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Commit 7ad42639 authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Rafael J. Wysocki
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ACPI: Make acpi_dma_configure() DMA regions aware 



Current ACPI DMA configuration set-up device DMA capabilities through
kernel defaults that do not take into account platform specific DMA
configurations reported by firmware.

By leveraging the ACPI acpi_dev_get_dma_resources() API, add code
in acpi_dma_configure() to retrieve the DMA regions to correctly
set-up PCI devices DMA parameters.

Rework the ACPI IORT kernel API to make sure they can accommodate
the DMA set-up required by firmware. By making PCI devices DMA set-up
ACPI IORT specific, the kernel is shielded from unwanted regressions
that could be triggered by parsing DMA resources on arches that were
previously ignoring them (ie x86/ia64), leaving kernel behaviour
unchanged on those arches.

Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Tested-by: default avatarNate Watterson <nwatters@codeaurora.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent c04ac679

drivers/acpi/arm64/iort.c

+35 −2
Original line number Diff line number Diff line
@@ -681,12 +681,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, 
}



/**

 * iort_set_dma_mask - Set-up dma mask for a device.

 * iort_dma_setup() - Set-up device DMA parameters.

 *

 * @dev: device to configure

 * @dma_addr: device DMA address result pointer

 * @size: DMA range size result pointer

 */

void iort_set_dma_mask(struct device *dev)

void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)

{

	u64 mask, dmaaddr = 0, size = 0, offset = 0;

	int ret, msb;



	/*

	 * Set default coherent_dma_mask to 32 bit.  Drivers are expected to

	 * setup the correct supported mask.
@@ -700,6 +705,34 @@ void iort_set_dma_mask(struct device *dev) 
	 */

	if (!dev->dma_mask)

		dev->dma_mask = &dev->coherent_dma_mask;



	size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);



	if (dev_is_pci(dev)) {

		ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);

		if (!ret) {

			msb = fls64(dmaaddr + size - 1);

			/*

			 * Round-up to the power-of-two mask or set

			 * the mask to the whole 64-bit address space

			 * in case the DMA region covers the full

			 * memory window.

			 */

			mask = msb == 64 ? U64_MAX : (1ULL << msb) - 1;

			/*

			 * Limit coherent and dma mask based on size

			 * retrieved from firmware.

			 */

			dev->coherent_dma_mask = mask;

			*dev->dma_mask = mask;

		}

	}



	*dma_addr = dmaaddr;

	*dma_size = size;



	dev->dma_pfn_offset = PFN_DOWN(offset);

	dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);

}



/**

drivers/acpi/scan.c

+4 −8
Original line number Diff line number Diff line
@@ -1446,20 +1446,16 @@ int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset, 
int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)

{

	const struct iommu_ops *iommu;

	u64 size;

	u64 dma_addr = 0, size = 0;



	iort_set_dma_mask(dev);

	iort_dma_setup(dev, &dma_addr, &size);



	iommu = iort_iommu_configure(dev);

	if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)

		return -EPROBE_DEFER;



	size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);

	/*

	 * Assume dma valid range starts at 0 and covers the whole

	 * coherent_dma_mask.

	 */

	arch_setup_dma_ops(dev, 0, size, iommu, attr == DEV_DMA_COHERENT);

	arch_setup_dma_ops(dev, dma_addr, size,

				iommu, attr == DEV_DMA_COHERENT);



	return 0;

}

include/linux/acpi_iort.h

+3 −2
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id); 
void acpi_configure_pmsi_domain(struct device *dev);

int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);

/* IOMMU interface */

void iort_set_dma_mask(struct device *dev);

void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);

const struct iommu_ops *iort_iommu_configure(struct device *dev);

#else

static inline void acpi_iort_init(void) { }
@@ -47,7 +47,8 @@ static inline struct irq_domain *iort_get_device_domain(struct device *dev, 
{ return NULL; }

static inline void acpi_configure_pmsi_domain(struct device *dev) { }

/* IOMMU interface */

static inline void iort_set_dma_mask(struct device *dev) { }

static inline void iort_dma_setup(struct device *dev, u64 *dma_addr,

				  u64 *size) { }

static inline

const struct iommu_ops *iort_iommu_configure(struct device *dev)

{ return NULL; }