[PATCH 1/2] iommu: Add M2 support to Apple DART driver

[Mark Kettenis]

> From: Janne Grunau <j at jannau.net>
> Date: Fri,  1 Jul 2022 00:06:16 +0200
> 
> "apple,t8112-dart" uses an incompatible register interface but still
> offers the same functionality. This DART is found on the M2 and M1
> Pro/Max/Ultra SoCs.
> 
> Signed-off-by: Janne Grunau <j at jannau.net>

Reviewed-by: Mark Kettenis <kettenis at openbsd.org>

> ---
>  drivers/iommu/apple_dart.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/apple_dart.c b/drivers/iommu/apple_dart.c
> index f2e170096072..2faacb8f3b6f 100644
> --- a/drivers/iommu/apple_dart.c
> +++ b/drivers/iommu/apple_dart.c
> @@ -24,6 +24,12 @@
>  #define  DART_TTBR_VALID	BIT(31)
>  #define  DART_TTBR_SHIFT	12
>  
> +#define DART_T8110_TCR(sid)	(0x1000 + 4 * (sid))
> +#define  DART_T8110_TCR_BYPASS_DAPF		BIT(2)
> +#define  DART_T8110_TCR_BYPASS_DART		BIT(1)
> +#define  DART_T8110_TCR_TRANSLATE_ENABLE	BIT(0)
> +#define DART_T8110_TTBR(sid)	(0x1400 + 4 * (sid))
> +
>  static int apple_dart_probe(struct udevice *dev)
>  {
>  	void *base;
> @@ -34,7 +40,16 @@ static int apple_dart_probe(struct udevice *dev)
>  		return -EINVAL;
>  
>  	u32 params2 = readl(base + DART_PARAMS2);
> -	if (params2 & DART_PARAMS2_BYPASS_SUPPORT) {
> +	if (!(params2 & DART_PARAMS2_BYPASS_SUPPORT))
> +		return 0;
> +
> +	if (device_is_compatible(dev, "apple,t8112-dart")) {
> +		for (sid = 0; sid < 256; sid++) {
> +			writel(DART_T8110_TCR_BYPASS_DART | DART_T8110_TCR_BYPASS_DAPF,
> +			       base + DART_T8110_TCR(sid));
> +			writel(0, base + DART_T8110_TTBR(sid));
> +		}
> +	} else {
>  		for (sid = 0; sid < 16; sid++) {
>  			writel(DART_TCR_BYPASS_DART | DART_TCR_BYPASS_DAPF,
>  			       base + DART_TCR(sid));
> @@ -49,6 +64,7 @@ static int apple_dart_probe(struct udevice *dev)
>  static const struct udevice_id apple_dart_ids[] = {
>  	{ .compatible = "apple,t8103-dart" },
>  	{ .compatible = "apple,t6000-dart" },
> +	{ .compatible = "apple,t8112-dart" },
>  	{ /* sentinel */ }
>  };
>  
> -- 
> 2.35.1
> 
>