Message-ID: <defcbb1a-599f-c905-1f4c-5c512d0a67c1@marcan.st>
Date:   Sat, 28 Jan 2023 20:45:37 +0900
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Subject: Re: [PATCH 3/4] iommu: dart: Write to all DART_T8020_STREAM_SELECT
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To:     Sven Peter <sven@svenpeter.dev>, Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        linux-arm-kernel@lists.infradead.org, asahi@lists.linux.dev,
        iommu@lists.linux.dev, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230128111114.4049-1-sven@svenpeter.dev>
 <20230128111114.4049-4-sven@svenpeter.dev>
From:   Hector Martin <marcan@marcan.st>
In-Reply-To: <20230128111114.4049-4-sven@svenpeter.dev>
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Precedence: bulk

On 28/01/2023 20.11, Sven Peter wrote:
> We're about to add support for a DART variant that use more than 16
> streams and requires writing to two separate stream select registers
> when issuing TLB flushes.
> 
> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> ---
>  drivers/iommu/apple-dart.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 7d8b2b90cdb6..7579c97a9062 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -372,12 +372,14 @@ apple_dart_t8020_hw_stream_command(struct apple_dart_stream_map *stream_map,
>  			     u32 command)
>  {
>  	unsigned long flags;
> -	int ret;
> +	int ret, i;
>  	u32 command_reg;
>  
>  	spin_lock_irqsave(&stream_map->dart->lock, flags);
>  
> -	writel(stream_map->sidmap[0], stream_map->dart->regs + DART_T8020_STREAM_SELECT);
> +	for (i = 0; i < BITS_TO_U32(stream_map->dart->num_streams); i++)
> +		writel(stream_map->sidmap[i],
> +		       stream_map->dart->regs + DART_T8020_STREAM_SELECT + 4 * i);
>  	writel(command, stream_map->dart->regs + DART_T8020_STREAM_COMMAND);
>  
>  	ret = readl_poll_timeout_atomic(

Acked-by: Hector Martin <marcan@marcan.st>

- Hector