From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: [PATCH v2 6/7] ACPI/IORT: Don't set default coherent DMA mask Date: Mon, 23 Jul 2018 23:16:11 +0100 Message-ID: <3525869e8e7530128bf9718ae8af7d7564b3c684.1532382222.git.robin.murphy@arm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: hch@lst.de, m.szyprowski@samsung.com Cc: lorenzo.pieralisi@arm.com, gregkh@linuxfoundation.org, joro@8bytes.org, x86@kernel.org, linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, robh+dt@kernel.org, hanjun.guo@linaro.org, sudeep.holla@arm.com, frowand.list@gmail.com, linux-arm-kernel@lists.infradead.org List-Id: linux-acpi@vger.kernel.org Now that we can track upstream DMA constraints properly with bus_dma_mask instead of trying (and failing) to maintain it in coherent_dma_mask, it doesn't make much sense for the firmware code to be touching the latter at all. It's merely papering over bugs wherein a driver has failed to call dma_set_coherent_mask() *and* the bus code has not initialised any default value. We don't really want to encourage more drivers coercing dma_mask so we'll continue to fix that up if necessary, but add a warning to help flush out any such buggy bus code that remains. CC: Lorenzo Pieralisi CC: Hanjun Guo CC: Sudeep Holla Signed-off-by: Robin Murphy --- drivers/acpi/arm64/iort.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index bc51cff5505e..08f26db2da7e 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -978,20 +978,20 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size) int ret, msb; /* - * Set default coherent_dma_mask to 32 bit. Drivers are expected to - * setup the correct supported mask. + * If @dev is expected to be DMA-capable then the bus code that created + * it should have initialised its dma_mask pointer by this point. For + * now, we'll continue the legacy behaviour of coercing it to the + * coherent mask if not, but we'll no longer do so quietly. */ - if (!dev->coherent_dma_mask) - dev->coherent_dma_mask = DMA_BIT_MASK(32); - - /* - * Set it to coherent_dma_mask by default if the architecture - * code has not set it. - */ - if (!dev->dma_mask) + if (!dev->dma_mask) { + dev_warn(dev, "DMA mask not set\n"); dev->dma_mask = &dev->coherent_dma_mask; + } - size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); + if (dev->coherent_dma_mask) + size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); + else + size = 1ULL << 32; if (dev_is_pci(dev)) { ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size); -- 2.17.1.dirty From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Mon, 23 Jul 2018 23:16:11 +0100 Subject: [PATCH v2 6/7] ACPI/IORT: Don't set default coherent DMA mask In-Reply-To: References: Message-ID: <3525869e8e7530128bf9718ae8af7d7564b3c684.1532382222.git.robin.murphy@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Now that we can track upstream DMA constraints properly with bus_dma_mask instead of trying (and failing) to maintain it in coherent_dma_mask, it doesn't make much sense for the firmware code to be touching the latter at all. It's merely papering over bugs wherein a driver has failed to call dma_set_coherent_mask() *and* the bus code has not initialised any default value. We don't really want to encourage more drivers coercing dma_mask so we'll continue to fix that up if necessary, but add a warning to help flush out any such buggy bus code that remains. CC: Lorenzo Pieralisi CC: Hanjun Guo CC: Sudeep Holla Signed-off-by: Robin Murphy --- drivers/acpi/arm64/iort.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index bc51cff5505e..08f26db2da7e 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -978,20 +978,20 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size) int ret, msb; /* - * Set default coherent_dma_mask to 32 bit. Drivers are expected to - * setup the correct supported mask. + * If @dev is expected to be DMA-capable then the bus code that created + * it should have initialised its dma_mask pointer by this point. For + * now, we'll continue the legacy behaviour of coercing it to the + * coherent mask if not, but we'll no longer do so quietly. */ - if (!dev->coherent_dma_mask) - dev->coherent_dma_mask = DMA_BIT_MASK(32); - - /* - * Set it to coherent_dma_mask by default if the architecture - * code has not set it. - */ - if (!dev->dma_mask) + if (!dev->dma_mask) { + dev_warn(dev, "DMA mask not set\n"); dev->dma_mask = &dev->coherent_dma_mask; + } - size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); + if (dev->coherent_dma_mask) + size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); + else + size = 1ULL << 32; if (dev_is_pci(dev)) { ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size); -- 2.17.1.dirty