Hi

Am 20.04.23 um 10:09 schrieb Jammy Huang:
ARM architecture only has 'memory', so all devices are accessed by
MMIO if possible.

Signed-off-by: Jammy Huang <jammy_hu...@aspeedtech.com>
---
  v2 changes:
   - Use MMIO after AST2500 which enable MMIO by default.
---
  drivers/gpu/drm/ast/ast_main.c | 9 +++++----
  1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index f83ce77127cb..d384e810fa4d 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -425,11 +425,12 @@ struct ast_private *ast_device_create(const struct 
drm_driver *drv,
                return ERR_PTR(-EIO);
/*
-        * If we don't have IO space at all, use MMIO now and
-        * assume the chip has MMIO enabled by default (rev 0x20
-        * and higher).
+        * After AST2500, MMIO is enabled by default, and it should be adapted

By 'adapted', you mean 'adopted'?

Apart from that:

Reviewed-by: Thomas Zimmermann <tzimmerm...@suse.de>

I also ran this patch on an AST2100, which still works as before.

Best regards
Thomas

+        * to be compatible with Arm.
         */
-       if (!(pci_resource_flags(pdev, 2) & IORESOURCE_IO)) {
+       if (pdev->revision >= 0x40) {
+               ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
+       } else if (!(pci_resource_flags(pdev, 2) & IORESOURCE_IO)) {
                drm_info(dev, "platform has no IO space, trying MMIO\n");
                ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
        }

base-commit: e62252bc55b6d4eddc6c2bdbf95a448180d6a08d

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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