drm/ast: Store precatch settings in struct ast_device_quirks

Add a precatch flag in struct ast_device_info and set it on AST2500
and AST2600. Remove calls to IS_AST_GENn() from ast_set_crtc_reg().

Also fix the coding style in several places.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Jocelyn Falempe <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/gpu/drm/ast/ast_2500.c

···
 static const struct ast_device_quirks ast_2500_device_quirks = {
 	.crtc_mem_req_threshold_low = 96,
 	.crtc_mem_req_threshold_high = 120,
+	.crtc_hsync_precatch_needed = true,
 };
 
 struct drm_device *ast_2500_device_create(struct pci_dev *pdev,

drivers/gpu/drm/ast/ast_2600.c

···
 static const struct ast_device_quirks ast_2600_device_quirks = {
 	.crtc_mem_req_threshold_low = 160,
 	.crtc_mem_req_threshold_high = 224,
+	.crtc_hsync_precatch_needed = true,
 };
 
 struct drm_device *ast_2600_device_create(struct pci_dev *pdev,

drivers/gpu/drm/ast/ast_drv.h

···
 	 */
 	unsigned char crtc_mem_req_threshold_low;
 	unsigned char crtc_mem_req_threshold_high;
+
+	/*
+	 * Adjust hsync values to load next scanline early. Signalled
+	 * by AST2500PreCatchCRT in VBIOS mode flags.
+	 */
+	bool crtc_hsync_precatch_needed;
 };
 
 struct ast_device {

drivers/gpu/drm/ast/ast_mode.c

···
 		ast_set_index_reg(ast, AST_IO_VGAGRI, i, stdtable->gr[i]);
 }
 
-static void ast_set_crtc_reg(struct ast_device *ast,
-			     struct drm_display_mode *mode,
+static void ast_set_crtc_reg(struct ast_device *ast, struct drm_display_mode *mode,
 			     const struct ast_vbios_enhtable *vmode)
 {
 	u8 jreg05 = 0, jreg07 = 0, jreg09 = 0, jregAC = 0, jregAD = 0, jregAE = 0;
-	u16 temp, precache = 0;
+	u16 temp;
+	unsigned char crtc_hsync_precatch = 0;
 
-	if ((IS_AST_GEN6(ast) || IS_AST_GEN7(ast)) &&
-	    (vmode->flags & AST2500PreCatchCRT))
-		precache = 40;
+	if (ast->quirks->crtc_hsync_precatch_needed && (vmode->flags & AST2500PreCatchCRT))
+		crtc_hsync_precatch = 40;
 
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x11, 0x7f, 0x00);
 
···
 		jregAD |= 0x01;  /* HBE D[5] */
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x03, 0xE0, (temp & 0x1f));
 
-	temp = ((mode->crtc_hsync_start-precache) >> 3) - 1;
+	temp = ((mode->crtc_hsync_start - crtc_hsync_precatch) >> 3) - 1;
 	if (temp & 0x100)
 		jregAC |= 0x40; /* HRS D[5] */
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x04, 0x00, temp);
 
-	temp = (((mode->crtc_hsync_end-precache) >> 3) - 1) & 0x3f;
+	temp = (((mode->crtc_hsync_end - crtc_hsync_precatch) >> 3) - 1) & 0x3f;
 	if (temp & 0x20)
 		jregAD |= 0x04; /* HRE D[5] */
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x05, 0x60, (u8)((temp & 0x1f) | jreg05));
···
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x09, 0xdf, jreg09);
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xAE, 0x00, (jregAE | 0x80));
 
-	if (precache)
+	if (crtc_hsync_precatch)
 		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0x3f, 0x80);
 	else
 		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0x3f, 0x00);