drm/i915/bios: rewrite sequence block parsing

Make everything a bit more readable and clear.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/e8f2a62d78d90981a6b49fdf9ab3594f60a46033.1450702954.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cf7e0fc..c6dd4db 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1477,7 +1477,7 @@ struct intel_vbt_data {
                u8 seq_version;
                u32 size;
                u8 *data;
-               u8 *sequence[MIPI_SEQ_MAX];
+               const u8 *sequence[MIPI_SEQ_MAX];
        } dsi;
 
        int crt_ddc_pin;

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 422ba76..71c739e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -697,73 +697,6 @@ parse_psr(struct drm_i915_private *dev_priv, const struct bdb_header *bdb)
        dev_priv->vbt.psr.tp2_tp3_wakeup_time = psr_table->tp2_tp3_wakeup_time;
 }
 
-static u8 *goto_next_sequence(u8 *data, u16 *size)
-{
-       u16 len;
-       int tmp = *size;
-
-       if (--tmp < 0)
-               return NULL;
-
-       /* goto first element */
-       data++;
-       while (1) {
-               switch (*data) {
-               case MIPI_SEQ_ELEM_SEND_PKT:
-                       /*
-                        * skip by this element payload size
-                        * skip elem id, command flag and data type
-                        */
-                       tmp -= 5;
-                       if (tmp < 0)
-                               return NULL;
-
-                       data += 3;
-                       len = *((u16 *)data);
-
-                       tmp -= len;
-                       if (tmp < 0)
-                               return NULL;
-
-                       /* skip by len */
-                       data = data + 2 + len;
-                       break;
-               case MIPI_SEQ_ELEM_DELAY:
-                       /* skip by elem id, and delay is 4 bytes */
-                       tmp -= 5;
-                       if (tmp < 0)
-                               return NULL;
-
-                       data += 5;
-                       break;
-               case MIPI_SEQ_ELEM_GPIO:
-                       tmp -= 3;
-                       if (tmp < 0)
-                               return NULL;
-
-                       data += 3;
-                       break;
-               default:
-                       DRM_ERROR("Unknown element\n");
-                       return NULL;
-               }
-
-               /* end of sequence ? */
-               if (*data == 0)
-                       break;
-       }
-
-       /* goto next sequence or end of block byte */
-       if (--tmp < 0)
-               return NULL;
-
-       data++;
-
-       /* update amount of data left for the sequence block to be parsed */
-       *size = tmp;
-       return data;
-}
-
 static void
 parse_mipi_config(struct drm_i915_private *dev_priv,
                  const struct bdb_header *bdb)
@@ -855,6 +788,39 @@ find_panel_sequence_block(const struct bdb_mipi_sequence *sequence,
        return NULL;
 }
 
+static int goto_next_sequence(const u8 *data, int index, int total)
+{
+       u16 len;
+
+       /* Skip Sequence Byte. */
+       for (index = index + 1; index < total; index += len) {
+               u8 operation_byte = *(data + index);
+               index++;
+
+               switch (operation_byte) {
+               case MIPI_SEQ_ELEM_END:
+                       return index;
+               case MIPI_SEQ_ELEM_SEND_PKT:
+                       if (index + 4 > total)
+                               return 0;
+
+                       len = *((const u16 *)(data + index + 2)) + 4;
+                       break;
+               case MIPI_SEQ_ELEM_DELAY:
+                       len = 4;
+                       break;
+               case MIPI_SEQ_ELEM_GPIO:
+                       len = 2;
+                       break;
+               default:
+                       DRM_ERROR("Unknown operation byte\n");
+                       return 0;
+               }
+       }
+
+       return 0;
+}
+
 static void
 parse_mipi_sequence(struct drm_i915_private *dev_priv,
                    const struct bdb_header *bdb)
@@ -863,7 +829,7 @@ parse_mipi_sequence(struct drm_i915_private *dev_priv,
        const u8 *seq_data;
        u16 seq_size;
        u8 *data;
-       u16 block_size;
+       int index = 0;
 
