drm/ast: dp501: Use struct drm_edid and helpers

Convert DP501 support to struct drm_edid and its helpers. Simplifies
and modernizes the EDID handling.

The driver reads 4 bytes at once, but the overall read length is now
variable. Therefore update the EDID read loop to never return more than
the requested bytes.

v2:
- fix reading EDID data

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240815151953.184679-8-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/ast/ast_dp501.c b/drivers/gpu/drm/ast/ast_dp501.c
index 3904f98ef8468bcf59bdffdcdb2af56e789c2b48..8cc7d20a8999465403e1c6cff4fd7c527a81bce2 100644 (file)
--- a/drivers/gpu/drm/ast/ast_dp501.c
+++ b/drivers/gpu/drm/ast/ast_dp501.c
@@ -318,32 +318,30 @@ static bool ast_dp501_is_connected(struct ast_device *ast)
        return true;
 }
 
-static bool ast_dp501_read_edid(struct drm_device *dev, u8 *ediddata)
+static int ast_dp512_read_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
 {
-       struct ast_device *ast = to_ast_device(dev);
-       u32 i, boot_address, offset, data;
-       u32 *pEDIDidx;
+       struct ast_device *ast = data;
+       size_t rdlen = round_up(len, 4);
+       u32 i, boot_address, offset, ediddata;
 
-       if (!ast_dp501_is_connected(ast))
-               return false;
+       if (block > (512 / EDID_LENGTH))
+               return -EIO;
+
+       offset = AST_DP501_EDID_DATA + block * EDID_LENGTH;
 
        if (ast->config_mode == ast_use_p2a) {
                boot_address = get_fw_base(ast);
 
-               /* Read EDID */
-               offset = AST_DP501_EDID_DATA;
-               for (i = 0; i < 128; i += 4) {
-                       data = ast_mindwm(ast, boot_address + offset + i);
-                       pEDIDidx = (u32 *)(ediddata + i);
-                       *pEDIDidx = data;
+               for (i = 0; i < rdlen; i += 4) {
+                       ediddata = ast_mindwm(ast, boot_address + offset + i);
+                       memcpy(buf, &ediddata, min((len - i), 4));
+                       buf += 4;
                }
        } else {
-               /* Read EDID */
-               offset = AST_DP501_EDID_DATA;
-               for (i = 0; i < 128; i += 4) {
-                       data = readl(ast->dp501_fw_buf + offset + i);
-                       pEDIDidx = (u32 *)(ediddata + i);
-                       *pEDIDidx = data;
+               for (i = 0; i < rdlen; i += 4) {
+                       ediddata = readl(ast->dp501_fw_buf + offset + i);
+                       memcpy(buf, &ediddata, min((len - i), 4));
+                       buf += 4;
                }
        }
 
@@ -511,29 +509,16 @@ static const struct drm_encoder_helper_funcs ast_dp501_encoder_helper_funcs = {
 
 static int ast_dp501_connector_helper_get_modes(struct drm_connector *connector)
 {
-       void *edid;
-       bool succ;
+       struct ast_device *ast = to_ast_device(connector->dev);
+       const struct drm_edid *drm_edid;
        int count;
 
-       edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
-       if (!edid)
-               goto err_drm_connector_update_edid_property;
-
-       succ = ast_dp501_read_edid(connector->dev, edid);
-       if (!succ)
-               goto err_kfree;
-
-       drm_connector_update_edid_property(connector, edid);
-       count = drm_add_edid_modes(connector, edid);
-       kfree(edid);
+       drm_edid = drm_edid_read_custom(connector, ast_dp512_read_edid_block, ast);
+       drm_edid_connector_update(connector, drm_edid);
+       count = drm_edid_connector_add_modes(connector);
+       drm_edid_free(drm_edid);
 
        return count;
-
-err_kfree:
-       kfree(edid);
-err_drm_connector_update_edid_property:
-       drm_connector_update_edid_property(connector, NULL);
-       return 0;
 }
 
 static int ast_dp501_connector_helper_detect_ctx(struct drm_connector *connector,