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Commit 23c04962 authored by Mitchel Humpherys's avatar Mitchel Humpherys
Browse files

iommu/iommu-debug: Provide debugfs for iommu_reg_{read,write} 



It can be useful to read and modify SMMU settings interactively.  Add a
debugfs interface for the recently added iommu_reg_read and
iommu_reg_write functions for this purpose.

Change-Id: If3c9bf1833dc950c7ca1e2ce1a373bcaa31ebcf0
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
parent 0e7c8c9d

drivers/iommu/iommu-debug.c

+103 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ struct iommu_debug_attachment { 
	struct device *dev;

	struct dentry *dentry;

	struct list_head list;

	unsigned long reg_offset;

};



static int iommu_debug_attachment_info_show(struct seq_file *s, void *ignored)
@@ -112,6 +113,84 @@ iommu_debug_attachment_trigger_fault_fops = { 
	.write	= iommu_debug_attachment_trigger_fault_write,

};



static ssize_t iommu_debug_attachment_reg_offset_write(

	struct file *file, const char __user *ubuf, size_t count,

	loff_t *offset)

{

	struct iommu_debug_attachment *attach = file->private_data;

	unsigned long reg_offset;



	if (kstrtoul_from_user(ubuf, count, 0, &reg_offset)) {

		pr_err("Invalid reg_offset format\n");

		return -EFAULT;

	}



	attach->reg_offset = reg_offset;



	return count;

}



static const struct file_operations iommu_debug_attachment_reg_offset_fops = {

	.open	= simple_open,

	.write	= iommu_debug_attachment_reg_offset_write,

};



static ssize_t iommu_debug_attachment_reg_read_read(

	struct file *file, char __user *ubuf, size_t count, loff_t *offset)

{

	struct iommu_debug_attachment *attach = file->private_data;

	unsigned long val;

	char *val_str;

	ssize_t val_str_len;



	if (*offset)

		return 0;



	val = iommu_reg_read(attach->domain, attach->reg_offset);

	val_str = kasprintf(GFP_KERNEL, "0x%lx\n", val);

	if (!val_str)

		return -ENOMEM;

	val_str_len = strlen(val_str);



	if (copy_to_user(ubuf, val_str, val_str_len)) {

		pr_err("copy_to_user failed\n");

		val_str_len = -EFAULT;

		goto out;

	}

	*offset = 1;		/* non-zero means we're done */



out:

	kfree(val_str);

	return val_str_len;

}



static const struct file_operations iommu_debug_attachment_reg_read_fops = {

	.open	= simple_open,

	.read	= iommu_debug_attachment_reg_read_read,

};



static ssize_t iommu_debug_attachment_reg_write_write(

	struct file *file, const char __user *ubuf, size_t count,

	loff_t *offset)

{

	struct iommu_debug_attachment *attach = file->private_data;

	unsigned long val;



	if (kstrtoul_from_user(ubuf, count, 0, &val)) {

		pr_err("Invalid val format\n");

		return -EFAULT;

	}



	iommu_reg_write(attach->domain, attach->reg_offset, val);



	return count;

}



static const struct file_operations iommu_debug_attachment_reg_write_fops = {

	.open	= simple_open,

	.write	= iommu_debug_attachment_reg_write_write,

};



/* should be called with iommu_debug_attachments_lock locked */

static int iommu_debug_attach_add_debugfs(

	struct iommu_debug_attachment *attach)
@@ -152,6 +231,30 @@ static int iommu_debug_attach_add_debugfs( 
		goto err_rmdir;

	}



	if (!debugfs_create_file(

		    "reg_offset", S_IRUSR, attach->dentry, attach,

		    &iommu_debug_attachment_reg_offset_fops)) {

		pr_err("Couldn't create iommu/attachments/%s/reg_offset debugfs file for domain 0x%p\n",

		       dev_name(dev), domain);

		goto err_rmdir;

	}



	if (!debugfs_create_file(

		    "reg_read", S_IRUSR, attach->dentry, attach,

		    &iommu_debug_attachment_reg_read_fops)) {

		pr_err("Couldn't create iommu/attachments/%s/reg_read debugfs file for domain 0x%p\n",

		       dev_name(dev), domain);

		goto err_rmdir;

	}



	if (!debugfs_create_file(

		    "reg_write", S_IRUSR, attach->dentry, attach,

		    &iommu_debug_attachment_reg_write_fops)) {

		pr_err("Couldn't create iommu/attachments/%s/reg_write debugfs file for domain 0x%p\n",

		       dev_name(dev), domain);

		goto err_rmdir;

	}



	return 0;



err_rmdir: