ARM architecture only has 'memory', so all devices are accessed by
MMIO if possible.
Signed-off-by: Jammy Huang <jammy_huang@xxxxxxxxxxxxxx>
---
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
+ * 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
--
2.25.1
