Re: [PATCH 12/17] iommu/omap: Integrate omap-iommu-debug into omap-iommu

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Suman,

Thank you for the patch.

On Tuesday 30 September 2014 16:16:07 Suman Anna wrote:
> The debugfs support for OMAP IOMMU is currently implemented
> as a module, warranting certain OMAP-specific IOMMU API to
> be exported. The OMAP IOMMU, when enabled, can only be built-in
> into the kernel, so integrate the OMAP IOMMU debug module
> into the OMAP IOMMU driver. This helps in eliminating the
> need to export most of the current OMAP IOMMU API.
> 
> The following are the main changes:
> - The OMAP_IOMMU_DEBUG Kconfig option is eliminated, and
>   the OMAP IOMMU debugfs support is built alongside the OMAP
>   IOMMU driver, and enabled automatically only when debugfs
>   is enabled.

That's the part I'm unsure about. We're loosing the ability to save space by 
not building the omap-iommu debugfs support when debugfs is enabled.

For the rest of the series,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> - The debugfs directory and entry creation logic is reversed,
>   the calls are invoked by the OMAP IOMMU driver now.
> - The current iffy circular logic of adding IOMMU archdata
>   to the IOMMU devices itself to get a pointer to the omap_iommu
>   object in the debugfs support code is replaced by directly
>   using the omap_iommu structure while creating the debugfs
>   entries.
> - The debugfs root directory is renamed from the generic name
>   "iommu" to a specific name "omap_iommu".
> - Unneeded headers have also been cleaned up while at this.
> - There will no longer be a omap-iommu-debug.ko module after
>   this patch.
> 
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
>  drivers/iommu/Kconfig            |   9 ----
>  drivers/iommu/Makefile           |   3 +-
>  drivers/iommu/omap-iommu-debug.c | 102
> ++++++++++++--------------------------- drivers/iommu/omap-iommu.c       | 
> 11 +++--
>  drivers/iommu/omap-iommu.h       |   7 +++
>  5 files changed, 45 insertions(+), 87 deletions(-)
> 
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index dd51122..9724d4a 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -143,15 +143,6 @@ config OMAP_IOMMU
>  	depends on ARCH_OMAP2PLUS
>  	select IOMMU_API
> 
> -config OMAP_IOMMU_DEBUG
> -       tristate "Export OMAP IOMMU internals in DebugFS"
> -       depends on OMAP_IOMMU && DEBUG_FS
> -       help
> -         Select this to see extensive information about
> -         the internal state of OMAP IOMMU in debugfs.
> -
> -         Say N unless you know you need this.
> -
>  config TEGRA_IOMMU_GART
>  	bool "Tegra GART IOMMU Support"
>  	depends on ARCH_TEGRA_2x_SOC
> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> index 18fa446..e0a4fed 100644
> --- a/drivers/iommu/Makefile
> +++ b/drivers/iommu/Makefile
> @@ -10,8 +10,7 @@ obj-$(CONFIG_DMAR_TABLE) += dmar.o
>  obj-$(CONFIG_INTEL_IOMMU) += iova.o intel-iommu.o
>  obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
>  obj-$(CONFIG_IRQ_REMAP) += intel_irq_remapping.o irq_remapping.o
> -obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
> -obj-$(CONFIG_OMAP_IOMMU_DEBUG) += omap-iommu-debug.o
> +obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o omap-iommu-debug.o
>  obj-$(CONFIG_TEGRA_IOMMU_GART) += tegra-gart.o
>  obj-$(CONFIG_TEGRA_IOMMU_SMMU) += tegra-smmu.o
>  obj-$(CONFIG_EXYNOS_IOMMU) += exynos-iommu.o
> diff --git a/drivers/iommu/omap-iommu-debug.c
> b/drivers/iommu/omap-iommu-debug.c index 28de657..54a0dc6 100644
> --- a/drivers/iommu/omap-iommu-debug.c
