drm/ast: Move Gen2 device initialization into separate helper

Split off device initialization for Gen2 hardware into the helpers
ast_2100_device_create() and ast_2100_detect_wide_screen(). The new
functions are duplicates of their counterparts in ast_main.c, but
stripped from most non-Gen2 support.

Simplifies maintenance as the driver's number of supported hardware
generations grows.

v2:
- simplify widescreen-detection logic (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250922083708.45564-7-tzimmermann@suse.de

3 files changed, 65 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ast/ast_2100.c b/drivers/gpu/drm/ast/ast_2100.c
index 16a279ec8351..540972daec52 100644
--- a/drivers/gpu/drm/ast/ast_2100.c
+++ b/drivers/gpu/drm/ast/ast_2100.c
@@ -27,6 +27,9 @@
  */
 
 #include <linux/delay.h>
+#include <linux/pci.h>
+
+#include <drm/drm_drv.h>
 
 #include "ast_drv.h"
 #include "ast_post.h"
@@ -417,3 +420,54 @@ bool __ast_2100_detect_wuxga(struct ast_device *ast)
 
 	return false;
 }
+
+static void ast_2100_detect_widescreen(struct ast_device *ast)
+{
+	if (__ast_2100_detect_wsxga_p(ast)) {
+		ast->support_wsxga_p = true;
+		if (ast->chip == AST2100)
+			ast->support_fullhd = true;
+	}
+	if (__ast_2100_detect_wuxga(ast))
+		ast->support_wuxga = true;
+}
+
+struct drm_device *ast_2100_device_create(struct pci_dev *pdev,
+					  const struct drm_driver *drv,
+					  enum ast_chip chip,
+					  enum ast_config_mode config_mode,
+					  void __iomem *regs,
+					  void __iomem *ioregs,
+					  bool need_post)
+{
+	struct drm_device *dev;
+	struct ast_device *ast;
+	int ret;
+
+	ast = devm_drm_dev_alloc(&pdev->dev, drv, struct ast_device, base);
+	if (IS_ERR(ast))
+		return ERR_CAST(ast);
+	dev = &ast->base;
+
+	ast_device_init(ast, chip, config_mode, regs, ioregs);
+
+	ast_2000_detect_tx_chip(ast, need_post);
+
+	if (need_post) {
+		ret = ast_post_gpu(ast);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	ret = ast_mm_init(ast);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ast_2100_detect_widescreen(ast);
+
+	ret = ast_mode_config_init(ast);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return dev;
+}
diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 3fecdc0fc7f7..bcf0b318b495 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -386,6 +386,10 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		drm = ast_2000_device_create(pdev, &ast_driver, chip, config_mode,
 					     regs, ioregs, need_post);
 		break;
+	case 2:
+		drm = ast_2100_device_create(pdev, &ast_driver, chip, config_mode,
+					     regs, ioregs, need_post);
+		break;
 	default:
 		drm = ast_device_create(pdev, &ast_driver, chip, config_mode, regs, ioregs,
 					need_post);
diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 369abdd81bbf..8f52ac3b0f45 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -439,6 +439,13 @@ struct drm_device *ast_2000_device_create(struct pci_dev *pdev,
 int ast_2100_post(struct ast_device *ast);
 bool __ast_2100_detect_wsxga_p(struct ast_device *ast);
 bool __ast_2100_detect_wuxga(struct ast_device *ast);
+struct drm_device *ast_2100_device_create(struct pci_dev *pdev,
+					  const struct drm_driver *drv,
+					  enum ast_chip chip,
+					  enum ast_config_mode config_mode,
+					  void __iomem *regs,
+					  void __iomem *ioregs,
+					  bool need_post);
 
 /* ast_2300.c */
 int ast_2300_post(struct ast_device *ast);