From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4563B584F2 for ; Tue, 21 Nov 2023 21:37:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FSNOEppC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78A28C433C8; Tue, 21 Nov 2023 21:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700602677; bh=kK9LzfZt6D3Gt4ZliyPofIg9r8bVnd54yLxBigI3P8Q=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=FSNOEppCFUuR8bEdizt5WFfa63bqJeeTsuMPB9YHGyagrl3KbEjJZvcyEI2ScJk8z AFYqJxId27DI6YNscx8+h//NL70SSdRaYKpIt0rPiMlElci7dFUdprtbRno+eG3vR1 nAcGM1RtL4tUEMZ53b3jP+kpzTZSoI35ZlUefGgLW7We/QkQd5whew9Awg5cfVB6uk b5YdOZiuh0jOFkHi1fmXrgANf8I2LsKjkZC9wgNk1F7vdTRh1WnNEcXpQgVM99mOcr RbCwXiXqXFxWxbiPCEKFHRdnOprSqBF8kJNlCO2kyX6TpVq3mFWI7ERlb9ahlwWyxc VgMFCX9qz92yA== Date: Tue, 21 Nov 2023 15:37:55 -0600 From: Bjorn Helgaas To: Stanislav Kinsburskii Cc: ryder.lee@mediatek.com, jianjun.wang@mediatek.com, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, skinsburskii@gmail.com Subject: Re: [PATCH] PCI: mediatek: Fix sparse warning caused to virt_to_phys() prototype change Message-ID: <20231121213755.GA258354@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <170052362584.21270.8345708191142620624.stgit@skinsburskii.> On Mon, Nov 20, 2023 at 03:40:33PM -0800, Stanislav Kinsburskii wrote: > Explicitly cast __iomem pointer to const void* with __force to fix the > following warning: > > warning: incorrect type in argument 1 (different address spaces) > expected void const volatile *address > got void [noderef] __iomem * I have two questions about this: 1) There's no other use of __force in drivers/pci, so I don't know what's special about pcie-mediatek.c. There should be a way to fix the types so it's not needed. 2) virt_to_phys() is not quite right to begin with because what we want is a *bus* address, not the CPU physical address we get from virt_to_phys(). Obviously the current platforms that use this must not apply any offset between bus and CPU physical addresses, but it's not something we should rely on. There are only three drivers (pci-aardvark.c, pcie-xilinx.c, and this one) that use virt_to_phys(), and they're all slightly wrong here. The *_compose_msi_msg() methods could use a little more consistency across the board. > Signed-off-by: Stanislav Kinsburskii > --- > drivers/pci/controller/pcie-mediatek.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > index 66a8f73296fc..27f0f79810a1 100644 > --- a/drivers/pci/controller/pcie-mediatek.c > +++ b/drivers/pci/controller/pcie-mediatek.c > @@ -397,7 +397,7 @@ static void mtk_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) > phys_addr_t addr; > > /* MT2712/MT7622 only support 32-bit MSI addresses */ > - addr = virt_to_phys(port->base + PCIE_MSI_VECTOR); > + addr = virt_to_phys((__force const void *)port->base + PCIE_MSI_VECTOR); > msg->address_hi = 0; > msg->address_lo = lower_32_bits(addr); > > @@ -520,7 +520,7 @@ static void mtk_pcie_enable_msi(struct mtk_pcie_port *port) > u32 val; > phys_addr_t msg_addr; > > - msg_addr = virt_to_phys(port->base + PCIE_MSI_VECTOR); > + msg_addr = virt_to_phys((__force const void *)port->base + PCIE_MSI_VECTOR); > val = lower_32_bits(msg_addr); > writel(val, port->base + PCIE_IMSI_ADDR); > > > >