[PATCH 1/2] iommu/omap: Reverse dependency between omap-iommu and omap-iommu2

[Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>]

The OMAP IOMMU driver supports both the OMAP1 and OMAP2+ IOMMU variants
by splitting the driver into a core module and a thin arch-specific
operations module.

(In practice only the OMAP2+ module omap-iommu2 is implemented, but
let's not denigrate the effort.)

The arch-specific operations module registers itself with the OMAP IOMMU
core module at initialization time. This initializes a module global
arch-specific operations pointer, used at runtime by the IOMMU
instances.

This scheme causes several issues. In addition to making it impossible
to support different OMAP IOMMU types in a single system (which in all
fairness is quite unlikely to happen), it also causes initialization
ordering issues by requiring the arch-specific operations module to be
loaded before any IOMMU user. This results in a probe breakage with the
OMAP3 ISP driver when not compiled as a module.

Fix the problem by inverting the dependency. Instead of having the
omap-iommu2 module register itself to iommu-omap, make the iommu-omap
retrieve the omap-iommu2 operations structure directly when probing the
IOMMU device. This ensures that a probed IOMMU will always have valid
arch-specific operations.

As the arch-specific operations pointer is now initialized at probe
time, this change requires turning it from a global variable into a
per-device variable.

Signed-off-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
---
 drivers/iommu/omap-iommu-debug.c |  6 ++-
 drivers/iommu/omap-iommu.c       | 94 ++++++++++++++--------------------------
 drivers/iommu/omap-iommu.h       | 10 ++++-
 drivers/iommu/omap-iommu2.c      | 18 +-------
 4 files changed, 45 insertions(+), 83 deletions(-)

diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
index 531658d..35a2c3a 100644
--- a/drivers/iommu/omap-iommu-debug.c
+++ b/drivers/iommu/omap-iommu-debug.c
@@ -33,7 +33,9 @@ static struct dentry *iommu_debug_root;
 static ssize_t debug_read_ver(struct file *file, char __user *userbuf,
 			      size_t count, loff_t *ppos)
 {
-	u32 ver = omap_iommu_arch_version();
+	struct device *dev = file->private_data;
+	struct omap_iommu *obj = dev_to_omap_iommu(dev);
+	u32 ver = omap_iommu_arch_version(obj);
 	char buf[MAXCOLUMN], *p = buf;
 
 	p += sprintf(p, "H/W version: %d.%d\n", (ver >> 4) & 0xf , ver & 0xf);
@@ -117,7 +119,7 @@ static ssize_t debug_write_pagetable(struct file *file,
 		return -EINVAL;
 	}
 
-	omap_iotlb_cr_to_e(&cr, &e);
+	omap_iotlb_cr_to_e(obj, &cr, &e);
 	err = omap_iopgtable_store_entry(obj, &e);
 	if (err)
 		dev_err(obj->dev, "%s: fail to store cr\n", __func__);
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index df579f8..192c367 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -76,45 +76,10 @@ struct iotlb_lock {
 	short vict;
 };
 
-/* accommodate the difference between omap1 and omap2/3 */
-static const struct iommu_functions *arch_iommu;
-
 static struct platform_driver omap_iommu_driver;
 static struct kmem_cache *iopte_cachep;
 
 /**
- * omap_install_iommu_arch - Install archtecure specific iommu functions
- * @ops:	a pointer to architecture specific iommu functions
- *
- * There are several kind of iommu algorithm(tlb, pagetable) among
- * omap series. This interface installs such an iommu algorighm.
- **/
-int omap_install_iommu_arch(const struct iommu_functions *ops)
-{
-	if (arch_iommu)
-		return -EBUSY;
-
-	arch_iommu = ops;
-	return 0;
-}
-EXPORT_SYMBOL_GPL(omap_install_iommu_arch);
-
-/**
- * omap_uninstall_iommu_arch - Uninstall archtecure specific iommu functions
- * @ops:	a pointer to architecture specific iommu functions
- *
- * This interface uninstalls the iommu algorighm installed previously.
- **/
-void omap_uninstall_iommu_arch(const struct iommu_functions *ops)
-{
-	if (arch_iommu != ops)
-		pr_err("%s: not your arch\n", __func__);
-
-	arch_iommu = NULL;
-}
-EXPORT_SYMBOL_GPL(omap_uninstall_iommu_arch);
-
-/**
  * omap_iommu_save_ctx - Save registers for pm off-mode support
  * @dev:	client device
  **/
@@ -122,7 +87,7 @@ void omap_iommu_save_ctx(struct device *dev)
 {
 	struct omap_iommu *obj = dev_to_omap_iommu(dev);
 
