drm/ast: Move Gen4 device initialization into separate helper

Split off device initialization for Gen4 hardware into the helpers
ast_2300_device_create() and ast_2300_detect_wide_screen(). The new
functions are duplicates of their counterparts in ast_main.c, but
stripped from most non-Gen4 support.

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

v2:
- simplify widescreen-detection logic

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250922083708.45564-9-tzimmermann@suse.de

3 files changed, 71 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ast/ast_2300.c b/drivers/gpu/drm/ast/ast_2300.c
index 68d269ef9b47..d1d63e58f3d6 100644
--- a/drivers/gpu/drm/ast/ast_2300.c
+++ b/drivers/gpu/drm/ast/ast_2300.c
@@ -27,8 +27,10 @@
  */
 
 #include <linux/delay.h>
+#include <linux/pci.h>
 #include <linux/sizes.h>
 
+#include <drm/drm_drv.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_print.h>
 
@@ -1394,3 +1396,61 @@ void ast_2300_detect_tx_chip(struct ast_device *ast)
 
 	__ast_device_set_tx_chip(ast, tx_chip);
 }
+
+static void ast_2300_detect_widescreen(struct ast_device *ast)
+{
+	if (__ast_2100_detect_wsxga_p(ast) || ast->chip == AST1300) {
+		ast->support_wsxga_p = true;
+		ast->support_fullhd = true;
+	}
+	if (__ast_2100_detect_wuxga(ast))
+		ast->support_wuxga = true;
+}
+
+struct drm_device *ast_2300_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_2300_detect_tx_chip(ast);
+
+	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);
+
+	/* map reserved buffer */
+	ast->dp501_fw_buf = NULL;
+	if (ast->vram_size < pci_resource_len(pdev, 0)) {
+		ast->dp501_fw_buf = pci_iomap_range(pdev, 0, ast->vram_size, 0);
+		if (!ast->dp501_fw_buf)
+			drm_info(dev, "failed to map reserved buffer!\n");
+	}
+
+	ast_2300_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 caf41c31cc9d..8d50abbd1c3c 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -394,6 +394,10 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		drm = ast_2200_device_create(pdev, &ast_driver, chip, config_mode,
 					     regs, ioregs, need_post);
 		break;
+	case 4:
+		drm = ast_2300_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 8a27835fd09c..6924f8a87e2c 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -459,6 +459,13 @@ struct drm_device *ast_2200_device_create(struct pci_dev *pdev,
 /* ast_2300.c */
 int ast_2300_post(struct ast_device *ast);
 void ast_2300_detect_tx_chip(struct ast_device *ast);
+struct drm_device *ast_2300_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_2500.c */
 void ast_2500_patch_ahb(void __iomem *regs);