Hi Alan,

	Thanks for the review... 

<Snip>

On Fri, Jul 27, 2018 at 1:22 AM, Appana Durga Kedareswara rao
[off-list ref] wrote:

Hi Appana,

There should be some documentation for the debugfs added under
Documentation/driver-api/fpga/

Also there are a lot of #ifdefs that were added due to the
CONFIG_FPGA_MGR_DEBUG_FS.  This has caused a kernel robot complaint.
The way to fix that is to have a separate c file for the debugfs
implementation.  I see a lot of other kernel drivers have done it this way.  I
have an implementation that I haven't submitted yet, it exposes different
functionality (exposing the image firmware file name and writing to the
image file).  It's on the downstream github.com/altera-opensource repo [1].
I'll clean this up and submit it to the mailing list, it may take a minute for me
to get to that.
Once that's done, your added functionality can be a patch on top of that.

Sounds good...
Let me know if you need any help on testing this will do.

Regards,
Kedar.

Alan

[1] https://github.com/altera-opensource/linux-socfpga/blob/socfpga-
4.17/drivers/fpga/fpga-mgr-debugfs.c
https://github.com/altera-opensource/linux-socfpga/blob/socfpga-
4.17/drivers/fpga/fpga-mgr-debugfs.h

quoted

Inorder to debug issues with fpga's users would like to read the fpga
configuration information.
This patch adds readback support for fpga configuration data in the
framework through debugfs interface.

Usage:
        cat /sys/kernel/debug/fpga/fpga0/image

Signed-off-by: Appana Durga Kedareswara rao
[off-list ref]
---
Changes for v4:
--> None.
Changes for v3:
--> None.
Changes for v2:
--> Fixed debug attribute path and name as suggested by Alan Add
--> config entry for DEBUG as suggested by Alan Fixed trival coding
--> style issues.

 drivers/fpga/Kconfig          |  7 +++++
 drivers/fpga/fpga-mgr.c       | 68

+++++++++++++++++++++++++++++++++++++++++++

quoted

 include/linux/fpga/fpga-mgr.h |  5 ++++
 3 files changed, 80 insertions(+)

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig index

53d3f55..838ad4e 100644

--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig

@@ -11,6 +11,13 @@ menuconfig FPGA

 if FPGA

+config FPGA_MGR_DEBUG_FS
+       tristate "FPGA Debug fs"
+       select DEBUG_FS
+       help
+         FPGA manager debug provides support for reading fpga

configuration

quoted

+         information.
+
 config FPGA_MGR_SOCFPGA
        tristate "Altera SOCFPGA FPGA Manager"
        depends on ARCH_SOCFPGA || COMPILE_TEST diff --git
a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c index
9939d2c..4bea860 100644

--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c

@@ -484,6 +484,48 @@ void fpga_mgr_put(struct fpga_manager *mgr)  }

EXPORT_SYMBOL_GPL(fpga_mgr_put);

+#ifdef CONFIG_FPGA_MGR_DEBUG_FS
+#include <linux/debugfs.h>
+
+static int fpga_mgr_read(struct seq_file *s, void *data) {
+       struct fpga_manager *mgr = (struct fpga_manager *)s->private;
+       int ret = 0;
+
+       if (!mgr->mops->read)
+               return -ENOENT;
+
+       if (!mutex_trylock(&mgr->ref_mutex))
+               return -EBUSY;
+
+       if (mgr->state != FPGA_MGR_STATE_OPERATING) {
+               ret = -EPERM;
+               goto err_unlock;
+       }
+
+       /* Read the FPGA configuration data from the fabric */
+       ret = mgr->mops->read(mgr, s);
+       if (ret)
+               dev_err(&mgr->dev, "Error while reading configuration
+ data from FPGA\n");
+
+err_unlock:
+       mutex_unlock(&mgr->ref_mutex);
+
+       return ret;
+}
+
+static int fpga_mgr_read_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, fpga_mgr_read, inode->i_private); }
+
+static const struct file_operations fpga_mgr_ops_image = {
+       .owner = THIS_MODULE,
+       .open = fpga_mgr_read_open,
+       .read = seq_read,
+};
+#endif
+
 /**
  * fpga_mgr_lock - Lock FPGA manager for exclusive use
  * @mgr:       fpga manager

@@ -581,6 +623,29 @@ int fpga_mgr_register(struct device *dev, const

char *name,

quoted

        if (ret)
                goto error_device;

+#ifdef CONFIG_FPGA_MGR_DEBUG_FS
+       struct dentry *d, *parent;
+
+       mgr->dir = debugfs_create_dir("fpga", NULL);
+       if (!mgr->dir)
+               goto error_device;
+
+       parent = mgr->dir;
+       d = debugfs_create_dir(mgr->dev.kobj.name, parent);
+       if (!d) {
+               debugfs_remove_recursive(parent);
+               goto error_device;
+       }
+
+       parent = d;
+       d = debugfs_create_file("image", 0644, parent, mgr,
+                               &fpga_mgr_ops_image);
+       if (!d) {
+               debugfs_remove_recursive(mgr->dir);
+               goto error_device;
+       }
+#endif
+
        dev_info(&mgr->dev, "%s registered\n", mgr->name);

        return 0;

@@ -604,6 +669,9 @@ void fpga_mgr_unregister(struct device *dev)

        dev_info(&mgr->dev, "%s %s\n", __func__, mgr->name);

+#ifdef CONFIG_FPGA_MGR_DEBUG_FS
+       debugfs_remove_recursive(mgr->dir);
+#endif
        /*
         * If the low level driver provides a method for putting fpga into
         * a desired state upon unregister, do it.

diff --git a/include/linux/fpga/fpga-mgr.h

b/include/linux/fpga/fpga-mgr.h index 3c6de23..e9e17a9 100644

--- a/include/linux/fpga/fpga-mgr.h
+++ b/include/linux/fpga/fpga-mgr.h

@@ -114,6 +114,7 @@ struct fpga_image_info {
  * @write: write count bytes of configuration data to the FPGA
  * @write_sg: write the scatter list of configuration data to the FPGA
  * @write_complete: set FPGA to operating state after writing is done
+ * @read: optional: read FPGA configuration information
  * @fpga_remove: optional: Set FPGA into a specific state during driver

remove

quoted

  * @groups: optional attribute groups.
  *

@@ -131,6 +132,7 @@ struct fpga_manager_ops {
        int (*write_sg)(struct fpga_manager *mgr, struct sg_table *sgt);
        int (*write_complete)(struct fpga_manager *mgr,
                              struct fpga_image_info *info);
+       int (*read)(struct fpga_manager *mgr, struct seq_file *s);
        void (*fpga_remove)(struct fpga_manager *mgr);
        const struct attribute_group **groups;  }; @@ -151,6 +153,9 @@

struct fpga_manager {
        enum fpga_mgr_states state;
        const struct fpga_manager_ops *mops;
        void *priv;
+#ifdef CONFIG_FPGA_MGR_DEBUG_FS
+       struct dentry *dir;
+#endif
 };

 #define to_fpga_manager(d) container_of(d, struct fpga_manager, dev)
--
2.7.4

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quoted

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