drm/i915: Add a control file for pipe CRCs

Note the "return -ENODEV;" in pipe_crc_set_source(). The ctl file is
disabled until the end of the series to be able to do incremental
improvements.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 215 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index e1d45aaf6881..0d8a9a397a24 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -27,6 +27,7 @@
  */
 
 #include <linux/seq_file.h>
+#include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>
 #include <linux/export.h>
@@ -1742,8 +1743,8 @@ static int i915_pipe_crc(struct seq_file *m, void *data)
         int i;
         int start;
 
-        if (!IS_IVYBRIDGE(dev)) {
-                seq_puts(m, "unsupported\n");
+        if (dev_priv->pipe_crc[pipe].source == INTEL_PIPE_CRC_SOURCE_NONE) {
+                seq_puts(m, "none\n");
                 return 0;
         }
 
@@ -1762,6 +1763,217 @@ static int i915_pipe_crc(struct seq_file *m, void *data)
         return 0;
 }
 
+static const char *pipe_crc_sources[] = {
+        "none",
+        "plane1",
+        "plane2",
+        "pf",
+};
+
+static const char *pipe_crc_source_name(enum intel_pipe_crc_source source)
+{
+        BUILD_BUG_ON(ARRAY_SIZE(pipe_crc_sources) != INTEL_PIPE_CRC_SOURCE_MAX);
+        return pipe_crc_sources[source];
+}
+
+static int pipe_crc_ctl_show(struct seq_file *m, void *data)
+{
+        struct drm_device *dev = m->private;
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        int i;
+
+        for (i = 0; i < I915_MAX_PIPES; i++)
+                seq_printf(m, "%c %s\n", pipe_name(i),
+                           pipe_crc_source_name(dev_priv->pipe_crc[i].source));
+
+        return 0;
+}
+
+static int pipe_crc_ctl_open(struct inode *inode, struct file *file)
+{
+        struct drm_device *dev = inode->i_private;
+
+        return single_open(file, pipe_crc_ctl_show, dev);
+}
+
+static int pipe_crc_set_source(struct drm_device *dev, enum pipe pipe,
+                               enum intel_pipe_crc_source source)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        u32 val;
+
+
+        return -ENODEV;
+
+        if (!IS_IVYBRIDGE(dev))
+                return -ENODEV;
+
+        dev_priv->pipe_crc[pipe].source = source;
+
+        switch (source) {
+        case INTEL_PIPE_CRC_SOURCE_PLANE1:
+                val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PRIMARY_IVB;
+                break;
+        case INTEL_PIPE_CRC_SOURCE_PLANE2:
+                val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_IVB;
+                break;
+        case INTEL_PIPE_CRC_SOURCE_PF:
+                val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PF_IVB;
+                break;
+        case INTEL_PIPE_CRC_SOURCE_NONE:
+        default:
+                val = 0;
+                break;
+        }
+
+        I915_WRITE(PIPE_CRC_CTL(pipe), val);
+        POSTING_READ(PIPE_CRC_CTL(pipe));
+
+        return 0;
+}
+
+/*
+ * Parse pipe CRC command strings:
+ *   command: wsp* pipe wsp+ source wsp*
+ *   pipe: (A | B | C)
+ *   source: (none | plane1 | plane2 | pf)
+ *   wsp: (#0x20 | #0x9 | #0xA)+
+ *
+ * eg.:
+ *  "A plane1"  ->  Start CRC computations on plane1 of pipe A
+ *  "A none"    ->  Stop CRC
+ */
+static int pipe_crc_ctl_tokenize(char *buf, char *words[], int max_words)
+{
+        int n_words = 0;
+
+        while (*buf) {
+                char *end;
+
+                /* skip leading white space */
+                buf = skip_spaces(buf);
+                if (!*buf)
+                        break;  /* end of buffer */
+
+                /* find end of word */