> +++ b/drivers/iommu/omap-iommu-debug.c
> @@ -10,15 +10,11 @@
>   * published by the Free Software Foundation.
>   */
> 
> -#include <linux/module.h>
>  #include <linux/err.h>
> -#include <linux/clk.h>
>  #include <linux/io.h>
>  #include <linux/slab.h>
>  #include <linux/uaccess.h>
> -#include <linux/platform_device.h>
>  #include <linux/debugfs.h>
> -#include <linux/omap-iommu.h>
>  #include <linux/platform_data/iommu-omap.h>
> 
>  #include "omap-iopgtable.h"
> @@ -31,8 +27,7 @@ static struct dentry *iommu_debug_root;
>  static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
>  			       size_t count, loff_t *ppos)
>  {
> -	struct device *dev = file->private_data;
> -	struct omap_iommu *obj = dev_to_omap_iommu(dev);
> +	struct omap_iommu *obj = file->private_data;
>  	char *p, *buf;
>  	ssize_t bytes;
> 
> @@ -55,8 +50,7 @@ static ssize_t debug_read_regs(struct file *file, char
> __user *userbuf, static ssize_t debug_read_tlb(struct file *file, char
> __user *userbuf, size_t count, loff_t *ppos)
>  {
> -	struct device *dev = file->private_data;
> -	struct omap_iommu *obj = dev_to_omap_iommu(dev);
> +	struct omap_iommu *obj = file->private_data;
>  	char *p, *buf;
>  	ssize_t bytes, rest;
> 
> @@ -141,8 +135,7 @@ out:
>  static ssize_t debug_read_pagetable(struct file *file, char __user
> *userbuf, size_t count, loff_t *ppos)
>  {
> -	struct device *dev = file->private_data;
> -	struct omap_iommu *obj = dev_to_omap_iommu(dev);
> +	struct omap_iommu *obj = file->private_data;
>  	char *p, *buf;
>  	size_t bytes;
> 
> @@ -181,93 +174,58 @@ DEBUG_FOPS_RO(pagetable);
>  #define __DEBUG_ADD_FILE(attr, mode)					\
>  	{								\
>  		struct dentry *dent;					\
> -		dent = debugfs_create_file(#attr, mode, parent,		\
> -					   dev, &debug_##attr##_fops);	\
> +		dent = debugfs_create_file(#attr, mode, obj->debug_dir,	\
> +					   obj, &debug_##attr##_fops);	\
>  		if (!dent)						\
> -			return -ENOMEM;					\
> +			goto err;					\
>  	}
> 
>  #define DEBUG_ADD_FILE_RO(name) __DEBUG_ADD_FILE(name, 0400)
> 
> -static int iommu_debug_register(struct device *dev, void *data)
> +void omap_iommu_debugfs_add(struct omap_iommu *obj)
>  {
> -	struct platform_device *pdev = to_platform_device(dev);
> -	struct omap_iommu *obj = platform_get_drvdata(pdev);
> -	struct omap_iommu_arch_data *arch_data;
> -	struct dentry *d, *parent;
> -
> -	if (!obj || !obj->dev)
> -		return -EINVAL;
> -
> -	arch_data = kzalloc(sizeof(*arch_data), GFP_KERNEL);
> -	if (!arch_data)
> -		return -ENOMEM;
> -
> -	arch_data->iommu_dev = obj;
> +	struct dentry *d;
> 
> -	dev->archdata.iommu = arch_data;
> +	if (!iommu_debug_root)
> +		return;
> 
> -	d = debugfs_create_dir(obj->name, iommu_debug_root);
> -	if (!d)
> -		goto nomem;
> -	parent = d;
> +	obj->debug_dir = debugfs_create_dir(obj->name, iommu_debug_root);
> +	if (!obj->debug_dir)
> +		return;
> 
> -	d = debugfs_create_u8("nr_tlb_entries", 0400, parent,
> +	d = debugfs_create_u8("nr_tlb_entries", 0400, obj->debug_dir,
>  			      (u8 *)&obj->nr_tlb_entries);
>  	if (!d)
> -		goto nomem;
> +		return;
> 
>  	DEBUG_ADD_FILE_RO(regs);
>  	DEBUG_ADD_FILE_RO(tlb);
>  	DEBUG_ADD_FILE_RO(pagetable);
> 
> -	return 0;
> +	return;
> 
> -nomem:
> -	kfree(arch_data);
> -	return -ENOMEM;
> +err:
> +	debugfs_remove_recursive(obj->debug_dir);
>  }
> 
> -static int iommu_debug_unregister(struct device *dev, void *data)
> +void omap_iommu_debugfs_remove(struct omap_iommu *obj)
>  {
> -	if (!dev->archdata.iommu)
> -		return 0;
> -
> -	kfree(dev->archdata.iommu);
> -
> -	dev->archdata.iommu = NULL;
> +	if (!obj->debug_dir)
