[PATCH 0/2] OMAP IOMMU cleanups

[PATCH 0/2] OMAP IOMMU cleanups

[Laurent Pinchart]

Hello,

Those two patches clean up the OMAP IOMMU driver. Please see individual commit
messages for more information.

Laurent Pinchart (2):
  iommu/omap: Reverse dependency between omap-iommu and omap-iommu2
  iommu/omap: Remove omap_iommu unused owner field

 drivers/iommu/omap-iommu-debug.c |   6 ++-
 drivers/iommu/omap-iommu.c       | 103 ++++++++++++---------------------------
 drivers/iommu/omap-iommu.h       |  11 +++--
 drivers/iommu/omap-iommu2.c      |  18 +------
 4 files changed, 44 insertions(+), 94 deletions(-)

-- 
Regards,

Laurent Pinchart

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

[Laurent Pinchart]

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

[PATCH 2/2] iommu/omap: Remove omap_iommu unused owner field

[Laurent Pinchart]

The owner field is never set. Remove it.

Signed-off-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
---
 drivers/iommu/omap-iommu.c | 11 -----------
 drivers/iommu/omap-iommu.h |  1 -
 2 files changed, 12 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 192c367..fdfe732 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -861,20 +861,11 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
 		goto err_enable;
 	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;
-	}
-
 	spin_unlock(&obj->iommu_lock);
 
 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
 	return obj;
 
-err_module:
-	if (obj->refcount == 1)
-		iommu_disable(obj);
 err_enable:
 	obj->refcount--;
 	spin_unlock(&obj->iommu_lock);
@@ -895,8 +886,6 @@ static void omap_iommu_detach(struct omap_iommu *obj)
 	if (--obj->refcount == 0)
 		iommu_disable(obj);
 
-	module_put(obj->owner);
-
 	obj->iopgd = NULL;
 
 	spin_unlock(&obj->iommu_lock);
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index 7a90800..2c3b85c 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -28,7 +28,6 @@ struct iotlb_entry {
 
 struct omap_iommu {
 	const char	*name;
-	struct module	*owner;
 	void __iomem	*regbase;
 	struct device	*dev;
 	void		*isr_priv;
-- 
1.8.5.5

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

[Suman Anna]

Hi Laurent,

On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
> 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.)

Thank you for the patch. I had something similar in my list of cleanup
TODO items on the OMAP IOMMU driver, but I was intending to cut down
more and consolidate the omap-iommu.c and omap-iommu2.c files into a
single one.

This had been the case from the introduction of the driver going back to
v2.6.30, and OMAP1 was never added and I doubt it would be added anytime
in the foreseeable future.

> 
> 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),

Yep, except for a few enhancements (like reporting Fault PC address on
OMAP4 DSPs, and dropping both endianness support), the core IOMMU
functionality hasn't changed much between OMAP2 and the latest OMAP4+
SoCs. So, my plan was to completely get rid of the iommu_functions (it
also eliminates the need for exporting most of the OMAP IOMMU API). So
while I am ok with the current patch, I prefer consolidation than
keeping the scalability alive, it can always be added if a need for that
arises. What do you think?

 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.

This can be fixed if we make the current omap-iommu2.c as a
subsys_initcall as well, right?

regards
Suman

> 
> 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");
> 

Re: [PATCH 2/2] iommu/omap: Remove omap_iommu unused owner field

[Suman Anna]

Hi Laurent,

On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
> The owner field is never set. Remove it.

Thanks, this seems to have been dead code since the days OMAP IOMMU has
been converted from building as modules to built-in as part of the IOMMU
API adoption. So,

