Date: Sat, 23 Apr 2016 14:03:19 -0400
From: Rich Felker <dalias@libc.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        guohanjun@huawei.com, Arnd Bergmann <arnd@arndb.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Rob Herring <robh+dt@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH] of: iommu: make of_iommu_init() postcore_initcall_sync
Message-ID: <20160423180319.GC21636@brightrain.aerifal.cx>
References: <1461403987-10697-1-git-send-email-wangkefeng.wang@huawei.com>
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On Sat, Apr 23, 2016 at 05:33:07PM +0800, Kefeng Wang 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.
> 
> Cc: Arnd Bergmann <arnd@arndb.de>
> 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>

Acked-by: Rich Felker <dalias@libc.org>

> ---
>  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 2c4bea3..18a29a0 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>
> @@ -902,7 +901,6 @@ 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 9dc6776..e20b64f 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>
> @@ -365,7 +364,6 @@ 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 5fea665..04cc80f 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 ffbe470..e2c2e71 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 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 struct iommu_ops *of_iommu_configure(struct device *dev,
>  					 struct device_node *master_np)
>  {
> -- 
> 2.6.0.GIT