameter).

+config IOMMU_API
+ bool
+
+#can't be tristate; iommu api doesn't support un-registration
config OMAP_IOMMU
- tristate
+ bool
+ select IOMMU_API

config OMAP_IOMMU_DEBUG
tristate "Export OMAP IOMMU internals in DebugFS"
diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
index 174f1b9..db1c492 100644
--- a/arch/arm/plat-omap/include/plat/iommu.h
+++ b/arch/arm/plat-omap/include/plat/iommu.h
@@ -167,8 +167,6 @@ extern void iopgtable_lookup_entry(struct iommu *obj, u32 da, u32 **ppgd,
extern size_t iopgtable_clear_entry(struct iommu *obj, u32 iova);

extern int iommu_set_da_range(struct iommu *obj, u32 start, u32 end);
-extern struct iommu *iommu_get(const char *name);
-extern void iommu_put(struct iommu *obj);
extern int iommu_set_isr(const char *name,
int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs,
void *priv),
@@ -185,5 +183,6 @@ extern int foreach_iommu_device(void *data,

extern ssize_t iommu_dump_ctx(struct iommu *obj, char *buf, ssize_t len);
extern size_t dump_tlb_entries(struct iommu *obj, char *buf, ssize_t len);
+struct device *omap_find_iommu_device(const char *name);

#endif /* __MACH_IOMMU_H */
diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index 34fc31e..f06e99c 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -18,6 +18,8 @@
#include <linux/ioport.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
+#include <linux/iommu.h>
+#include <linux/mutex.h>

#include <asm/cacheflush.h>

@@ -30,6 +32,19 @@
(__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;
+ struct mutex lock;
+};
+
/* accommodate the difference between omap1 and omap2/3 */
static const struct iommu_functions *arch_iommu;

@@ -852,31 +867,50 @@ 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. Users of that API
+ * may look up the device using PCI credentials when relevent, and when
+ * not, this helper should be used to find a specific iommu device by name.
+ *
+ * This may be relevant to other platforms as well (msm ?) so consider
+ * moving this to the generic iommu framework.
+ */
+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);

- 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;

@@ -893,13 +927,12 @@ err_enable:
mutex_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;
@@ -911,11 +944,12 @@ void iommu_put(struct iommu *obj)

module_put(obj->owner);

+ obj->iopgd = NULL;
+
mutex_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 +984,6 @@ 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;
@@ -1009,22 +1042,9 @@ 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:
@@ -1072,6 +1092,202 @@ 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;
+
+ mutex_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:
+ mutex_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);
+
+ mutex_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:
+ mutex_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 fail_nomem;
+ }
+
+ omap_domain->pgtable = (u32 *)__get_free_pages(GFP_KERNEL,
+ get_order(IOPGD_TABLE_SIZE));
+ if (!omap_domain->pgtable) {
+ pr_err("__get_free_pages failed\n");
+ goto fail_nomem;
+ }
+
+ BUG_ON(!IS_ALIGNED((long)omap_domain->pgtable, IOPGD_TABLE_SIZE));
+ memset(omap_domain->pgtable, 0, IOPGD_TABLE_SIZE);
+ clean_dcache_area(omap_domain->pgtable, IOPGD_TABLE_SIZE);
+ mutex_init(&omap_domain->lock);
+
+ domain->priv = omap_domain;
+
+ return 0;
+
+fail_nomem:
+ kfree(omap_domain);
+ 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);
+}
+
+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 +1300,8 @@ 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);
diff --git a/arch/arm/plat-omap/iopgtable.h b/arch/arm/plat-omap/iopgtable.h
index c3e93bb..33c7aa9 100644
--- a/arch/arm/plat-omap/iopgtable.h
+++ b/arch/arm/plat-omap/iopgtable.h
@@ -56,6 +56,19 @@

#define IOPAGE_MASK IOPTE_MASK

+/**
+ * omap_iommu_translate() - va to pa translation
+ * @d: omap iommu descriptor
+ * @va: virtual address
+ * @mask: omap iommu descriptor mask
+ *
+ * va to pa translation
+ */
+static inline phys_addr_t omap_iommu_translate(u32 d, u32 va, u32 mask)
+{
+ return (d & mask) | (va & (~mask));
+}
+
/*
* some descriptor attributes.
*/
@@ -64,10 +77,15 @@
#define IOPGD_SUPER (1 << 18 | 2 << 0)

#define iopgd_is_table(x) (((x) & 3) == IOPGD_TABLE)
+#define iopgd_is_section(x) (((x) & (1 << 18 | 3)) == IOPGD_SECTION)
+#define iopgd_is_super(x) (((x) & (1 << 18 | 3)) == IOPGD_SUPER)

#define IOPTE_SMALL (2 << 0)
#define IOPTE_LARGE (1 << 0)

+#define iopte_is_small(x) (((x) & 2) == IOPTE_SMALL)
+#define iopte_is_large(x) (((x) & 3) == IOPTE_LARGE)
+
/* to find an entry in a page-table-directory */
#define iopgd_index(da) (((da) >> IOPGD_SHIFT) & (PTRS_PER_IOPGD - 1))
#define iopgd_offset(obj, da) ((obj)->iopgd + iopgd_index(da))
--
1.7.1