-	arch_iommu->save_ctx(obj);
+	obj->arch_iommu->save_ctx(obj);
 }
 EXPORT_SYMBOL_GPL(omap_iommu_save_ctx);
 
@@ -134,16 +99,16 @@ void omap_iommu_restore_ctx(struct device *dev)
 {
 	struct omap_iommu *obj = dev_to_omap_iommu(dev);
 
-	arch_iommu->restore_ctx(obj);
+	obj->arch_iommu->restore_ctx(obj);
 }
 EXPORT_SYMBOL_GPL(omap_iommu_restore_ctx);
 
 /**
  * omap_iommu_arch_version - Return running iommu arch version
  **/
-u32 omap_iommu_arch_version(void)
+u32 omap_iommu_arch_version(struct omap_iommu *obj)
 {
-	return arch_iommu->version;
+	return obj->arch_iommu->version;
 }
 EXPORT_SYMBOL_GPL(omap_iommu_arch_version);
 
@@ -153,7 +118,7 @@ static int iommu_enable(struct omap_iommu *obj)
 	struct platform_device *pdev = to_platform_device(obj->dev);
 	struct iommu_platform_data *pdata = pdev->dev.platform_data;
 
-	if (!arch_iommu)
+	if (!obj->arch_iommu)
 		return -ENODEV;
 
 	if (pdata && pdata->deassert_reset) {
@@ -166,7 +131,7 @@ static int iommu_enable(struct omap_iommu *obj)
 
 	pm_runtime_get_sync(obj->dev);
 
-	err = arch_iommu->enable(obj);
+	err = obj->arch_iommu->enable(obj);
 
 	return err;
 }
@@ -176,7 +141,7 @@ static void iommu_disable(struct omap_iommu *obj)
 	struct platform_device *pdev = to_platform_device(obj->dev);
 	struct iommu_platform_data *pdata = pdev->dev.platform_data;
 
-	arch_iommu->disable(obj);
+	obj->arch_iommu->disable(obj);
 
 	pm_runtime_put_sync(obj->dev);
 
@@ -187,20 +152,21 @@ static void iommu_disable(struct omap_iommu *obj)
 /*
  *	TLB operations
  */
-void omap_iotlb_cr_to_e(struct cr_regs *cr, struct iotlb_entry *e)
+void omap_iotlb_cr_to_e(struct omap_iommu *obj, struct cr_regs *cr,
+			struct iotlb_entry *e)
 {
 	BUG_ON(!cr || !e);
 
-	arch_iommu->cr_to_e(cr, e);
+	obj->arch_iommu->cr_to_e(cr, e);
 }
 EXPORT_SYMBOL_GPL(omap_iotlb_cr_to_e);
 
-static inline int iotlb_cr_valid(struct cr_regs *cr)
+static inline int iotlb_cr_valid(struct omap_iommu *obj, struct cr_regs *cr)
 {
 	if (!cr)
 		return -EINVAL;
 
-	return arch_iommu->cr_valid(cr);
+	return obj->arch_iommu->cr_valid(cr);
 }
 
 static inline struct cr_regs *iotlb_alloc_cr(struct omap_iommu *obj,
@@ -209,22 +175,22 @@ static inline struct cr_regs *iotlb_alloc_cr(struct omap_iommu *obj,
 	if (!e)
 		return NULL;
 
-	return arch_iommu->alloc_cr(obj, e);
+	return obj->arch_iommu->alloc_cr(obj, e);
 }
 
-static u32 iotlb_cr_to_virt(struct cr_regs *cr)
+static u32 iotlb_cr_to_virt(struct omap_iommu *obj, struct cr_regs *cr)
 {
-	return arch_iommu->cr_to_virt(cr);
+	return obj->arch_iommu->cr_to_virt(cr);
 }
 
