[PATCH v2] of: iommu: make of_iommu_init() postcore_initcall_sync

[PATCH v2] of: iommu: make of_iommu_init() postcore_initcall_sync

[Kefeng Wang]

The of_iommu_init() is called multiple times by arch code,
make it postcore_initcall_sync, then we can drop relevant
calls fully.

Note, the IOMMUs should have a chance to perform some basic
initialisation before we start adding masters to them. So
postcore_initcall_sync is good choice, it ensures of_iommu_init()
called before of_platform_populate.

Acked-by: Rich Felker <dalias@libc.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---

Change since v1:
- Rebase to v4.7-rc1
- Add ack/test

 arch/arm/kernel/setup.c     | 2 --
 arch/arm64/kernel/setup.c   | 2 --
 arch/sh/boards/of-generic.c | 2 --
 drivers/iommu/of_iommu.c    | 5 ++++-
 include/linux/of_iommu.h    | 2 --
 5 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 7b53500..7e455339 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -19,7 +19,6 @@
 #include <linux/bootmem.h>
 #include <linux/seq_file.h>
 #include <linux/screen_info.h>
-#include <linux/of_iommu.h>
 #include <linux/of_platform.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
@@ -903,7 +902,6 @@ static int __init customize_machine(void)
 	 * machine from the device tree, if no callback is provided,
 	 * otherwise we would always need an init_machine callback.
 	 */
-	of_iommu_init();
 	if (machine_desc->init_machine)
 		machine_desc->init_machine();
 #ifdef CONFIG_OF
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 3279def..8412520 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -39,7 +39,6 @@
 #include <linux/fs.h>
 #include <linux/proc_fs.h>
 #include <linux/memblock.h>
-#include <linux/of_iommu.h>
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 #include <linux/efi.h>
@@ -305,7 +304,6 @@ void __init setup_arch(char **cmdline_p)
 static int __init arm64_device_init(void)
 {
 	if (of_have_populated_dt()) {
-		of_iommu_init();
 		of_platform_populate(NULL, of_default_bus_match_table,
 				     NULL, NULL);
 	} else if (acpi_disabled) {
diff --git a/arch/sh/boards/of-generic.c b/arch/sh/boards/of-generic.c
index bf3a166..b4d4313 100644
--- a/arch/sh/boards/of-generic.c
+++ b/arch/sh/boards/of-generic.c
@@ -11,7 +11,6 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_fdt.h>
-#include <linux/of_iommu.h>
 #include <linux/clocksource.h>
 #include <linux/irqchip.h>
 #include <linux/clk-provider.h>
@@ -185,7 +184,6 @@ static int __init sh_of_device_init(void)
 {
 	pr_info("SH generic board support: populating platform devices\n");
 	if (of_have_populated_dt()) {
-		of_iommu_init();
 		of_platform_populate(NULL, of_default_bus_match_table,
 				     NULL, NULL);
 	} else {
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index af499ae..57f23ea 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -174,7 +174,7 @@ err_put_node:
 	return NULL;
 }
 
-void __init of_iommu_init(void)
+static int __init of_iommu_init(void)
 {
 	struct device_node *np;
 	const struct of_device_id *match, *matches = &__iommu_of_table;
@@ -186,4 +186,7 @@ void __init of_iommu_init(void)
 			pr_err("Failed to initialise IOMMU %s\n",
 				of_node_full_name(np));
 	}
+
+	return 0;
 }
+postcore_initcall_sync(of_iommu_init);
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index bd02b44..e80b9c7 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -11,7 +11,6 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix,
 			     int index, unsigned long *busno, dma_addr_t *addr,
 			     size_t *size);
 
-extern void of_iommu_init(void);
 extern const struct iommu_ops *of_iommu_configure(struct device *dev,
 					struct device_node *master_np);
 
@@ -24,7 +23,6 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
 	return -EINVAL;
 }
 
-static inline void of_iommu_init(void) { }
 static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
 					 struct device_node *master_np)
 {
-- 
1.7.12.4

Re: [PATCH v2] of: iommu: make of_iommu_init() postcore_initcall_sync

[Rob Herring]

On Wed, Jun 1, 2016 at 1:06 AM, Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
> The of_iommu_init() is called multiple times by arch code,
> make it postcore_initcall_sync, then we can drop relevant
> calls fully.
>
> Note, the IOMMUs should have a chance to perform some basic
> initialisation before we start adding masters to them. So
> postcore_initcall_sync is good choice, it ensures of_iommu_init()
> called before of_platform_populate.

What ever happened to doing deferred probe for IOMMUs?

Rob

Re: [PATCH v2] of: iommu: make of_iommu_init() postcore_initcall_sync

[Robin Murphy]

On 08/06/16 16:44, Rob Herring wrote:
> On Wed, Jun 1, 2016 at 1:06 AM, Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>> The of_iommu_init() is called multiple times by arch code,
>> make it postcore_initcall_sync, then we can drop relevant
>> calls fully.
>>
>> Note, the IOMMUs should have a chance to perform some basic
>> initialisation before we start adding masters to them. So
>> postcore_initcall_sync is good choice, it ensures of_iommu_init()
>> called before of_platform_populate.
>
> What ever happened to doing deferred probe for IOMMUs?

Sricharan has been trying to resurrect it recently[1], although the fact 
that we're starting to need more or less the same thing for certain 
interrupt controllers as well (and I'm not sure how immune ACPI IORT is 
to the problem) suggests a more general rethink might be in order. I've 
got a big TODO item hanging over me on that one...

Robin.

[1]:http://thread.gmane.org/gmane.linux.kernel.iommu/13243

>
> Rob
>