+                for (end = buf; *end && !isspace(*end); end++)
+                        ;
+
+                if (n_words == max_words) {
+                        DRM_DEBUG_DRIVER("too many words, allowed <= %d\n",
+                                         max_words);
+                        return -EINVAL; /* ran out of words[] before bytes */
+                }
+
+                if (*end)
+                        *end++ = '\0';
+                words[n_words++] = buf;
+                buf = end;
+        }
+
+        return n_words;
+}
+
+static int pipe_crc_ctl_parse_pipe(const char *buf, enum pipe *pipe)
+{
+        const char name = buf[0];
+
+        if (name < 'A' || name >= pipe_name(I915_MAX_PIPES))
+                return -EINVAL;
+
+        *pipe = name - 'A';
+
+        return 0;
+}
+
+static int
+pipe_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *source)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(pipe_crc_sources); i++)
+                if (!strcmp(buf, pipe_crc_sources[i])) {
+                        *source = i;
+                        return 0;
+                    }
+
+        return -EINVAL;
+}
+
+static int pipe_crc_ctl_parse(struct drm_device *dev, char *buf, size_t len)
+{
+#define MAX_WORDS 2
+        int n_words;
+        char *words[MAX_WORDS];
+        enum pipe pipe;
+        enum intel_pipe_crc_source source;
+
+        n_words = pipe_crc_ctl_tokenize(buf, words, MAX_WORDS);
+        if (n_words != 2) {
+                DRM_DEBUG_DRIVER("tokenize failed, a command is 2 words\n");
+                return -EINVAL;
+        }
+
+        if (pipe_crc_ctl_parse_pipe(words[0], &pipe) < 0) {
+                DRM_DEBUG_DRIVER("unknown pipe %s\n", words[0]);
+                return -EINVAL;
+        }
+
+        if (pipe_crc_ctl_parse_source(words[1], &source) < 0) {
+                DRM_DEBUG_DRIVER("unknown source %s\n", words[1]);
+                return -EINVAL;
+        }
+
+        return pipe_crc_set_source(dev, pipe, source);
+}
+
+static ssize_t pipe_crc_ctl_write(struct file *file, const char __user *ubuf,
+                                  size_t len, loff_t *offp)
+{
+        struct seq_file *m = file->private_data;
+        struct drm_device *dev = m->private;
+        char *tmpbuf;
+        int ret;
+
+        if (len == 0)
+                return 0;
+
+        if (len > PAGE_SIZE - 1) {
+                DRM_DEBUG_DRIVER("expected <%lu bytes into pipe crc control\n",
+                                 PAGE_SIZE);
+                return -E2BIG;
+        }
+
+        tmpbuf = kmalloc(len + 1, GFP_KERNEL);
+        if (!tmpbuf)
+                return -ENOMEM;
+
+        if (copy_from_user(tmpbuf, ubuf, len)) {
+                ret = -EFAULT;
+                goto out;
+        }
+        tmpbuf[len] = '\0';
+
+        ret = pipe_crc_ctl_parse(dev, tmpbuf, len);
+
+out:
+        kfree(tmpbuf);
+        if (ret < 0)
+                return ret;
+
+        *offp += len;
+        return len;
+}
+
+static const struct file_operations i915_pipe_crc_ctl_fops = {
+        .owner = THIS_MODULE,
+        .open = pipe_crc_ctl_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = single_release,
+        .write = pipe_crc_ctl_write
+};
+
 static int
 i915_wedged_get(void *data, u64 *val)
 {
@@ -2297,6 +2509,7 @@ static struct i915_debugfs_files {
         {"i915_gem_drop_caches", &i915_drop_caches_fops},
         {"i915_error_state", &i915_error_state_fops},
         {"i915_next_seqno", &i915_next_seqno_fops},
+        {"i915_pipe_crc_ctl", &i915_pipe_crc_ctl_fops},
 };
 
 int i915_debugfs_init(struct drm_minor *minor)