-static u32 get_iopte_attr(struct iotlb_entry *e)
+static u32 get_iopte_attr(struct omap_iommu *obj, struct iotlb_entry *e)
 {
-	return arch_iommu->get_pte_attr(e);
+	return obj->arch_iommu->get_pte_attr(e);
 }
 
 static u32 iommu_report_fault(struct omap_iommu *obj, u32 *da)
 {
-	return arch_iommu->fault_isr(obj, da);
+	return obj->arch_iommu->fault_isr(obj, da);
 }
 
 static void iotlb_lock_get(struct omap_iommu *obj, struct iotlb_lock *l)
@@ -250,12 +216,12 @@ static void iotlb_lock_set(struct omap_iommu *obj, struct iotlb_lock *l)
 
 static void iotlb_read_cr(struct omap_iommu *obj, struct cr_regs *cr)
 {
-	arch_iommu->tlb_read_cr(obj, cr);
+	obj->arch_iommu->tlb_read_cr(obj, cr);
 }
 
 static void iotlb_load_cr(struct omap_iommu *obj, struct cr_regs *cr)
 {
-	arch_iommu->tlb_load_cr(obj, cr);
+	obj->arch_iommu->tlb_load_cr(obj, cr);
 
 	iommu_write_reg(obj, 1, MMU_FLUSH_ENTRY);
 	iommu_write_reg(obj, 1, MMU_LD_TLB);
@@ -272,7 +238,7 @@ static inline ssize_t iotlb_dump_cr(struct omap_iommu *obj, struct cr_regs *cr,
 {
 	BUG_ON(!cr || !buf);
 
-	return arch_iommu->dump_cr(obj, cr, buf);
+	return obj->arch_iommu->dump_cr(obj, cr, buf);
 }
 
 /* only used in iotlb iteration for-loop */
@@ -317,7 +283,7 @@ static int load_iotlb_entry(struct omap_iommu *obj, struct iotlb_entry *e)
 		struct cr_regs tmp;
 
 		for_each_iotlb_cr(obj, obj->nr_tlb_entries, i, tmp)
-			if (!iotlb_cr_valid(&tmp))
+			if (!iotlb_cr_valid(obj, &tmp))
 				break;
 
 		if (i == obj->nr_tlb_entries) {
@@ -384,10 +350,10 @@ static void flush_iotlb_page(struct omap_iommu *obj, u32 da)
 		u32 start;
 		size_t bytes;
 
-		if (!iotlb_cr_valid(&cr))
+		if (!iotlb_cr_valid(obj, &cr))
 			continue;
 
-		start = iotlb_cr_to_virt(&cr);
+		start = iotlb_cr_to_virt(obj, &cr);
 		bytes = iopgsz_to_bytes(cr.cam & 3);
 
 		if ((start <= da) && (da < start + bytes)) {
@@ -432,7 +398,7 @@ ssize_t omap_iommu_dump_ctx(struct omap_iommu *obj, char *buf, ssize_t bytes)
 
 	pm_runtime_get_sync(obj->dev);
 
-	bytes = arch_iommu->dump_ctx(obj, buf, bytes);
+	bytes = obj->arch_iommu->dump_ctx(obj, buf, bytes);
 
 	pm_runtime_put_sync(obj->dev);
 
@@ -452,7 +418,7 @@ __dump_tlb_entries(struct omap_iommu *obj, struct cr_regs *crs, int num)
 	iotlb_lock_get(obj, &saved);
 
 	for_each_iotlb_cr(obj, num, i, tmp) {
-		if (!iotlb_cr_valid(&tmp))
+		if (!iotlb_cr_valid(obj, &tmp))
 			continue;
 		*p++ = tmp;
 	}
@@ -666,7 +632,7 @@ iopgtable_store_entry_core(struct omap_iommu *obj, struct iotlb_entry *e)
 		break;
 	}
 
