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Date:   Mon, 26 Jun 2023 00:58:22 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Mark Brown <broonie@kernel.org>,
        Yingkun Meng <mengyingkun@loongson.cn>,
        Arnd Bergmann <arnd@arndb.de>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ASoC: loongson: fix address space confusion
Message-ID: <ZJlFHtmJE6vPyT0k@infradead.org>
References: <20230622101235.3230941-1-arnd@kernel.org>
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On Thu, Jun 22, 2023 at 12:12:22PM +0200, Arnd Bergmann wrote:
> Change the driver to instead use the physical address as stored in the
> PCI BAR resource directly. Since 'dev_addr' is a 32-bit address, I think
> this results in the same truncated address on loongarch but is otherwise
> closer to portable code and avoids the warning.

This gets rid of the warning, but is still broken.
pci_resource_start retuns a resource_size_t, which really is a
phys_addr_t, but certainly no DMA address.  To map PCI(e) resources
for DMA the driver needs to call dma_map_resource.