drm/ast: Move Gen5 device initialization into separate helper

Split off device initialization for Gen5 hardware into the helpers
ast_2400_device_create() and ast_2400_detect_wide_screen(). The new
functions are duplicates of their counterparts in ast_main.c, but
stripped from most non-Gen5 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/20250922083708.45564-10-tzimmermann@suse.de

drivers/gpu/drm/ast/Makefile

@@ -8,6 +8,7 @@ ast-y := \
 	ast_2100.o \
 	ast_2200.o \
 	ast_2300.o \
+	ast_2400.o \
 	ast_2500.o \
 	ast_2600.o \
 	ast_cursor.o \

drivers/gpu/drm/ast/ast_2400.c

@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2012 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ */
+/*
+ * Authors: Dave Airlie <airlied@redhat.com>
+ */
+
+#include <linux/pci.h>
+
+#include <drm/drm_drv.h>
+#include <drm/drm_print.h>
+
+#include "ast_drv.h"
+
+static void ast_2400_detect_widescreen(struct ast_device *ast)
+{
+	if (__ast_2100_detect_wsxga_p(ast) || ast->chip == AST1400) {
+		ast->support_wsxga_p = true;
+		ast->support_fullhd = true;
+	}
+	if (__ast_2100_detect_wuxga(ast))
+		ast->support_wuxga = true;
+}
+
+struct drm_device *ast_2400_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_2400_detect_widescreen(ast);
+
+	ret = ast_mode_config_init(ast);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return dev;
+}

drivers/gpu/drm/ast/ast_drv.c

@@ -398,6 +398,10 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		drm = ast_2300_device_create(pdev, &ast_driver, chip, config_mode,
 					     regs, ioregs, need_post);
 		break;
+	case 5:
+		drm = ast_2400_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);

drivers/gpu/drm/ast/ast_drv.h

@@ -467,6 +467,15 @@ struct drm_device *ast_2300_device_create(struct pci_dev *pdev,
 					  void __iomem *ioregs,
 					  bool need_post);
 
+/* ast_2400.c */
+struct drm_device *ast_2400_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);
 int ast_2500_post(struct ast_device *ast);