-	prot = get_iopte_attr(e);
+	prot = get_iopte_attr(obj, e);
 
 	spin_lock(&obj->page_table_lock);
 	err = fn(obj, e->da, e->pa, prot);
@@ -873,8 +839,10 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
 	dev = driver_find_device(&omap_iommu_driver.driver, NULL,
 				(void *)name,
 				device_match_by_alias);
-	if (!dev)
+	if (!dev) {
+		dev_err(dev, "%s: can't find IOMMU %s\n", __func__, name);
 		return ERR_PTR(-ENODEV);
+	}
 
 	obj = to_iommu(dev);
 
@@ -894,6 +862,7 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
 	flush_iotlb_all(obj);
 
 	if (!try_module_get(obj->owner)) {
+		dev_err(obj->dev, "%s: can't get owner\n", __func__);
 		err = -ENODEV;
 		goto err_module;
 	}
@@ -969,6 +938,7 @@ static int omap_iommu_probe(struct platform_device *pdev)
 
 	obj->dev = &pdev->dev;
 	obj->ctx = (void *)obj + sizeof(*obj);
+	obj->arch_iommu = &omap2_iommu_ops;
 
 	spin_lock_init(&obj->iommu_lock);
 	spin_lock_init(&obj->page_table_lock);
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index 1275a82..7a90800 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -46,6 +46,9 @@ struct omap_iommu {
 
 	int		nr_tlb_entries;
 
+	/* accommodate the difference between omap1 and omap2/3 */
+	const struct iommu_functions *arch_iommu;
+
 	void *ctx; /* iommu context: registres saved area */
 
 	int has_bus_err_back;
@@ -193,9 +196,10 @@ static inline struct omap_iommu *dev_to_omap_iommu(struct device *dev)
 /*
  * global functions
  */
-extern u32 omap_iommu_arch_version(void);
+extern u32 omap_iommu_arch_version(struct omap_iommu *obj);
 
-extern void omap_iotlb_cr_to_e(struct cr_regs *cr, struct iotlb_entry *e);
+extern void omap_iotlb_cr_to_e(struct omap_iommu *obj, struct cr_regs *cr,
+			       struct iotlb_entry *e);
 
 extern int
 omap_iopgtable_store_entry(struct omap_iommu *obj, struct iotlb_entry *e);
@@ -214,6 +218,8 @@ omap_iommu_dump_ctx(struct omap_iommu *obj, char *buf, ssize_t len);
 extern size_t
 omap_dump_tlb_entries(struct omap_iommu *obj, char *buf, ssize_t len);
 
+extern const struct iommu_functions omap2_iommu_ops;
+
 /*
  * register accessors
  */
diff --git a/drivers/iommu/omap-iommu2.c b/drivers/iommu/omap-iommu2.c
index 5e1ea3b..e72fe62 100644
--- a/drivers/iommu/omap-iommu2.c
+++ b/drivers/iommu/omap-iommu2.c
@@ -296,7 +296,7 @@ static void omap2_cr_to_e(struct cr_regs *cr, struct iotlb_entry *e)
 	e->mixed	= cr->ram & MMU_RAM_MIXED;
 }
 
-static const struct iommu_functions omap2_iommu_ops = {
+const struct iommu_functions omap2_iommu_ops = {
 	.version	= IOMMU_ARCH_VERSION,
 
 	.enable		= omap2_iommu_enable,
@@ -319,19 +319,3 @@ static const struct iommu_functions omap2_iommu_ops = {
 	.restore_ctx	= omap2_iommu_restore_ctx,
 	.dump_ctx	= omap2_iommu_dump_ctx,
 };
-
-static int __init omap2_iommu_init(void)
-{
-	return omap_install_iommu_arch(&omap2_iommu_ops);
-}
-module_init(omap2_iommu_init);
-
-static void __exit omap2_iommu_exit(void)
-{
-	omap_uninstall_iommu_arch(&omap2_iommu_ops);
-}
-module_exit(omap2_iommu_exit);
-
-MODULE_AUTHOR("Hiroshi DOYU, Paul Mundt and Toshihiro Kobayashi");
-MODULE_DESCRIPTION("omap iommu: omap2/3 architecture specific functions");
-MODULE_LICENSE("GPL v2");
-- 
1.8.5.5