Acked-by: Suman Anna <s-anna@ti.com>

regards
Suman

> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/iommu/omap-iommu.c | 11 -----------
>  drivers/iommu/omap-iommu.h |  1 -
>  2 files changed, 12 deletions(-)
> 
> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> index 192c367..fdfe732 100644
> --- a/drivers/iommu/omap-iommu.c
> +++ b/drivers/iommu/omap-iommu.c
> @@ -861,20 +861,11 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
>  		goto err_enable;
>  	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;
> -	}
> -
>  	spin_unlock(&obj->iommu_lock);
>  
>  	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
>  	return obj;
>  
> -err_module:
> -	if (obj->refcount == 1)
> -		iommu_disable(obj);
>  err_enable:
>  	obj->refcount--;
>  	spin_unlock(&obj->iommu_lock);
> @@ -895,8 +886,6 @@ static void omap_iommu_detach(struct omap_iommu *obj)
>  	if (--obj->refcount == 0)
>  		iommu_disable(obj);
>  
> -	module_put(obj->owner);
> -
>  	obj->iopgd = NULL;
>  
>  	spin_unlock(&obj->iommu_lock);
> diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
> index 7a90800..2c3b85c 100644
> --- a/drivers/iommu/omap-iommu.h
> +++ b/drivers/iommu/omap-iommu.h
> @@ -28,7 +28,6 @@ struct iotlb_entry {
>  
>  struct omap_iommu {
>  	const char	*name;
> -	struct module	*owner;
>  	void __iomem	*regbase;
>  	struct device	*dev;
>  	void		*isr_priv;
> 

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

[Laurent Pinchart]

Hi Suman,

On Tuesday 09 September 2014 16:33:11 Suman Anna wrote:
> On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
> > 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.)
> 
> Thank you for the patch. I had something similar in my list of cleanup
> TODO items on the OMAP IOMMU driver, but I was intending to cut down
> more and consolidate the omap-iommu.c and omap-iommu2.c files into a
> single one.
> 
> This had been the case from the introduction of the driver going back to
> v2.6.30, and OMAP1 was never added and I doubt it would be added anytime
> in the foreseeable future.
> 
> > 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),
> 
> Yep, except for a few enhancements (like reporting Fault PC address on
> OMAP4 DSPs, and dropping both endianness support), the core IOMMU
> functionality hasn't changed much between OMAP2 and the latest OMAP4+
> SoCs. So, my plan was to completely get rid of the iommu_functions (it
> also eliminates the need for exporting most of the OMAP IOMMU API). So
> while I am ok with the current patch, I prefer consolidation than
> keeping the scalability alive, it can always be added if a need for that
> arises. What do you think?

I agree with your approach, but in the meantime we have a problem to solve. 
How about applying this patch now (it goes in the right direction anyway), and 
then removing the iommu functions when you will have time ?

>  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.
> 
> This can be fixed if we make the current omap-iommu2.c as a
> subsys_initcall as well, right?
> 
> regards
> Suman
> 
> > 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(-)

-- 
Regards,

Laurent Pinchart

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

[Suman Anna]

Hi Laurent,

> On Tuesday 09 September 2014 16:33:11 Suman Anna wrote:
>> On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
>>> 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.)
>>
>> Thank you for the patch. I had something similar in my list of cleanup
>> TODO items on the OMAP IOMMU driver, but I was intending to cut down
>> more and consolidate the omap-iommu.c and omap-iommu2.c files into a
>> single one.
>>
>> This had been the case from the introduction of the driver going back to
>> v2.6.30, and OMAP1 was never added and I doubt it would be added anytime
>> in the foreseeable future.
>>
>>> 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),
>>
>> Yep, except for a few enhancements (like reporting Fault PC address on
>> OMAP4 DSPs, and dropping both endianness support), the core IOMMU
>> functionality hasn't changed much between OMAP2 and the latest OMAP4+
>> SoCs. So, my plan was to completely get rid of the iommu_functions (it
>> also eliminates the need for exporting most of the OMAP IOMMU API). So
>> while I am ok with the current patch, I prefer consolidation than
>> keeping the scalability alive, it can always be added if a need for that
>> arises. What do you think?
> 
> I agree with your approach, but in the meantime we have a problem to solve. 
> How about applying this patch now (it goes in the right direction anyway), and 
> then removing the iommu functions when you will have time ?

Can you give the subsys_initcall solution a try to see if that resolves
the problem at hand? That would be a much smaller change, if that
doesn't work we can go with this patch.

I will work on my cleanup list for 3.19.

regards
Suman

> 
>>  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.
>>
>> This can be fixed if we make the current omap-iommu2.c as a
>> subsys_initcall as well, right?
>>
>> regards
>> Suman
>>
>>> 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@ideasonboard.com>
>>> ---
>>>
>>>  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(-)
> 

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

[Laurent Pinchart]

