ath6kl: add blocking debugfs file for retrieving firmware logs

When debugging firmware issues it's not always enough to get
the latest firmware logs, sometimes we need to get logs from a longer
period. To make this possible, add a debugfs file named fwlog_block. When
reading from this file ath6kl will send firmware logs whenever available
and otherwise it will block and wait for new logs.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath6kl/core.h b/drivers/net/wireless/ath/ath6kl/core.h
index 9a58214..4ff06a3 100644 (file)
--- a/drivers/net/wireless/ath/ath6kl/core.h
+++ b/drivers/net/wireless/ath/ath6kl/core.h
@@ -653,6 +653,9 @@ struct ath6kl {
 #ifdef CONFIG_ATH6KL_DEBUG
        struct {
                struct sk_buff_head fwlog_queue;
+               struct completion fwlog_completion;
+               bool fwlog_open;
+
                u32 fwlog_mask;
 
                unsigned int dbgfs_diag_reg;

diff --git a/drivers/net/wireless/ath/ath6kl/debug.c b/drivers/net/wireless/ath/ath6kl/debug.c
index 98b5f15..ec32ff6 100644 (file)
--- a/drivers/net/wireless/ath/ath6kl/debug.c
+++ b/drivers/net/wireless/ath/ath6kl/debug.c
@@ -290,6 +290,7 @@ void ath6kl_debug_fwlog_event(struct ath6kl *ar, const void *buf, size_t len)
        spin_lock(&ar->debug.fwlog_queue.lock);
 
        __skb_queue_tail(&ar->debug.fwlog_queue, skb);
+       complete(&ar->debug.fwlog_completion);
 
        /* drop oldest entries */
        while (skb_queue_len(&ar->debug.fwlog_queue) >
@@ -303,6 +304,28 @@ void ath6kl_debug_fwlog_event(struct ath6kl *ar, const void *buf, size_t len)
        return;
 }
 
+static int ath6kl_fwlog_open(struct inode *inode, struct file *file)
+{
+       struct ath6kl *ar = inode->i_private;
+
+       if (ar->debug.fwlog_open)
+               return -EBUSY;
+
+       ar->debug.fwlog_open = true;
+
+       file->private_data = inode->i_private;
+       return 0;
+}
+
+static int ath6kl_fwlog_release(struct inode *inode, struct file *file)
+{
+       struct ath6kl *ar = inode->i_private;
+
+       ar->debug.fwlog_open = false;
+
+       return 0;
+}
+
 static ssize_t ath6kl_fwlog_read(struct file *file, char __user *user_buf,
                                 size_t count, loff_t *ppos)
 {
@@ -347,12 +370,87 @@ static ssize_t ath6kl_fwlog_read(struct file *file, char __user *user_buf,
 }
 
 static const struct file_operations fops_fwlog = {
-       .open = ath6kl_debugfs_open,
+       .open = ath6kl_fwlog_open,
+       .release = ath6kl_fwlog_release,
        .read = ath6kl_fwlog_read,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
 };
 
+static ssize_t ath6kl_fwlog_block_read(struct file *file,
+                                      char __user *user_buf,
+                                      size_t count,
+                                      loff_t *ppos)
+{
+       struct ath6kl *ar = file->private_data;
+       struct sk_buff *skb;
+       ssize_t ret_cnt;
+       size_t len = 0, not_copied;
+       char *buf;
+       int ret;
+
+       buf = vmalloc(count);
+       if (!buf)
+               return -ENOMEM;
+
+       spin_lock(&ar->debug.fwlog_queue.lock);
+
+       if (skb_queue_len(&ar->debug.fwlog_queue) == 0) {
+               /* we must init under queue lock */
+               init_completion(&ar->debug.fwlog_completion);
+
+               spin_unlock(&ar->debug.fwlog_queue.lock);
+
+               ret = wait_for_completion_interruptible(
+                       &ar->debug.fwlog_completion);
+               if (ret == -ERESTARTSYS)
+                       return ret;
+
+               spin_lock(&ar->debug.fwlog_queue.lock);
+       }
+
+       while ((skb = __skb_dequeue(&ar->debug.fwlog_queue))) {
+               if (skb->len > count - len) {
+                       /* not enough space, put skb back and leave */
+                       __skb_queue_head(&ar->debug.fwlog_queue, skb);
+                       break;
+               }
+
+
+               memcpy(buf + len, skb->data, skb->len);
+               len += skb->len;
+
+               kfree_skb(skb);
+       }
+
+       spin_unlock(&ar->debug.fwlog_queue.lock);
+
+       /* FIXME: what to do if len == 0? */
+
+       not_copied = copy_to_user(user_buf, buf, len);
+       if (not_copied != 0) {
+               ret_cnt = -EFAULT;
+               goto out;
+       }
+
+       *ppos = *ppos + len;
+
+       ret_cnt = len;
+
+out:
+       vfree(buf);
+
+       return ret_cnt;
+}
+
+static const struct file_operations fops_fwlog_block = {
+       .open = ath6kl_fwlog_open,
+       .release = ath6kl_fwlog_release,
+       .read = ath6kl_fwlog_block_read,
+       .owner = THIS_MODULE,
+       .llseek = default_llseek,
+};
+
 static ssize_t ath6kl_fwlog_mask_read(struct file *file, char __user *user_buf,
                                      size_t count, loff_t *ppos)
 {
@@ -1623,6 +1721,7 @@ static const struct file_operations fops_power_params = {
 int ath6kl_debug_init(struct ath6kl *ar)
 {
        skb_queue_head_init(&ar->debug.fwlog_queue);
+       init_completion(&ar->debug.fwlog_completion);
 
        /*
         * Actually we are lying here but don't know how to read the mask
@@ -1647,6 +1746,9 @@ int ath6kl_debug_init(struct ath6kl *ar)
        debugfs_create_file("fwlog", S_IRUSR, ar->debugfs_phy, ar,
                            &fops_fwlog);
 
+       debugfs_create_file("fwlog_block", S_IRUSR, ar->debugfs_phy, ar,
+                           &fops_fwlog_block);
+
        debugfs_create_file("fwlog_mask", S_IRUSR | S_IWUSR, ar->debugfs_phy,
                            ar, &fops_fwlog_mask);