[PATCH v2] drm/ast: Fix ARM compatibility

[PATCH v2] drm/ast: Fix ARM compatibility

[Jammy Huang]

ARM architecture only has 'memory', so all devices are accessed by
MMIO if possible.

Signed-off-by: Jammy Huang <jammy_huang@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
+	 * 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

Re: [PATCH v2] drm/ast: Fix ARM compatibility

[Thomas Zimmermann]

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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_huang@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 <tzimmermann@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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Re: [PATCH v2] drm/ast: Fix ARM compatibility

[Jammy Huang]

Hi Thomas,

Thanks for help. I will update a new patch per your comments

On 2023/4/20 下午 04:57, Thomas Zimmermann wrote:
> 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_huang@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 <tzimmermann@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
>
-- 
Best Regards
Jammy