Hi Suman,

On Tuesday 09 September 2014 17:31:44 Suman Anna wrote:
> > On Tuesday 09 September 2014 16:33:11 Suman Anna wrote:
> >> On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
> >>> 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.)
> >> 
> >> Thank you for the patch. I had something similar in my list of cleanup
> >> TODO items on the OMAP IOMMU driver, but I was intending to cut down
> >> more and consolidate the omap-iommu.c and omap-iommu2.c files into a
> >> single one.
> >> 
> >> This had been the case from the introduction of the driver going back to
> >> v2.6.30, and OMAP1 was never added and I doubt it would be added anytime
> >> in the foreseeable future.
> >> 
> >>> 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),
> >> 
> >> Yep, except for a few enhancements (like reporting Fault PC address on
> >> OMAP4 DSPs, and dropping both endianness support), the core IOMMU
> >> functionality hasn't changed much between OMAP2 and the latest OMAP4+
> >> SoCs. So, my plan was to completely get rid of the iommu_functions (it
> >> also eliminates the need for exporting most of the OMAP IOMMU API). So
> >> while I am ok with the current patch, I prefer consolidation than
> >> keeping the scalability alive, it can always be added if a need for that
> >> arises. What do you think?
> > 
> > I agree with your approach, but in the meantime we have a problem to
> > solve.
> > How about applying this patch now (it goes in the right direction anyway),
> > and then removing the iommu functions when you will have time ?
> 
> Can you give the subsys_initcall solution a try to see if that resolves
> the problem at hand? That would be a much smaller change, if that
> doesn't work we can go with this patch.

It seems to work.

> I will work on my cleanup list for 3.19.

Does that schedule still hold ? If so I'll submit a simple subsys_initcall() 
patch for v3.18.

> >>  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.
> >> 
> >> This can be fixed if we make the current omap-iommu2.c as a
> >> subsys_initcall as well, right?
> >> 
> >> regards
> >> Suman
> >> 
> >>> 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(-)

-- 
Regards,

Laurent Pinchart

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

[Suman Anna]

Hi Laurent,

>
> On Tuesday 09 September 2014 17:31:44 Suman Anna wrote:
>>> On Tuesday 09 September 2014 16:33:11 Suman Anna wrote:
>>>> On 09/09/2014 10:45 AM, Laurent Pinchart wrote:
>>>>> 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.)
>>>>
>>>> Thank you for the patch. I had something similar in my list of cleanup
>>>> TODO items on the OMAP IOMMU driver, but I was intending to cut down
>>>> more and consolidate the omap-iommu.c and omap-iommu2.c files into a
>>>> single one.
>>>>
>>>> This had been the case from the introduction of the driver going back to
>>>> v2.6.30, and OMAP1 was never added and I doubt it would be added anytime
>>>> in the foreseeable future.
>>>>
>>>>> 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),
>>>>
>>>> Yep, except for a few enhancements (like reporting Fault PC address on
>>>> OMAP4 DSPs, and dropping both endianness support), the core IOMMU
>>>> functionality hasn't changed much between OMAP2 and the latest OMAP4+
>>>> SoCs. So, my plan was to completely get rid of the iommu_functions (it
>>>> also eliminates the need for exporting most of the OMAP IOMMU API). So
>>>> while I am ok with the current patch, I prefer consolidation than
>>>> keeping the scalability alive, it can always be added if a need for that
>>>> arises. What do you think?
>>>
>>> I agree with your approach, but in the meantime we have a problem to
>>> solve.
>>> How about applying this patch now (it goes in the right direction anyway),
>>> and then removing the iommu functions when you will have time ?
>>
>> Can you give the subsys_initcall solution a try to see if that resolves
>> the problem at hand? That would be a much smaller change, if that
>> doesn't work we can go with this patch.
> 
> It seems to work.
> 
>> I will work on my cleanup list for 3.19.
> 
> Does that schedule still hold ? If so I'll submit a simple subsys_initcall() 
> patch for v3.18.

Yes, that would be great. I am working on the patches and will post them
in a couple of days.

regards
Suman

> 
>>>>  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.
>>>>
>>>> This can be fixed if we make the current omap-iommu2.c as a
>>>> subsys_initcall as well, right?
>>>>
>>>> regards
>>>> Suman
>>>>
>>>>> 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(-)
> 

Re: [PATCH 2/2] iommu/omap: Remove omap_iommu unused owner field

[Joerg Roedel]

On Tue, Sep 09, 2014 at 06:45:45PM +0300, Laurent Pinchart wrote:
> The owner field is never set. Remove it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> ---
>  drivers/iommu/omap-iommu.c | 11 -----------
>  drivers/iommu/omap-iommu.h |  1 -
>  2 files changed, 12 deletions(-)

Applied this one to arm/omap, thanks.