        /* Only our generic panel driver uses the sequence block. */
        if (dev_priv->vbt.dsi.panel_id != MIPI_DSI_GENERIC_PANEL_ID)
@@ -883,59 +849,43 @@ parse_mipi_sequence(struct drm_i915_private *dev_priv,
 
        DRM_DEBUG_DRIVER("Found MIPI sequence block\n");
 
-       block_size = get_blocksize(sequence);
-
-       /*
-        * parse the sequence block for individual sequences
-        */
-       dev_priv->vbt.dsi.seq_version = sequence->version;
-
        seq_data = find_panel_sequence_block(sequence, panel_type, &seq_size);
        if (!seq_data)
                return;
 
-       dev_priv->vbt.dsi.data = kmemdup(seq_data, seq_size, GFP_KERNEL);
-       if (!dev_priv->vbt.dsi.data)
+       data = kmemdup(seq_data, seq_size, GFP_KERNEL);
+       if (!data)
                return;
 
-       /*
-        * loop into the sequence data and split into multiple sequneces
-        * There are only 5 types of sequences as of now
-        */
-       data = dev_priv->vbt.dsi.data;
-       dev_priv->vbt.dsi.size = seq_size;
+       /* Parse the sequences, store pointers to each sequence. */
+       for (;;) {
+               u8 seq_id = *(data + index);
+               if (seq_id == MIPI_SEQ_END)
+                       break;
 
-       /* two consecutive 0x00 indicate end of all sequences */
-       while (1) {
-               int seq_id = *data;
-               if (MIPI_SEQ_MAX > seq_id && seq_id > MIPI_SEQ_UNDEFINED) {
-                       dev_priv->vbt.dsi.sequence[seq_id] = data;
-                       DRM_DEBUG_DRIVER("Found mipi sequence - %d\n", seq_id);
-               } else {
-                       DRM_ERROR("undefined sequence\n");
+               if (seq_id >= MIPI_SEQ_MAX) {
+                       DRM_ERROR("Unknown sequence %u\n", seq_id);
                        goto err;
                }
 
-               /* partial parsing to skip elements */
-               data = goto_next_sequence(data, &seq_size);
+               dev_priv->vbt.dsi.sequence[seq_id] = data + index;
 
-               if (data == NULL) {
-                       DRM_ERROR("Sequence elements going beyond block itself. Sequence block parsing failed\n");
+               index = goto_next_sequence(data, index, seq_size);
+               if (!index) {
+                       DRM_ERROR("Invalid sequence %u\n", seq_id);
                        goto err;
                }
-
-               if (*data == 0)
-                       break; /* end of sequence reached */
        }
 
-       DRM_DEBUG_DRIVER("MIPI related vbt parsing complete\n");
+       dev_priv->vbt.dsi.data = data;
+       dev_priv->vbt.dsi.size = seq_size;
+       dev_priv->vbt.dsi.seq_version = sequence->version;
+
+       DRM_DEBUG_DRIVER("MIPI related VBT parsing complete\n");
        return;
-err:
-       kfree(dev_priv->vbt.dsi.data);
-       dev_priv->vbt.dsi.data = NULL;
 
-       /* error during parsing so set all pointers to null
-        * because of partial parsing */
+err:
+       kfree(data);
        memset(dev_priv->vbt.dsi.sequence, 0, sizeof(dev_priv->vbt.dsi.sequence));
 }
 

diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 21c162e..4e87df1 100644 (file)
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -954,7 +954,7 @@ struct bdb_mipi_sequence {
 
 /* MIPI Sequnece Block definitions */
 enum mipi_seq {
-       MIPI_SEQ_UNDEFINED = 0,
+       MIPI_SEQ_END = 0,
        MIPI_SEQ_ASSERT_RESET,
        MIPI_SEQ_INIT_OTP,
        MIPI_SEQ_DISPLAY_ON,
@@ -964,7 +964,7 @@ enum mipi_seq {
 };
 
 enum mipi_seq_element {
-       MIPI_SEQ_ELEM_UNDEFINED = 0,
+       MIPI_SEQ_ELEM_END = 0,
        MIPI_SEQ_ELEM_SEND_PKT,
        MIPI_SEQ_ELEM_DELAY,
        MIPI_SEQ_ELEM_GPIO,