> +		return;
> 
> -	return 0;
> +	debugfs_remove_recursive(obj->debug_dir);
>  }
> 
> -static int __init iommu_debug_init(void)
> +void __init omap_iommu_debugfs_init(void)
>  {
> -	struct dentry *d;
> -	int err;
> -
> -	d = debugfs_create_dir("iommu", NULL);
> -	if (!d)
> -		return -ENOMEM;
> -	iommu_debug_root = d;
> -
> -	err = omap_foreach_iommu_device(d, iommu_debug_register);
> -	if (err)
> -		goto err_out;
> -	return 0;
> -
> -err_out:
> -	debugfs_remove_recursive(iommu_debug_root);
> -	return err;
> +	if (debugfs_initialized()) {
> +		iommu_debug_root = debugfs_create_dir("omap_iommu", NULL);
> +		if (!iommu_debug_root)
> +			pr_err("can't create debugfs dir\n");
> +	}
>  }
> -module_init(iommu_debug_init)
> 
> -static void __exit iommu_debugfs_exit(void)
> +void __exit omap_iommu_debugfs_exit(void)
>  {
> -	debugfs_remove_recursive(iommu_debug_root);
> -	omap_foreach_iommu_device(NULL, iommu_debug_unregister);
> +	debugfs_remove(iommu_debug_root);
>  }
> -module_exit(iommu_debugfs_exit)
> -
> -MODULE_DESCRIPTION("omap iommu: debugfs interface");
> -MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@nokia.com>");
> -MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> index 9ace5557..717d654 100644
> --- a/drivers/iommu/omap-iommu.c
> +++ b/drivers/iommu/omap-iommu.c
> @@ -472,8 +472,6 @@ static void flush_iotlb_all(struct omap_iommu *obj)
>  	pm_runtime_put_sync(obj->dev);
>  }
> 
> -#if defined(CONFIG_OMAP_IOMMU_DEBUG) ||
> defined(CONFIG_OMAP_IOMMU_DEBUG_MODULE) -
>  #define pr_reg(name)							\
>  	do {								\
>  		ssize_t bytes;						\
> @@ -602,8 +600,6 @@ int omap_foreach_iommu_device(void *data, int
> (*fn)(struct device *, void *)) }
>  EXPORT_SYMBOL_GPL(omap_foreach_iommu_device);
> 
> -#endif /* CONFIG_OMAP_IOMMU_DEBUG_MODULE */
> -
>  /*
>   *	H/W pagetable operations
>   */
> @@ -1077,6 +1073,8 @@ static int omap_iommu_probe(struct platform_device
> *pdev) pm_runtime_irq_safe(obj->dev);
>  	pm_runtime_enable(obj->dev);
> 
> +	omap_iommu_debugfs_add(obj);
> +
>  	dev_info(&pdev->dev, "%s registered\n", obj->name);
>  	return 0;
>  }
> @@ -1086,6 +1084,7 @@ static int omap_iommu_remove(struct platform_device
> *pdev) struct omap_iommu *obj = platform_get_drvdata(pdev);
> 
>  	iopgtable_clear_entry_all(obj);
> +	omap_iommu_debugfs_remove(obj);
> 
>  	pm_runtime_disable(obj->dev);
> 
> @@ -1403,6 +1402,8 @@ static int __init omap_iommu_init(void)
> 
>  	bus_set_iommu(&platform_bus_type, &omap_iommu_ops);
> 
> +	omap_iommu_debugfs_init();
> +
>  	return platform_driver_register(&omap_iommu_driver);
>  }
>  /* must be ready before omap3isp is probed */
> @@ -1413,6 +1414,8 @@ static void __exit omap_iommu_exit(void)
>  	kmem_cache_destroy(iopte_cachep);
> 
>  	platform_driver_unregister(&omap_iommu_driver);
> +
> +	omap_iommu_debugfs_exit();
>  }
>  module_exit(omap_iommu_exit);
> 
> diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
> index 0516e0e..6e9a8d2 100644
> --- a/drivers/iommu/omap-iommu.h
> +++ b/drivers/iommu/omap-iommu.h
> @@ -30,6 +30,7 @@ struct omap_iommu {
>  	void __iomem	*regbase;
>  	struct device	*dev;
>  	struct iommu_domain *domain;
> +	struct dentry	*debug_dir;
> 
>  	spinlock_t	iommu_lock;	/* global for this whole object */
> 
> @@ -202,6 +203,12 @@ 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);
> 
> +void omap_iommu_debugfs_init(void);
> +void omap_iommu_debugfs_exit(void);
> +
> +void omap_iommu_debugfs_add(struct omap_iommu *obj);
> +void omap_iommu_debugfs_remove(struct omap_iommu *obj);
> +
>  /*
>   * register accessors
>   */

-- 
Regards,

Laurent Pinchart